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Abdock
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Ethernet interference FM Tower

Sun Aug 26, 2012 9:24 am

Hello,

After giving up at one of the towers which had lots of FM and AM and also Television equipment we moved to another tower which only had 2 FM stations, well things were ok and then after a week same problem started to appear, on Ethernet side we cannot go above 10mb, we are using STP cables with metal RJ-45 connectors, and earth both points, any further help ? as in this area there are no other towers which do not have FM stations on them. I have tried ever possibility here but failed to get 100mbps on the link.

Thanks.
 
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Ethernet interference FM Tower

Sun Aug 26, 2012 9:57 am

You could always try using a fibre link up the tower and keeping the copper network cable as short as possible. If you are using PoE you will of course have to run a desperate power cable
 
Abdock
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Re: Ethernet interference FM Tower

Sun Aug 26, 2012 11:17 am

Thats the last thing I want to try is the keep the equipment box up, and see if that helps, I would need to run power cable up as equipment are PoE. Will try and keep UTP as short as possible, but has this helped ?

Thanks,
 
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Ethernet interference FM Tower

Sun Aug 26, 2012 11:46 am

I haven't had to do this as we don't put gear on towers with broadcast gear on them. One of my friends fixed the 10m problem with fibre - ran mains power up the tower and ran all the mast head equipment from a PoE switch using the ubiquity PoE converters.
 
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Re: Ethernet interference FM Tower

Sun Aug 26, 2012 2:26 pm

some people have had good results using FM chokes on the Ethernet cable. But generally FM + Ethernet = problems
 
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Re: Ethernet interference FM Tower

Sun Aug 26, 2012 2:33 pm

Thats the last thing I want to try is the keep the equipment box up, and see if that helps, I would need to run power cable up as equipment are PoE. Will try and keep UTP as short as possible, but has this helped ?

Thanks,
In theory this will solve the problem. Never done it so cant confirm. The problem is the frequency that ethernet cable runs at is almost the same as FM radio hence the noise injected into the cable doing the damage.
 
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Re: Ethernet interference FM Tower

Sun Aug 26, 2012 6:54 pm

I kept it last cause we had similar issue with other tower where we had equipment on top of tower and very short ethernet runs, and this problem surfaced, so we moved it down the tower and earthed all we could find, but the problem appeared with different radios, been fighting same issue with this tower again and again ! so we went with another less dense tower but again same story, so lets see if getting equipment up the tower can solve this one. thanks for input everyone. if i manage to solve i would report back here.
 
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Re: Ethernet interference FM Tower

Mon Aug 27, 2012 7:56 pm

you must be shure WHERE inteference enters in your router.
you have 4 options: ethernet cable, antenna, radio case, power supply.
to debug an installation you must measure all these channels, using a spectrum analyzer.
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Re: Ethernet interference FM Tower

Wed Aug 29, 2012 4:37 am

The advice about a spectrum analyzer is solid. If you're not that patient you might try putting ferrite toroids on every cable entering the router, including the power cord.
 
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Re: Ethernet interference FM Tower

Wed Aug 29, 2012 11:37 am

Hello,

..................on Ethernet side we cannot go above 10mb, we are using STP cables with metal RJ-45 connectors, and earth both points, any further help ?........................................

Thanks.
If i read this correctly you haver earthed both sides of the cat5/6 cables and would i be correct that the antenna is earthed on to the mast and the router is also earthed if this is done would it not create a earth loop, earthing should be to one point only (star earthing) i would suggest earthing only one end of the ethernet cable and not both end also maybe try if possible to remove the earthing on the antenna, I assume as this is a commercial mast there is a de-ioniser on the mast top.
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Re: Ethernet interference FM Tower

Wed Aug 29, 2012 2:51 pm

Hi,

In my experience no amount of earthing will completely stop the ingress of noise from a high power FM transmitter.

Also you must follow the advice of Roadie, Earthing both ends of your ethernet cable is very dangerous. If a potential difference occurs between both ends you can have a massive current flowing even to point of causing a fire.
 
