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Do you also have problems with interference between cards using RB433/433AH?

YES!
34 (74%)
no
12 (26%)
 
Total votes: 46
 
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rb433ah interference between mpci cards

Fri Mar 27, 2009 3:59 pm

Hi all.
I have a huge problem with rb433ah'a. I have bought several of them and unfortunately every one has got the same problem.
Configuration on every base station is the same.
Three mpci cards (cm9, cm10, sparklans, ub5 tested), every card working at 5Ghz 20Mhz band. Frequency gaps between evry card frequency are more than 40mhz.
hardware - aluminium sealed IP66 box, long - 30cm pigtails, andrew N clamp connectors, andrew cnt400 cables, at the ends grid antennas or sector antennas (good brand antennas)

Problem shows up while all three cards are enabled or transmitting as small bandwidth speed on links. The CCQ drops down to ~10% or even less.
When I enable nstreme protocol on one card - it works. Great nstreme :)
But when all cards have nstreme enabled, it is even worse than working without it. Long response times, even lower bandwidth speed on every card, lost of packages.

While tested every link separately (cards disabled or not inserted to rb) it works great.


I assume that the problem is connected with small space between cards/slots.
Does anyone have right solution to my problem? Do I have to shield additionally every card with copper or aluminium tapes/sheets?
 
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nest
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Re: rb433ah interference between mpci cards

Sat Mar 28, 2009 1:55 am

The cards are interfering with each other, directly from one PCB to the next. The shielding on each card and between the cards is not sufficient for operating all three on the same band. You would have to design your own earthed shielding, or better still, use a separate box for each card/RB pair. You could be able to possibly get away with two cards in one RB, but I have found you still will get degraded performance. It all depends on how much degrading of the signal your link can withstand.
Last edited by nest on Sat Mar 28, 2009 5:09 pm, edited 1 time in total.
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Re: rb433ah interference between mpci cards

Sat Mar 28, 2009 7:18 am

You basically need to run one card at 5200 MHz and the other card at 5800 MHz to get good results.
 
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Re: rb433ah interference between mpci cards

Sat Mar 28, 2009 8:20 am

Hi all.
I have a huge problem with rb433ah'a. I have bought several of them and unfortunately every one has got the same problem.
Configuration on every base station is the same.
Three mpci cards (cm9, cm10, sparklans, ub5 tested), every card working at 5Ghz 20Mhz band. Frequency gaps between evry card frequency are more than 40mhz.
hardware - aluminium sealed IP66 box, long - 30cm pigtails, andrew N clamp connectors, andrew cnt400 cables, at the ends grid antennas or sector antennas (good brand antennas)

Problem shows up while all three cards are enabled or transmitting as small bandwidth speed on links. The CCQ drops down to ~10% or even less.
When I enable nstreme protocol on one card - it works. Great nstreme :)
But when all cards have nstreme enabled, it is even worse than working without it. Long response times, even lower bandwidth speed on every card, lost of packages.

While tested every link separately (cards disabled or not inserted to rb) it works great.


I assume that the problem is connected with small space between cards/slots.
Does anyone have right solution to my problem? Do I have to shield additionally every card with copper or aluminium tapes/sheets?
Does it help to lower tx-power?
Have u tried to disable csma/cd?
Have u tried to shield the pigtails?

Stefan
 
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Re: rb433ah interference between mpci cards

Sat Mar 28, 2009 10:05 am

well, its always better a RB with single minipci slot i mean its always better to use 411AH instead of 433AH (exceptions may be there)
because of the following reasons:

1. if u are having only one 433ah and three mini pci crad then u must be using a single POE and adapotor and again only one Cat5 to the router box. if there is nay isue in both of them the entire RB will be like a dead body.. all the network behind it will get affected

2. may be sometime the combination of all three mini pci card on 433Ah show issues like hanging reebot of routerboard.

3. IF one card is damged or dead u hav to climb for it and bring the entire BOX down and then replace it with new one. till that time ur entire network would be agian down behind that RB433AH

so using 411Ah is better in place of 433Ah if there is no special compulsions.

hope this helps u..this is my personal opinion.
hav a great time.
 
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Re: rb433ah interference between mpci cards

Sat Mar 28, 2009 12:22 pm

Hi all.
I have a huge problem with rb433ah'a. I have bought several of them and unfortunately every one has got the same problem.
Configuration on every base station is the same.
Three mpci cards (cm9, cm10, sparklans, ub5 tested), every card working at 5Ghz 20Mhz band. Frequency gaps between evry card frequency are more than 40mhz.
hardware - aluminium sealed IP66 box, long - 30cm pigtails, andrew N clamp connectors, andrew cnt400 cables, at the ends grid antennas or sector antennas (good brand antennas)

Problem shows up while all three cards are enabled or transmitting as small bandwidth speed on links. The CCQ drops down to ~10% or even less.
When I enable nstreme protocol on one card - it works. Great nstreme :)
But when all cards have nstreme enabled, it is even worse than working without it. Long response times, even lower bandwidth speed on every card, lost of packages.

While tested every link separately (cards disabled or not inserted to rb) it works great.


I assume that the problem is connected with small space between cards/slots.
Does anyone have right solution to my problem? Do I have to shield additionally every card with copper or aluminium tapes/sheets?
What is the distance between your antennas?
 
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Re: rb433ah interference between mpci cards

Sat Mar 28, 2009 12:38 pm

well, its always better a RB with single minipci slot i mean its always better to use 411AH instead of 433AH (exceptions may be there)
because of the following reasons:

1. if u are having only one 433ah and three mini pci crad then u must be using a single POE and adapotor and again only one Cat5 to the router box. if there is nay isue in both of them the entire RB will be like a dead body.. all the network behind it will get affected

2. may be sometime the combination of all three mini pci card on 433Ah show issues like hanging reebot of routerboard.

