Which way is the band spread capacitor facing? Capacitance should
be minimum with dial at zero. This is Halicrafters design, on
non-calibrated band spreads the dial indicates the amount of capitance.
I think calibrated dials are set for the logging scale to be the same
but in any case the band set is generally at the high end of the band.
The dial cord is backwards of its orientation on later receivers
like the S-40. The string crosses over.
BTW, I wondered about this. My S-40A came with the band spread
string reversed and stop peg facing the opposite way to that shown in
the handbooks. I reversed it. In its original position the band spread
went from zero to 100 but in what I thought was the correct position it
stops at about 95. Same for the S-20R. It made me wonder if the original
position was correct and there is a global error in the handbooks for
all this series of receivers. The position as shown in the S-85 handbook
seems to confirm this. A puzzle. At some point I will try reversing the
cable in both receivers. In any case, at ZERO the band spread is at
minimum band spread capacitance, plates turned out from stator, this is
as it should be regardless of the cord.
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On 2/6/2025 1:13 PM, don Root wrote:
Emanuele
I NEED EDUCATION ?on reading these new scopes and such
Wrt your previous post; I have no reason to believe there is a problem
in the IF.
My last post made wrong assumptions on the reading the scope, so my
conclusions are wrong; and I agree the RF tuning on the first tank in
band 1? is way out it seems.
I keep wondering why 4 tanks seem to have the same problem. ?Is it
possible that the bandspread dial stringing is reversed?
*From:*[email protected]
[mailto:[email protected]] *On Behalf Of *Emanuele Girlando
via groups.io
*Sent:* Thursday, February 6, 2025 4:25 AM
*To:* [email protected]
*Subject:* Re: [HallicraftersRadios] S-85 refurbish: I've got a problem
during the RF alignment of bands 1 and 2 - trimcaps don't peak!
Don,
here is my picture interpretation:
Richard:
¡¤"/So, what is this about .5Mhz and /*/370/*/and /*/220/*/Khz?/ ". Those
are the delta values between peak and the desired frequency as reported
by the Delta marker (rounded).
¡¤The IF alignment has been remade from scratch by using the "visual"
approach (first 3 pictures).
¡¤"/The position of the peaks on the RF will be affected somewhat by the
dummy load/". If you meant the "dummy antenna" *I fully agree*. I'm
gonna try the same test removing the dummy antenna from the equation.
I'll report as soon as I get time to work on that.
Correction to my previous post:
"/...all signals (and the noise as well) tend to disappear below /
*/.5MHz/*" should read "... below *1MHz*" that is in the lower half of
the band.
Thank you guys!
Emanuele (IU1KNR).
<>
--
don??? va3drl
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