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Re: Ethernet interference FM Tower

Wed Aug 29, 2012 2:57 pm

I remember reading a post somewhere, The person found that earthing the cable actually made matters worse. I cannot clarify this as never tried it.

I have some antennas on a FM mast and was able to attenuate the noise just enough by using the best quality CAT6 and earthing the cable only at the bottom end directly into the ground with its own independant stake. Also check your cable run. make sure there is good distance from it and any FM RF cable over its entire run. If the FM Rf cable is poor quality or damaged it can leak noise all over your cables
 
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Re: Ethernet interference FM Tower

Wed Aug 29, 2012 4:45 pm

Would fibre cable be more suitable for attenuating the noise than cat6, has anyone tried this?
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Re: Ethernet interference FM Tower

Wed Aug 29, 2012 5:33 pm

Fibre would most likely resolve the situation
 
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Re: Ethernet interference FM Tower

Thu Aug 30, 2012 12:52 am

Fibre would most likely resolve the situation
Can indoor fibre cable be used if inserted into plastic conduit and sealed weather proof from antenna to router switch,
How much does 30M or 50M cost.
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Re: Ethernet interference FM Tower

Thu Aug 30, 2012 9:03 am

Just spotted your post!

Disconnect earth to top end of STP cable.

And you cannot go above 10MB because of what?

Is it because you interfere with the FM services or are you saying that they are interfering with you?

Simon

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Abdock
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Re: Ethernet interference FM Tower

Thu Aug 30, 2012 9:14 am

Thanks a lot for all the responses, had been busy trying all methods to get away with noise, tried using non STP cables just to see if earthing made it worse, but we still see erros on ethernet side if we put any link above the 10mbps, the interference could be on device, wireless side, and cable. when the link is run at 10 it uses different freq and when run at 100 the frequency used is nearly to the FM one hence the interference, after doing lot of troubleshooting we found some radios worked better then other, the ones with metal cage then the ones with plastic, so we changed most of them to metal cases, and also the equipment box is metal and earthed, looks to be stable now, if the radios would support fiber i would change all to fiber ! and forget this problem :)

fiber is cheap you can use it on tower, and its durable too then ethernet cables, the only thing expensive is then to run DC up for the converters, and Radios, and splicing ! somebody asked running indoor fiber cable, its possible but jackets are not good for indoor cables, better to use armored, 50/30 meters don't cost much and splicing remains same, be careful with sharp turns and you are good for future.
 
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Ethernet interference FM Tower

Fri Aug 31, 2012 2:14 pm

Yes - I agree - RB411ah with a single SFP would be awesome
 
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Re: Ethernet interference FM Tower

Thu Oct 18, 2012 11:41 am

Thanks a lot for all the responses, had been busy trying all methods to get away with noise, tried using non STP cables just to see if earthing made it worse, but we still see erros on ethernet side if we put any link above the 10mbps, the interference could be on device, wireless side, and cable. when the link is run at 10 it uses different freq and when run at 100 the frequency used is nearly to the FM one hence the interference, after doing lot of troubleshooting we found some radios worked better then other, the ones with metal cage then the ones with plastic, so we changed most of them to metal cases, and also the equipment box is metal and earthed, looks to be stable now, if the radios would support fiber i would change all to fiber ! and forget this problem :)

fiber is cheap you can use it on tower, and its durable too then ethernet cables, the only thing expensive is then to run DC up for the converters, and Radios, and splicing ! somebody asked running indoor fiber cable, its possible but jackets are not good for indoor cables, better to use armored, 50/30 meters don't cost much and splicing remains same, be careful with sharp turns and you are good for future.
We can I get price for 30/50 meters of armored outdoor cable.
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Re: Ethernet interference FM Tower

Thu Feb 21, 2013 6:13 pm

Thanks a lot for all the responses, had been busy trying all methods to get away with noise, tried using non STP cables just to see if earthing made it worse, but we still see erros on ethernet side if we put any link above the 10mbps, the interference could be on device, wireless side, and cable. when the link is run at 10 it uses different freq and when run at 100 the frequency used is nearly to the FM one hence the interference, after doing lot of troubleshooting we found some radios worked better then other, the ones with metal cage then the ones with plastic, so we changed most of them to metal cases, and also the equipment box is metal and earthed, looks to be stable now, if the radios would support fiber i would change all to fiber ! and forget this problem :)

fiber is cheap you can use it on tower, and its durable too then ethernet cables, the only thing expensive is then to run DC up for the converters, and Radios, and splicing ! somebody asked running indoor fiber cable, its possible but jackets are not good for indoor cables, better to use armored, 50/30 meters don't cost much and splicing remains same, be careful with sharp turns and you are good for future.

