[Hallicrafters] SX-42, Band 4 Progress

[Mike Everette]

Somebody else wondered how much signal you're
injecting from the generator on Band 4.

So... How much?

Consider that the primary of the antenna coil on that
band "might" be open, or that the trouble might be
around the band switch section for that coil.  If you
are shooting a lot of microvolts into it, you could
possibly get enough coupling through the circuit to
pick up a signal from the generator, and get fooled
into thinking the circuit is OK when it isn't. 
Especially easy to do when using an uncalibrated
generator, or when trying to feed a 50-ohm line from
something like a URM-25 into a hi-Z input without a
proper matching network.  

Some of these old receivers have been known to exhibit
an open winding on the input coil on at least one
band, if the antenna was left connected during a storm
and a nearby lightnink stroke caused enough induction
to create enough current to burn the coil out.  It
doesn't take a direct hit to do this.

I'd also check the grid circuit of the first RF stage
real closely.

Did you recap the front end, and maybe accidentally
break a lead or short something out with a solder
blob?  Easy to do, hard to spot later.

73

Mike
WA4DLF



__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com