3. IF one card is damged or dead u hav to climb for it and bring the entire BOX down and then replace it with new one. till that time ur entire network would be agian down behind that RB433AH

so using 411Ah is better in place of 433Ah if there is no special compulsions.

hope this helps u..this is my personal opinion.
hav a great time.
Problem is when your network grows. E.g. a site with uplink two connected towers and 3 sectors. If you cant plug more than one card per board you have a lot of boards and cableruns. Operating a wireless network I've learned to reduce equipment as far as possible. Each device has its lifetime and outages. More equipment=more alarms at night, more updates more work.
Stefan
 
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Re: rb433ah interference between mpci cards

Sat Mar 28, 2009 3:02 pm

Had a similar problem with high power mpci cards on rb433ah.
Ended up installing one rb433ah and two rb411ah in one box with metal plates seperating them.
Used one cat5 run. 24vdc 2A poe injector. Split the power at the box to power all three via dc jacks and plugged ethernet only into ether1 on the rb433ah.
Used short cat5 jumpers from each rb411ah to ether2 and ether3 on the rb433ah and bridged the ethernet ports on the rb433ah.
This was on a rooftop mounted box.
If it were on a tower, I think I'd run two more cat5 to each unit.
Aug
 
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Re: rb433ah interference between mpci cards

Sat Mar 28, 2009 4:09 pm

hi.
thanx for many suggestions.

But ... I make my living from wireless networks for some years. What all of you had written is not the problem (or it was checked and marked out in first place).
Using separate boards is an idea, byt the 433 target is totally burned.
When there is any hardware with "possibilities" such as operating 3 mpci cards at once it should work. Nobody said that the 433 series can't operate all cards at the same band.

the concept of setting 2 cards at 5180 and 5700 gives some quality back.. but not the same as used in previous versions of multi mpci rb's. And still only 2 cards working right. so the $ given for hi performance 3mpci board is wasted ...

alu box, grounded.. so there can't be doubt that reason is inside the box. (of course the rb is also grounded)
antennas at same mast - 3 antennas at 2m length. grid and sector types, so there is no back lobs.

now running 2 UB5 cards (as U know, they have shielding all over the surface) and one CM10 cards.
Tx powers @ default, all running 36-54mbits so the lowest power from defaults table ~15-18db

pigtails are made from rg-178 cable, so it is capable of transmitting well over 6ghz. shielding the cables? haven't tried..

I'll try with self made shields between cards... if there won't be any improvement gonna sell this $hity boards and replace with multi card PC's.


These boards were stored as backup hardware... because once we have tried to use them in config of replacing the big station - 6 cards.
They where tested in steel box. grounded. two rb433ah side by side, all slots used.... the result? we have removed them faster than lightning... nothing could compare to earlier PC base station....


Anyone has got working station similar to my config?
Maybe there are some mpci cards that have got "ideal" shielding?
 
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Re: rb433ah interference between mpci cards

Thu Apr 02, 2009 4:03 pm

Vspace,

This may not appear like what you have over there bcos I am not into WISP.

I have a box containing RB433AH. It has 3 R52 mpci, 3 pigtail and 3 secor antennas. This is my base radio and it operates on 5GHz freq spectrum.

AIM:
Backhaul link to 3 nodes in about 1km distance from the base to forward video traffic from those nodes.

Each node has a crossroad as an AP for 4 802.11b/g compliant wireless cameras. Also at each node, I have one RB433AH with one R52 mpci in an integrated antenna. What a performance!!!!

Though the installation is just about 2 weeks now, I have not noticed any interference. I hope I am not off topic?

Thank you
Best Regards,
Oladipupo Salako
Double D Communications Engineering Services,
Lagos, Nigeria.
 
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Re: rb433ah interference between mpci cards

Thu Apr 02, 2009 4:54 pm

I wish the voting button came with comments box.
I've only experienced interference with the 433's using high power ubiquity cards. The ones with R52H's work fine for me.
Aug
 
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Re: rb433ah interference between mpci cards

Fri Apr 24, 2009 5:06 pm

I've seen some receiving issues on one of my main towers. We upgraded to the 433 boards. One AP has 1 XR2 card in it and the other has 2 XR2's in it. Each card going to a 120 degree sector. Both APs appear to be having receive issues to some customers and some are fine. Some that are having this issue have good signals. Has it been determined there is a problem with the 433 board and if so is there a fix being worked on for it?
 
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Re: rb433ah interference between mpci cards

Fri Apr 24, 2009 7:44 pm

I have 2 cards CM9+R5H on 5570 and 5800Mhz...no problems.
 
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Re: rb433ah interference between mpci cards

Fri Apr 24, 2009 10:59 pm

I have same problems. you can find on this forum several my posts about this issue. I allso notice that more people are having the same problems. I just don't understand why are mikrotik stuff ignoring this problem.
 
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Re: rb433ah interference between mpci cards

Mon Apr 27, 2009 12:13 pm

I have same problems. you can find on this forum several my posts about this issue. I allso notice that more people are having the same problems. I just don't understand why are mikrotik stuff ignoring this problem.
Ignoring what exactly? What problem do you have, you have not written
No answer to your question? How to write posts
 
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Re: rb433ah interference between mpci cards

Mon Apr 27, 2009 1:36 pm

It may be interference between antennas not between cards...
 