Old topic but may help someone for keeping it alive.

You say about 10Mbps Ethernet connection between the upper box (link) and the router/swicther inside the building/container!

Well..........TRY to connect an OSBRIDGE Evolution 560 or similar to it and tell me IF you CAN at LEAST connect it at 10Mbps...... :lol:
NO f(l)ucken way man!......NOT EVEN connected!......We put another cable, we put the cable away from the other RF transmiting cables, we shield it, we un-shieled it, we grounded both ends, we grounded each end at a time, we had ~35m of cable and at the end we had ~5m (below the linkbox) by bringing AC close to it, we got a BIG NOTHING with the OSBRIGDE link......BULL shi(f)t!........ :shock:

I afterwards puted a Mikrotik one and BOOOOMMMM , 10MBps linkage locked.
After that, and a lot of experiments, I can now lock even at 1Gbps no matter what, with a LOT of hardware changings, which I will upload to this forum with photos anytime soon to help some guys out there.

Companies who build these things (Wi-Fi links) are NOT RF familiar (they don't care) and they can't encode/at least simulate somehow, what we RF guys encode on HIGH RF mountains with a LOT of FM radio stations, TV stations, and mobile stations/repeaters.
Last edited by hipro5 on Sat Feb 23, 2013 10:36 am, edited 1 time in total.
 
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Re: Ethernet interference FM Tower

Thu Feb 21, 2013 8:03 pm

That is good news you got it working, will wait for more information.
 
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Re: Ethernet interference FM Tower

Thu Feb 21, 2013 8:31 pm

Wait for more information too
 
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Re: Ethernet interference FM Tower

Tue Mar 05, 2013 7:15 pm

any update here ?
 
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Re: Ethernet interference FM Tower

Tue Mar 05, 2013 8:36 pm

why don't you just power up the gear, forget about passing data right now and try using a 100Mhz scope with current and voltage probes and look at what is on the:

1: ethernet shield
2: data pairs

If you think there are currents on the outer shield and I wouldn't recommend bonding the top to the tower,, then you could break up the current distributions on the cable by bonding the shield to the tower legs at IRREGULAR intervals.

What frequency are the FM transmitters?

Use a disc capacitor, short the 2 legs together with a pair of electronic cutters without actually cutting through them, use a GDO to measure the reasonant frequency of the shorted capacitor ( make sure its the same as the FM station)

Disconnect the shield from the ethernet cable at the base and insert the capacitor between shield and ground.

Is your ground really at ground,, RF ground or electric ground... You haven't got anything hanging a half wavelength above electric ground have you!!!!

Dont you know any good radio hams where you are who can help you out?
 
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Re: Ethernet interference FM Tower

Tue Mar 05, 2013 8:51 pm

why don't you just power up the gear, forget about passing data right now and try using a 100Mhz scope with current and voltage probes and look at what is on the:

1: ethernet shield
2: data pairs

If you think there are currents on the outer shield and I wouldn't recommend bonding the top to the tower,, then you could break up the current distributions on the cable by bonding the shield to the tower legs at IRREGULAR intervals.

What frequency are the FM transmitters?

Use a disc capacitor, short the 2 legs together with a pair of electronic cutters without actually cutting through them, use a GDO to measure the reasonant frequency of the shorted capacitor ( make sure its the same as the FM station)

Disconnect the shield from the ethernet cable at the base and insert the capacitor between shield and ground.

Is your ground really at ground,, RF ground or electric ground... You haven't got anything hanging a half wavelength above electric ground have you!!!!

