[Boatanchors] Halli HA-5 vfo to Millen 90800 transmitter

[Ian Wilson]

If the schematic is similar to the 90800, the "crystal/vfo" switch does
nothing
more than insert a large capacitor from the cathode of the oscillator
(5763) to
ground when in VFO mode.

This works because the oscillator is a Colpitts type - ground the cathode
for AC
and you remove the feedback.

73, ian K3IMW


On Fri, Dec 26, 2014 at 9:05 AM, John Saxon via Boatanchors <
boatanchors at mailman.qth.net> wrote:

> Merry Christmas and a prosperous 2015 to all:
>
> This is John, K5ENQ, in Pearland, TX and I just acquired a Hallicrafters
> HA-5 vfo (in beautiful condition, thank you Pat).  Ready to hook it up to
> my Millen 90800 (6L6-807).  Not sure how to do it.  The osc in the Millen
> does not have one side of the xtal going to ground, but the xtal is between
> the cathode and grid of the 6L6 oscillator.  The cathode is above ground
> through a 200 ohm resistor.  The ground is made with keying.
> So...not sure how to feed the 6L6, as one side of the HA-5 output is
> ground, doesn't look to me like I can directly plug it in.   Out of
> curiosity I checked with info from the Millen 90711 vfo, which has one side
> of the ouput at gound, which seems to indicate a link is required to the
> transmitter unless going through the Millen adapter box, which permits
> direct plug-in to the xtal socket of the transmitter.
> I can think of a couple of approaches, but, as you can tell, I am not the
> expert you folks are.
> Any suggestions appreciated,73,JohnK5ENQ
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