[Boatanchors] Johnson Valiant II VFO

[Glen Zook]

The problem with the resistor is that it is too small
of a wattage not that it is within the VFO cabinet. 
The "fix" is to replace the resistor with one of at
least 5 watts capability, 10 watts is better.

There have been some experiments done by several
amateur radio operators trying the resistor both
within the VFO compartment and on the outside.  Those
experiments showed that the VFO was actually more
stable with the resistor INSIDE the compartment.  It
stabilized much sooner and held stability better when
on the inside.  The consensus of opinion is that
Johnson designed the VFO with the resistor on the
inside and that the temperature compensation
capacitors were optimized considering the heat
generated by the resistor.

Glen, K9STH


--- Al Parker <anchor at ec.rr.com> wrote:

The Valiant/Ranger, etc., VFO's have a dropping
resistor in the line to the VR tube which is inside
the VFO box IIRC.  The resisitor is abt 12k or 15k, 2
watts, and goes high in value as it gets very hot. 
Then the VFO chirps.  I can't remember if the resistor
is inside or outside of the box, but it should be
mounted outside, and be a 10watter if posible, at
least 5w.

Some guys have moved the VR tube out of the box, but I
think just getting the dropping resisstor out helps
the drift. I suspect the 122 VFO is much the same. 
I've been into both the Ranger & Valiant to make the
resistor change, without removing the VFO, but it's
tight, and tough to get into it.










Glen, K9STH

Website:  http://k9sth.com


 
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