Dont you know any good radio hams where you are who can help you out?
Excellent suggestion
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Re: Ethernet interference FM Tower

Tue Mar 05, 2013 9:22 pm

Opppsss.....I have forgoten you guys a bit due to work....sorry... :?

Now let's see some photos of some Mods (modifications) which MUST be made in case that we want to "lock" our ethernet at 100Mbps on HIGH RF mountains.

Take a GOOD LOOK at them.

Image

Image

Image

Image



..........and the below is the "cursed" OSBRiDGE EvolutioN 560 (OEM from JJPLUS company http://www.jjplus.com/?page_id=183 - http://www.jjplus.com/?page_id=356)one of the WORST links that I have ever worked with on HIGH RF mountains - NO grounded PCB AT ALL - :o( (good luck to anyone who tries one of these up there :lol: ).


Image

Image

Image

Image



Keep in mind to GROUND EVERYTHING in and out and use CAT-7 cable.
Good luck guys.
George.
 
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Re: Ethernet interference FM Tower

Tue Mar 05, 2013 9:34 pm

why don't you just power up the gear, forget about passing data right now and try using a 100Mhz scope with current and voltage probes and look at what is on the:
I only keep this phrase of yours. :)

Why don't you better ask first IF a 100Mhz scope with current and voltage probes WORKS up there?? :lol:
I'll upload you some photos from up there if you'd like to see how a scope looks like and what it "shows" on its screen WITHOUT plugging any probes in it. IF you plug its probes too, you're f(l)ucked).

I've seen the LEDS of the OSBRIDGE Evolution 560, LIGHT UP without even feeding it with voltage or plug the PoE ethernet in it :D
I've seen the ETHERNET's Leds (orange and green) BOTH LIGHT UP without even feeding it with voltage or plug the PoE ethernet in it
 
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Re: Ethernet interference FM Tower

Tue Mar 05, 2013 9:52 pm

Well I have worked on dozens of commercial radio sites, it used to be my occupation..

If your site is so badly engineered in the first place and you cannot use the most rudementary piece of test equipment, then you may as well give up.
 
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Re: Ethernet interference FM Tower

Tue Mar 05, 2013 10:08 pm


If your site is so badly engineered in the first place and you cannot use the most rudementary piece of test equipment, then you may as well give up.
Unfortunatelly here in Greece we have a LOT of so called "technical engineers" and our transmiting mountains are HORRIBLE as of RF flowing around here and there. (I'll upload you some pics one of these days that I'll go up there to see what I mean.)
I once, went to Germany on a "transmiting mountain" of them and I though that I was in a A Class hotel or something...NOT even dust in their transmiting rooms... :D
We, up there, have snakes, mouses, insects, etc., NOT ONLY in the containers BUT in the transmiters too (in the 19" boxes) :lol:
Out of 100 containers or so (it's like a small village up there) on one of our mountains, "clean" and well made containers are counted in ONE hand fingers.
 
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Re: Ethernet interference FM Tower

Tue Mar 05, 2013 10:31 pm

@hipro5
From the pictures the board is earthed to the alumimum inside plate via brass stand-offs and it looks like this plate is screwed onto the alumimum housing which will be earthed by the mounting clamps - earth loop if the ethernet cable is earthed on both ends?
I would have used nylon stand-off's or nylon isolators for this internal plate or maybe use a internal alumimum box for board + card ( allow vent holes) but ensuring it is not earthed to the enclosure?
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Re: Ethernet interference FM Tower

Tue Mar 05, 2013 10:48 pm

You have to ground EVERYTHING.
Thank God (for my situation), Mikrotik's routerboards are grounded through their pcb screewing holes (at least they use a "midle side layer" on their pcb that is "ground").
IF your tower is well grounded and the container is grounded on the SAME ground as the tower, you have nothing to fear about "differences" on grounding points up and down.
 
