I'm most familiar with Maxtrac's with regards to "less than full power" operation, i.e. that they can produce spurs & other undesirables when run that way.
So other radios can have the same issues? I read that it is because when running below rated levels (anywhere in the tx chain) there exist impedance mismatches between stages, so "things" aren't running correctly. E.g. bandpass filters might be mismatched to active stages so they can't do what they're supposed to do. I'm thinking that most (all?) stages of an FM tx are running at saturation(?). We (repeater club) run our Maxtrac's at 4-10 Watts; I don't know if anyone has ever looked at spectrum of output for junque. Is there some better way of running at lower power w/o making RF crud? Thanks --John WB0EQ/VE6 --- On Thu, 9/17/09, Kevin Custer <[email protected]> wrote: From: Kevin Custer <[email protected]> Subject: Re: [Repeater-Builder] Re: Micor Station question To: [email protected] Date: Thursday, September 17, 2009, 8:44 AM w7nikw7nik wrote: > I had to tune the 1st band pass and the second band pass. I did not know > about the metal soldered cover that needs removed to allow tunning. I have > about 019 watts on a 1 watt scale out the exciter . > Thanks for the info . This may seem obvious - but realize that the exciter in a UHF Micor Station runs at VHF. If you have a frequency sensitive RF meter, make sure you are looking for RF power at 1/3 your operating frequency. If you are having trouble getting 400 mW or so on your new frequency, take another element in the commercial VHF band and re-tune the exciter to make sure it is (still?) working correctly. The exciter makes 400 mW at 1/3 the transmitter operating frequency, then there are filters - which also operate at VHF, then is the tripler which makes about 1 - 2 watts at UHF. All stages should be re-tuned to insure PA saturation, otherwise the transmitter will be spurious. Hope this helps... Kevin Custer _
