interference

[wrfc]

There's a new repeater 70 miles from my repeater in Kaufman on the same frequency .625 with the same pl tone 136.5 that ID's about every 10 minutes .

It interferes. with guys using my repeater and our Tuesday night net . Not sure what can be done about it if anything . My repeater has been up and running fine for the last four years with no problems what so ever till now .  I have tried to contact the owner WRBQ478 with no response .

Anybody got any ideas ?

[WRKC935]

So, he's 70 miles away, same freq and PL.  And somehow he's 'interfering' with your local users during their nets?

You're gonna need to explain the 'interfering' part a bit better.  Are they just hearing that repeater when yours is not transmitting or are you getting hetrodyne interference when both are transmitting or is he completely blanking your repeater from being received?  How far are your users from the repeater?  Are they closer to that repeater than yours?  I know this is a LOT of questions, but I need to know these things to actually tell you what can be done.  If he's being heard at 70 miles at all, he's obviously got a good bit of elevation on his repeater antenna.  What about yours?

What power level are you running, antenna height, antenna gain and coax type you are using.

Are HIS users bringing up your repeater at any point or are you just hearing his repeater in your operating area?

Is the interference consistent or only certain times of the day?  Some days and not others?

What sort of coverage footprint did you system have prior to that repeater going on the air.  Radius of 5 miles, 10 miles, 20 miles or greater?

At first look, it would seem that he's running a high gain antenna and a power level far exceeding the 50 watt limit we have with GMRS.  Or your system is under engineered and designed.  But my system talks and hears 60 miles and is only getting 12 watts out of the building after the losses in the transmit combiner. 

Receivers work on 'capture' so to speak.   A transmit signal need to be great enough to capture the receiver and hold the signal at a level high enough that other offending signals are NOT strong enough to interfere with that 'capture' and be heard over the other signal. This is regardless of the PL involved.  If your users are only hearing that repeater when your repeater is NOT transmitting, then it's really not 'interference' in the eyes of the FCC.  If his signal is overriding users within 5 miles of your site, and they are hearing that repeater over top your repeater, then that's considered interference. 

Some other questions. 

Is your repeater listed here or on any publicly searchable database?  Does it have a coverage map that is CORRECT?  If the answer no, then how would the other guy know that you were on the air, and if your coverage doesn't reach his site, then he would have zero idea that he was interfering at all. 

I am not trying to defend anyone here.  I am just looking for technical solutions to your issue.  But if you are running a 5 watt Retivis repeater on a 30 foot pole with a unity gain antenna.  The fix is different than if you have 400 feet of height on a db-420 (9dB gain) with 7/8 cable and running a 100 watt MTR repeater turned down to 50 watts.  And creating harmful interference to the Retivis is a bit easier than interfering with the MTR and 400 feet of height.

 

 

[WRKC935]

Wait.  I just looked up the call sign you posted.  He has a repeater listed IN Kaufman.  The PL isn't listed so I don't know if it matches what you have listed here.

That repeater is NOT 70 miles away from Kaufman, It's in Kaufman.  I don't see any other repeater in a 70 mile radius on 625, so I am gonna guess you aren't listed.

Gonna guess you don't have a lot of footprint either. 

Not sure what to tell you on this.  If he dropped a repeater in place on the freq you are using, running the PL YOU were using, and it has that sort of footprint I am seeing on the map on here.  I would turn your repeater off and start using his instead.  When he questions it, tell him you were there first and he started interfering and your just turned your stuff off.  But you were operating on the freq with that PL in that area before he showed up. 

He can like it or reprogram his equipment and change his PL. 

 

But I can't find your listing.  While there is no requirement to have your repeater listed.  If you don't list it, then no one else is gonna know it's there when they are in process of putting up other equipment on the frequency.

 

[MarkInTampa]

In doing a quick search it looks like the Canton 700 repeater that shows offline is at the same location and same owner as the Kaufman 625 repeater that is online. I'd assume he changed changed the frequency not to long ago for some reason. 

I did notice the repeater owner is also vice president of the Canton Area Radio Emergency Services (CARES) club that run a dozen or so ham repeaters and two GMRS repeaters in the area. Almost all of their repeaters use a PL of 136.5. I'd take a guess that the Kaufman 625 repeater is part of that group.