[ETO_Alpha] Alpha 78 on 12 Meters

[gmguerin at voyager.net]

Hi Bob:

There are articles somewhere on doing just that, but it
sacrifices at least one lower band.

There is too much stray
capacity between the center partition and the new RF Choke and the
sub-chassis with the tubes and sockets, lowering a self resonance in
the RFC so the 78 will not work somewhere else... maybe 30 meters, but I
do not remember for sure.  On the choke I bought from RF Parts to put
in my 77, there were self resonances at 12 and 16 MHz and I am told that
they will move down when installed in the 78 or 76 models.

Go
to the www.n4uq.com website for more
information.

If you put the RF Parts choke in and intend to
operate on 12 meters, use the 10 meter band manually tuned switch
position.  I believe there is too much inductance in the 15 meter
position to get a good resonance in the plate tank circuits.

If
you decide to put in an RF Parts plate choke, then before operating the
amplifier, use a grid dip meter or similar instrument to find the self
resonances of the choke before you apply any voltages.  

GL    George  K8GG


> If
the RF choke is replace with the choke from RF Parts can the 78 be used

> on 12 meters?  If so, what band position - 15 meters? 
> 
> Thanks 
> Bob  W6VY 
> 
>
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