> The grungy audio isn't related to the amp.
Yes, I know, you said that. My question was whether the grunge was there
whether or not the repeater transmitter was keyed.
> The TKR may be turned down to 20-30 watts and not trip the
> amp.
By "not trip", do you mean "not key" or "not cause the amp to fault"? I'm
guessing the latter. What power output do you measure at 20-30 watts drive?
> The amp may easily be made continuous duty by driving it
> at a lower level and adding fans and blowing on it from an
> inch or so away, or by sucking on it.
For the heck of it, I looked at Mirage's specs on their web site. They have
a handy-dandy chart showing power in to power out. They're showing that
with 25 watts of drive it puts out 165 watts. Doubling the drive to 50
watts, it puts out 200 watts. In other words, a 3 dB increase in drive is
yielding only a 0.8 dB increase in output. That tells me you're way into
saturation at 200 watts output. Now, saturation in class C is generally "a
good thing", but that's kind of pushing it. Looking at the power saturation
profile, it seems to me that somewhere in the 150-175 watt range is really
where that amp would seem to want to be run. And that's based on the
intermittant mobile/HT kind of use it was designed for. I think you're only
asking for trouble trying to run that amp continuous duty at 20-30 watts of
drive no matter how much forced air cooling you push through the fins.
> We know that the repeater, amp and antenna play nicely and
> show a 1.1:1 SWR. It's just the duplexer and it appears that
> the tuning was not done based on the reference I was given
> earlier.
But you said that the VSWR from the "amp to the duplexer shows 1.1:1" and
"the cans are tuned right on the money", so why do you think the duplexer is
the problem?
> Yes, it's a G6-144 and I typed in a state of near exhaustion.
> I'm living in a children's hospital with a seriously ill daughter.
My best wishes for your harmonic.
Again, without being there with a spectrum analyzer, it sure sounds like
your Mirage is off wandering in the weeds. There's more to building a
repeater-grade amplifier than just being able to make gobs of power...
--- Jeff WN3A
