Pete, You are experiencing the old 3rd order intermod problem. squelling often is an intermod results...often feedback.
2 x 147.285 (Your output) - 146.685 = 147.885 (your input) The same at the other repeater: 2 x 146.685 -147.285 (Your output) = 146.085 (his input) The mix can be anywhere, even a rust spot on the tower. Do you and the other repeater have an isolator. The mix could be in your repeater PA and the isolator would keep the other repeater out. The mix could also be in your receiver. Never the less you have this mix problem coming from some where. A notch at 146.685 on your repeater MIGHT solve the problem. I would not rule out the mix not being in the other repeater. Again it can be at many places not in either of the repeaters. 73, ron, n9ee/r >From: Pete <[EMAIL PROTECTED]> >Date: 2008/07/06 Sun AM 11:23:08 EDT >To: Repeater-Builder@yahoogroups.com >Subject: [Repeater-Builder] Interference / Intermod ? > >Hello, Looking for some help or advice on a problem. > >I started get a "squealing" sound on my VHF repeater a while back. It >was not consistent so it was hard to try and track the source. Well I >found out a few days ago what the problem was. > >First let me fill you in on the Repeater. > >Motorola MSF5000 VHF @ 200 watts (its a 425 watt repeater) >TX/RX 4 can cavities (about 2 yrs old, bought tuned from TX/RX) >Cellwave StationMaster VHF Antenna @ 380' >Andrews 1-5/8" Hardline from the Duplexers to the Antenna > >Second Repeater (backup) > >Motorola MSR2000 VHF @ 107 watts >Wacom BpBr 4 can cavities > >Here's the issue. > >There is a new repeater, that came on the air, at the same time the >"squeal/intermod" came on my repeater. My repeater is on 147.285 with >a tone of 118.8. His repeater is on 146.685 (600khz lower then mine) >about 20 miles away. His TX antenna is up at 155' Every time his >repeater keys up, and mine keys up, the intermod noise is there, until >his repeater drops, then it goes away. At first I thought it was HIS >repeater causing the issue, which in a way it is, but I figured out it >is not entirely his fault. > >I tried the other repeater, with the TX/RX cavities, and it still did >the same thing. > >I tried the WACOM cavities on both repeaters, and still, the same issue. > >Now I can go outside the repeater site, in my car, and key up on >146.685mhz, and produce the same issue. > >I tried turning the power back to 100watts on the MSF5000, but still >have the same issue. > >The only other test I have done, is put the MSF5000 in Disable, and >when his repeater keyed up, I forced the MSF5000 into transmit, and >the issue was not there. > >I dont have access, to any high end test equipment anymore. This >repeater worked flawlessly for many years, until this issue came up. > >My question is... has anyone else experienced a problem like this> >Does anyone have any ideas for me to try to solve this issue, shy of >me changing the repeater frequency? I already talked with this >gentleman, and he has no interest at all, and changing frequencies >back to 146.985... where he was. > >Thanks in advance to any help. > >73, Pete >K4QHR > > > Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
