Additional stories ...
> Re: Hamtronics 224MHz Repeater Kits
> I had all the same problems. My first all Hamtronics 224 MHz
> Repeater went right next to a 3kw fm broadcast transmitter in
> Vacaville.
Before that time I had been "punching the clown" trying to
get any kind of performance from a VHF Engineering Receiver
Kit. Now there's a dead horse you can beat twice...
> So I had to learn how to bypass everything with disc caps and
> properly cover/seal any holes in the metal chassis.
In the case of the VHF Engineer Receivers, I had to do "a heck'a"
lot of changes to their original receiver circuit.
> The receiver squelch is also mushy, part of the hamtronic rx
> circuit, which is based pretty much out of the Motorola Data
> Book for the MC-3357 or MC-3359 chip they used at the time. I
> know they're using a different receiver combo chip in the newer
> generation receivers, so you'd have to look up the data sheet
> to begin changing the squelch circuit around. Our good friends
> at Spectrum Actually have/had the best squelch circuit for the
> above name chips.
The first Hamtronics receivers didn't even have the Motorola
receiver chips in them circa mid late 1970's. You had to have
a whip and a chair to keep the early VHF Engineer and Hamtronics
Receivers under control... or just learn what really needed
to be done and did the mods/updates.
> I removed or changed the squelch hysterisis resistor(s) to make
> the operation more crisp (think I actually took that resistor
> out or changed it to a very different value.
The urge to tinker struck at an early age.
> I also had put an additional helical resonator preamp on the
> front of the receiver to help protect the front end.
There was no such easy help for the real early kits. We had to
make our own helical front ends using a modified GE Master
Pro Receiver front end... cut off the chassis with a very
large band saw. Also required a really huge soldering iron
to rework the helicoils.
> The duplexer you park in front of the repeater also makes a
> big difference.
And you learned those PC Board Duplexers didn't work very
well most of the time.
> With a homebrew 35 watt pa
Those early repeaters often used the Midland 13-509 as
the transmitter (and many times as the receiver). Got a
smokin' 10 watts output.
> > Oh well, it'll give us another thing to talk & compare
> > notes about in Dayton.
Probably see a lot of that early gear for sale at Dayton...
What a deal...
> chow for now
> skipp
and those brauts...
s.
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