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Re: rb433ah interference between mpci cards

Mon Apr 27, 2009 4:42 pm

Ignoring what exactly? What problem do you have, you have not written
I can not find right now a themes on the forum. There's 5-6 of them.It's about interferences between the cards as already stated.
Here's example: a RB 433 with two mini PCI (CM9), so two links in direction of 2 towns. One card on 5240, the second on 5560, Neither one of them does not work ok until one of them is disabled. So when both cards are enabled ping is 20-40 ms and max troughput per link is 2 Mbit.
when I disable any of these two interfaces, ping on the one which is enabled goes to 1 ms and troughput to 30 Mbit. These problems I had at a few locations. I solved some of them by replacing the rb433 with alix. Only to note that there is no interferences from other links, Thre's also another link to the 5800 which was Backhaul in second RB.

If someone from mikrotik staff want me to give them access to routerboard with that problem, I can do that. Just let me know.


similar topics:
http://forum.mikrotik.com/viewtopic.php?f=7&t=29872
http://forum.mikrotik.com/viewtopic.php ... le#p147995

It may be interference between antennas not between cards...
No,there's no interferences between the antennas, because previously the rb133 was working there and everything was ok!!!
 
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Re: rb433ah interference between mpci cards

Mon Apr 27, 2009 6:36 pm

here's two screenshot that you can see what's this about.

wlan1 ENABLE
wlan2 ENABLE

Image


wlan1 DISABLE
wlan2 ENABLE

Image
 
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Re: rb433ah interference between mpci cards

Mon Apr 27, 2009 9:03 pm

I agree that something has to be going on with the 433 board an these ubiquity cards. Like I said earlier. I have 3 sectors 2 are on 1 AP and 1 is on another AP. I having this problem even on the one with just 1 ubiquity card in it and was not seeing this issue untill the board was upgraded from a 532 board to a 433 board.
 
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Re: rb433ah interference between mpci cards

Tue Apr 28, 2009 6:13 am

I have two XR5 on a RB532 running for a few months with no problem.

I also have on 433 one XR5 and one XR2 with no problems

I have two XR5 testing on Alix right now. They are side by side on this board.
 
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Re: rb433ah interference between mpci cards

Thu Aug 13, 2009 12:38 am

I have THE SAME problem, but with two cards at 2.4Ghz. If I disable a card, the other one works fine!
 
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Re: rb433ah interference between mpci cards

Wed Dec 23, 2009 10:59 pm

Same problem here, a lot of people have this problem. The only thing I know is to use xr cards(they dont have this issue). It is sad that mikrotik is not take care of his customers(support their needs) and a lot of imporant problems stays unsolved. And I think that we should get here explanation how to solve it, what is the problem, what cards are witnesses of these problems. I had rb532 no problems, after changing for 433 big problems. I dont say that it is bad router, but how was said, it is for 3 cards so it should work(and there is not so much minipci wifi cards in market). Alix boards are great, but are more expensive, but next time there are my only choice. I would rather pay 30euros more for something what is totaly stable like something problemous.
 
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Re: rb433ah interference between mpci cards

Wed Dec 23, 2009 11:25 pm

I'm running a 433AH with a R52h and a Kingston 1000mw radio next to each other (due to the heat sink of the kingston it has to go on the topmost miniPCI slot and the R52h on the lowest). I'm running a 1km back haul on the R52h non-line of sight with about 20 trees in the way, whilst the signal strength is low because of the trees I'm not getting interference on this. Both are running on the 2.4ghz without a massive spread in channels!

Just thought I'd add my thumbs up, whilst I appreciate it doesn't help anyone in this specific setting.
 
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Re: rb433ah interference between mpci cards

Thu Dec 24, 2009 9:39 am

I have been dealing with this issue lately as well. I wanted to use on RB600A w/ 3 XR5s on a daughter board. Running the XR5s in the same box creates large issues. Each card can "see" the other card w/ -40 to -50 signal strength. Not good. Ended up separating to 1:1 ratio of XR5 to Routerboard and the problem was greatly reduced (though not eliminated.)

Seems to be very difficult to run high power cards @ similar frequencies side by side.
Amateurs built the Ark.
Professionals built the Titanic.
 
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Re: rb433ah interference between mpci cards

Thu Dec 24, 2009 11:54 am

but it is problem mainly of low power cards. Why this problem is not in alix, rb532a? just in new mikrotik boards
 
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Re: rb433ah interference between mpci cards

Thu Dec 24, 2009 6:16 pm

I had the problem initially because the cards are so close that they touch - heat transference! The the slots need to spaced further apart.

I used tooth picks to seperate them and create an air space - I stopped having problems then.

Although if you run 3 UB cards (XR#) you need to boost the amps - to solve this I ran electric to the top of all my towers and grounded and plugged directly - no POE.

Rod

PS - I still need to know what replaces nStreme in v4.4 for all my BH - I caint upgrade beyond v3.30 without loosing all connections - anybody want to start a new thread?
 
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Re: rb433ah interference between mpci cards

Wed Jan 06, 2010 2:10 am

I think this problem is best explained as poor design in the RB433. Many people didn't have such problems with RB532 because one card on each side and they were not directly behind each other. With RB433, cards are stacked VERY VERY close and this increases chance for interference.

I still maintain that the RB532 was the best designed MT board. It may not have had the fast CPUs that the newer boards have, but I feel that the RB532 had the best form factor, best power options, best reliability and best physical design layout. I was extremely disappointed when it was discontinued.
 
