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changeip
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Solving 20km wireless link issues

Fri Jul 17, 2009 7:44 pm

Okay guys, I've been on Mikrotik for years now and know it inside and out, except I don't have a grasp on wireless stuff completely yet. I just put up my first backhaul 2 weeks ago - 20km! Woo Hoo I tell myself.

433ah w/ XR5 on each end
PacWireless GD5W wideband grid dish, 28db

Ive been struggling over low signal strength since installation. -76 is the best I could get, with -80 being the average. That's horrible I tell myself, must be something blocking the signal, or these antennas suck. Well out of the blue last night, without touching ANYTHING for days, I see this:

Image

Excellent signal, -60db! Nothing changed that I have control over, so what happened? We'll some thoughts I wanted to bounce off the 'team':

1 - The data center side is on a huge roof thats metal, although I am 15 feet above it.

Image

2 - I am shooting over an air conditioning unit, as shown in the picture, but I believe I am 4-5 feet higher than it still.

3 - RadioMobile shows a good view of the link, about half way there is a community that I probably am just barely shooting over.

Image

4 - At first I thought I was just getting into the fresnel zone and was going to find another option. Now last night the signal increases by 20db and is giving excellent performance.

5 - Without even touching anything the signal is affected - but why ? My guess is that there is noise - but every single channel gives me the same results, if I can get connected on them that is.

6 - Noise floor before and after this is the same, -102db average.

Image

So how do I go about tracking down what's crushing the signal across the entire spectrum ?

One side is on a water tower, however moving 100 yards either way doesnt seem to help:
Image

And the other side on the data center:
Image

Any help troubleshooting would be appreciated.
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Re: New 20km link, weird interference.

Fri Jul 17, 2009 7:59 pm

I believe the Frequency Use tool is only showing you 802.11a frames received. It does not measure raw energy received at the antenna like a spectrum analzer would. You could have an interference source and not know it from that tool. You could hook up a real spectrum analyzer to see what noise you might really have; however, you said it's consistent performance across all the channels, so I doubt you have interference across every 5.2, 5.4, and 5.7 channel (it's possible just not probable).

Given that it suddenly changes and if you see that sudden 20db change on all channels, you should look into the equipment. I'd check the pigtails and coax. Also, I'm not a fan of those antennas for backhaul links (much prefer Radiowaves or Andrews parabolics).
 
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Re: New 20km link, weird interference.

Fri Jul 17, 2009 8:00 pm

BTW: GREAT posting. Lots of clear data, good descriptions, graphs -- I wish everyone posted like that. Very professional.
 
changeip
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Re: New 20km link, weird interference.

Fri Jul 17, 2009 8:25 pm

yeah im tired of posting like 'my signal isnt good, help me' : )

I did order a completely separate rb433ah with an XR5, exact same setup - but portable enough for me to drag it around for testing. I got the same results using the test setup 100 -200 yards away (on the water tower side). I think that would rule out bad hardware / power at the one site, and I am going to do the same on the other side this weekend. However, if one side was bad wouldnt the signal tx / rx be way different if it was only 1 side with the problem ?

It is 20db across the entire spectrum, which makes me wonder if it's the air conditioning on the roof that stopped working, or a massive power line thats in middle that went out or something. I am using horizontal polarity, I am going to try vertical in the next day or two as well.
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Re: New 20km link, weird interference.

Fri Jul 17, 2009 9:11 pm

However, if one side was bad wouldnt the signal tx / rx be way different if it was only 1 side with the problem ?
Not really. What if the pigtail at the data center side is a 20db attenuator? Wouldn't that affect tx/rx at the same time? If you had highly asymmetric signal levels, then you would start to look at the card(s).

You didn't mention lightning arrestors. Are you using any? If so, try swapping it out for a pass-through.
 
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Re: New 20km link, weird interference.

Fri Jul 17, 2009 9:23 pm

Currently it is the built in cable from the GD5W directly to a MMCX / N pigtail - no arrestor or LMR in there anywhere yet. The radio is directly mounted behind the antenna so the cabling is very short; I thought that might interfere as well, but why would it get better for just 8 hours and then go back to the way it has been since installation? If it was cabling would I possibly see that signal increase for 8 hours and then back to what it has been doing ? I won't rule out the cabling / hardware until I test both sides with another unit, but I'm leaning towards something outside of my control causing this. Just trying to figure out how to pin-point it. Thanks for your input too : )
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Re: New 20km link, weird interference.

Mon Jul 20, 2009 11:54 am

It's not a problem from pigtail, or connectors; I had the same problem, there is problem regarding the propagatin; I couldn't find a fix, maybe replacing with bigger antennas or/and changing polarization; sun also causes to loose signal. In my case also when it was cloudy the signal was excellent or during nights.

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Re: New 20km link, weird interference.

Mon Jul 20, 2009 3:16 pm

Great post changeip!
Looking at radiomobile it seems you have your fresnel kinda messed up but try to put the correct values of antenna height maybe it's not that bad once u set at around 15-20 meters the antenna over the roof of that building..
And i experienced the same problem on links over the sea ( http://forum.mikrotik.com/viewtopic.php?f=7&t=25362 ). I almost fixed it raising a little the azimuth of both antennas, losing few points of signal strenght but avoiding a lot of those problems..
Also i suggest you to do a backup link in another frequency... it should solve you all the problems i guess..
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Re: New 20km link, weird interference.

Mon Jul 20, 2009 7:51 pm

The signal strength is the signal strength, regardless of interference. Interference changes the SNR, and interference isn't so easy to reliably measure.

I would suggest pigtails, cables, feedhorn changing/swapping, etc... We've seen feedhorns go bad on grids and dishes where the signal is usually weak but intermittently good. This has happened to us with Pac Wireless and Gabriel feedhorns. You might have started off with a feedhorn that is mostly bad. If you have a spare antenna, borrow that part or antenna to test.

It is possible the shape of the metal roof causes some destructive multipath interference at times. You would have to temporarily move the setup to a place where it didn't shoot over the metal roof, but other aspects were the same to test this. Some metal roofs do affect signal, but it's really hard to predict.
 
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Re: New 20km link, weird interference.

Tue Jul 21, 2009 5:47 am

Sorry JP, but that is not necessarily true.

Reflections can be strong enough to cause the LNA to become saturated causing the low signal strengths.
Metal structures can be troublsome.
Try lowering the Output power and see if the receive strength increases.

Metal distorts magnetic fields.
Microwave can be viewed in a simular manner, in which the field can and will be distorted by nearby metals.

Not to mention any evapoartive effects from the metals heating and cooling.

(Have you ever tryed a radio shot over loadstone?)
 
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Re: New 20km link, weird interference.

Tue Jul 21, 2009 7:06 am

I thought I'd mention... the signal has sucked for at least 3 weeks, but it has been VERY consistent. -80db almost all the time. However, that one evening it went from -80 to -60 and then back again after about 8 hours or so.

Tomorrow I will be testing an entire new setup on the data center side to see if its hardware / antenna. Will post more info w/ more pics shortly.
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Re: New 20km link, weird interference.

Tue Jul 21, 2009 9:30 am

I also have 25km link with similar behavior. Night sometime signal goes to -69 usually is -80 but sometime goes to -90 and drop. But I possible have problem with fresnel zone one of antenna is not very high.
If you find what cause this please write here.

First setup I use R52 card and latter replace with R5H with R5H work better sometime drop but establish very quick.
 
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Re: New 20km link, weird interference.

Tue Jul 21, 2009 9:39 am

It might have something to do with temperature changes within the path.
 
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Re: New 20km link, weird interference.

Tue Jul 21, 2009 10:32 am

I had the same problem and would like to ask you if the signal was increasing when it was cloudy on both sides?
First I used for this link SR5 with dished of 85cm and the signal was -81, throughput 28Mbps and then replaced with XR5 and dished of 120cm and the signal increased to -77. Use only dishes(offset) for backhaule because it works well even when interference is present.
 
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Re: New 20km link, weird interference.

Wed Jul 22, 2009 7:56 am

Not to mention any evapoartive effects from the metals heating and cooling.

(Have you ever tryed a radio shot over loadstone?)
Sounds like a problem I've had here.

I've got one customer who only lost signal between 2:30 and 3:00 PM, usually for under 10 minutes, same time, every day.

The heat coming off of the roof of his house was causing the problem. Once the sun went down, the problem disappeared. No problems at all during the winter. Still need to raise his antenna a bit, but apparently the system is more resilient than it was in the past.
 
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Re: New 20km link, weird interference.

Fri Jul 24, 2009 7:32 pm

Okay, some updates.

Image

Yesterday I changed out the data center side completely. New rb411ah, XR5, antenna, cable, pigtails, etc. I also made a point to swap over to vertical polarization (from horizontal) to see if that helped.

1 - I gained a db or two during the horizontal to vertical change, however I think that's probably because of the extra effort during alignment. Still sitting around -78 to -80 very steadily.

2 - Antenna alignment on horizontal was 10x easier... in vertical I really had to get it within a few millimeters turn to get it locked on. In horizontal it seemed like I could move the antennas 3-4 inches either way and still be connected.

The link has been up for 3-4 weeks now. It has been right between -78 and -82 the entire time. Only 2-3 times has it magically gotten perfect, -60db for about 4-8 hours each time.

Some thoughts, tell me if I'm way off on any of these:

1 - the freznel zone has nothing to do with this (directly), otherwise I wouldn't see it all of a sudden get better (unless some obstacle in the fresnel zone all of a sudden moved).

2 - the freznel zone is indirectly related in that when the weather has effects (temperature inversion, fog, atmosphere)it helps the overall freznel zone effect. Rather than weather affecting it in a worse way it might be making it better? I can't confirm it was weather when it got better, but that's my guess.

3 - I'm shooting thru a high voltage powerline about 0.5 miles away, is it possible thats affecting it? Maybe the power on that line was turned off that time it got better? I wouldn't think so, but just a long shot.

Both sides have been replaced independently. Each side was moved 100 meters to the side with no changes.

I'm somewhat at a loss at what to try next. I do know that with the existing hardware and link path I have gotten -60db, but what options do I have to try to keep that as the normal strength? If I change out antennas for dishes is that going to make any difference? If I raise either side 10ft (on a 20km link) would that help much? Should I switch to 2.4ghz? I assume that will make the freznel zone larger...
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Re: New 20km link, weird interference.

