GR1225 Repeater

[johnny1225]

I have a UHF GR1225 Repeater that i have just installed as a Rental Repeater for a couple of months. It is only a 5 story building and only one antenna on the roof. The Repeater was not working right because the minute we left the room that the repeater was installed in we couldn't communicate. So we tested the repeater for power, freq error, devation and reciever sens. The repeater before the duplexer is putting out 50 watts and with the duplexer hooked up 43 watts. Freq error was0.19Khz and devations is about 2.28 khz for 12.5 spacing. Sensitivity was about 0.32 uV. After about a hr of looking at the repeater we installed another Repeater, same GR1225 with the same frequncy and bang it worked awsome. My question is everything on the first repeater looks good but why wouldn't it work, could it be the duplexer there should be more of a lost of power through the duplexer. The duplexer is a celwave notch type duplexer and the fre we were using was 452.5375/457.5375 with a DPL of 306. Hope someone can tell me what went wrong here or is there any other test i can perform on the GR1225 that is not working right.

Thanks

John

[wavetar]

Do you have a tester with a duplex generator so you can test the repeater from the antenna port of the duplexer? It's the only real way to test the "complete package" properly. I do agreee though, you should have more loss on the TX side of the duplexer if it's properly tuned to give you proper isolation...somewhere around 35watts for 1.5dB insertion loss at 50watts. I believe that's what the little black mobile duplexers are rated for insertion loss.

FYI, although those little duplexers are rated for maximum 50 watts, I find they work much better if you lower the power to 35 watts to begin with. You end up with 25watts after insertion loss, but it's not noticeable in the field.

Todd