I have a tower with a UHF RX only antenna mounted about 10 ft away from a TDR Incadescent side beacon light on a rental tower
The issue anytime the beacon flashes it wipes out the signal coming into the UHF antenna
The tower owner has changed the bulbs with no help and TDR is saying they have nerver had a issue with incadescent bulbs interferring they make a rf filter for strobe but nothing for standard incasdesecnt
Anyone have any suggestions
This is used for a RX antenna for some remote Voter sites
What is odd is the South site isnt affected but the north site is
i can disable the beacon during its flash and the signal immedailtely clears up on the north site incoming signal keep that site keyed up turn the breaker back on and as soon as the bulb flashes the signal comes back
Tower lighting Issue
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celltech25
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Re: Tower lighting Issue
Does the lamp have some form of soft-start controller on it? Maybe that device has developed a fault?
This is my opinion, not Aeroflex's.
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I WILL NOT give you proprietary information. I make too much money to jeopardize my job.
I AM NOT the Service department: You want official info, manuals, service info, parts, calibration, etc., contact Aeroflex directly, please.
Re: Tower lighting Issue
What type of controller is being used to control the lights? If by some chance the lights are being controlled by an SCR type power device, there is the chance that it is generating hash. If so, then it is being carried up the tower by the electrical wiring. Might take some good ferrite cores to kill the noise.
Next question, is the power wiring in metal conduit or in an SO type service cord? The conduit is the correct way of doing it. If it's the SO type cord, I would say it needs to be replaced. Hopefully if it is SO type cord, the owner will understand the issues and replace it with metal conduit and run the wires inside of it.
Jim
Next question, is the power wiring in metal conduit or in an SO type service cord? The conduit is the correct way of doing it. If it's the SO type cord, I would say it needs to be replaced. Hopefully if it is SO type cord, the owner will understand the issues and replace it with metal conduit and run the wires inside of it.
Jim
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celltech25
- Posts: 509
- Joined: Fri Apr 29, 2005 3:54 am
Re: Tower lighting Issue
Will look into the type of cord not for sure I think its in conduit and the controller im unsure on
are you saying to put the ferrite cores on the power wire where it comes out of the controller to go up the tower
are you saying to put the ferrite cores on the power wire where it comes out of the controller to go up the tower
Jim202 wrote:What type of controller is being used to control the lights? If by some chance the lights are being controlled by an SCR type power device, there is the chance that it is generating hash. If so, then it is being carried up the tower by the electrical wiring. Might take some good ferrite cores to kill the noise.
Next question, is the power wiring in metal conduit or in an SO type service cord? The conduit is the correct way of doing it. If it's the SO type cord, I would say it needs to be replaced. Hopefully if it is SO type cord, the owner will understand the issues and replace it with metal conduit and run the wires inside of it.
Jim
Re: Tower lighting Issue
There is a chance that the controller is causing the noise problem. I would try taking a portable radio and run it close to the controller and wiring and see if the noise gets stronger. You might have to take the antenna off to reduce the sensitivity of the portable. If it seems to be the source, you can make sure by killing the power breaker feeding it. If it is alarmed, it will send an alarm that the power just went off, so check with the tower owner before killing the power.
If the control box is the source, the next step is to call the company that made it and see what they have to say about the noise. Let them do the legwork after you inform them of the problem.
If it isn't the control box for the tower lights, at least you have eliminated one potential source. My suggestion of the ferrite cores on the power wiring is only if you can be positive that that is where the source of the noise is from. But I would wait for the company that made the controller to give you some feedback first.
Jim
If the control box is the source, the next step is to call the company that made it and see what they have to say about the noise. Let them do the legwork after you inform them of the problem.
If it isn't the control box for the tower lights, at least you have eliminated one potential source. My suggestion of the ferrite cores on the power wiring is only if you can be positive that that is where the source of the noise is from. But I would wait for the company that made the controller to give you some feedback first.
Jim
celltech25 wrote:Will look into the type of cord not for sure I think its in conduit and the controller im unsure on
are you saying to put the ferrite cores on the power wire where it comes out of the controller to go up the tower
Jim202 wrote:What type of controller is being used to control the lights? If by some chance the lights are being controlled by an SCR type power device, there is the chance that it is generating hash. If so, then it is being carried up the tower by the electrical wiring. Might take some good ferrite cores to kill the noise.
Next question, is the power wiring in metal conduit or in an SO type service cord? The conduit is the correct way of doing it. If it's the SO type cord, I would say it needs to be replaced. Hopefully if it is SO type cord, the owner will understand the issues and replace it with metal conduit and run the wires inside of it.
Jim
Re: Tower lighting Issue
I would first identify the actual type of interference, as a beacon should not cause this much crap since it is a standard lamp, and not a strobe.
