[CQ-Contest] Pre tuned Hf amps

Peter Voelpel df3kv at t-online.de
Sun Sep 24 17:04:07 EDT 2006

I would never want to change monoband amps to a single or two "autotune"

Optimized homebrew monoband amps are the far better solution:
- much better components, never bandswitch failures
- better efficieny
- usually better harmonic reduction
- no single point of failure
- more power
- instant switching of bands, no tune at all
- much cheaper

As an alternative, I am in the process of building an additional three band
amplifier for the low bands, 3 Pi-L output circuits, switched in by vacuum
switches and a common input.
No antenna relays necessary since receiving antennas are separate.
This one is to feed additional antennas and will be driven through a ratio
adjustable power splitter.

My amplifiers are not in the shack, except those with radiation cooled
I just monitor automatically SWR and overcurrent states which drop the
ptt-line in case of failure, or automatic shutdown of voltages if necessary.

I think this thread will be better discussed in the amp reflector


-----Original Message-----
From: cq-contest-bounces at contesting.com
[mailto:cq-contest-bounces at contesting.com] On Behalf Of Eric Hilding

> I'am looking for some information to put an hf amp in an other room I 
> thinking to build monoband amps who are pre tuned and no need to 
> retune if you go from ssb part to the cw part of the band.
> Has any one done ths before?
> How do you make the protection/feedback to the operator if something 
> goes wrong?

Why re-invent the wheel?  Get ***ONE*** "Auto-Tune" amp.  ACOM, ALPHA or
check out the new Elecraft KPA amps ("coming soon" :-)

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