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Re: rb433ah interference between mpci cards

Thu Jan 07, 2010 8:32 pm

iam also having this problem... with 2 xr5 cards in rb433ah units and plenty of power. The cards only fit in the 1st and 3rd slots since they are thick. As soon as both cards associate the other will drop to about half speed. When you force one registration off the speed picks back up after about 4-5 seconds and then will drop again as soon as you let it reconnect.

I have 2 of these on the way to test to see if it helps to move one card away from the other:
http://www.adexelec.com/pci32.htm#MPCIFLEX

Sam
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Re: rb433ah interference between mpci cards

Thu Jan 07, 2010 8:43 pm

Also make sure you are running at _least_ 80Mhz of channel separation for running cards in the same board. I find that adjacent channels don't work at all, and one or two channels away still gets some interference depending on the transceivers.
 
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Re: rb433ah interference between mpci cards

Thu Jan 07, 2010 8:54 pm

one at 5200 and the other at 5850 or so. should be plenty of separation. after a little experimenting it seems like if i turn off nstreme it works better, and possibly rolling back to 3.30 fixes that. i will do more testing and post later.
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Re: rb433ah interference between mpci cards

Fri Jan 08, 2010 1:44 am

It may be interference between antennas not between cards...
No,there's no interferences between the antennas, because previously the rb133 was working there and everything was ok!!!
We have same experience - rb433ah interference between mpci cards.
But no in RB600 with 2 XR5 cards.
 
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Re: rb433ah interference between mpci cards

Wed Jan 13, 2010 7:55 pm

i have in hand two of these:

http://www.adexelec.com/pci32.htm#MPCIFLEX
Image

I don't have a quick way to test the theory of moving the radios further apart, but am willing to ship these to someone who can test them. If you are interested, and are in the USA, email me sales at changeip.com and I will mail them to you to test. I would hope you could test and send them back within a week so I can decide if I should return them (evals) or buy a bunch at a discount.

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Re: rb433ah interference between mpci cards

Thu Jan 28, 2010 8:59 am

okay everyone, here is a flash video of this as its happening.

http://h1x.com/jing/dualcards.swf

here is the setup:

rb433ah's
3.30 w/ dual xr5 cards.
32db dual polarity pacwireless hdd5w dishes
nstreme on each wlan individually
pacwireless 24i PoE

I just have the btest going between two identical routers on a 22km link. I am somewhat amazed I am getting 50+ mbps thru a single radio : )

I can kind of understand interference ... but in this video why would disassociating the remote side fix the issue? The second card / AP is still transmitting. I can even run an align / scan and it doesnt happen, but the 2nd radio is still transmitting correct? Are we sure this isn't some other problem? Please take the time to watch the video and help us all figure this out.
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Re: rb433ah interference between mpci cards

Thu Jan 28, 2010 7:18 pm

Looks like CSMA in action to me.
 
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Re: rb433ah interference between mpci cards

Thu Jan 28, 2010 8:03 pm

im still learning here ... should I try turning on and off the CSMA setting?

I tried 'disable CSMA' on the nstreme tab on one and the other and then both and it didn't change the outcome.
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Re: rb433ah interference between mpci cards

Thu Jan 28, 2010 8:26 pm

Then it probably wasn't CSMA.

Maybe just having the carrier active increases your BER, thus reducing the modulation rates (which is in turn reducing your TCP throughput).
 
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Re: rb433ah interference between mpci cards

Fri Jan 29, 2010 12:26 pm

I think everyone makes some valid points especially nest & valnet. Also someone is using a R52 and 1000mW kingston, very interesting. The point is with 2 Hi-Power card such as XR5, Kingston, F50-PRO stacked on top of each other, you will get inteference. The best analogy I could think of is putting 2 cell phones on top of each other and expecting great reception versus pointing in different directions or side by side.

Of course, you might get it to work with no problems at different frequencies, and other ways, my opinion is the rb532 was better because of the separation of cards.

For example, If you put a R52H or R5H or cm9 with XR5 or F50-PRO, you shouldn't have any problems....cause one is 350mW or less and one is is 5-600mW. Yes the R52H is called high powered, but the actual mW is only 350mW.

Looking at an analyzer, 1dB to 5dB is huge. That's 5 times the power! 1dB to 2dB is same, that's 2x the power, directly on top of each other.

I'll do some tests more in depth tests if people want.
 
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Re: rb433ah interference between mpci cards

Fri Jan 29, 2010 7:03 pm

I guess I have to test that theory by using those minipci flex extenders... i will install one on each side to move one of the XR5 cards to the other side of the case and see what happens.
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Re: rb433ah interference between mpci cards

Fri Jan 29, 2010 7:37 pm


Looking at an analyzer, 1dB to 5dB is huge. That's 5 times the power! 1dB to 2dB is same, that's 2x the power, directly on top of each other.

I'll do some tests more in depth tests if people want.
1dB to 2dB is 1.23x the power. 1 to 5dB is 2.46x the power. Decibel is logarithmic.
 
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Re: rb433ah interference between mpci cards

Sat Jan 30, 2010 7:16 am

Yes, I stand corrected. I probably shouldn't have described it in that fashion. Obviously, 400mW at 26dBm to 800dBm 27dBm is double based on mW. Yes, it's logarithmic in terms of actual power.

I was thinking and describing in a more linear fashion for easier understanding, but...I shouldn't and I'll more careful next time.
 
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Re: rb433ah interference between mpci cards

Tue Feb 02, 2010 10:36 pm

I have had similar issues with poor quality components, other than that radios and boards, such as pigtails specifically. Normally, when I have these issues, it is from working on someone else's equipment. I've ran 4 xr5s on a single 600, as well as 3 on a 433ah with no issues.