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Re: Ethernet interference FM Tower

Tue Mar 05, 2013 11:56 pm

You have to ground EVERYTHING.
Thank God (for my situation), Mikrotik's routerboards are grounded through their pcb screewing holes (at least they use a "midle side layer" on their pcb that is "ground").
IF your tower is well grounded and the container is grounded on the SAME ground as the tower, you have nothing to fear about "differences" on grounding points up and down.
I don't disagree with grounding but in the manner it's done, I would have one return path for ground to earth and not via Ethernet cable + mast or whatever route, there is another possible issue from the pictures which comes to mind and that is if using separate enclosure for boards + radio cards to antenna's is by using low loss RF link leads and these are 50ohm impedance plus the length of these leads could be close to full/half/quarter wavelength on 88-108Mhz and this is on RF side of radio cards is a situation i would avoid by using integrated antenna's.

88MHz= 3.41m /2 = 1.70m /4 = 0.8525m
108MHz= 2.78m /2 = 1.39m /4 = 0.695m
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Re: Ethernet interference FM Tower

Wed Mar 06, 2013 10:59 am

Seems like there are employment opportunities for us radio engineers in Greece eh n2roadie?

As an aside from my own EMC experiences, the PCB earth should go back to one earth point only to avoid circulating rf currents.
 
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Re: Ethernet interference FM Tower

Wed Mar 06, 2013 11:11 am

When we talk about RF, EVERYTHING must be grounded - Take for example an RF amplifier - every 1mm and less has ground points.
 
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Re: Ethernet interference FM Tower

Wed Mar 06, 2013 11:32 am

When we talk about RF, EVERYTHING must be grounded - Take for example an RF amplifier - every 1mm and less has ground points.
Correct but as mentioned it's the route and not routes the earth path has to ground that is important.
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Re: Ethernet interference FM Tower

Wed Mar 06, 2013 12:41 pm

You have to ground EVERYTHING.
Thank God (for my situation), Mikrotik's routerboards are grounded through their pcb screewing holes (at least they use a "midle side layer" on their pcb that is "ground").
IF your tower is well grounded and the container is grounded on the SAME ground as the tower, you have nothing to fear about "differences" on grounding points up and down.
I don't disagree with grounding but in the manner it's done, I would have one return path for ground to earth and not via Ethernet cable + mast or whatever route, there is another possible issue from the pictures which comes to mind and that is if using separate enclosure for boards + radio cards to antenna's is by using low loss RF link leads and these are 50ohm impedance plus the length of these leads could be close to full/half/quarter wavelength on 88-108Mhz and this is on RF side of radio cards is a situation i would avoid by using integrated antenna's.

88MHz= 3.41m /2 = 1.70m /4 = 0.8525m
108MHz= 2.78m /2 = 1.39m /4 = 0.695m
Not bad but let's start with some maths... :D
On 88MHz you wrote down that the cable lenth should be 0.852m.......OK.....Have you ADDed the velocity factor of the EXACT cable that you will use - for example one cable has to be cutted x 0.66, other x 0.80 and other x 0.88?
Your lenth at 88MHz - for example - is a THEORITICAL lenth "no losses lenth" with AIR dielectric, thus x 1.
In theory EVERYTHING is perfect but "up there" starts the difficulties.

For example.

I have TWO FM stations (plus a couple of TV stations) together on the SAME mast that I have the link, on 93,4MHz and on 104,1MHz.........How should I cut the l/2 or l/4 cables?....At what frequency?........Ooopppsss........I forgot to add that at Northeast and at 5m away from my mast, I have another 2 FM stations at 87,5MHz and at 99,2MHz......and - and at West and at 6m away from me there are another 2 FM stations at 95,2MHz and 107,2MHz.......ooopppssss and at east at 7m away from me there are another 2 of them at 96,8MHz and 102,1MHz...........and...........and............about 70 FM stastion on the mountain ALL over FM band, 40 TV stations ALL over UHF band(470 - 860MHz), Cell-phone companies with OVER 50 - 70 dishes tranmiting/receiving - and....and........ Please give me a solution........ j/k...... :D
Last edited by hipro5 on Wed Mar 06, 2013 12:46 pm, edited 1 time in total.
 
