"Ron" wrote in message
...

Hi
Yes I had problems with both the setting of the dial and the tracking
on Band 4 I think you have to accept a little variance but I'm very
pleased with its performance and have been using it on 40mtrs CW
alongside my Home Brew QRP CW Tx.


I got my S-40A in perfect band 4 alignment at 2 points (17 and 34 Mc), but
it wasn't easy. I had to remove the band 4 oscillator coil and spread the
turns. Actually, I ended up rewinding the coil because I messed up the
original. I overworked the coil because I didn't realize the importance of
lead dress on this radio, even at 17 Mc. There's a longish wire coming from
the bandswitch which should be routed under the capacitor shelf on the coil
form. Routing it over the top of the form cost me about 250 Kc. That's
about half of the range from the tuning slug.

If you don't get enough range with the ferrite slug, the radio books say you
can try a brass slug. I didn't have a brass slug, and I don't have the
brass rod to make one. In one of my experiments, I coiled some 16 gauge
copper wire around the shank of a phillips head screwdriver, and threaded
the coil into the form. If you've ever worked with Heli-Coil thread
inserts, you can picture what I did. The copper coil worked fine, but I got
the radio aligned with the ferrite slug, once I rewound the coil for a
little less inductance.

Also, good clean connections at the bandswitch and the solder joints are
important. Band 4 is a high C low L circuit, and should generate a fair
amount of current in the LC tank assuming a reasonable Q.
You can clean the bandswitch better if you remove the two screws which hold
the witch detent in place. You can then rock the switch past the postition
the contacts stop for band 4. This will work any contact cleaner in better,
and work out the crud which normally builds up where the switch dead ends.


It's strange this radio goes into the low VHF band. I think Hallicrafters
designed it with the experimental Apex radio band in mind, which ran from
about 40 to 45 Mc.

Frank Dresser