I've even posted in the forums before regarding running 2 radios on the same frequency, on the same 433ah. http://forum.mikrotik.com/viewtopic.php?f=7&t=36230

I hadn't noted a response to a question on antenna spacing, could you answer that question?
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Re: rb433ah interference between mpci cards

Tue Feb 02, 2010 10:37 pm

in my case it's a dual polarity 32db pacwireless dish on each end.

you can only fit 2 xr5s into the rb433ah, there isnt enough room for 3...
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Re: rb433ah interference between mpci cards

Tue Feb 02, 2010 10:52 pm

in my case it's a dual polarity 32db pacwireless dish on each end.

you can only fit 2 xr5s into the rb433ah, there isnt enough room for 3...
We use a flexible extender when we have 3 in a single box. http://www.adexelec.com/pci32.htm and look for the flexible MPCI-FLEX towards the bottom.
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Re: rb433ah interference between mpci cards

Wed Feb 03, 2010 12:49 pm

Yeah, we bought 2 of the MPCI-FLEX from http://www.adexelec.com as well, and then realized that they overcharged us when it's almost half the price here in Taiwan :P. I admit, it's not the easiest thing to find, probably why adexelec charges so much.

In any case, the MPCI-FLEX type extender is convenient
 
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Re: rb433ah interference between mpci cards

Tue Apr 13, 2010 9:28 am

okay just an update on this. maybe i have defective rb433 boards or something.

been running with the second xr5 card disabled on a dual polarity setup. anytime both xr5 cards are used bandwidth drops in half. i have tried adding those mini pci flex cables to both sides, no difference. tonight i just placed the dual radios into nstreme dual mode. linked up, but same issue, half the bandwidth of a single link.

i dont believe its interference, because the 'half the bandwidth' problem does happen if im using the other cards in active alignment mode. thats transmitting at full power correct?
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Re: rb433ah interference between mpci cards

Tue Apr 13, 2010 12:21 pm

You offered to do some more tests right.

What I suggest is to connect a length of leeky feedy to 2 RB units. Each end of Leeky feeder terminated into "PERFECT" 50 ohm loads.

Couple the 2 units together, being careful not to expose either radio card to levels in excess of -50dbm

Do the exact same of other router board setup.

Use frequencies suggested.

Run the same tests again.

Then replace pigtails with skinny feeder. Turn units off, replace one load with 3 x 50 ohm resistors in series.

Thus substituting load for a poor VSWR.. VSWR now = 3:1
Return loss high and reflected power around 25%.

Repeat test.

The test is trying to prove whether in circumstances of high VSWR. That the return currents and the phase differences are now finding inappropriate paths in the radio cards ground plane or the RB itself and especially whether the skinny type pigtails are re-radiating.

And whether the RF stage is intollerant and producing Harmonics when presented with poor VSWR.

Its the only conclusion that I can come up with, but no one has done any form of test like it yet as far as I am aware of.

At least if this test is done it could probably rule out this issue.
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Re: rb433ah interference between mpci cards

Tue Apr 13, 2010 10:33 pm

i can try someting like you mentioned. are you saying that the antenna and cabling themselves have bad vswr and therefore causing this problem?

I always come back to this - if I can run active alignment mode on the second cards, which is transmitting and receiving full power, why doesnt it affect the other card? Only when its associated...
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Re: rb433ah interference between mpci cards

Wed Apr 14, 2010 1:33 am

I've got R52H's in a 600, one on 5280 and one on 5825, both interfere horribly if the frequencies are closer, and both still are locked at 18mb to keep CCQ around 90%.

I've got a couple of 433's I'm working on with an R52 or R52H as the 5GHz backhaul, R52H as a 2.4GHz AP and an XR5 as a 5GHz AP (likely all to be swapped for N equip before I'm done).

The XR5 and R52 don't cause any drop in CCQ when on adjacent channels, though my signal is in the -60's on the R52 and -70's on the XR5. Both are using the same antenna as the tower with the RB600, Pac Wireless 5GHz grids, just in the testing case, no grid, just the feedhorn. In this case I did place the 2.4GHz AP card in between the XR5 and R52.

The XR5's see the R52's @ -40 or so, the R52's see the XR5 and each other in the -20s.
 
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Re: rb433ah interference between mpci cards

Wed Apr 14, 2010 2:17 pm

Hi Change IP

I dont know whether its VSWR related.

My experience used to be in the design of VHF and MF equipment. I have no practical experience in microwave design, however the theories remain the same whether its SW, MW UHF or Microwave.

I also don't have access to 10Ghz spectrum analyser, else I would already have done the test myself.

So without the aid of proper test gear I can only relate on past experiences in RF design.

It may be very inappropriate for me to suggest the following, but some manufacturers may have omitted some fundamental tests.

a: The performance of the RF stage when the power level is decreased considerably, eg: intermods, distortion, harmonics etc.
In RF stage design, the Impedance of the final devices are dependant on both drive level and current/voltage. So a card may behave as expected and in accordance to the original engineers design at say 26dBm, but things could go horribly wrong when the device is set at lower powers. (equally so at higher powers too). What is not known, is how the gain of the final stages are controlled. But in any case I would expect impedance changes throughout the final stages according to how the devices are driven.

Suffice to say that, usually the impedance looking into the port is around 50ohm and maintained that way in order to transfer maximum power. However, it is unlikely that the final amplifier stages are single ended. They are more likely to be a complex arrangement of push-pull or parallel devices in some form of substrate. What is not known is by how much these internal complex impedances change between stages as the power levels change.

Note that the transport concept has some form of feedback/control loop, self adjusting in order to meet the best CCQ. ie power levels change in accordance to throughput. Thus complex impedances are likely to change too.