Sat Jul 25, 2009 5:56 am

changeip,

Try lowering your tx power in half at both ends.
Check rx strengths again.
 
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Re: New 20km link, weird interference.

Sun Jul 26, 2009 8:33 am

okay, i did test that just now. changed the setting to 'card rates' and then stepped down a little each time (on both sides at the same time).

xr5 card rates:
20 - 86db-88db
22 - 84db
24 - 82db-83db
25 - 80db-81db
26 - 77db-78db
27 - 76db-77db

any lower than 20 and i couldn't get a link at all.
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Re: New 20km link, weird interference.

Sun Jul 26, 2009 8:22 pm

Sam..

You said that the signal for better for 4 - 8 hrs at a time,,,,

The data center ( am assuming Sandiego L3 ) follow me here...

Dont they use DC rack equipment... Isnt there a LARGE btty UPS... system... (charging system and inverters)

Also, the other antennas on the platform..

What I am getting at... is is ther a chance that you could look at the schedual that the signal improvovrd, and see of one of the other systems in the area (eather sise) went off line for maintanance , schedualed or not,

I am NO wireless expert, but the timming sounds "interresting",, 4 then 8 her usualy at 10:PM or so...

It would possably allow you to find the source by "connecting the dots" if there was a maint outage of a system, then find out when it will be down next or if "crashes" when it did and match it to your graphs... Then smite the offending pice of equipment with a few well placed hammer blows.. :D

I think I would wander down that road for at least a short while,,,
Things that make you go "Hmmmmmmmm"...

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Re: New 20km link, weird interference.

Sun Jul 26, 2009 9:48 pm

Looks like propagation effects, not interference.

I did some multipath calculation and the expected signal at the receiver, for 28dBi antennas and 23dBm TX should be -56dBm. At this distance even over sea surface, same antennas, the SLA is 99,99935% (e.g. 4 minutes total outages in one year). As your RSL is -80dBm ... the fresnell zone obstruction at the middle of the path can not be neglected.

Since the modulation is OFDM I think that multipath desctrutive atenuation is out of question because this kind of interference is mostly narrowband so you miss some OFDM carriers but the avereage received power must remain the same (except if there is several paths with different time delays but the terrain seems pretty mixed).

Along the day when there is not any significant changes at temp X humidity in the valley between the mountain and the obstruction the signal still stable. But after sunset or just before sunrise (e.g overnight) some ducts can show up, acting as waveguides or reflectors, making the beam change its direction or elevation. This can exist durying the day, depends on the local weather.

The obstruction at the middle can create something called knife effect too, e.g. bending the beam downwards (good if you have a probe receiver some meters down hill :D).

And looking at the antena place at the building ... microwaves does not like very much big surfaces in front/below the antenna (the metal roof, a mirror). Sugestion: assemble anoter rig at this metal roof edge and take some RSL readings. I had some trouble once at 2.35GHz STL from a TV ENG van which was assembled in the middle of the van roof. Depending on the parking position the signal desapear. One (1) meter movment and lots of signal show up.

Regards;
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Re: New 20km link, weird interference.

Thu Jul 30, 2009 10:19 pm

Regarding your height above the roof... Traditional microwave theory states that a 22 degree plane exist between the radiator and the edge of the roof.

I've 'fixed' many troublesome links where other companies have installed the equipment to close to the roof and simply moving it to the roof line nearest your far end corrected the issue.

Horizontal polarity is also more susceptible to multipath reflections off near-field objects such as a roof.

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changeip
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Re: New 20km link, weird interference.

Mon Aug 03, 2009 9:21 pm

I am starting to think its freznel zone effects as well, but really can't figure out why it would increase tremendously every once in a while:

Image

If it was the roof reflecting would it do what I see above?

If it was the weather (temperature inversion) would I see it only happen for 30 mins or so as shown above?

Now if it was another source putting off RF interference I would see the above. Is there an easier way to test that / track it down?
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Re: New 20km link, weird interference.

Mon Aug 03, 2009 11:23 pm

I think only a spectrum analyzer would most likely help and show the RF interference levels, if any, as I have a few doubts about the interference theory. If it were RF interference, then changing your polarization would show different SNR levels. Have you checked that? Have you tried any other cards besides XR5s? Have you tried other boards? Have you checked both sides close to each other in a controlled environment and compared the results with other working units?

But I strongly believe the answer is really simple and the most obvious one. I think you have underestimated the middle community height and that those excellent signals you receive every now and then, are only the results of some type of passive reflection somewhere in the community every now and then.
 
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Re: New 20km link, weird interference.

Tue Aug 04, 2009 12:03 am

yep, agreed. Suppose it is truly freznel zone getting me, is there anything I can do to improve my situation? Bigger antennas - circular polarization - Wireless N - ? I know I have gotten near -60db signal at times, so there must be something I can do to get that to be more stable... I hope :)

I have replaced the radios completely, both with XR5s each time, but same results. Swapped from horizontal to vertical, etc.
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Re: New 20km link, weird interference.

Tue Aug 04, 2009 2:16 am

Well, searching that community in the middle and finding the surface that reflects those waves and keeping it that way, is one way to go!

Seriously though, N will help if signals are reflected but in your case I doubt if it will help much. Increasing gain in general (TX/RX, antennas, minimize losses) will definitely help but I would personally research a bit more the height factor. That seems to be your whole problem and you should focus on that. It should be easy with a good GPS to measure the community's height and the 2 remote points as well as the distances and figure out if it is the fresnel zone you are dealing with here. If you are within the fresnel zone, and not way below it, moving the antenna around and/or lifting it a few meters at both points will definitely help, otherwise, an active repeater with good visibility to both points may be a better, in many ways, alternative.
 
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Re: New 20km link, weird interference.

Tue Aug 04, 2009 7:11 pm

Thanks for everyones input, I appreciate it. I know it's helping me narrow it down and get this fixed.

Image

This morning it did it again - the past 2 weeks have been very steady around -80db. This morning I see increases all the way to -60db it looks like.

I can rule out that roof being a problem, correct? The roof hasn't moved since I installed it : ) I did move it about 50 feet forward with the same result but didn't get quite to the edge of the roof. I will try this next time I am up there.

I think I can rule out that its my rb433 or xr5 cards. I've swapped both sides and get the same result.

I can't quite rule out that it's a weather effect. It is hot as heck here (and more humid that normal), but it has been for a while. I think I might talk to a weatherman around here to see if they can correlate this mornings signal increase to weather... Typically I would think the weather would make the link worse, not better however.

I will take some GPS readings at 3 sites, the 2 ends and the middle. I can visibily see each end on a clear day, 20km away... it is barely skimming that community in the middle, but still clears it by 20-40ft I would think.

My question now is - if there is something in the freznel zone causing interference, would that affect my 2 endpoints? Imagine I am shooting over and R&D company's building that is performing high powered RF or 2 way satellite communications, would that affect my path in the middle of a 20km link ? Part of the path is a military base, maybe there is something interfering on their land?
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Re: New 20km link, weird interference.

Thu Aug 06, 2009 9:07 pm

I'm starting to think it's the fact I'm shooting within a few hundred yards of a doppler radar ball in the very middle of my link. I am reading that weather doppler sends out 1cm - 10cm wavelengths. 5ghz wifi is about 5cm right? I also realized that the FCC mandates DFS on 5ghz links because of the radars? Does anyone have any experience with a doppler radar interfering with signal?

Image

Really makes me wonder if those increases in signal were when they were doing maintenance or changing parameters on the doppler. I even heard the weatherman on the local news a few nights ago say they were going to fine tune a few things to see if they could detect different size water droplets. Hmmmmmm.

I'm going to swap the 5ghz antennas and XR5 cards with the 24dbi PacWireless grids and XR2 cards today and see what happens...

And a picture from the other side:

Image

Could this radar theory explain why the signal on every single 5ghz frequency is around -80db, and when it has it's moment and is good every single frequency is good again?
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Re: New 20km link, weird interference.

Sun Aug 09, 2009 2:33 am

ChangeIP,

I really believe your question has been answered by nramos. I see this all the time on my longer links, except the periods of better than normal signals are usually followed by signals 10-15 dB below normal or in your case a -95. In my area this mainly happens at night or early AM and only when there is absolutely no wind blowing. I need to have a signal in the low to mid 60's to provide enough fade margin for a 99.9% link in my area. Hams call this 'thermal ducting'. Hot and cold pockets of air acting like a conductor. Signals get crazy good when both your antennas are in the same layer of air or 'duct' and when one of them is above or below the layer of air(duct) you are sucking mud. :-)

If this were my link I would try increasing the gain on the antennas first and then possibly height. I've tried the antennas you are using, they are not even close to the gain of the Pac solid 28 dB dishes. I would recommend the Pac 32 dB antennas or at least on one end of the link and a Pac 28 dB solid on the other end. The antennas suggested earlier are very good quality, I'm just telling you what I am familiar with. The Pac 28 dB grid I tried seemed to be more like a 20 dB in the real world. I do use the smaller grids sometimes for links less than 3 miles. Good luck!

You've helped a lot of folks on this forum and I thought I would toss in my two cents to try to help.

Good luck in the RF world.
 
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Re: New 20km link, weird interference.

Sun Aug 09, 2009 5:05 am

The Pac 28 dB grid I tried seemed to be more like a 20 dB in the real world.
Really? I have a few in the field and they do seem to be in the 28 dB area.
Either that, or the 24 dB panel antennas are really 16 dB.
 
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Re: New 20km link, weird interference.

Sun Aug 09, 2009 6:28 am

Really? I have a few in the field and they do seem to be in the 28 dB area.
Either that, or the 24 dB panel antennas are really 16 dB.
Maybe 20 db is an exaggeration on my part. I replaced a small 24~25 dB dish with one of the 28 dB grids when they first came out. After realigning for quite some time with no better than a loss of 4 or 5 dB I finally took the grid down and put the dish back up on the tower. A few weeks later I replaced the small dish with a Pac 28 dB dish and saw a slight improvement instead of a loss. This was a 19.5 mile link. These antennas had just come out, maybe I had a bad one........
 
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Re: New 20km link, weird interference.

Sun Aug 09, 2009 7:29 pm

Image

BTW ... the RSL when those humps happen are vy close to the calculated RSL as if there is no obstruction at all. Ducting here are common and sometimes makes signals on 1296 or 2304MHz travels 600Km+ inside them.
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Re: New 20km link, weird interference.

