[Boatanchors] Signal Shifter Stuff
infomet at embarqmail.com
Thu Apr 24 08:43:01 EDT 2014
I got the “new” Shifter on the air yesterday and it actually works well.
Quite microphonic, of course, but not very drifty and keys well, actually better than my Deluxe.
One reason it works well is that it has had substantial modification, basically conversion of the circuit to the Deluxe design!
Someone has (apparently) punched two holes and installed VR tubes to help calm it down.
I have only a hand drawn schematic of the ‘38 model, which has no VR tubes, but no official schematic.
According to http://www.radiomuseum.org/tubes/tube_0d3.html , VR tubes came out in 1942.
Curiously, when they installed the VR tubes they left a dropping resistor in series with the oscillator B+, which enhanced the chirp somewhat.
When I jumpered across the resistor, the note improved substantially!
Now it’s quite usable, at least on 80m, and I have made several QSOs, including NYC. Not bad for seven 1938 Watts!
So if you have ever heard of upgrading a 1938 Shifter or have any factory literature on them, please let me know.
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