So it is not that surprising that some folk are finding more stable throuputs and higher CCQ's when the levels are fixed... In other words some of the complex control/feedback mechanism has been disabled... And then I guess, the intermediate power amp stages within the RF amp are now more stable, since their interstage impedances are now stable.


2: What tests have the manufacturers done when the RF amp is subjected to impedances beyond 50ohm.

Its quite possible that the Rf amp in the card could produce spurious emission, harmonics and various nasties, that from a few metres away could be quite undetectable. But how many manufacturers designed the fundamental operations of the card based around the theory that 2 cards were going to be virtually plonked on top of one another enclosed within a metal case where circulating currents would bread!

Forcing a card to operate into anything else other than its design impedance of 50ohm would I am certain create higher than expected VSWR. Some of which is quite likely to find itself on the outer skin of the shield rather than on the inside surface area of the shield. If the RF currents are allowed to propagate on the outside skin of the shield, then who knows where they will end up.

The return VSWR will propagate back and forth and at varying phases. Adding and subtracting to power levels too.

So it may be a long shot! But its a simple enough test and I wouldnt mind betting that there may be more than one or two manufacturers out there who just didn't consider such implications as I bet most had visions of their cards being used on a 1 per board basis and certainly not stacked a few millimetres apart!

I know there are some other RF engineers out there, maybe they have some feedback on this, since I am an HF/VHF man and would naturally bow to the experiences of any microwave RF engineers on the forum.
 
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Re: rb433ah interference between mpci cards

Wed Apr 14, 2010 4:28 pm

Actually HF and UHF theory is not so far. Typically wireless card have baseband radio chip with software controlled exchangeable gain preamplifier and analog feed back input for wide band correction and additional two or three stage power amplifier. Circuit between baseband radio and PA most sensitive from external electromagnetic field. Other wireless card transmission can conducted to this circuit can be reason for output signal degradation. As higher power wireless card you have as higher signal degradation you acquire.
 
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Re: rb433ah interference between mpci cards

Thu Apr 15, 2010 1:26 am

Antenna placement matters here too. Make sure you don't have two antennas that are mounted so close together that their signals are bleeding into each other. If you have signal strengths that are insanely high (stronger than -40), we have found it can frequently be attributed to a combination of radios mounted close together in a board along with antennas that are mounted too close together. In these situations just moving the antennas farther apart from each other can be enough to improve the quality of a link to a point where it will function at the levels you need.
 
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Re: rb433ah interference between mpci cards

Thu Apr 15, 2010 1:29 am

what about a dual polarity antenna that you have no way to separate? With -20s since they are on the same antenna. is it just not feasable to use a HDDA-5W dish and expect them to not interefere with each other?
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Re: rb433ah interference between mpci cards

Fri Apr 23, 2010 9:03 am

I have a spectrum analyzer. I will be hooking it up to the antenna port on a stacked card in a RB433 to see what is visible between the two cards. I will upload pictures. I tested this once before and I can confirm there was significant bleed over.
 
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Re: rb433ah interference between mpci cards

Fri Apr 23, 2010 5:44 pm

check the following images - test done with one card transmitting into a dummy load and spectrum analyzer hooked up to the antenna port on the stacked card that is not transmitting.
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Re: rb433ah interference between mpci cards

Fri Apr 23, 2010 5:50 pm

Tests below are all 20mhz channels with different power settings. at full power 25db you could only run two cards if they were on on channels 5745 and 5825 and you woud "get by." Even then they are still seeing each other at -93 on the edges.
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Re: rb433ah interference between mpci cards

Fri Apr 23, 2010 5:54 pm

Now this is 10mhz channels. Now we are able to put two cards on top of each other with full power and not bleed over too much. You could run 3 non overlapping channels at full power 25db or use all 5 if you are running a lower power setting such as 15db.
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Re: rb433ah interference between mpci cards

Fri Apr 23, 2010 5:57 pm

Side by side comparision. I didn't have a RB600 laying around at the moment so i just put two RB433/333 beside each other and did the test again. Bleed over was almost completely gone. Very minimal bleed over at 25db power. If i dropped back to 20db power it was gone compleatly.
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Re: rb433ah interference between mpci cards

Fri Apr 23, 2010 6:32 pm

my problem is that even if i use 5200 and 5805 (600+ mhz separation) I still get half speed. I dont think its intereference really, i think its a software problem possibly. or a power problem on the minipci riser ... who knows.
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Re: rb433ah interference between mpci cards

Fri Apr 23, 2010 6:32 pm

ps - thank you for doing some testing and posting pics. thats how we will finally solve this.
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Re: rb433ah interference between mpci cards

Fri Apr 23, 2010 8:01 pm

Now try with High power cards, such as XR2s ;) And as well R52N.. I think the results would be interesting to see.

We always sell 1 radio card in one board on the same freq, we typically don't have much issue with putting a 5 gig and 2.4 gig card in the same box though.
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Re: rb433ah interference between mpci cards

Fri Apr 23, 2010 11:08 pm

wirelesswaves

I too am a ham and have run this RB433AH/2-XR5 config. Without spectrum analyzers, just intuition--and just plain old RF experience DXing and running VHF/UHF and above contest stations that have come in #1 or close to it (AA9D) I have come to some conclusions. I worried about the use of two high power, especially XR5's, cards in the same box before I even powered it up. It just felt wrong--and certainly doesnt work.

Some in this thread seem to want to squeeze more blood out of this rock than could possibly be available. I think many are trying to solve the wrong problem, my opinion only.