Mon Aug 10, 2009 3:35 pm

sorry for interrupting, but this thread is super useful! keep it up guys!
No answer to your question? How to write posts
 
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Re: Solving 20km wireless link issues

Mon Aug 10, 2009 5:47 pm

sorry but i think your problem is the Fresnel zone
i have link of 16 km, first i set the power at 28dBm and the signal strength was about -40dBm then i decrease it to 100mW 20dBm to set the signal strength at -60dBm,
so you must have the power signal receive at least -55dBm.
try to set another point between the two tower
 
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Re: Solving 20km wireless link issues

Mon Aug 10, 2009 8:04 pm

I think mramos is correct possibly. I will be replacing the system with XR2 cards and the 2.4ghz grid dishes today or tomorrow to test things on another frequency, I need to be sure it's not the doppler radar I am shooting thru causing the problem.
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Re: Solving 20km wireless link issues

Tue Aug 11, 2009 2:39 pm

A solve is to use dishes of more dBi or/and to rise-up your antennas; I don't think if you do some settings you will gain more signal. If you use 2Ghz you will get a lot of interferences; I would try 802.11n (with 2xpair of separate atennas) that works nearLOS
 
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Re: Solving 20km wireless link issues

Thu Aug 13, 2009 9:20 am

How is the 20km link doing now? Any updates to this useful thread?
 
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Re: Solving 20km wireless link issues

Thu Aug 13, 2009 8:00 pm

I'm trying to be thorough in testing, so I did swap out both ends with XR2 cards and Pac Wireless 24dbi Grid Dishes. It's been running since yesterday so not enough time to see if those increases of signal happen sporadically.

Image

The noise floor on 2.4ghz is way worse than 5ghz, but I am getting about the same results. Poor signal - 85db or so. I didn't think a different frequency would help, but I had to test that just to be sure.

This picture was taken from directly in front of the grid dish and shows that I'm shooting over the AC handlers by a few feet. They are about 50 feet in front of me. I tested walking to the front edge to get out of the way and I get the same result, so I don't think it's those. The white arrow shows where it's aimed - just barely above the hillside.

Image

Here is a zoomed in shot, white line is where I'm shooting, the black arrows are the doppler ball and trees you can see from the other side. I am shooting very close to that doppler, and still have thoughts it's what's causing me problems:

Image

Image

That doppler ball is HUGE!

Anyhow, my next test will be to go up the mountain higher on the non-data center side. I don't have permanent mounting options there, but just to test.

Sam
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Re: Solving 20km wireless link issues

Fri Aug 14, 2009 2:32 pm

I hate those PW Grids
If you have some handy, try some panels, they seem to preform better for me when Fresnel is a problem.
 
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Re: Solving 20km wireless link issues

Fri Aug 14, 2009 3:55 pm

If the test in the mountain is satisfactory, I would put a tower together with the datacenter of approximately 24 meters. With antirotation star.

regards
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Re: Solving 20km wireless link issues

Fri Aug 14, 2009 8:23 pm

I have been reading this thread and looking at the Radio Mobile path. From My experience in using Radio Mobile, I see the major problem is the obstruction where most of the lower half of the Fresnel zone is blocked. Radio Mobile is showing you the expanding Fresnel zone with the dashed white lines around the direct path. That is why Radio Mobile is so good. It is predicting a -85dB signal level so is close to what you are experiencing. The occasional bursts of good signal is indeed a ducting effect from cool to hot transisions or visa versa.

In my opinion, the ONLY fix is to get both ends much higher or put a repeater at the obstruction so you can "bend" the signal so to speak.

I have had 5 gig links of about 15 miles that ran well most of the time, then went bad for a short duration of an hour or so, mostly during the Spring or Fall seasons. I did as someone posted, increased the gain of the antennas to get above the weakest durations. Once that was done, the problem almost never occurs.
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Re: Solving 20km wireless link issues

Sun Aug 16, 2009 6:55 am

If you think your link is odd, consider this image for a 1.5km city link with perfect visual LOS:
Image

As you can see, it regularly goes from between -50 to -70.
 
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Re: Solving 20km wireless link issues

Thu Aug 20, 2009 2:05 am

Hello,

Please tell me where do You generate that nice signal graphs?
http://www.mreza-wisp.ba/
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Re: Solving 20km wireless link issues

Thu Aug 20, 2009 4:14 pm

Hello,

Please tell me where do You generate that nice signal graphs?
I use mojiro's cacti template from http://forum.mikrotik.com/viewtopic.php?f=2&t=21189
 
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Re: Solving 20km wireless link issues

Thu Aug 20, 2009 8:57 pm

I use mojiro's cacti template from http://forum.mikrotik.com/viewtopic.php?f=2&t=21189
RK, thanx...
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Re: Solving 20km wireless link issues

Sat Aug 22, 2009 10:16 pm

Maybe try looking at the problem upside down, in so far as, your signal of -80 was the norm (all be it less than expected)

And that the periods of -60 are from times of signal enhancement.

The terrain looks like a candidate for temperature inversions. You can spot the phenonema crudely when smoke from a stack ceases to rise but drifts horizontally.

Temperature Inversion also preludes ducting another phenonema affecting VHF, UHF and less commonly Microwaves.

Maybe it was raining somewhere in the path those days, or there was high humity, causing refraction and then multipath.

What about a car that was parked somewhere in that link, that may have caused a mulipath affect, causing the signals arriving partly in phase to add.

Anyhow, interesting thread.

Best of luck... Simon
Last edited by wirelesswaves on Sat Aug 22, 2009 10:45 pm, edited 2 times in total.
 
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Re: Solving 20km wireless link issues

Sat Aug 22, 2009 10:29 pm

http://www.ips.gov.au/IPSHosted/NCRS/wa ... erans1.pdf

http://sirkova.com/documents/ICEST_2003 ... tances.pdf

http://www.its.bldrdoc.gov/pub/ntia-rpt ... hap1-3.pdf

http://www.dxinfocentre.com/propagation/tr-modes.htm

Some of the above links are tiring reading, especially the third. For 30 years I played around with VHF communications, exploiting the uses of all known propagation phenonema, including meteor scatter and moonbounce.

Maybe as I suggested, its not equipment related in any way, just that the freznel zone has given you less than your first expectations, and on the days of 20dB extra, your signal is actually enhanced.

The last link is the simplest explanation from us radio ham chappies

73's EA5/G0MGA
 
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Re: Solving 20km wireless link issues

Fri Sep 18, 2009 3:36 pm

Those power lines in the image you posted can also create anomalies.
They will also expand and contract with temp fluctuations, etc.

My beleif is that there is not one or two things, but several things, all working against you on this shot.
 
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Re: Solving 20km wireless link issues

Fri Sep 18, 2009 4:02 pm

THE MACHINE IS AGAINST YOU!
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Re: Solving 20km wireless link issues

Thu Sep 24, 2009 11:50 pm

biger dishes - beter signal ;-) simle as that ... with two 90cm solid state, and some LOS ... there is no way of having any problems on 20km ;-)
 
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Re: Solving 20km wireless link issues

Fri Sep 25, 2009 9:09 am

have you tryed moving your link o the front of the roof so that you cut out the noise on the roof?


so your 20km link becomes 19.7km


i always try keep my anntennas close

and another thing whay power are you using ups power and 12v or 48?

just a question i did not see any answers to
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Re: Solving 20km wireless link issues

Sun Dec 20, 2009 2:28 am

Just an update. A few weeks ago I placed at the data center side a pacwireless 32db solid dish, single polarity as a test to see what happens. This increased the signal to -66 or so, a huge improvement. I also went up about 5 more feet. This weekend I am installing on both ends the pacwireless 32db dual polarity solids ($49 each on ebay!) and hope to be in the low 60's. Will post pictures and other info shortly. Thanks for the help everyone!
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Re: Solving 20km wireless link issues

Sun Dec 20, 2009 2:38 am

pacwireless 32db dual polarity solids ($49 each on ebay!)
Nice. Very nice.
They got more?
 
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Re: Solving 20km wireless link issues

Sun Dec 20, 2009 3:54 am

nope, the guy said he had 3. they were listed as satellite dishes, in the wrong category. he didn't know they were $280+ new :) these 3 were all new. cost me $300 total with shipping for 3 of them, yeee haw. The surplus seller said he got them from a lost shipping palette, so someone here is probably missing them : )
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Re: Solving 20km wireless link issues

Tue Dec 22, 2009 4:17 am

Just to cast my vote, the effects you are seeing sound just like what I have on my long links, which is the thermal ducting that was mentioned earlier. I see it most after a hot day, late at night when things start cooling off, but usually only when there is almost no wind.

The effects of thermal ducting can help or hurt you depending on which "layer" you are in. Think of it this way, when the layers develop, if both of your antennas are within the same layer, your signal gets "stuck" in the layer and it helps increase the signal since less of it is getting lost in the fresnel zone. If your antennas happen to fall into different layers, it can hurt your signal as much as it helped.

I can watch my 35 mile 5ghz link. Normally it hovers in the -75 area. Late at night, I can watch it go into the -90's and start to disconnect.... In a matter of minutes, it can be back to the -70's, and actually increase into the -50's. As the layers disappear, the signal levels back out around -75.

Happens like clockwork. About the only solutions I know of are to throw more signal at it (bigger dishes) or add a repeater in the middle.

Joe
 
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Re: Solving 20km wireless link issues

Tue Dec 29, 2009 2:17 am

This has been a very long thread. Please update us with your new antennas. I am sitting on the edge of my chair waiting to see a resolution...

In my experience, fixing a very difficult problem will teach you more than you ever expected to learn. That is the saving grace of these kinds of problems. Everyone following this will benefit from your frustrations.
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Re: Solving 20km wireless link issues

Wed Jan 06, 2010 1:56 am

If your Fresnel is really 0.3F1, then in my opinion that is your problem.

It is my opinon that for a reliable link you should have 0.8F1. I consider (again my opinion) 0.6F1 to be the absolute minimum.

Given your description, I would both increase the height of the antenna at the data center and also if possible at the water tower.

Also if possible move the antenna at the data center so that you are not pointed across the metal roof, I have had many problems in the field going over metal roofs in that manner.
 
