Amen Larry, I know of a case first hand where the crap from a micor mobile cost the site owner more than $10k to deal with/fix. And the FCC was not the expense...
cheers, s. --- In [email protected], "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> wrote: > > That's for sure about the MICOR UHF transmitter - follow the instructions, including the special MICOR section notes on the Repeater-Builder web site. Lately, every UHF MICOR Repeater transmitter that I've converted to the 440-450 ham band has had a big, nasty spur about 30 MHz above the desired Transmit frequency. I've tuned the filters, circulator, etc. but one transmitter in particular gave me fits. > > I tried tuning the exciter filter repeatedly (which is actually a VHF exciter, 1/3 of the intended UHF transmit frequency) using a signal generator and spectrum analyzer. I tried different exciters, filters, IPAs, 75-watt PA decks, etc. but still had that big spur. I finally hit on the right combination of tweaks in the exciter filter by just using a VHF hand-held radio on the exciter's frequency and looking for maximum output at the filter output on a wattmeter/dummy load. Success, finally - everything was clean. > > A few weeks ago, I was "volunteered" to help another local Repeater group go through their 75-Watt UHF MICOR Repeater, since I had just done one for myself and everything was still fresh in my memory about the things to look out for. Sure enough, this one also had a big spur about 30 MHz above the 440 transmit frequency. We'd never have known except by looking at the spectrum analyzer, and by the excessive power loss through the duplexer since a bunch of the Power Output was not on the intended frequency. This time, I took their exciter filter out, tuned it for maximum power output with the VHF handheld and wattmeter/dummy load and then reinstalled it. Everything was clean and all the power output was on the desired 440 frequency. Lesson learned and verified a second time.... > > LJ
