Fiber optic interferance

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KB0VWG

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I work for a telephone company and I have fiber optic at my house and its on the outside wall of my shack and haven't noticed any interference. The battery backup is around the corner away from the shack as well so far haven't noticed a thing. Do you have a backup battery device hooked up to your fiber optic box? if you unplug it from the ac,. If you can also might try to unplug the fiber optic box from the battery backup device. But depends on your situation and setup. If you do have a battery backup unit unplugging it from the ac wont kill the fiber box. The battery backup power last about 10 hours but all installation are different and you might not have a device like that at all.
Michael
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mmckenna

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Fiber optic cable on its own will not radiate any noise as it's not metallic, unless it has a gopher shield or it's "siamese'd" with twisted pair.
The transceiver/router can certainly generate some noise, and the copper twisted pair/Cat5/6 cable can radiate that noise.
Best thing you can do is make sure the stuff that is supposed to be grounded is really grounded. I can't tell you how many times I find equipment at work that has a grounding lug that isn't utilized. Manufacturers don't put those on there for looks….
If your equipment doesn't have a grounding lug, then you need to start looking at other solutions. Shielded cable can be a good start, but you need to make sure at least one side of it is actually connected to ground.
The easier solutions include moving the equipment around. Putting space space between your equipment and antennas is your cheapest solution.

Unfortunately consumer grade equipment is made fast and cheap, and taking scanners and other receivers into consideration is rarely done. Part 15 rules that cover sort of stuff is very lax.
 

ampulman

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Fiber optic cable on its own will not radiate any noise as it's not metallic, unless it has a gopher shield or it's "siamese'd" with twisted pair.

Don't know if it will radiate, but Verizon installer stated that the underground FO cable (mine) includes a metal wire to enable detection if necessary. My cable runs into the house and connects to the EMTA.

Amp
 

jackj

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Almost all fiber cable has a metallic element in its construction. It is used to power regens, varmint shields and to transmit the locater signal. But your interference is probably coming from the electronics. It is digital with digital to analog converters and, as you know, digital electronics is known for generating noise.
 

mmckenna

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Almost all fiber cable has a metallic element in its construction. It is used to power regens, varmint shields and to transmit the locater signal. But your interference is probably coming from the electronics. It is digital with digital to analog converters and, as you know, digital electronics is known for generating noise.

Short residential runs shouldn't involve regens. Locater signals are way down in the long wave, in the tens or hundreds of kilohertz at the most. Gopher shields should be grounded on at least one end. I'm willing to bet a cold beer that it's going to be in the electronics somewhere in the house. For RF to radiate like that, it's either coming directly from the electronics, or it's being radiated by one of your copper cables. Consumer grade routers are known for RF noise. The fact that he's got (what sounds like) the guts in the basement, and he's on the 2nd floor, seems to suggest it's being radiated by the copper.
 

n5ims

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It's not the fiber optic cable that is causing any interference to your scanner since it doesn't operate on frequencies your scanner will pick up. What may be causing interference is the ONT (that box the fiber optic cable plugs into that converts the light to the electrical signals your phone, computer, and cable-tv boxes use. The ONT is known for having interference issues, but generally this is due to issues with your router (for internet) or coax distribution (for TV).

You may have some unternimated connections on the coax. You may have some damaged coax. You may have some old coax. You may have some old splitters or amps. You may have some connections that aren't correctly tightened. All can cause the Cable-TV signal to leak out of the feed and reach your scanner. Since the Cable-TV signals use a very wide path of frequencies, it's easy for your scanner to pick them up if there are issues with your installation.

There is a known issue with the Fios ONT that's too close to a "smart meter" where the signals from the electric meter causes interference with the ONT, causing pixilation on the TV and intermittent outages on the internet side. It is recommended that the ONT be mounted no closer than 18" away from the smart meter.

This thread also discusses interference issues folks that have Fios experienced. http://forums.radioreference.com/hf-mw-lw-general-discussion/270623-interference-verizon-fios.html
 
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