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Re: Solving 20km wireless link issues

Wed Jan 06, 2010 8:06 pm

I have replaced both ends with PacWireless 32db dual polarity dishes. I also increased height at the data center by about 4-5 feet, and on the water tower about 2-3 feet. Signal went from -80's to -50's. I have a feeling those PacWireless 29db grids aren't really 29db. Going to the data center over the next week to flush out installation and will take more pictures and post the final solution. Will be testing nstreme2 today with the dual polarity dishes, hopefully there is enough isolation to not cause me problems. BUT - WOOO HOOO, finally a link that is working. I'm hoping to get 80-120mbps from the data center into the wireless mesh, could be a pipe dream : )

Oh yeah, when ducting happens the signal goes down into the -40s now...

Thanks everyone for the help. I really appreciate it.
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Re: Solving 20km wireless link issues

Wed Jan 06, 2010 8:27 pm

I have replaced both ends with PacWireless 32db dual polarity dishes. I also increased height at the data center by about 4-5 feet, and on the water tower about 2-3 feet. Signal went from -80's to -50's. I have a feeling those PacWireless 29db grids aren't really 29db. Going to the data center over the next week to flush out installation and will take more pictures and post the final solution. Will be testing nstreme2 today with the dual polarity dishes, hopefully there is enough isolation to not cause me problems. BUT - WOOO HOOO, finally a link that is working. I'm hoping to get 80-120mbps from the data center into the wireless mesh, could be a pipe dream : )

Oh yeah, when ducting happens the signal goes down into the -40s now...

Thanks everyone for the help. I really appreciate it.
I have used plenty of the pac 29's (probably 50 of 'em), they are perfectly good antennas. Improving your fresnel is what actually helped.

The importance of good fresnel cannot possibly be understated. It is absolutely the single most important property of any link!
Last edited by nickb on Wed Jan 06, 2010 8:49 pm, edited 1 time in total.
 
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Re: Solving 20km wireless link issues

Wed Jan 06, 2010 8:37 pm

I vote for sticky :roll:
This thread is very helpfull and usefull.
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Re: Solving 20km wireless link issues

Thu Jan 07, 2010 7:19 pm

Assuming different antennas but exact same alignment and heights, that improves fresnel because of the degree of beamwidth correct? Going from 4 degree to 3 degree increases fresnel simply because its a narrower path?

Now I have the problem of RB433 w/ 2 radios and getting half speed when the other associates, but I'll keep that to the original thread if I can find it. Pictures coming shortly on the link...
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Re: Solving 20km wireless link issues

Fri Jan 08, 2010 3:48 am

Assuming different antennas but exact same alignment and heights, that improves fresnel because of the degree of beamwidth correct? Going from 4 degree to 3 degree increases fresnel simply because its a narrower path?
No, the fresnel zone does not depend on the beamwidth of the antenna.
It depends only on frequency and distance.
 
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Re: Solving 20km wireless link issues

Fri Jan 29, 2010 2:25 am

Very interesting tread changeip.
Some pictures and last info would give it a nice end.
The tread is dead now for 20 days, any last info?

And yes, vote to make it sticky. This is a very educational topic for lots of us... well done!

R.
 
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Re: Solving 20km wireless link issues

Fri Jan 29, 2010 2:58 am

No, the fresnel zone does not depend on the beamwidth of the antenna.
It depends only on frequency and distance.
True. But the beamwidth does have an effect on the amount of energy transported in the LOS tunnel.
Thus with the same Fresnel and same radio output you get better signal (=more energy) on the other end. Thus higher readings. The negative impact of the ´blocked´part of the Fresnel is the same in % but since the amount of signal received by the other end is higher, you have better signal levels.

Now before we think this can then also be achieved by just more power on the transmitter. It is not the same.
Bigger dishes or bigger mesh antenna's are not only better in converging (´tunnelling´) the signal, thus delivering more energy at the other end, but are also better in ´hearing´ in its focus direction when receiving the signal. So you win twice here instead of only once with higher power outputs. Aiming becomes more important now.
But this is an important element some of us forget. Just increasing power is usually not the way to go.
(Apart from the fact that most radios perform better under mediate power settings then max. settings. If possible leave them at default or drop a bit.)

Look at this radio link issue as an adjustable focus torch that you use to signal a guy with binoculars some miles away.
If your torch's light beam is wide you'll have a nice light close to you but your guy at the other end won't probably see you with its bare eyes, special if there are lots of other light around you and him.
Now converge the beam of the torch to the max and he might pick up the light if you point at the right direction. Your light will stand out compared to other surrounding light seen by the ´looker´.
It will make it all much better for the distant guy if he then starts to use binoculars.

You could also put a much higher voltage to the lamp of the torch when not converged yet. Your other guy will then also pick up the light from you, just before you bulb burns....

In the ´receiving end´ (the ´looker´) imagine the following:
When he uses bare eyes or a cheap binocular, he will only see the torch if it is focussed heavy and pointed in his direction or when it is unbelievably bright. But at the same time he will also see other lights in its surroundings, like a car using its head lights while hunting rabbits.... (Doppler radar hunting for rain...).
Now, if your ´looker´uses a telescope he will pick up your torch easy if he is pin pointed to the torch while probably doesn't even see the hunters car any more. You can even put some lesser volts to the bulb to extends it life time (not too low, the bulb then also start becoming to work less and shortens its life time. Just like a radio.)

In using the high dB dish antenna's you do both. Converge the beam and maximise the hearing while at the same time keep as much of unwanted signal out of your receivers (so lower noise level)

The only risk here is that when a strong signal happens to fall into the antenna and the signal is picked up by the receiver it might blow its receiver circuits.
(Imaging the ´looker´ uses the telescope to look comfortably at the torch and then lightning strikes direct in your path of vision. Worst case is he looses sight for ever.... In radio terminology, it will damage your receiver.)

So now you also have a tip to ´blow´ your competition out of the sky.
I know, not the purpose of this topic, but imagine you are the competition...... be aware!
 
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Re: Solving 20km wireless link issues

Fri Jan 29, 2010 11:38 pm

Very informative post, I will be interested to see how it turns out.
 
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Re: Solving 20km wireless link issues

Wed Feb 17, 2010 2:27 pm

have you solved your issue?

1. try to add 50m antenna pole on the side which is lower (to avoid power line radiation. the height is depended to their transmit voltage)
2. try to reduce the 20mzh channel to 5mzh, if that helped then use a more powerful card or use a amplifier.
3. try to replace your antenna where you have a sharp (more towards 90 degree angle on those powerline)

We had very much the same problem as you did a few years ago.
when there was a high power line in the path similar to what you have in one of the photos.

if the power line has angle it will do unknown and strange behavior which no-one may never know.

although in these scenario we did a test with dual antenna and 11n card and it did greatly improved the speed and the signal.

Beside installing a tall poll at low end I can't recommend anything.

to test , you can use a GI pipe and use a temporary cable to hold it for signal testing and see if going above the power line will help or not...

in our case 50m above the power helped a lot.


Good luck
 
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Re: Solving 20km wireless link issues

Mon May 31, 2010 8:04 am

Kan you please send me the google earth place marks and the hight of each antenna from ground I would like to run it in a tool we have

you can mail it to erastus at theweb.co.za

It would be very nice to run it in our simulator. Mark each spot with place mark and then mail the place mark
 
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Re: Solving 20km wireless link issues

Sat Jul 17, 2010 7:25 pm

Hello, people.

Reading the entire posted. I realize maybe a design error in the pacwireless new grids. I recently installed a new wireless network with about 6 25km distance links. Each site has the same config as the others, same antenna, same board, same minipci. I found out my links barely can get -78dBm Rx signal. I have test another minipcis and have the same signal strenght. The only option left is to try another antenna to test.

I would like to ask you people to share your experience with these grid antennas.


Best regards..
 
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Re: Solving 20km wireless link issues

Mon Jul 19, 2010 8:41 pm

Hi changeip, which software is it? that graphs the signal from RB's...
I am starting to think its freznel zone effects as well, but really can't figure out why it would increase tremendously every once in a while:

Image

If it was the roof reflecting would it do what I see above?

If it was the weather (temperature inversion) would I see it only happen for 30 mins or so as shown above?

Now if it was another source putting off RF interference I would see the above. Is there an easier way to test that / track it down?
 
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Re: Solving 20km wireless link issues

Tue Jul 20, 2010 10:05 am

MRTG
No answer to your question? How to write posts
 
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Re: Solving 20km wireless link issues

Tue Oct 05, 2010 3:44 am

Great thread.
I have an almost identical 5Ghz backhaul link. Much much better looking fresnel zone however.
There is a hill at approx the halfway point, not quite in the zone.
The link runs almost constantly at -66 both ends, EXCEPT on hot and calm dog days when the trees on the hill are giving off quantities of water vapor.
Then it drops to -74 to -76 and stays there until the wind comes up or the water vapor dissipates.
I totally agree with mramos and jcremin.
 
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Re: Solving 20km wireless link issues

Mon Nov 15, 2010 6:05 pm

Hello Forum Guru

Let tell you some facts based on your Radio Mobile information, per experience I have many Links working even with more distance using Mikrotik's without problems, but the whole idea of Radio mobile is to help to avoid you waste time deploying a link that won't work, the signal predictions are good in Radio mobile if all data in is correct and results are correctly interpreted.

I'm seeing many issue on your information posted:

1- You configured a maximum TX power of 27dBm, I'm not sure but I do not think this TX power is possible, maximum 25dBm depends of the Wireless card used.
2- Your received sensitivity is too good, for a link budget you have to be conservative so -93 dB is too good, you should configure on Radio mobile a little more conservative value like -86dB
3- Antenna Gain is important, also antenna pattern, so if you use the right antenna gain and the right antenna pattern then should be not poroblem, I can not tell if this correct based on your information without seein the whole prpject file.
4- The signal is blocked more than 50% on certain point of the path by a hill, you have to calculated the fressnel zone to verify this will be an issue or not.
5- Never deploy a link is you do not have a margin at least of 20dB's, on your Link budget the Profile shows on few dB's margin, so weather, atmospheric events make the signal fade a lot, so with the few margin calculated by Radio Mobile you won't have a stable link.

In summary Radio Mobile works only is all data is entered correctly and some extra conservative values are considered.

remember the law "Trash IN = Trash OUT"

If Link budget data is not entered correctly the link budget is useless, also if all is right link budget is also telling you never deploy a link if you do not have at least 20dB's S/N level to account for FADE
 
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Re: Solving 20km wireless link issues

Sat Jan 15, 2011 5:29 am

Go higher!!! metal buildings are mirrors for wireless. I dont know if you have any water ( as in lakes ) but they can have the same effect. The best thing is higher or move away from the metal building.
 
