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Author Topic: Cell Phone Tower Antenna Interference  (Read 7896 times)

Shad Groverland

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Cell Phone Tower Antenna Interference
« on: May 22, 2017, 01:28:06 pm »

There seems to be very little information online about cell towers interfering with audio gear, but that is my issue.  The threads I have found are very old and basically conclude it is not possible. Yet my church has cell antennas mounted on the roof, roughly only 15 above our audio rack and there is a distinctly digital tapping sound (similar to morse code) bleeding into ALL of my audio gear at mostly 4k 6k and 8k. When I say all my audio gear, that means each unit alone, only connected to power with nothing else attached. My O2r96, RF mics Sennheiser and SHURE in the 500 and 600 range, Crest amps, CD player, everything.

I have tried ground isolation, power conditioning, better cabling, audio filters and on and on  and on. In my 30 years in audio I have never run into this or a hum/buzz I couldn't get rid of with the usual tricks. All the gear sounds clean in other locations, just not in that building.
I have started a complaint with the FCC but would love some advice if you all have some. It has been 3 years of troubleshooting with not much improvement. Thanks.

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Diogo Nunes Pereira

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Re: Cell Phone Tower Antenna Interference
« Reply #1 on: May 22, 2017, 01:42:54 pm »

There seems to be very little information online about cell towers interfering with audio gear, but that is my issue.  The threads I have found are very old and basically conclude it is not possible. Yet my church has cell antennas mounted on the roof, roughly only 15 above our audio rack and there is a distinctly digital tapping sound (similar to morse code) bleeding into ALL of my audio gear at mostly 4k 6k and 8k. When I say all my audio gear, that means each unit alone, only connected to power with nothing else attached. My O2r96, RF mics Sennheiser and SHURE in the 500 and 600 range, Crest amps, CD player, everything.

I have tried ground isolation, power conditioning, better cabling, audio filters and on and on  and on. In my 30 years in audio I have never run into this or a hum/buzz I couldn't get rid of with the usual tricks. All the gear sounds clean in other locations, just not in that building.
I have started a complaint with the FCC but would love some advice if you all have some. It has been 3 years of troubleshooting with not much improvement. Thanks.

Sent from my SPH-L520 using Tapatalk
Pertinent as your question may be you have to change your name to your real name (as per forum conditions) before anyone can help you with some real answers. D

Sent from my Xylophone using Tapatalk...

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Diogo Nunes Pereira
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Shad Groverland

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Re: Cell Phone Tower Antenna Interference
« Reply #2 on: May 22, 2017, 02:59:36 pm »

Pertinent as your question may be you have to change your name to your real name (as per forum conditions) before anyone can help you with some real answers. D

Sent from my Xylophone using Tapatalk...
Thank you for pointing that out, it was unintentional but corrected now.

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Jean-Pierre Coetzee

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Re: Cell Phone Tower Antenna Interference
« Reply #3 on: May 22, 2017, 03:06:28 pm »

Thank you for pointing that out, it was unintentional but corrected now.

Sent from my SPH-L520 using Tapatalk

Download Shure Wireless Workbench and ensure that your frequency co-ordination is correct. It could also honestly be that your RX units are being overdriven be an excessively amplified cellphone signal, this is the most likely cause.

Install a Faraday shield around your wireless RX units, that will get rid of your tapping sound but will likely also make them unusable. I think your only options here are to go wired or to install some sort of shield above your venue that is large enough to block the strong RF from the towers on your roof(if they are run by your venue I would conciser having the transmission power reduced).

Another option might be to up the TX power on your TX units(don't know if this is possible since you didn't give us any useful information such as model numbers) and attenuate your antennas.

EDIT:

Maybe directional antennas pointed straight down will do the trick but at most it's still a compromise and may give you issues, you would want to drop this in the wireless forum since there are some really intelligent people there that may for some reason not read this forum.

2nd EDIT:

Unless those towers are doing something illegal I doubt that you will get anywhere with the FCC since your gear is probably being used in the unlicensed band and has to accept any interference handed to it. This is purely caused by IM from the cell antennas.
« Last Edit: May 22, 2017, 03:12:16 pm by Jean-Pierre Coetzee »
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Keith Broughton

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Re: Cell Phone Tower Antenna Interference
« Reply #4 on: May 22, 2017, 03:25:02 pm »

Download Shure Wireless Workbench and ensure that your frequency co-ordination is correct. It could also honestly be that your RX units are being overdriven be an excessively amplified cellphone signal, this is the most likely cause.

Install a Faraday shield around your wireless RX units, that will get rid of your tapping sound but will likely also make them unusable. I think your only options here are to go wired or to install some sort of shield above your venue that is large enough to block the strong RF from the towers on your roof(if they are run by your venue I would conciser having the transmission power reduced).

Another option might be to up the TX power on your TX units(don't know if this is possible since you didn't give us any useful information such as model numbers) and attenuate your antennas.

EDIT:

Maybe directional antennas pointed straight down will do the trick but at most it's still a compromise and may give you issues, you would want to drop this in the wireless forum since there are some really intelligent people there that may for some reason not read this forum.