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Re: Ethernet interference FM Tower

Wed Mar 06, 2013 12:44 pm

As an aside from my own EMC experiences, the PCB earth should go back to one earth point only to avoid circulating rf currents.
Errrmmmm..........which screw should I GROUND M8, Only ONE and left all others with plastic washers?......j/k...... :D

Image
 
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Re: Ethernet interference FM Tower

Wed Mar 06, 2013 1:17 pm

Let me give you an example of what we're dealing with because one picture = a thousand words. :)

Image

Image

Image

Image



Image

Though you can't "see" the whole thing through these pictures - NOT even the 1/6th of it.
 
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Re: Ethernet interference FM Tower

Wed Mar 06, 2013 1:52 pm

...........................

Not bad but let's start with some maths... :D
On 88MHz you wrote down that the cable lenth should be 0.852m.......OK.....Have you ADDed the velocity factor of the EXACT cable that you will use - for example one cable has to be cutted x 0.66, other x 0.80 and other x 0.88?
Your lenth at 88MHz - for example - is a THEORITICAL lenth "no losses lenth" with AIR dielectric, thus x 1.
In theory EVERYTHING is perfect but "up there" starts the difficulties.

For example.

I have TWO FM stations (plus a couple of TV stations) together on the SAME mast that I have the link, on 93,4MHz and on 104,1MHz.........How should I cut the l/2 or l/4 cables?....At what frequency?........Ooopppsss........I forgot to add that at Northeast and at 5m away from my mast, I have another 2 FM stations at 87,5MHz and at 99,2MHz......and - and at West and at 6m away from me there are another 2 FM stations at 95,2MHz and 107,2MHz.......ooopppssss and at east at 7m away from me there are another 2 of them at 96,8MHz and 102,1MHz...........and...........and............about 70 FM stastion on the mountain ALL over FM band, 40 TV stations ALL over UHF band(470 - 860MHz), Cell-phone companies with OVER 50 - 70 dishes tranmiting/receiving - and....and........ Please give me a solution........ j/k...... :D
I said in my post I WOULD NOT use low loss cable (LR400 or whatever) by using integrated antennas which can hold board + Radio card then the pigtail can be very short and in actual fact most integrated antennas have space for a second internal enclosure could be used to provide additional RF shielding and allow some vent holes ,
My point was simple by using say LMR400 you could by its length be close to Full/half/quarter wavelength of FM frequencies and remembering it is also part of the tuned 50Ohm circuit for TX/RX radio card it could pick up interference unless you are lucky to happen to have this cable length to be the exact length for FM stubs and let us not forget the actual insertion loss ( I have recorded 5dBm loss on 1M – maybe bad LMR400 cable?)
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Re: Ethernet interference FM Tower

Wed Mar 06, 2013 4:26 pm

hipro5
Stop being annoying, if you already have the answers, why are you posting

http://www.learnemc.com/tutorials/Curre ... Paths.html

Go learn it, then you can tell those of us who have letters after our names and degrees etc, that we don't know what we are talking out!

When you have your post grad degree, come back again and we can argue more.
 
hipro5
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Re: Ethernet interference FM Tower

Wed Mar 06, 2013 5:03 pm

hipro5
Stop being annoying, if you already have the answers, why are you posting

http://www.learnemc.com/tutorials/Curre ... Paths.html

Go learn it, then you can tell those of us who have letters after our names and degrees etc, that we don't know what we are talking out!

When you have your post grad degree, come back again and we can argue more.
I'm not being annoying and I'm not posting for YOU (master) - I've got answers for myself BUT these guys in here which is called FORUMS, asked for advice/help - THIS is the reason that I'm posting - NOT for you or for anyone else with master degrees on their back 8) . I have degrees myself and you know till NOW at what they have helped me?.....To clean my butt after a good shi(f)t.... :)

I have encoded the SAME problem (have you???) with them, degrees DIDN'T helped me at all and trying to help as much as I can and help EACH OTHER finding a solution.
I think that this is PUBLIC FORUMS and on public forums everyone is trying to HELP EACH OTHER with FACTS and not with THEORIES and "degrees" with "letters after their names" .....Plus that we don't have to take them out and see who has it bigger (the degree :p ) :? - Don't you aggree?
 
n21roadie
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Re: Ethernet interference FM Tower

Fri Mar 08, 2013 10:25 pm

......