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Re: Solving 20km wireless link issues

Mon Mar 07, 2011 11:28 am

I would like to know the end result too, seems like the problem was still there?

When I was reading this, I seen the picture of the air conditioning unit.
Also seeing the graphs, where I believe it was between 4 am and 6 am where it got better....
My theory is that, since this building is a data center, that AC unit would probably be going most of the time, but possibly the days, as intermittent as they were, when the temprature falls low enough that AC is not needed in the building, but just use outside air, then it would shut down. Im sure the unit on the roof is actually an Air Make up Unit, not just an AC unit.

It would be interesting to see if the outside temp for that area fell low enough during those nights so that the AC compressor unit was not working, or even if that AC/ Air make up unit was shut down for that duration. The hot air exhausted from the unit may have been effecting the link, when it was off, it got better.

Hopefully we find out for sure if the link got better???

My OTHER Idea was that that may not be doppler radar ( Weather) It may be Radar for an airport? I had a couple links that were to the North of my AP, and in the direction of the airport, that ALWAYS had a very low signal, -78 - -84. at some point that same hardware was moved to locations south of the AP and even further away and the signals got up to -70. There was no LOS, there was trees that were taller then the height of the AP, and even a house litterally in the way of the shot. To be honsest Im suprised it works.... as for the advice of if there is less then 20 DB fade margin, dont bother setting up the link, well, I think its faster and easier to run the data in radio mobile, and see if it is remotley possible, then just set it up, after all you obviosley need the link, why else are you trying to get it to work?
 
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Re: Solving 20km wireless link issues

Mon Mar 07, 2011 5:52 pm

I did get this to work a long time ago - we ended up using the 3ft pacwireless dish on both ends versus the grid dish I started with. Its a very stable link now, almost 200 days uptime I think. The main issue was temperature inversions on the path. The link barely changes signal now with the 3ft dish, very solid.

Image
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Re: Solving 20km wireless link issues

Mon Mar 07, 2011 6:01 pm

Hi changeip, which software is it? that graphs the signal from RB's...
I am starting to think its freznel zone effects as well, but really can't figure out why it would increase tremendously every once in a while:

Image

If it was the roof reflecting would it do what I see above?

If it was the weather (temperature inversion) would I see it only happen for 30 mins or so as shown above?

Now if it was another source putting off RF interference I would see the above. Is there an easier way to test that / track it down?
sorry about hijacking this thread but what about that program that visually showed the fresnel zon and his link across the vertical slice of the land. what program is that and how do i get it :)
 
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Re: Solving 20km wireless link issues

Mon Mar 07, 2011 7:09 pm

sorry about hijacking this thread but what about that program that visually showed the fresnel zon and his link across the vertical slice of the land. what program is that and how do i get it :)
Radio Mobile, here http://www.cplus.org/rmw/english1.html
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Re: Solving 20km wireless link issues

Tue Mar 08, 2011 6:21 pm

Hi,,

Im make link for 36KM distance links :

2*RB433AH
2*XR5 with cables.
Dish 32db dual 90cm
antenna dual 32db

the link working very good the signal is :
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Thanks!

Best Regards.


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If my answer helped you and my question good too, please give me karma
 
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Re: Solving 20km wireless link issues

Sun Mar 20, 2011 4:15 am

If this would not be enough, you can also try plugging in signal repeaters on specific spots which has low signal levels. This is pretty much applicable on schools which have class rooms with mobile phone signal jammers but if you still want a wireless internet signal, then might as well right. ^ your network looks really impressive if that covers the 36km distance.
 
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Re: Solving 20km wireless link issues

Fri May 20, 2011 1:43 pm

Greetings!

Does anyone have antenna templates for 2,4 and 5 GHz, that i can import in RadioMobile?
 
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Re: Solving 20km wireless link issues

Fri May 20, 2011 6:10 pm

Greetings!

Does anyone have antenna templates for 2,4 and 5 GHz, that i can import in RadioMobile?
If you join the Radio Mobile Yahoo group (mailing list), you can get access to the Files section of the group site at http://groups.yahoo.com/group/Radio_Mobile_Deluxe/ which has many useful antenna pattern files, including many patterns for Pacific Wireless (Laird) antennas.
 
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Re: Solving 20km wireless link issues

Mon May 23, 2011 10:32 am

Thank you!
 
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Re: Solving 20km wireless link issues

Fri Jul 22, 2011 10:39 am

I am glad seeing this post which has explained the Solving 20km wireless link issues. Well, I am looking for some experts for Data Center Relocation. Please do share some information regarding that.

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Re: Solving 20km wireless link issues

Wed Sep 14, 2011 10:44 pm

tgrand is right about the power lines. Don't forget that electromagnetic field around the cables may also change the direction of the beam or create out of phase waves.
If you have reflected waves that are out of phase, the RX signals of both points will be different.
Looking at the pictures, I don't see something in you even frensel zones.

Do you observe these changes in RX signals to be connected with the weather conditions, for example with rainfall ?
 
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Re: Solving 20km wireless link issues

Mon Sep 19, 2011 11:18 pm

Hi,,

Im make link for 36KM distance links :

2*RB433AH
2*XR5 with cables.
Dish 32db dual 90cm
antenna dual 32db

the link working very good the signal is :

Whats the throughput you have on that distance? the REAL deal.
 
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Re: Solving 20km wireless link issues

Tue Nov 01, 2011 3:57 pm

Found this one the internet:
http://j-walk.com/other/wifispray/
Should it improve long-range links and should I try to make an automatic dispensing system?
 
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Re: Solving 20km wireless link issues

Tue Nov 01, 2011 4:08 pm

Can you tell me how I can start 20 Km wireless project using mikrotik instrumentation Plz I am in hurry
thanks
 
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Re: Solving 20km wireless link issues

Wed Dec 07, 2011 12:18 am

Image
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Re: Solving 20km wireless link issues

Wed Dec 07, 2011 7:21 am

Mr. mramos

Why you did not mount the antenna in considerable height?
How far your second antenna?

thanks
 
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Re: Solving 20km wireless link issues

Wed Dec 07, 2011 10:32 pm

Why you did not mount the antenna in considerable height?How far your second antenna?
Hi ...

Well, it's not really necessary. Trees at this site have more than 15 .. 20m height. Signal path is 1.6Km. This antenna height have some clearence between the smaller trees leaves and the taller ones (like a window).

I only posted this chart to complement some old posts about moving antenna mount along a flat surface versus the effects reflection of radio signal on such surfaces in front of the antenna can cause.

But even with signal variations this link is in production this way for almost 2 year, uptimes normally more than 1 week. If any disconnection occurr it's restored in a fraction of a second.

I only "fine tune" its position because I installed there a second grid antenna to give access to 5 or 6 small properties 4Km away and this second antenna was obstructed by a water reservatory. As I need to move it from the old position I decided to search a new spot where those signal notches are smaller than I used to have at the original position.

A bigger tower - to clean up radio path - must have at least 25m. Too expensive to feed 10 customers :D

Regards;
Marcus Ramos
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Re: Solving 20km wireless link issues

Thu Dec 08, 2011 7:29 am

Mr. mramos
I have to construct a wisp but I am not sure of the following:
1- Mounting a 24 dbi grid (2.4 G Hz) on a house building height (8 Meter) and the second 24 dbi antenna on the same height with 14 KM far away (Distance between both antennas) but no obstacle between them.
behind these antenna I have 26 dbm transmit power wireless router.
so can I have 26 MB or above bandwidth?

thanks a lot
 
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Re: Solving 20km wireless link issues

Thu Dec 08, 2011 8:43 pm

Mounting a 24 dbi grid (2.4 G Hz) on a house building height (8 Meter) and the second 24 dbi antenna on the same height with 14 KM far away (Distance between both antennas) but no obstacle between them.behind these antenna I have 26 dbm transmit power wireless router.so can I have 26 MB or above bandwidth?
I don't think it will work.

Even without obstruction in the path there will be earth curvature itself. Small at 14km anyway but it's there. The main obstacle is fresnel zones blocking.

On such path at 2.4GHz to clear up at least 0.6 F both antennas must be at ~22m height each side. If it was 5.8GHz, for the same 0.6 F antennas must be ~16m each side.

Regards;
Marcus Ramos
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Re: Solving 20km wireless link issues

Sat Dec 10, 2011 11:18 am

Mounting a 24 dbi grid (2.4 G Hz) on a house building height (8 Meter) and the second 24 dbi antenna on the same height with 14 KM far away (Distance between both antennas) but no obstacle between them.behind these antenna I have 26 dbm transmit power wireless router.so can I have 26 MB or above bandwidth?
I don't think it will work.

Even without obstruction in the path there will be earth curvature itself. Small at 14km anyway but it's there. The main obstacle is fresnel zones blocking.

On such path at 2.4GHz to clear up at least 0.6 F both antennas must be at ~22m height each side. If it was 5.8GHz, for the same 0.6 F antennas must be ~16m each side.

Regards;

I am using this calculator : http://www.afar.net/fresnel-zone-calculator
I use equal height antenna section with 0.6 Fresnel zone.
This calculator give 12.9 meter height.
so if I change 8 height to 12.9 it will work Am I right?

thanks a lot brother
 
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Re: Solving 20km wireless link issues

Sat Dec 10, 2011 12:07 pm

I use equal height antenna section with 0.6 Fresnel zone.
This calculator give 12.9 meter height.
so if I change 8 height to 12.9 it will work Am I right?
Well, I took a look at this calculator.

12.9 meter is the radius of 0.6F at the midpoint.

But you have a 14km path so it's necessary to add earth curvature.

Assuming it's a perfect surface (like a path over a calm lake), according with this calculator both antennas must be at 15.3m height.

At this height 0.6F at the middle path will have 0m clearence. Rising both antennas to 16m will give you 1m clearence to 0.6F at the middle of the path.

The numbers I gave you before came from another tool (radiomobile) but I simply picked up some geographic area with a "flat" surface (a beach) near my hometown. But I'm not sure how accurate RM can be in this case.

