Kevin Berlen, K9HX wrote: >I am helping a friend put together a split site 2-meter repeater. We >are using a UHF Micor receiver for one end of the link, tuned to >446.500MHz. I have tuned it per the alignment instructions in the >manual, and everything tunes and resonates as it should, but the >sensitivity is only about 1.5uv. The injection string has good meter >readings. Anyone have any ideas? Thanks and 73, > >Kevin, K9HX >
First of all, *some* Micor UHF receivers are just plain deaf. I have found that the sensitivity of them are not as consistent as the VHF models that 99% of the time end up being within a few dB of one another. The first thing to do is replace the channel element with a commercial frequency and test the receiver at 45X.XXX and see where your receiver is at. If it is deaf on the commercial band, there may not be much you can do but try another receiver. Typically, a properly tuned barefoot (no preamp) UHF Micor 'just makes' book specification of -116 dBm for 12 dB SINAD, and it is not at all common to see them a few to several dB worst than that. Make damn sure you tune them per the instructions in the manual religiously. There is no better procedure than the one in the manual. If you find that your receiver is fairly good in the commercial portion of the spectrum, you could do the modification suggested here, even though you are above 445.000: <http://www.repeater-builder.com/rbtip/uhfsensitronRX.html> Sometimes it helps..... If the receiver is not part of a UHF Micor mobile transmitting system where the injection 'side' matters, you could also try the other side injection, as sometimes that helps too. At any rate, don't expect your receiver to be any better on the ham band than you see at the commercial frequency, and a little worse is to be expected. I just converted two Micor UHF receivers for someone. Both were operating below 445.000 after conversion. Before conversion, they were 'quite good' in the commercial band at -117 and -118 dBm. They ended up at -116 and -117 respectively after the conversion mentioned above. Hope this helps... Kevin Custer Repeater-Builder Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