Why don't you better ask first IF a 100Mhz scope with current and voltage probes WORKS up there?? :lol:
I'll upload you some photos from up there if you'd like to see how a scope looks like and what it "shows" on its screen WITHOUT plugging any probes in it. IF you plug its probes too, you're f(l)ucked).
Can't wait to see the photo's of ".....scope looks like and what it "shows" on its screen WITHOUT plugging any probes in it...."
N21roadie,
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TomjNorthIdaho
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Re: Ethernet interference FM Tower

Sat Mar 09, 2013 12:59 am

I have some Mikrotiks next to some FM towers and something much much worse... I am also very near a 1,000,000 watt military/FAA radar system!
The building I am in has double metal doors and there is also a copper screen mesh on the walls inside the building.

Anyways - here is what I have had to do to get things working...

I run three cat6 shielded gelly filled ethernet cables up to the Mikrotik 433AH boards. I do not communicate to the Ether1 POE port - that will never work. I use ether2 and ether3 for all data over Ethernet.

I grounded everything everywhere - however on the Ethernet shield I only grounded the building side.

FYI - I even grounded the N connectors on both ends of my 3-foot long coax cables. You might even consider wrapping your coax in foil then wrapping some stranded copper wire around the foil on the coax and ground that also.

FYI - I am NOT using ethernet surge supressors. They only made things worse.

It works without any problems.

Prior to doing this - I worked for weeks to make it work and I could only get 10 meg half duplex when using the POE on ether1. Now I am running at 100 full on Ether2 and Ether3 and have almost no problems.
 
n21roadie
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Re: Ethernet interference FM Tower

Sat Mar 09, 2013 2:03 am

.......................
FYI - I even grounded the N connectors on both ends of my 3-foot long coax cables. You might even consider wrapping your coax in foil then wrapping some stranded copper wire around the foil on the coax and ground that also.
....................
Have you tried integrated antennas which will eliminate the 3 foot long coax cables?
N21roadie,
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TomjNorthIdaho
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Re: Ethernet interference FM Tower

Sat Mar 09, 2013 2:15 am

re: Have you tried integrated antennas which will eliminate the 3 foot long coax cables?

YES I tried integrated antenna/boards - I was not happy with them.

None of the plastic cases worked. Or the Mikrotik board would work but there was to much back-side noise on the antenna.

I needed 90 degree horizontal 2.4 Ghz sector antennas. I ended up using a Laird antenna which was inclosed in a thick aluminum case.
 
n21roadie
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Re: Ethernet interference FM Tower

Sat Mar 09, 2013 11:20 am

re: Have you tried integrated antennas which will eliminate the 3 foot long coax cables?

YES I tried integrated antenna/boards - I was not happy with them.

None of the plastic cases worked. Or the Mikrotik board would work but there was to much back-side noise on the antenna.

I needed 90 degree horizontal 2.4 Ghz sector antennas. I ended up using a Laird antenna which was inclosed in a thick aluminum case.
Careful selection of integrated antenna is important for rf screening
N21roadie,
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TomjNorthIdaho
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Re: Ethernet interference FM Tower

Sat Mar 09, 2013 3:03 pm

re: Careful selection of integrated antenna is important for rf screening

You are very correct - however I also know when a near-by one-million-watt phased array millitary radar pulses in your direction - that flying birds in the air explode, your digital wrist watch resets and your mikrotik takes a dump.

No matter how much you thought you knew about RF noise, you also have to use tricks like - positioning your cables, electronics and antenna on the tower in a manner that the tower also acts like a shield and blocks direct line of site from the radar dome.
 
hipro5
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Re: Ethernet interference FM Tower

Sat Mar 09, 2013 8:30 pm

re: Careful selection of integrated antenna is important for rf screening

You are very correct - however I also know when a near-by one-million-watt phased array millitary radar pulses in your direction - that flying birds in the air explode, your digital wrist watch resets and your mikrotik takes a dump.