Regards;
Marcus Ramos
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(Microwave HW, RF, antennas, propagation)
S.Paulo - Brazil
 
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Re: Solving 20km wireless link issues

Mon Dec 12, 2011 8:03 am

Can you tell me what do you mean by 1m clearance?
I understood that I have to add the objects reside in line of side eclipse like tree or some unequal earth
Am I right?

thanks
 
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Re: Solving 20km wireless link issues

Mon Dec 12, 2011 12:06 pm

Can you tell me what do you mean by 1m clearance?
I understood that I have to add the objects reside in line of side eclipse like tree or some unequal earth
Am I right?
Image

1 meter clearence is the distance between terrain and the lowest part of above elipse (where at this wikipedia picture the letter "P" is). In your case I assumed a perfectly flat terrain.

And - yes - you have to add those objects and terrain roughness.

Regards;
Marcus Ramos
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Re: Solving 20km wireless link issues

Mon Dec 12, 2011 4:09 pm

Thank you mramos I hope you fine and doing well,
If I have clear line of site and 24 dbi grid antenna with 23 dbm output power using 2.4 Ghz unlicensed. I will be able to transmit at least 10 MB or not?

If I use 5.8 Ghz can I get 10 MB or still not?

thanks a gain
 
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Re: Solving 20km wireless link issues

Tue Dec 13, 2011 12:33 am

If I have clear line of site and 24 dbi grid antenna with 23 dbm output power using 2.4 Ghz unlicensed. I will be able to transmit at least 10 MB or not?

If I use 5.8 Ghz can I get 10 MB or still not?
Of course. If there's no obstruction nor interference I thing even using 10MHz channel + NV2 (or Nstreme) you can reach 10Mbps. If the cards you choosed are N capable, better. Most of my cards at 2.4 (and 5.8 in near future) are R52nM.

And if you want a PTP solution, there's Groove for 5G (and 2 GHz in some time I read). No cables, no pigtails, just attach them at the antenna connectors and that's it.

Take a look at some examples at the forum, several success stories > 20Mbps.

Regards;
Marcus Ramos
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S.Paulo - Brazil
 
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Re: Solving 20km wireless link issues

Sat Jan 07, 2012 1:44 pm

Hello dears,
How I can make surveillance setup for my WISP using google map or something similar?
this action will help to mount the antenna truly.

thanks
 
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Re: Solving 20km wireless link issues

Fri Jan 20, 2012 5:28 pm

wow Nice job !!! congratulation
 
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Re: Solving 20km wireless link issues

Sat Feb 11, 2012 9:23 pm

Hi Seniors . . .

Thanks for useful post ,yet i experienced with this issue on 45km link backhaul,
Thanks again to my seniors.
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Re: Solving 20km wireless link issues

Sun Mar 11, 2012 2:28 am

This is something I am getting over my 6k and 1k links, it has been happening for about 5 weeks, always between 4:30 and 8:30 PM GMT, the spectrum anylyser shows interference across every single channel of the 5Ghz range, it is across the whole range and lasting about 5 mins max, it knocks out all the bridge links but not the AP's, except I am using Ubiquiti, that is why I have just purchased the Sextant radios to see if they are working any better.

Could it be the solar flares.
 
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Re: Solving 20km wireless link issues

Wed Mar 14, 2012 10:18 am

at a regular time and daily?

I have never known the sun to be that specific with it schedules.
Anyways, it may be something else, but i doubt it is the sun.

One question though, I'd like to know if those sextants work better then the UBNTs, i'm trying to get my boss to use the Mtik equipment over the UBNT equipment for transparent links
 
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Re: Solving 20km wireless link issues

Wed Oct 03, 2012 5:48 pm

it's clear that sextants work better then the UBNT
 
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Re: Solving 20km wireless link issues

Sun Dec 09, 2012 8:17 pm

maybe something industrial/military ?
or commercial stuff improperly installed ?
If you had spectrum analyzer, GNURadio, WinRadio with this band module and etc - you can actually get some details.
but generally only feds had hardware and experience to locate this both in time, frequency and location.
maybe worth contacting your region communications suprevisors/inspectors.
generally NOBODY should shouting with SUCH transmission power on ISM bands. ever !![in civilian time]
talking about YOU case - such bands and such outputs - usual[similar] to radio-relay stations and [Especially!]for tropo-scatters. some mobile Tropo stations [usually military/gov't]use, despite small size - output measured in KW and even MW !! [but more densely occupied tropo was in K-Band]. Radars can do too, but they working on persistent basis, except some space-sensing and other specific, so wouldn't be related to timed/sheduled issues/troubles.

p..s
remind me one story when overloaded cell station with improperly installed[broken] bandpass filter severely cripple other stations nearby and even wi-fi in proximity.
 
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Re: Solving 20km wireless link issues

Mon Feb 11, 2013 7:31 am

at a regular time and daily?

I have never known the sun to be that specific with it schedules.
Anyways, it may be something else, but i doubt it is the sun.

One question though, I'd like to know if those sextants work better then the UBNTs, i'm trying to get my boss to use the Mtik equipment over the UBNT equipment for transparent links
Im running Ubiquiti 90 degree 5GHz sectors 19dbi with 711GA-5HnD as an AP, and have hooked around 30 sextants and 15 SXT 5HnD and the farest SExtant its at 13.2 km from the ap and have a -72dBm and a 14mbps throghput. They work like charm with nv2 and dual chain enabled.
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Have a great day!
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Re: Solving 20km wireless link issues

Mon Feb 11, 2013 7:34 am

maybe something industrial/military ?
or commercial stuff improperly installed ?
If you had spectrum analyzer, GNURadio, WinRadio with this band module and etc - you can actually get some details.
but generally only feds had hardware and experience to locate this both in time, frequency and location.
maybe worth contacting your region communications suprevisors/inspectors.
generally NOBODY should shouting with SUCH transmission power on ISM bands. ever !![in civilian time]
talking about YOU case - such bands and such outputs - usual[similar] to radio-relay stations and [Especially!]for tropo-scatters. some mobile Tropo stations [usually military/gov't]use, despite small size - output measured in KW and even MW !! [but more densely occupied tropo was in K-Band]. Radars can do too, but they working on persistent basis, except some space-sensing and other specific, so wouldn't be related to timed/sheduled issues/troubles.

p..s
remind me one story when overloaded cell station with improperly installed[broken] bandpass filter severely cripple other stations nearby and even wi-fi in proximity.
You are replying to someone?... i get lost with your reply.

regards.
Have a great day!
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Re: Solving 20km wireless link issues

Fri Mar 08, 2013 7:32 pm

Hi sir. I don't think i am suppose to say this but i am just sharing my knowledge out. may be it might help. Well i am a guy who is mostly with the surfboard but i have learned that the more distance a connection has from the centre of the company or i guess its called the portal, the less the speed you get. Even i have experienced it out. Just saying. Might something be like that.
 
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Re: Solving 20km wireless link issues

Wed Apr 03, 2013 2:17 am

...
Last edited by Cal on Tue Apr 23, 2013 3:52 pm, edited 1 time in total.
 
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Re: Solving 20km wireless link issues

Sat May 04, 2013 10:02 pm

never will work u need put more high the antenna is ground on the moutain fresnel
 
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Re: Solving 20km wireless link issues

Sun Jun 16, 2013 1:24 pm

In my years of experience I came through a very strange distortion unit An old tv. maybe in this small community someone has it ; this is not the answer but it might be try to elevate your antenna el little bit more
 
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Re: Solving 20km wireless link issues

Sat Oct 19, 2013 10:13 am

, i did test that just now. changed the settings....
 
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Re: Solving 20km wireless link issues

Wed Dec 11, 2013 4:37 pm

I completely agree with Steve Loomis, you have ignored what RadioMobile is telling you about the path; that it is impeded in the first and second fresnel and I could not tell for sure but may be more than that. Increase your height, clear at least your second fresnel and I would be dollars to doughnuts you will see your 20db.
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Re: Solving 20km wireless link issues

Fri Jan 10, 2014 5:55 am

I'm shooting thru a high voltage powerline about 0.5 miles away, is it possible thats affecting it? Maybe the power on that line was turned off that time it got better? I wouldn't think so, but just a long shot.
 
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Re: Solving 20km wireless link issues

Fri Jan 10, 2014 3:58 pm

I'm shooting thru a high voltage powerline about 0.5 miles away, is it possible thats affecting it? Maybe the power on that line was turned off that time it got better? I wouldn't think so, but just a long shot.
I'v links running straight through low, medium and high voltage power lines. Some at distance, some relative close (<500mtr) and I have so far never noticed any disruption because of these.
The towers on the other hand, usually metal, can be a problem, specially when relative close (reflection of signals). So stay away from these...
Show your appreciation of this post by giving me Karma! Thanks.

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Re: Solving 20km wireless link issues

Tue Mar 11, 2014 8:06 pm

I don't think this has something to do with the distance. Signal should be around -51dBm with 28dBi antenna and 28dBm XR5 Transmitter.

I think the problem it's that the Fresnel zone isn't clear enough and you are having a knife effect just like mramos clearly said.

I think will help to put both antennas a little higher to clear the Fresnel zone completely.

Good day!
JB
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Re: Solving 20km wireless link issues

Wed May 21, 2014 6:54 am

You need some AP, high gain atenna!
 
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Re: Solving 20km wireless link issues

Sat Jun 28, 2014 6:43 am

nope, the guy said he had 3. they were listed as satellite dishes, in the wrong category. he didn't know they were $280+ new :) these 3 were all new. cost me $300 total with shipping for 3 of them, yeee haw. The surplus seller said he got them from a lost shipping palette, so someone here is probably missing them : )
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Re: Solving 20km wireless link issues

Tue Nov 04, 2014 1:58 pm

At the begining of this post, for me is clear that height of warehousse's roof antenna is too low. The relfexion induced by metals warehouse's roofs is a nightmare for me on most situasions that I experienced.

For example, lift two meters the pole is enough for gain signa quality. The same occurs if you carry the pole at the edge of warehouse. This is even enough fresnel zone.

Also, I see on some photos that AC machines are on LOS and near of antenna, bad escenario too.
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Re: Solving 20km wireless link issues

Fri Mar 06, 2015 1:40 pm

which cisco ac can do this?
 
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Re: Solving 20km wireless link issues

Thu Aug 13, 2015 12:05 am

Here is one for you....

I company I know had a 30+ mile DS3 microwave link somewhere in the low 6GHz band. A DS3 is a 45 Meg full duplex link. They replaced their old out-dated DS3 microwave equipment inside their buildings (the shelter side of the wave guide (think of a wave guide like a hollow antenna coax) with a set of dual-polarity Mikrotiks connected to the wave guides. The tower mounted dishes were 8 or 10 foot dishes. The new Mikrotiks linked at 30+ miles had a signal strength somewhere in the 30s.. WOW !!!

