Thanks guys I'll have another go tomorrow (it's 0.30 a.m. in my place now).
Concerning the isolation question I was obviously wrong, I came up with the idea because the duplexer is a commercial tetra duplexer of which I had the factory test certificate filed and only remembered something like 80 dB. So I hooked it up (in factory condition) and only got 40 dB difference between the high point of the curve to the low when I looked at it in the spectrum analyzer with the tracking generator on (same value on both legs). My first calculation was 40 + 40... In the meantime I dug out that spec sheet and indeed there are values of Rejection (Ant - RX Port) : -80 dB Rejection (Ant - TX Port) : -80 dB Now what am I doing wrong in this case? Somewhere there are missing 40 dB each... I have to admit that I don't have double-shielded cables available at the moment, first need to get some, but that can't make such a difference can it? 73 Martin
