[Boatanchors] Question about swinging link output circuit

[Don Buska]

Hi Chris,

The Millen 80881 Amplifier has two clips beside the output coil.  They 
look like large fuse holder ends and are about four inches apart.  Like 
your they connect across the tank circuit.  What they are used for is 
operation on 160 meters requires the installation of a vacuum capacitor 
to allow proper tuning of the tank circuit for those lower frequencies. 
Sounds like the same for your transmitter.

That is a great looking transmitter and something to be proud of when 
you finally get it generating RF.

Have Fun es 73

Don N9OO

Chris Howard wrote:
> I'm working on this old homebrew transmitter (been at it off and on for
> a year!)
> 
> The PA has two 250TH tubes in push-pull.  The output circuit is a 
> swinging link arrangement using a B&W HDVL plugin coil set.
> 
> Hanging under the B&W coil socket is a fitting.  The only things
> I have that fit there are three rf-choke like coils, about 6 inches
> long.  The three are different only in the number of turns.  Wire
> size and coil size looks the same on all three.
> 
> According to my grid-dipper, having the choke there does not change the
> resonance of the output circuit that I can tell.
> 
> I'm not 100% sure that those choke-like coils even fit in this
> place.  Why would someone put such a thing in parallel to the
> output plugin coil?  Does it make sense? 
> 
> You can see schematics here  (but I left out the choke in question
> from the PA schematic)
> 
> https://users.frii.com/yipyap/twiki/bin/view/Main/TransmitterProject
> 
> Chris
> w0ep
> chris at yipyap.com
> 
> 
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