[AMRadio] new antenna and matchbox a bust.


Geoff/W5OMR ars.w5omr at gmail.com
Tue Jan 30 14:11:06 EST 2007


Brett gazdzinski wrote:
> Ok, I have some diodes marked fast switching,
> rated at 200 volts and 200ma I think.
> The 1N34a's are rated at something like 60 volts
> and 40ma.
> I wonder if the fast switchers would work.
> Its such a pain in the butt to get at the diodes
> in the tuner, and I don't think you can adjust
> the pots with the tuner working as its built
> into the antenna switch part.

I seem to recall that you're using the Heathkit SA-2060 impedance 
matching device, Brett.  Is this correct?

I'm watching this thread with baited anticipation.  Let me know how you 
come out with it.

I had the same problem with mine, when moving back up from 3650kc/s to 
3880kcs on the day after the Band warming party on 15 December, 2006.
I moved back to 3880kc/s and hit the thing with what was 350w into an 
infinite SWR.

Makes me wish I had a 20w monolithic RF power -brick- in which I could 
just punch up a frequency, adjust the impedance matching device.

Perhaps some little 100w ricebox w/built-in SWR protection on a coax 
switch with the AM receiver.  Flip to the solid-state rig, key it up, 
adjust the knobs, and then fire up the big-rig into the load.

Anyway... fast switching diodes. are what's needed, and as little of 
forward bias as possible.

There's an adjustment trimmer capacitor in there, that looks like it 
couldn't handle 25w.  You might check it as well, and see if it's not 
zorched.

Good luck

--
73, etc
-Geoff/W5OMR




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