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I have a VHF MTR2000 with a Repeater Builder MMDVM board running DMR and analog. The duplexer is a Sinclair Q2330E that has about 1.3DB of IL and right around 105DB in the reject notches, I just tuned them up earlier today. I have the MTR dumping 55 watts into the cans while testing at home. The problem I'm running into is that the repeater is basically deaf to 5 watt portables barely a mile from my house, mobiles work a bit further but both DMR and Analog don't work when this happens. I've gone as far as to recheck the duplexer tuning and they are tuned properly as far as I can tell.

I've measured the MTR2000 12db SINAD at around 0.35?V which meets factory specs. I set up a densense test with the repeater connected to the duplexer and the antenna port terminated into a dummy load. I took the receiver from the MTR hooked to the receive side of the duplexer through an ISO-T. It took my signal generator set to -54DBM to get 20DB SINAD. With the transmitter putting out power into the duplexer, I had to adjust the output to -53DBM to get it back to 20DB SINAD. Now, this may all be margin of error as Motorola R1200 I'm using as a signal generator acts flaky and the other service monitor I'm using, the SINAD meter always jumps around so I may be chasing a ghost here.

I have had a similar issue on a UHF MTR that was deaf in the same way, even though it met sensitivity specs, it was still deaf. I took it back to the dealer and they fixed the alignment and I've never had an issue since with it.

I aligned this VHF MTR2000 myself with my somewhat questionable equipment so it is possible something is messed up on the alignment. I've already decided to send the repeater away in a few days so they can check my handy work.

Do my crude desense test results point to an issue, if indeed the results are 100% accurate??