Larry did you try RB site. Try this link http://www.repeater-builder.com/db/pdfs/db-4048.pdf
Randy --- In [email protected], "larynl2" <lar...@...> wrote: > > > Hi all I'm working on a 1 mc. split repeater using this duplexer. > Transmitter is a VHF Engineering; output is 1 watt. I'm using a Mastr II > receiver with no preamp. Interconnect cables are RG142. The old VHF > Engineering receiver developed problems not worth fixing, so everything is on > the bench for the new receiver and re-tuning. > > Desense was always an issue with this repeater, with 1-3db pretty normal. So > I decided to re-tune the duplexer. I used a signal generator and receiver. > All ports were either terminated in 50 ohms or had a 10db pad in series with > the generator and receiver during tuning for minimum signal through the > respective halves. It seems to tune well and predictably. However, I'm > getting 20db+ of desense with the duplexer operating into a known good dummy > load. I can reduce the desense considerably by *winging it* and tuning the > cavities while the repeater is operating. (Maybe that's the way I should > tune it.......!) So something isn't right. > > I'm not totally convinced that this duplexer wasn't <played with> at some > point, so it is possible that cables in the harness were mixed up. There is > no labeling or other info on the duplexer, since the metal box that it was in > when new is gone along with the nameplate. So it is not clear which side is > which, and I may have been trying to use it reversed (although I don't think > so). I believe that this duplexer was originally ordered for 2M, but I could > be wrong, which could account for some troubles. > > So where would I find info on harness cable lengths so I can check them? Or > if someone has one of these working on 2M and is willing to make some > measurements that would be awesome. And which half of the duplexer is for > the high and low frequencies? > > Laryn K8TVZ >