Strobe supplies are notorious for wideband noise. Does he interference simply cycle on and off, or does it remain constant, with additional noise upon lamp power cycling?
Steady noise might indicate a faulty power supply, and the additional noise comes from the drain(sag) on the supply as it powers the light.
This added drain can cause additional noise that can increase the transmitted noise that wipes out your RX radio.
The coupling by close proximity, and the potential of P.I.M caused by diode action from rusty tower connections(structural), might be an added contributor to your problem. I would also check out your RX radio's entire connections, look over grounding, power routing and tower grounds from the feedline straps bolted to the tower.
Never overlook a single item, any one or all can conribute to IMD products, but the beacon is probably the worst of the others.
As another pointed out, are all the beacon wires running inside conduit that is directly bolted to the tower(as they should be), or did they simply ty-wrap the wires to the tower and walk away? How about shielding of the OBL supply in the room?
Even a power supply, and especially, a strobe supply should be properly grounded and shielded to prevent interference inside the entire radio room.
Having your RX antenna so close to the beacon may also be a small part of the issue at hand. If possible, can you relocate to another level, or side of that tower?
Even a move such as this can be costly, and I don't take that choice with pleasure, but it may be the only way if you get no usable remedy to your problem.
In negotiations covering interference, all tower occupants need to chime in on this, as a single user can affect all the others, especially if a physical move is required.
I would suspect the power supply and wiring, with the wiring being the transmitting 'antenna' for that noise. Are there any decoupling caps anywhere on the strobe/beacon wires? What about ESD 'gap-caps', or Polyphasors?
Shorted gas discharge tubes can cause noise too. They no longer function, and are dead shorts to noise, allowing conduction.
Get help from the supply Mfr. first and see if they have any remedies you can put to use.
Strobe supplies are notorious for wideband noise. Does he interference simply cycle on and off, or does it remain constant, with additional noise upon lamp power cycling?
Steady noise might indicate a faulty power supply, and the additional noise comes from the drain(sag) on the supply as it powers the light.
This added drain can cause additional noise that can increase the transmitted noise that wipes out your RX radio.
The coupling by close proximity, and the potential of P.I.M caused by diode action from rusty tower connections(structural), might be an added contributor to your problem. I would also check out your RX radio's entire connections, look over grounding, power routing and tower grounds from the feedline straps bolted to the tower.
Never overlook a single item, any one or all can conribute to IMD products, but the beacon is probably the worst of the others.
As another pointed out, are all the beacon wires running inside conduit that is directly bolted to the tower(as they should be), or did they simply ty-wrap the wires to the tower and walk away? How about shielding of the OBL supply in the room?
Even a power supply, and especially, a strobe supply should be properly grounded and shielded to prevent interference inside the entire radio room.
Having your RX antenna so close to the beacon may also be a small part of the issue at hand. If possible, can you relocate to another level, or side of that tower?
Even a move such as this can be costly, and I don't take that choice with pleasure, but it may be the only way if you get no usable remedy to your problem.
In negotiations covering interference, all tower occupants need to chime in on this, as a single user can affect all the others, especially if a physical move is required.
I would suspect the power supply and wiring, with the wiring being the transmitting 'antenna' for that noise. Are there any decoupling caps anywhere on the strobe/beacon wires? What about ESD 'gap-caps', or Polyphasors?
Shorted gas discharge tubes can cause noise too. They no longer function, and are dead shorts to noise, allowing conduction.
Get help from the supply Mfr. first and see if they have any remedies you can put to use.
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celltech25
- Posts: 509
- Joined: Fri Apr 29, 2005 3:54 am
Re: Tower lighting Issue
Sorry Been Busy,
Its a incadescent tower light ran in conduit, the noise is only there when the light is lit, we have moved the RX antenna down the tower 50 ft below the light and its still there, Our next option is going to mount the RX antenna on the roof of the buidling and see if there is noise still present, I have changed rx radios, and RX frequency for testing and it doesnt amtter it effects that radio every time,
One odd thing is that this system has 4 remote rx sites and the light seems to only effect this one the others come in on the same antenna only diff is rx frequency and i dont notice it on the other 3 sites just this one
Its a incadescent tower light ran in conduit, the noise is only there when the light is lit, we have moved the RX antenna down the tower 50 ft below the light and its still there, Our next option is going to mount the RX antenna on the roof of the buidling and see if there is noise still present, I have changed rx radios, and RX frequency for testing and it doesnt amtter it effects that radio every time,
One odd thing is that this system has 4 remote rx sites and the light seems to only effect this one the others come in on the same antenna only diff is rx frequency and i dont notice it on the other 3 sites just this one