Kinda makes me wonder - how far this could actually work if you had line-of-site beyond several hundred miles with 10 foot dishes? Anybody know what the distance record is for a Mikrotik ? I wonder if it would be possible to take two huge dishes and point them at the moon and bounce off the surface and connect to another Mikrotik. Might as well try to blow away the world record (about 237 miles) and beat it by 1/2 million miles - lol.
 
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Re: Solving 20km wireless link issues

Tue Sep 01, 2015 8:49 am

No every noise in audio systems using wireless is due to interference, or even to the wireless equipment itself. Because interference is a known problem with wireless, it is common to blame it for unwanted audio noise.
 
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Re: Solving 20km wireless link issues

Mon Dec 28, 2015 9:02 pm

No every noise in audio systems using wireless is due to interference, or even to the wireless equipment itself. Because interference is a known problem with wireless, it is common to blame it for unwanted audio noise.
which is making sense, btw. by basically nature of EMI itself.
for example - my cellphones (of two kind)affect my speakers very notably, during use(even when system send something or just SMS arrived ;) and new graphics card of my friend - cause similar sound issue for him. that was one kind of 970 GPU's AFAIK he was tried to switch exemplar, brand, but problem persist so he vent to 980ti, desperate. and its solved issue only partially according to him(i quote "i miss good times with R280" or something alike that).
 
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Re: Solving 20km wireless link issues

Mon Dec 28, 2015 10:45 pm

No every noise in audio systems using wireless is due to interference, or even to the wireless equipment itself. Because interference is a known problem with wireless, it is common to blame it for unwanted audio noise.
which is making sense, btw. by basically nature of EMI itself.
for example - my cellphones (of two kind)affect my speakers very notably, during use(even when system send something or just SMS arrived ;) and new graphics card of my friend - cause similar sound issue for him. that was one kind of 970 GPU's AFAIK he was tried to switch exemplar, brand, but problem persist so he vent to 980ti, desperate. and its solved issue only partially according to him(i quote "i miss good times with R280" or something alike that).
Some good rules of thumb when it comes to electronic or radio noise out speakers:
- If the two devices are very close to each other, then you may get some cross-talk. If you double the distance, then you might cut the noise in half.
- Try putting a metal ferried bead around all cables (over the power cables and the speaker cables and all audio cables). The metal bead functions like a choke to block high-frequency noise.
- Try grounding everything possible.
- Very high power and/or very close side-by-side electronics will often have some from of noise to the other device.
- If possible, you might try flipping the power cord 180 degrees where it connects to the wall.

- If none of the above helps - then try these steps: Wrap everything in foil, ground the foil, put everything in separate solid metal trash cans with the lids on. Ooo - and also ground the trash cans using a #1 copper wire
 
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Re: Solving 20km wireless link issues

Tue Dec 29, 2015 2:58 am

Kinda makes me wonder - how far this could actually work if you had line-of-site beyond several hundred miles with 10 foot dishes? Anybody know what the distance record is for a Mikrotik ? I wonder if it would be possible to take two huge dishes and point them at the moon and bounce off the surface and connect to another Mikrotik. Might as well try to blow away the world record (about 237 miles) and beat it by 1/2 million miles - lol.
Polish students have managed to establish 250 km 5GHz link with Mikrotik and use Skype to verify quality.
http://mobirank.pl/2015/06/28/studenci- ... -z-250-km/
http://radiolinia.wireless-group.pwr.ed ... surements/
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Re: Solving 20km wireless link issues

Tue Dec 29, 2015 10:16 pm

im afraid combating EMI is more complex than can be emplained by few rules. or even few books :)
 
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Re: Solving 20km wireless link issues

Tue Dec 29, 2015 10:54 pm

im afraid combating EMI is more complex than can be emplained by few rules. or even few books :)
Yea - I totally know what your are saying about noise.

I have one remote location where my APs are about 500 feet from a multi-million watt military radar over-the-horizon system. You want noise - this is it. Even an Ethernet cable tester connected to both ends of a cable (not connected to equipment) shows the cable is active !

To somewhat remedy the noise problem, I used grounded metal shield backings on my antennas to shield the antennas from the radar. I also had to run my shielded Ethernet cables down the tower where the cable is located on the opposite side of the radar - thus I am using the tower legs to help shield and block the microwave from getting to my Ethernet cables. I also had to ground the shields on my shielded Ethernet cables in multiple places. Also, the building at the bottom of the tower is wrapped with a copper/metal screen mesh to help keep the radar microwave signals out of the building. The building has double metal doors where you open one metal door then close it behind you as you enter the building then you open the next inner metal door. Inside the building, everything possible is grounded.

I don't care for working up on the tower, I know it can't be good for your health - unless you are working on very cold day and want to stay warm - almost like a fly inside a microwave oven - lol
 
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Re: Solving 20km wireless link issues

Tue Jan 05, 2016 4:09 pm

i would mount the equipment on a rubber pipe on the top so its isolated from the mask
and run this cable

http://www.assemblymag.com/ext/resource ... ation1.jpg

to the bottom and ground as far away from the mask(reactor) generating the noice

so its a insulated grounding away from the source of the problem
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Re: Solving 20km wireless link issues

Tue Jan 05, 2016 7:00 pm

i would mount the equipment on a rubber pipe on the top so its isolated from the mask
and run this cable

http://www.assemblymag.com/ext/resource ... ation1.jpg

to the bottom and ground as far away from the mask(reactor) generating the noice

so its a insulated grounding away from the source of the problem

Re - the rubber pipe
I tried that several times and it fried both ends of the equipment on the Ethernet several times - and I could not pass 10 or 100 meg full duplex Ethernet traffic without heavy data errors.

With the way I have things grounded now, with the non-POE ports, I can now pass 1 gig full duplex with very few data errors. If I try running the POE ports at anything beyond 10 meg, I still get high data errors. So I now use at least two Ethernet cables - the POE port for power only and a second (and sometimes a third) Ethernet port(s) for data.
 
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Re: Solving 20km wireless link issues

Wed Jan 06, 2016 9:58 am

do you have photos of this install on this location you have problems
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Re: Solving 20km wireless link issues

Wed Jan 06, 2016 11:33 pm

do you have photos of this install on this location you have problems
Next time I am up there I will take some photos of our tower and the surroundings - elevation almost 4300 feet.
Right now, there is 5 to 7 feet of snow up there. (FYI - there is also a door on the roof so that we can get in when the snow is really deep)
 
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Re: Solving 20km wireless link issues

Wed Jan 06, 2016 11:55 pm

i would mount the equipment on a rubber pipe on the top so its isolated from the mask
and run this cable

http://www.assemblymag.com/ext/resource ... ation1.jpg

to the bottom and ground as far away from the mask(reactor) generating the noice

so its a insulated grounding away from the source of the problem

Re - the rubber pipe
I tried that several times and it fried both ends of the equipment on the Ethernet several times - and I could not pass 10 or 100 meg full duplex Ethernet traffic without heavy data errors.

With the way I have things grounded now, with the non-POE ports, I can now pass 1 gig full duplex with very few data errors. If I try running the POE ports at anything beyond 10 meg, I still get high data errors. So I now use at least two Ethernet cables - the POE port for power only and a second (and sometimes a third) Ethernet port(s) for data.
Some idea; Install Netmetal radios. Use ethernet cable for POE-in only+backup, run fibre from central to the radio. No more issues on the ethernet side..... now you can focus on the radio signals....
(About the Radar, wouldn't it melt the snow away for you? :D )
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Re: Solving 20km wireless link issues

Thu Jan 07, 2016 12:03 am

re: (About the Radar, wouldn't it melt the snow away for you?

I can't help but wonder how 2,000,000 plus watts will effect a bird flying through the radar beam.

I have only seen a bird explode one time - and that was when an eagle landed on a very very very high voltage transformer. Everything on the bird was instantly vaporized and it smelled horrible and the light was blinding and the noise was a very loud buzzzzzz for about 3 seconds.
 
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Re: Solving 20km wireless link issues

Thu Jan 07, 2016 12:12 am

re: (About the Radar, wouldn't it melt the snow away for you?

I can't help but wonder how 2,000,000 plus watts will effect a bird flying through the radar beam.

I have only seen a bird explode one time - and that was when an eagle landed on a very very very high voltage transformer. Everything on the bird was instantly vaporized and it smelled horrible and the light was blinding and the noise was a very loud buzzzzzz for about 3 seconds.
Well, if the bird starts to smoke in full flight I think he is signalling dinner is ready..... :lol:

But yeah, most radars are revolving, so the beam is only pointed in some direction for a split second. And they will have a safety distance off course. I don't presume anybody is allowed to run in front of the radar for a while at relative short distance on a military installation.
But electronics might get a burst each time the signal beam will pass close or hit it/the building....
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Re: Solving 20km wireless link issues

Thu Jan 07, 2016 12:28 am

re: (About the Radar, wouldn't it melt the snow away for you?

I can't help but wonder how 2,000,000 plus watts will effect a bird flying through the radar beam.

I have only seen a bird explode one time - and that was when an eagle landed on a very very very high voltage transformer. Everything on the bird was instantly vaporized and it smelled horrible and the light was blinding and the noise was a very loud buzzzzzz for about 3 seconds.
Well, if the bird starts to smoke in full flight I think he is signalling dinner is ready..... :lol:

But yeah, most radars are revolving, so the beam is only pointed in some direction for a split second. And they will have a safety distance off course. I don't presume anybody is allowed to run in front of the radar for a while at relative short distance on a military installation.
But electronics might get a burst each time the signal beam will pass close or hit it/the building....
Although this is a military radar system with some FAA use also, I heard it is also a phased array system. Where the inside will rotate on a round track and the antenna on the track is a multi-frequency phased-array set of panel antennas. Which allows the rotating track antenna to stop rotating and still have a decent over-the-horizon radar information.

FYI - I have 16 huge 180 pound 2.4 GHz phased-array 802.11 b/g systems from Vivato. They are still the most powerful point-to-multipoint 2.4 FCC licensed system out there. They managed to get them FCC registered as point-to-point which allows for higher power. Using a stock notebook computer, I could connect at 10 miles away (in a 90 degree beamwidth). Vivato went out of business because nobody could get past the price of $30K per AP. Each AP needed 48 volts at 400 watts.
 