No matter how much you thought you knew about RF noise, you also have to use tricks like - positioning your cables, electronics and antenna on the tower in a manner that the tower also acts like a shield and blocks direct line of site from the radar dome.
Here's a guy who totaly understand me..... :)
You just CAN'T "predict" RF - In EVERY place you go with different configuration, you HAVE to improvise as well - No?... :)
P.S. We also have a millitary radar up there in about ~200m far or so. :?
 
rodolfo
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Re: Ethernet interference FM Tower

Sun Apr 07, 2013 11:21 am

Could be better to isolate radio and antenna from the mast and provide a good earth for both of them ?
(indipendently from the problem of rain or ice)
rodolfo
IZ0UQV
 
hipro5
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Re: Ethernet interference FM Tower

Sun Apr 07, 2013 2:07 pm

@rodolfo: It doesn't matter were you will place them. I have tried everywere, here, there, a few meters around, in front, back, etc..
ONLY grounding EVERYTHING (antenna, motherboard to metalic chassis/box, inside the box manual made shield LAN pigtale with ground too, at the other end, ALSO ground the LAN cable to the chassis/box/router - grounded too, etc.)

I made the day before yesterday TWO links.
One 18km from town to the FIRST RF mountain and the other one, 25km from the FIRST RF mountain to the SECOND (even worse) RF mountain, with the way I describe and EVERYWERE I was locked BOOOM at 100Mbps (router's speed) - NO MORE RF problems encoded for this thing.
On the following days ,I'll write something like tutorial for this to help some guys "up there".

Here are some photos of the first mountain (Radomes haven't been placed yet because they were not ready - I'll place them on Thursday on the dishes).

FIRST link 18km from town to the FIRST RF mountain:

Image

Image

Image

Image


...........and THE BELOW is the DIRECTION I was obliged to link......NO other place on the container to place the dish.... The ARROW shows the other Radio down to the town :?

Image


..............and the below is the next link (link to link connected to a router/bridged RB750UP MODIFIED) to the SECOND RF mountain......

Image


AGAIN SECOND's link direction to other mountain 25km distance.
AGAIN the RED arrow shows EXACTLY the spot of the other Radio..... :?

Image

Image

Image

Image

Image

SECOND dish/Radio pointing to the SECOND mountain, has been place to other spot, which "shows" the other mountain a bit "easier" now (yesterday).

Problem with this guys, is that they DON'T let you place your links werever you want, they want you to place them werever they want.... :(

I did't take some photos of the other mountain to show you from were the signal passes through because it was night - next time I'll do - .......

FIRST LINK 18km has -55dB SIGNAL strenth and SECOND link 25km, has -61dB SIGNAL strenth.
BOTH links are "CUTTED DOWN" to 180Mbps/180Mbps (and all below) for Tx/Rx CCQ stability.
OVERAL ping 18km + 25km on NV2


Image
Last edited by hipro5 on Mon Apr 08, 2013 12:22 pm, edited 1 time in total.
 
hipro5
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Re: Ethernet interference FM Tower

Sun Apr 07, 2013 6:20 pm

Here are some "NOW measurements" of both of them:

Image

Image
 
hipro5
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Re: Ethernet interference FM Tower

Wed Apr 10, 2013 5:15 pm

.........and with FINAL alligments (moving ~4m away one dish from the other to avoid internal RF interfaces from one to other during both transmit/recieve).

Signal Strenth and QUALITY of the 18km Link.

Image


Bandwidth test Tx, Rx of 18km Link manual "Locked on 180Mbps/180Mbps" for HIGH CCQ.

Image

Image


Signal Strenth and QUALITY of the 25km Link.

Image


Bandwidth test Tx, Rx of 25km Link manual "Locked on 180Mbps/180Mbps" for HIGH CCQ.

Image

Image


OVERAL BANDWIDTH from 18km and 25km Links (side to side)

Image

Image

and both directions bandwidth test Rx and Tx.

Image


EVERYWERE LOCKED at 100Mbps Ethernet.

Isn't that a beauty or not?.... :D
 
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karina
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Re: Ethernet interference FM Tower

Wed Apr 10, 2013 5:48 pm

ay Mt is wonderfull Kit thats why I love it. I don't care what the UBNT boys say Mikrotik is truly the master of the wireless world. with so much tweakage available you can usually get a usable link in most scenarios when you know what you are doing.

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