Unknown interference?

[jrud03]

I recently hooked up my RS 2096 to a RS 20-176 antenna mounted to a 12ft steal pole on my roof. I am receiving incredible distance and great reception on conventional and digital freqs but for some reason my 800mhz trunking system which is 3 miles away I'm getting interference on those systems. The control channels tell me I'm receiving a 99% signal strength yet every so often I will get really bad interference.

It's not static but sounds like a possible power interference.
So I tried to resolve this by plugging my 2096 into a grounded power bar and unplugging different things in the room but it's still getting the interference. The interference isn't constant thing but happens periodically.

One thought is my grounding. I have the antenna grounded to a exhaust pipe on my roof my thought was that it was grounded but I wasn't sure.

Any advice would be helpful.

 

[N1BHH]

If it's a cast iron pipe, sometimes depending on construction, and reconstruction, it may not have a complete connection down the full length of DWV (drain, waste, vent) pipe. I would go check everything in your house first, throw breakers to isolate the source location. Maybe you have a loose connection somewhere. It could also be something at the trunking site. Do some more detective work, I'm sure you can find it.

 

[Ghost4658]

Have you tried the ATT on the trunking channels.
I have some 800Mhz trunk digital close to me and i have to use the ATT on them to make them work clear.

 

[zz0468]

A few possibilities... I've seen people call digital modulation "interference" when they had no clue what it is. Can you capture a recording and post it here? There's a lot of technical talent here, and someone may be able to identify the sound.

I've also seen plenty of real interference on 800 MHz, including sources like illegal import security cameras, frequency hopping SCADA devices, bi-directional amplifiers oscillating because of poor installation practices, and intermod, just to name a few. If it's a real signal out there, it's highly unlikely you'll be able to do anything about it without the ability to hunt it down, and the resources to actually get someone to fix it if necessary.

 

[kb2vxa]

When it comes to interference the possibilities are endless so the focus now becomes grounding. A vent pipe even if cast iron is anything but electrically continuous. There are no firm connections, only ends sitting in flanges with oakum stuffed in to make them airtight. If you want your antenna properly grounded run the standard copper (never aluminium) grounding wire and earthing rod.

Actually a vent pipe mount can be dangerous, I wouldn't want to be sitting on the toilet when the antenna takes a hit.