[Boatanchors] Which one tube TX ?

[Bill Cromwell]

On Sat, 2012-04-28 at 07:44 -0700, Doug Forbes wrote:
> I am building a one-tube transmitter and am concerned over the crystal 
> current. How much current will an HC-49 handle safely ? How about an 
> FT-243 ? Is there a one-tuber that is nicer to the crystals than another ?
> 
> I really appreciate any help you can give. I know you folks have 
> probably answered these questions many times.
> 
> Doug WA6VYN
> ______________________________________________________________

Hi Doug,

Do you want to build a one stage power oscillator or do you want to
build a one tube transmitter. If you use a tube that has two (or more)
devices in one envelope you can realize a MOPA with one tube. Something
like the 6U8A comes immediately to mind. Some of the Compctrons have
three or more devices inside one glass tube (and more power than a 6U8).

For the power oscillator there are some tuning tricks in the plate
circuit that help the crystal survive. If I remember correctly some of
the hams tune the plate circuit to the low frequency side of resonance
to take it easy on the xtal. It may be the other way round. Some others
put a light bulb in series with the xtal. Some do both. I didn't make
good notes because my personal minimal transmitter starts at MOPA and
goes up from there.

73,

Bill  KU8H