[CQ-Contest] Pre tuned Hf amps

Ed k4sb at comcast.net
Sun Sep 24 15:24:33 EDT 2006

Eric Hilding wrote:
> On Sat, 23 Sep 2006, Peter wrote:
> > Hi
> >
> > 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" :-)
Even without knowing what mode(s) Peter operates, the question he 
asked is relevant. And one very good reason to "reinvent" the wheel
if that if Peter uses either RTTY or CW predominately, he can very
inexpensively build class C amplifiers, which will give him about
20-30% more efficiency.

And the answer to his quedstion is to use an antenna switch to route
the drive to the amplifier he wants. As for protection, a single SWR
bridge at the rig will do that job, although personally, I would build
one which had the ability to immediately shut down the Tx, IF the SWR
exceeded a certain limit. Most Txs have the capability to reduce power
drastically as a function of SWR, but in this case, I think I might
work on a "lockout".


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