The first hint at what I am taking an educated guess on is IF connectivity. I had two XR3 cards connect on a 5GHz frequency, i.e. one not convertable to the offset 3.65GHz frequency. Seems like simple proximity allowed connectivity between the two cards. Who knows at what frequency? Dont even want to know. What would you possibly expect with two or more stacked cards? I too was contemplating putting in a 'ham engineered' shield of aluminum foil inside of the static bags that cards or boards come in. Seemed a little too rigged up before I proceeded. Of course that begs the question, why are there three mini-pci slots. Another topic all together.

However......I already had two XR5's in the top and bottom slot to separate them by a slot (wow). Trying to get something out of a config that was mounted in a place not readily accessible, AND, coincidentally I had the cards connected to a dual-pol Gabriel 2ft 'drum' dish I surmised that a workable config could be had. The cards have pretty good receive characteristics, and ample power for sure, and I if I operated with only one of them transmitting, maybe I had a chance. Two cards transmitting produced the expected results--de-reg, de-reg. Of course you know where I am going. Dual Nstreme with 220MHz separation actually worked--to a fashion. A short 7 mile link, more than 700ft off the ground at each end with nothing in between was able to connect.

Where is the catch? Band was pretty crowded, so results must be interpreted with a grain or more of salt. Attempting to config the correct polarity/frequency/direction combo is very critical in the ability to obtain reasonable bitrates and stability of the link of course. I was able to operate turbo in one direction (downstream the desirable direction if you can make it work), and 20MHz channel on the other. The isolated feedhorn collared dish provided excellent near field ingress from many other co-located APs. However, putting out copius power into the cross-pol feedhorn has the expected effect. Lowering power (1dBm increments) gave me the best possible compromise.......

Now, for the real world performance of this highly utilized backhaul. The more traffic either direction sustained, had a direct relation to the CCQ of the 'other' direction. CCQ of course is estimated by performance and jitter only, since it doesnt seem to be a metric available in dual-nstreme. This was expected, and could even make this config unusable, but I believe it provides some empirical evidence that multiple cards can be used in thee 433 class environment, with the caveat that you might not get maximum bitrate. However again[!], I was able to run the turbo channel at 54Mbps@2, with the cost of lowered stable bandwith in the other direction. With careful tuning of power and micro adjustment of channel (5MHz increments), a full-duplex, albeit asymmetric backhaul can be operated. Many times the asymmetry matches the real world bandwidth requirement.

The moral of this verbose ham-engineered story is that I got what I expected out of something that was deployed with a useless second card. As with DXing and contesting, it all seemed to be in the antenna guys. Put up 4-18el beams on 144MHz, and you know its going to burn through a lot more distance than the same EIRP obtained using a single 18el beam with 6dB more output power. Im sure that could be disputed. Thats why we used 4 different yagis on six meters. Some could hear a certain distant station, while other antennas could not hear a peep out of the same station....

Bottom line is that I believe IMHO that the wrong problem was attempting to be solved. For those that just want it to work with all three slots filled, eventually the stress will beat you.....BTW, an RB600 with two cards doing the same thing doesnt have these problems...Hmmm....Is there a significant null to the side of the cards that takes you below the threshold of pain?

Thats my story, and Im stickin to it...Hope this in some way helps someone leverage what they have invested and obtains the benefit of an asymmetric--and very fast (done properly) backhaul that leverages just the benefits and good characteristics of each component of the total link........If I missed something obvious, forum, or helped in any way, please advise...
 
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Re: rb433ah interference between mpci cards

Sat Apr 24, 2010 1:48 am

Hi Znet

To be sure it'll be us hams that cure the problem. I will read your post a few times more when I am less under the influence of Spanish liquer, but its a friday night and in this tiny village, 1 nights bar life is all I have to look forward to.



kblazk
Can you run the test again, with the 2 cards stacked on top of one another.
Can you put a Tee piece on the 50ohm port and insert 2 x 50 ohm loads to create a VSWR of 2:1.

kblack, you will need to give the card some gusto and get it to pass 20mbps to a neighbouring client unit ie bandwidth test.

Then can you somehow couple the analyser onto the pigtail of the second radio card or use an RF probe at the ground point of the antenna port.

I want to know what happens when the card is subject to VSWR. And its effects on the second card.

Are there any circulating RF currents on the outer of the sheath?

My gut feeling is that the cheap pigtails radiate when mismatched.

73's de Simon EA5/G0MGA
 
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Re: rb433ah interference between mpci cards

Sat Apr 24, 2010 1:50 am

kblazk

One more thing, current probe and voltage probe!!!!!
 
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Re: rb433ah interference between mpci cards

Sat Apr 24, 2010 1:58 am

kblazk

Just looked at your test again.. And not so sure I agree with your method.

I assume the card connected to the SA is disabled, but in this state what is Zsource? I do not have access to a circuit for the PA and I am not sure where the diversity switch is, are we sure that the pigtail to the SA is terminated under these conditions?

Or was the card enabled? and PA powered up?
 
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Re: rb433ah interference between mpci cards

Sat Apr 24, 2010 2:21 am

znet

Yes, I see where you are coming from, IMHO and going slightly of thread, there seems to be a gang of folk who are hell bent on trying to get 108Mbps throughput at any costs on a backhaul yet at the expense of quality, and at higher frame retries.

Yet with narrower bandwidths and hence increased SNR, quality improves and retries are less.

Why spend 20% of my day trying to figure out why I have 20% packet retries on my backhaul, reduce the bandwidth and enjoy the 20% wasted time with a paella and sangria.


