hey guys, I've got my hands on a GR1225 repeater with an RFE4000a (Celwave 633-2a-2n) notch duplexer and a phone patch.
The repeater had some questionable solder problems on the output of the final due very likely to the poorly tuned duplexer. The solder was a quick fix and repeater has a healthy 30 watt output with clean rx (opening about .25uV). My current problem is the tuning of this duplexer, I started out with decent rx at the dx antenna input but no tx power was passing. Checked with watt meter at the tx port and had full reflect. Tried retuning tx side and lost rx sens. I can't seem to get either the rx or tx lined up now. I can get the notches placed right but the pass portion does not get much higher than -10dB (incoming set to 0dB) usually lower. Is there a start from scratch tuning procedure on these? I contacted celwave and they gave me a very simple tuning procedure. My problem is that I do not know what the original frequencies were on this duplexer. The documentation says that these units are good across 450-470MHz but could there be certain frequencies that they just don't work well at. I am using an IFR 1900CSA Monitor with a tracking gen and a 50ohm load on the opposite port being tuned. Any thoughts on what I am doing wrong would be great...I'm starting to think I've over-promised on this unit. Thanks guys, Dave
