Discovered the rear 15 pin plug is used to activate the repeater, pins are soldered together and there is a small link wire, bit of an odd way really. Other pins appear to be PTT (remote PTT keying??) 12v out, not sure on others. Links A/B on the board are used for duplex repeater or cross band ...

I'm putting in around 40watts into the notch duplexer and getting a miserable 20watts out of it. I have very little knowledge of notch duplexers. It does seem to be tuned when I test it using sig gen and H/H signal meter. I'm not sure why, probably something simple?? What is an acceptable loss ...

SOLVED

Anybody know about these?

Hello, I have a GB300 repeater, basically two GM300/M120 mounted with out heads in a 19" rack. Conducted to an interface. I'm wanting to know what the jumpers (2 of with A or B options) on the interface board are for and also the 25?pin connector on the rear.

I gather it is programmed with GM300 ...