My caveat, sometimes quality beats capacity, you are 5-9+20 old man, but can you repeat your callsign again :?
 
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Re: rb433ah interference between mpci cards

Tue Apr 27, 2010 8:57 pm

BTW, an RB600 with two cards doing the same thing doesnt have these problems...Hmmm....Is there a significant null to the side of the cards that takes you below the threshold of pain?
I've got 600's with the same problem. The setup I have that seems to work well is an XR5 and R52 or R52H combination. R52s or R52H's in the band cause problems, -20dB signal inside the box. XR5 with either card doesn't seem to have the same issue.

As long as my signal levels are in the low 70's or better, I've had good CCQ @ 54mb, even with R52H. Mid 70's or worse, then I have problems with two radios on the same band.
 
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Re: rb433ah interference between mpci cards

Wed Apr 28, 2010 12:20 am

Well at least we are getting somewhere. Maybe there is a problem when 2 of MT designed cards are connected on the same backplane.

Interesting that a Ubiquity mixed with an MT does not give issues. That is the first comment I have heard so far relating to mixed manufacturers on same backplane.

But I surely would like to know if the problem is related to radiated RF cos of a mismatch. At this point your feedback is great, but no doubt your antennas are perfectly matched.

WHAT HAPPENS WHEN ONE RADIO FACES A MISMATCHED LOAD.

Wish ZNET would confirm and further tests as there are very few of us with access or even own an SA at these frequencies.
 
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Re: rb433ah interference between mpci cards

Wed Apr 28, 2010 2:39 am

Well at least we are getting somewhere. Maybe there is a problem when 2 of MT designed cards are connected on the same backplane.

Interesting that a Ubiquity mixed with an MT does not give issues. That is the first comment I have heard so far relating to mixed manufacturers on same backplane.

But I surely would like to know if the problem is related to radiated RF cos of a mismatch. At this point your feedback is great, but no doubt your antennas are perfectly matched.

WHAT HAPPENS WHEN ONE RADIO FACES A MISMATCHED LOAD.

Wish ZNET would confirm and further tests as there are very few of us with access or even own an SA at these frequencies.
Do you want me to do the same test with two Ubiquity XR5's ???
 
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Re: rb433ah interference between mpci cards

Wed Apr 28, 2010 12:19 pm

Yeah, we bought 2 of the MPCI-FLEX from http://www.adexelec.com as well, and then realized that they overcharged us when it's almost half the price here in Taiwan :P. I admit, it's not the easiest thing to find, probably why adexelec charges so much.

In any case, the MPCI-FLEX type extender is convenient
Can you send me 10 of this to Spain at Taiwan cost? : D!
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Re: rb433ah interference between mpci cards

Fri May 21, 2010 5:11 am

okay, im following up to the original topic here. I previously had 2 XR5 cards in rb433ah boxes providing ptp backhaul about 22km. Anytime the second card associated I would get bad CCQ and bandwidth would drop in half or less. Originally I thought it was interference with multiple cards in the same box. Today I finally was able to test the second link with 2 additional rb411ah boxes. Completely separate routerboards enclosed in their own metal enclosures. The only thing being shared still is the HDDA-5W dual polarity dish, one radio link on vertical and the other on horizontal. End result, same result as before... if both are associated I get horrible CCQ and less than half the bandwidth. Even if the second link isn't doing anything but associated. So, my conclusion is that the HDDA-5W dish isn't usable - does this sound plausable?

For testing I had one radio at 5845 and the other at 5210. I figure thats plenty of separation. I moved the second radio from 5210 to a handful of other freqs and no noticeable changes. Does anyone have any other ideas? Even with nstreme2, one radio doing tx and the other doing rx I had the same problem.
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Re: rb433ah interference between mpci cards

Fri May 21, 2010 6:20 pm

So, my conclusion is that the HDDA-5W dish isn't usable - does this sound plausable?
Yes. There is a 32dB difference between the two polarities, but with 2 separate radio cards we have seen some interference issues between the two pols due to that not being enough separation. This isn't an issue on 802.11n 2x2 links due to the way the standard works, so you could go to a single 802.11n radio on each side using 2 antenna connections to resolve the issue. Another option is multiple single pol antennas with some vertical separation to help reduce the interference.
 
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Re: rb433ah interference between mpci cards

Sat May 22, 2010 1:39 am

You may have significantly better luck if you properly line the enclosures with Microwave absorber material.

hxxp://www.cumingmw.com/Product%20Applications ... ssion.html


My Appologies:
I did not read changeip's post about the seperate enclosures.
Perhaps someone else may benefit from this.
 
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Re: rb433ah interference between mpci cards

Sat May 22, 2010 4:54 am

If I perform a scan I see the other radio at -23db. One horizontal the other verticle. Is this a normal value when using a dual polarity dish?
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Re: rb433ah interference between mpci cards

Sat May 22, 2010 4:56 am

Another option is multiple single pol antennas with some vertical separation to help reduce the interference.
Is vertical separation better than horizontal?
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Re: rb433ah interference between mpci cards

Sat May 22, 2010 11:55 pm

By vertical seperation the assumption must be made that it is on a vertical structure ie. tower.
On building tops the option may be either vertical or horizontal.

Spacial diversity is the key.

Which is better is dependant upon the environment.
 
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Re: rb433ah interference between mpci cards

Thu Aug 05, 2010 5:08 pm

Definitely, according to the results of the spectrum analyzer, two high-powered cards in a rb433ah, overlap among themselves.
Solution db down at least tolerable?
Use rb433ah in two different bands 2.4 and 5.8 GHz. to avoid overlap?

kblazk thanks for your great contribution.!

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