2nd EDIT:

Unless those towers are doing something illegal I doubt that you will get anywhere with the FCC since your gear is probably being used in the unlicensed band and has to accept any interference handed to it. This is purely caused by IM from the cell antennas.
From what I read, it's not the RF side of the mics that is the problem.
The noise is getting directly into all the gear.
OP...explain how you are testing to hear the noise.
Are you testing each piece of equipment disconnected from any other devices?
« Last Edit: May 22, 2017, 03:32:11 pm by Keith Broughton »
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Kevin Maxwell

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Re: Cell Phone Tower Antenna Interference
« Reply #5 on: May 22, 2017, 03:28:56 pm »

There seems to be very little information online about cell towers interfering with audio gear, but that is my issue.  The threads I have found are very old and basically conclude it is not possible. Yet my church has cell antennas mounted on the roof, roughly only 15 above our audio rack and there is a distinctly digital tapping sound (similar to morse code) bleeding into ALL of my audio gear at mostly 4k 6k and 8k. When I say all my audio gear, that means each unit alone, only connected to power with nothing else attached. My O2r96, RF mics Sennheiser and SHURE in the 500 and 600 range, Crest amps, CD player, everything.

I have tried ground isolation, power conditioning, better cabling, audio filters and on and on  and on. In my 30 years in audio I have never run into this or a hum/buzz I couldn't get rid of with the usual tricks. All the gear sounds clean in other locations, just not in that building.
I have started a complaint with the FCC but would love some advice if you all have some. It has been 3 years of troubleshooting with not much improvement. Thanks.

Sent from my SPH-L520 using Tapatalk

The cell phone company or whoever is overseeing this cell equipment is paying for the privilege of having this equipment in this location. Someone needs to look at that agreement that the church signed. There should be wording in there that they canít interfere with your equipment in your church. There should also be some contact information that the church has. Find all of that out and then you need to call them and have them come in and work with you to find the problem and a solution. 
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Shad Groverland

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Re: Cell Phone Tower Antenna Interference
« Reply #6 on: May 22, 2017, 03:31:50 pm »

Thank you Kevin for the suggestion, we don't own the building and are just renting space in it but your point is still valid and worth looking into with the building owner.

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Shad Groverland

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Re: Cell Phone Tower Antenna Interference
« Reply #7 on: May 22, 2017, 03:33:05 pm »

Download Shure Wireless Workbench and ensure that your frequency co-ordination is correct. It could also honestly be that your RX units are being overdriven be an excessively amplified cellphone signal, this is the most likely cause.

Install a Faraday shield around your wireless RX units, that will get rid of your tapping sound but will likely also make them unusable. I think your only options here are to go wired or to install some sort of shield above your venue that is large enough to block the strong RF from the towers on your roof(if they are run by your venue I would conciser having the transmission power reduced).

Another option might be to up the TX power on your TX units(don't know if this is possible since you didn't give us any useful information such as model numbers) and attenuate your antennas.

EDIT:

Maybe directional antennas pointed straight down will do the trick but at most it's still a compromise and may give you issues, you would want to drop this in the wireless forum since there are some really intelligent people there that may for some reason not read this forum.

2nd EDIT:

Unless those towers are doing something illegal I doubt that you will get anywhere with the FCC since your gear is probably being used in the unlicensed band and has to accept any interference handed to it. This is purely caused by IM from the cell antennas.
These are things I initially tried, but as Keith pointed out, it is not a strictly RF issue.

Sent from my SPH-L520 using Tapatalk

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Shad Groverland

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Re: Cell Phone Tower Antenna Interference
« Reply #8 on: May 22, 2017, 03:35:21 pm »

From what I read, it's not the RF side of the mics that is the problem.
The noise is getting directly into all the gear.
OP...explain how you are testing to hear the noise.
Are you testing each piece of equipment disconnected from any other devices?
Yes. Headphones straight into CD player, consol, RF receivers etc. Amps with no input connection and just a speaker connected... all scenarios have interference sound still there.

Sent from my SPH-L520 using Tapatalk

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Jean-Pierre Coetzee

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Re: Cell Phone Tower Antenna Interference
« Reply #9 on: May 22, 2017, 03:37:18 pm »

This does not address the fact that the noise is getting directly into equipment that is not related to RF mics.
I missed that one but it really could depending on what power level is coming off that tower.

It could honestly be induced onto the speaker cables coming from the amp or the XLR cables going to the amp (common mode rejection either works or it doesn't, if the noise is greater than the CMRR it will be there at full volume unattenuated)

What shielding is on your XLR cables, a proper braided shield or simply one of these wrap around kind of things or is it a foil shield with a drain wire.

Considering what you are describing the problem could even be on the actual system ground or being induced onto any ground cable. This might be a dangerous suggestion and don't try it if you feel unsafe and definitely don't keep it that way but lift the ground to each device individually and then all at once to see if it solves your problem, I re-iterate this is a testing measure and you should not leave it that way you simply want to find the problem.

Give us as much information as you have, what model and brand of mics, brand of mic cables, brand of connectors. Your using an 02r and I'm not sure how the RF isolation is on them, likewise with the crest amps.

If has happened a few times at our national broadcaster where a correctly wired XLR cable just so happens to have to exact correct characteristics to pickup a radio station being broadcasted there louder than the mic it is attached to, never underestimate the power of an RF signal.
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ProSoundWeb Community

Re: Cell Phone Tower Antenna Interference
¬ę Reply #9 on: May 22, 2017, 03:37:18 pm ¬Ľ


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