Meissner Signal Shifter Coils and Advice

Wilson Lamb infomet at EMBARQMAIL.COM
Sat Mar 13 08:31:31 EST 2010

Well, I'm well into my "new" Signal Shifter.  There was nothing "wrong" with 
it, except for filter caps, which smoked nicely.
BUT, as usual, there are many questions about old stuff:

COILS- I need ham band coils.  I have a source of forms and a great turns 
count (Thanks, Jim!), but would not be ashamed to buy some coils, if they 
show up.  Life is short and getting shorter!

COMPONENT VALUES-I have the book, but the tuning and neutralizing cap values 
are not called out.  My output tank cap may be falling apart, so I'd like to 
prepare to replace it.

OPERATIONAL CONCERNS-I got 160m going fine, with neutralizing and tuning, 
but, when I tried 40m, the only other full set of coils I have (Thanks, 
Mac!), I have strange results.  When I wasn't able to get a good SWR with my 
MFJ tuner, I looked for reasons.  When I looked at the output waveform 
(Thanks, Terry), I saw quite a lot of 3.5MHz energy, maybe only 3-4dB down 
from the 7 MHz signal.  The 6L6 is doubling on this band, but I'm surprised 
the output tank does not reject more of the 3.5 MHz energy.  Tuning the 
output cap does not effect the output amplitude or waveshape, as it does 
very nicely on 160m, leading me to think it may be defective/wrong value.  I 
have scope pictures of the waveform at the 6L6 plate and the link output 
when feeding a dummy load.  Anyone interested can have them via email.

It's odd that the design seems to rely on the same output cap, set to the 
same value, for all bands.  One might guess there were fixed caps in the 
coils, but they are not shown on the schematic.  All the original coils I 
have have paper labels pasted on top and I don't want to disturb them.

QUESTIONS-So, has anyone checked Signal Shifter output levels/waveforms on 
any ham bands?

Has anyone changed the 6L6 stage to fixed bias or made any other changes to 
make the doubling operation more efficient.  The original circuit uses a 
combination of grid leak and cathode bias and may not be going into true 
class C operation.

Does anyone have documentation other than the original ops manual?  I 
haven't come across a Photofact on the SS, but will keep checking for one.

Why am I doing all this?  BA fever, of course!
It's a nicer unit than I thought and easily stable enough for normal 
operation.  It keys very nicely and is mechanically robust, with good 
components.  The power transformer is big enough to run the Shifter AND a 
40W final!  It's going to make a fine BA VFO and CX rig, but really needs 
its waveform cleaned up for use into an antenna.

I'd pay a few bucks for a true junker worthy of furnishing a tuning cap or 
for original 80/40/20m coils.  Otherwise, I'll be doing some winding before 
Most of all, I'd like to find an original 1938 model Shifter, the one in an 
all black wrinkle case.

OK, OTs, let's have some of that priceless info you are holding onto, 

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