I agree with Doug and add that RG58 and foil/braid cables should not be used. Heliax is best and short jumpers from RG-400 or RG-142 (both of these cables are silver, double-braid construction with a teflon jacket) are typically recommended.
Chuck WB2EDV ----- Original Message ----- From: "Doug Bade" <[email protected]> To: <[email protected]> Sent: Tuesday, June 23, 2009 12:33 PM Subject: Re: [Repeater-Builder] Re: Completely Stumped on Noise (UHF Repeater) > Operating a VHF or UHF stationary repeater in a potentially > high RF environment ( i.e. other repeaters nearby) with a mobile > style receiver ( maxtrac ) and no filtering of any kind ( Like a > bandpass/reject duplexer) is not a suggested configuration in my world.. > > In many sites this will yield interference from other nearby > repeaters due to RF overload... > > Unshielded cables for mic wires and rx vol hi wires in a > high RF environment is also not suggested. > > Mobile duplexers ( not suggested in this case) are designed > to protect you from yourself and pretty much that is all they do... > but in a station duplexer with pass/reject filtering .. it is > designed to protect your receiver from overload from just about all > sources besides a mobile or portable within a couple hundred > kiloherts.. and any of that off freq is supposed to be filtered by > your I.F. filters.. > > They are suggested for many other reasons besides a single antenna > solution....if the interference is overload.. it would probably help... > > Alternately try a bandpass filter on your rx, if that does not help, > then the source of the interference is probably another > transmitter... and without friendly support from the owner may be > difficult to resolve... > > Doug > KD8B > > At 11:10 AM 6/23/2009, you wrote: > > >>The receive radio has a 20 ft piece of RG-58 Belden and the TX radio >>has 40 ft of LMR 400. After I had already purchased and installed >>the LMR braid cable I then learned to my knowledge this was not >>recomended for duplex use and it could cause noise and other >>problems but there is no LMR on the receive end of the radio and it >>still does it when the TX radio is turned off. >> >>--- In >><mailto:Repeater-Builder%40yahoogroups.com>[email protected], >>"Chuck Kelsey" <wb2...@...> wrote: >> > >> > Like Nate said, sounds like an intermod product with your >> transmitter being >> > part of the mix. >> > >> > My standard question has become -- are you using any LMR400, 9913 >> or similar >> > foil/braid coax anywhere in your system? >> > >> > Chuck >> > WB2EDV >> > >> > >> > >> > ----- Original Message ----- >> > From: "agrimm0034" <agrimm0...@...> >> > To: >> <<mailto:Repeater-Builder%40yahoogroups.com>[email protected]> >> > Sent: Monday, June 22, 2009 11:24 PM >> > Subject: [Repeater-Builder] Completly Stumped on Noise (UHF Repeater) >> > >> > >> > > This noise in my repeater has me completly stumped. I've tried >> everything >> > > I know possible to make it stop but nothing has helped. Here are some >> > > quick specs on what my repeater is... >> > > GMRS repeater RX 467.600 TX 462.600 DPL 054 TX 30 watts. >> > > >> > > My local repeater when I key opens up to a scratchy noise with the >> > > local >> > > police department in the background. It ONLY opens up when they >> key up the >> > > same time my repeater is being keyed. It is not perfectly clear it is >> > > scratchy but I have no idea how they are squeezing in on myn. I did >> > > find >> > > there frequency's and location of there repeater so mabye >> someone can help >> > > tell me what is wrong. Here is the Police Dept Repeater Details... >> > > PD Repeater - RX 460.4500 TX 465.4500 PL 6A 75 watt. (There >> tower is also >> > > located directly across from mine roughly 1/2 mile horizontally >> > > separated.) >> > > >> > > I've also tried changing my frequency and PL tones and it still has >> > > not >> > > made one bit of difference. I'f someone could help me out I'd gladly >> > > appreciate it. Thanks >> > > >> > > >> > > >> > > ------------------------------------ >> > > >> > > >> > > >> > > Yahoo! Groups Links >> > > >> > > >> > > >> > >> >> > > > > ------------------------------------ > > > > Yahoo! Groups Links > > >