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Re: Solving 20km wireless link issues

Fri Apr 15, 2016 2:26 pm

Anyway helpful post for the guys those who are working in ISP. keep it up. :) :) http://www.cybertelusa.com/
 
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Re: Solving 20km wireless link issues

Thu Jul 21, 2016 11:38 am

have you ever saw some new SOHO Wi-Fi routers ? 6x antennas !! 8x antennas !! and announced development of router with 10x and 12x !!!(but 4x and 6x of them advertised as "internal", Godness :)
thats crazy ! (and crazy-looking IMHO :) and eventually become mainstream so routers/AP become AFAR-alike radars in many respects. its Already in standard. all those "beam-froming" and aligned to, features...
just need bit more powerful CPU for calculations in radios and here you go .... fully manageable/adaptable in time/space/spectrum ;)
 
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Re: Solving 20km wireless link issues

Thu Jul 21, 2016 5:50 pm

have you ever saw some new SOHO Wi-Fi routers ? 6x antennas !! 8x antennas !! and announced development of router with 10x and 12x !!!(but 4x and 6x of them advertised as "internal", Godness :)
thats crazy ! (and crazy-looking IMHO :) and eventually become mainstream so routers/AP become AFAR-alike radars in many respects. its Already in standard. all those "beam-froming" and aligned to, features...
just need bit more powerful CPU for calculations in radios and here you go .... fully manageable/adaptable in time/space/spectrum ;)
A bit unrelated - however ...
Around 5 to 8 years ago ... I had some people here testing out a Google branded SOHO indoor Wi-Fi wireless router.  I think it had something like 8 internal antennas with some special kind of a directional diversity chip in it.  We drove out 12 miles from one of my towers, then placed it on the hood of my vehicle and got a connection.  My tower had a Vivato phased beam steering 2.4 GHz connection with the Google Wi-Fi at 11 meg 802.11 B mode.  The Google Wi-Fi was pretty awesome for a SOHO with no external antenna(s).  (FYI - I believe the Vivato base station is still the most powerful legal 2.4 GHz base-station access-point on the planet - because it functions as a sector multi-point but because of the beam forming directional steering of the signals, it was registered as a point-to-point system which can then use the higher power FCC regulations/laws.  FYI - A tower mounted 2.4 GHz Vivato weighs in at 180 pounds !!!
I can only assume the newer stuff these days is far better than the stuff we had back then.
 
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Re: Solving 20km wireless link issues

Thu Jul 21, 2016 6:13 pm

have you ever saw some new SOHO Wi-Fi routers ? 6x antennas !! 8x antennas !! and announced development of router with 10x and 12x !!!(but 4x and 6x of them advertised as "internal", Godness :)
thats crazy ! (and crazy-looking IMHO :) and eventually become mainstream so routers/AP become AFAR-alike radars in many respects. its Already in standard. all those "beam-froming" and aligned to, features...
just need bit more powerful CPU for calculations in radios and here you go .... fully manageable/adaptable in time/space/spectrum ;)
A bit unrelated - however ...
Around 5 to 8 years ago ... I had some people here testing out a Google branded SOHO indoor Wi-Fi wireless router.  I think it had something like 8 internal antennas with some special kind of a directional diversity chip in it.  We drove out 12 miles from one of my towers, then placed it on the hood of my vehicle and got a connection.  My tower had a Vivato phased beam steering 2.4 GHz connection with the Google Wi-Fi at 11 meg 802.11 B mode.  The Google Wi-Fi was pretty awesome for a SOHO with no external antenna(s).  (FYI - I believe the Vivato base station is still the most powerful legal 2.4 GHz base-station access-point on the planet - because it functions as a sector multi-point but because of the beam forming directional steering of the signals, it was registered as a point-to-point system which can then use the higher power FCC regulations/laws.  FYI - A tower mounted 2.4 GHz Vivato weighs in at 180 pounds !!!
I can only assume the newer stuff these days is far better than the stuff we had back then.
Look, if you make the antenna big enough versus you put enough power behind it you can reach the moon. That's not an issue.
In regard to the amount of antenna, Ruckus already had 3 years ago 24stream 'n' multi-mimo system with beamforming. Browse for some pictures and you can count them yourself, all internal.
But because they'd work withing the regulatory domain my laptop in the open field lost connection after 100 meters. (And had to walk back 25 meters to get it back again, that's the disadvantage of beam forming. If the beam is lost there is no more beam.....)
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Re: Solving 20km wireless link issues

Thu Jul 21, 2016 6:59 pm

If you are talking about complying with FCC rules and regulations for point-to-point and multi-point 2.4 GHz Wi-Fi connections, there is a huge difference.

FCC rules for multi-point (sector) 2.4 GHz Wi-Fi networks requires that for every 3-db of antenna gain, you must lower the radio transmit power by 3-db.
FCC rules for point-to-point 2.4 GHz Wi-Fi networks requires that for every 3-db of antenna gain, you must lower the radio transmit power by 1-db.

Thus - a point-to-point system following FCC rules and regulations will always give you a stronger signal.

Additional info and thoughts ...
a) A multi-point system is also subject to more noise because it has a wider area that is can also hear.  Thus no matter how much power you use to transmit with, if you can't hear the remote side because of local noise the network will have a lower SNR (signal to noise ratio).
b) The Vivato beam forming base stations I still have and use not only steer the transmit beam, but it also steers the direction you are listening from.
c) A Vivato (used in a multi-point environment) also will talk (transmit) to up to two clients at the same time - and can listen to up to two clients at the came time. (on the same channel)
d) A Vivato could handle 1,500 client Wi-Fi connections and still function.

The only reason Vivato went out of business is because buyers of long-reach Wi-Fi systems did not understand what the Vivato was actually doing and could not justify $30,000 dollars for an access-point.

About 9 years ago, we had some DOD (Military Department-of-Defense) engineers testing our 17 Vivato coverage in a 600 square mile coverage area.  They were blown-away by how well the system worked.  Thus the Military became one of Vivato's largest customers.

If is sounds like I am a Vivato fan - sorry about that - I am a huge Mikrotik NV2 fan with thousands of Mikrotiks in my network these days.

North Idaho Tom Jones
 
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Re: Solving 20km wireless link issues

Thu Jul 21, 2016 8:20 pm

Isn't it all about the money in the end? 
If we see here in Europe people are getting used to € 30,-/month for 10, 20 or up to 100megs nowadays, the earning model becomes more and more difficult.
I'll bet these Vivato CPE's weren't cheap neither...if they already had beamforming.

I've been testing some Ruckus stuff two years ago and although impressive in their prospects and many new technologies (beam forming, frequency hopping, band sharing, interference avoidance etc.) their price policy is such it doesn't make it interesting for bulk roll outs as we see with MT and Ubnt.

I have been tempted for a while to go for the eCambium product line but if I am to swap my network to something new I might as well go for something new that offers all in Wifi (a/c, beamforming and high capacity chipsets, GPS and smart noise reduction) at the same time. So I hope to deploy a Mimosa AP with some 70 clients within a month or two and got sort of guarantee I should be able to offer top speeds upto 50Meg and total aggregated throughput of over 1Gig per AP. Let's see how that works out. If it fails I lost a lot of money. If it works I'l probably say goodbye to MT-wifi in most of my network. (Their routers are still nice....)
I'd love MT but we are in such a high density spectrum with so many competition (mainly ubnt) I need something to stand out to still get my clients...
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Re: Solving 20km wireless link issues

Thu Jul 21, 2016 8:40 pm

You are totally dead-on correct with the earning model being more and more difficult these days.

I am fortunate in one way that I have just about zero WISP competitors.  My business is owned by the Coeur d'Alene indian tribe here in North Idaho.  We have close to 400 square miles and my customers have little choice for who to go to for Internet.  Other than my company, customers can use a dish satellite company or a cell phone company data plan - both are very expensive if you move lots of data.

My only real problem is that 10+ years ago we started out with thousands of older B/G 802.11 networks in the 2.4 GHz band.  Now days, the 2.4 GHz band is saturated with customer owned home wireless Wi-Fi networks - which has resulted in the 2.4 GHz band becoming un-stable for Wi-Fi connections from my towers to the customer homes.  Within the last 2 years we have almost completed migrating most customers to fiber (fiber to the home) or to the 5Ghz bands using Mikrotik NV2 protocols.  With 5GHz Mikrotiks we offer account speeds up to 25 meg - and with fiber we offer speeds up to 1 Gig or faster (10-gig possible).

Ruckus is some good stuff if you want to follow industry compatible protocols where just about any Wi-Fi device can connect up.  One of my customers is an engineer/manager with Ruckus - and we had a good long talk about what I am doing and what Ruckus is doing.

North Idaho Tom Jones
 
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Re: Solving 20km wireless link issues

Sat Nov 12, 2016 6:24 am

Hi all, I felt the key issues here is the freshnel zone which would be better if you fully cleared them either by raising the height of either end points, a little bit higher such as 10-metre instead of 5-metre currently and that would improves your radio connectivity right away. Hope it helps.
 
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Re: Solving 20km wireless link issues

Thu Dec 08, 2016 11:33 am

That link looks normal to me without full line of sight I doubt you would do better. It's easy to get carried away with the fact that once the signal appeared to go to -60 in logs but that may have been an error or even that somebody setup a ap with same ssid and it had connected for a min giving false signal. I've only ever seen signals fluctuate like that over water naturally when it's very still but over land they don't normally.
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Re: Solving 20km wireless link issues

Wed Apr 26, 2017 1:53 pm

Woah, Nice one! Is it stable now enough? The distance is way too long.
 
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Re: Solving 20km wireless link issues

Thu Jun 15, 2017 11:37 am

Surely it is 20kms is a a lot i think.
 
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Re: Solving 20km wireless link issues

Thu Jun 15, 2017 1:55 pm

Indeed. These guys pulled hell of a job! good work guys!
 
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Re: Solving 20km wireless link issues

Tue Jun 27, 2017 8:48 pm

This is a very bold idea, I think you can do
 
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Re: Solving 20km wireless link issues

Mon Jul 17, 2017 9:05 am

From my point, signal strength has nothing to do with interference. I would like to suggest pigtail, fiber patch cable, and fiber optic transceiver for you! You can take 40G optical transceiver for a try! At present, there are many such optical transceivers on the market, such as 40G QSFP+ LR4, ER4 and R4...Using 40G-lr4 qsfp+, 40G-lr4l qsfp+ transceivers both can achieve that 20km network conectivity.

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