Thread: S-40A Question
View Single Post
  #7   Report Post  
Old March 5th 09, 06:27 AM posted to rec.radio.amateur.boatanchors
Richard Knoppow Richard Knoppow is offline
external usenet poster
 
First recorded activity by RadioBanter: Oct 2006
Posts: 527
Default S-40A Question


"elaich" wrote in message
...
"Richard Knoppow" wrote in
m:

I will
change the stringing on my RX since I don't think I can
get
the stop peg out without damaging the cap.


I really don't see why you have a problem. All the
bandspread cap does is
finetune a space around the center freq. To use it
correctly, you leave it
set at 50, and then you can finetune either up or down.
The stringing will
only affect which side is up or down. Obviously, you want
less than 50 to
be down, so string it so it gains capacitance (lowers
frequency) as you
tune down.


I think you don't understand the function of
bandspread. Even though this is not a calibrated bandspread
it does have definite position it must be in for the main
dial to be calibratable. For most Hallicrafters receivers
that is 0 on the dial representing minimum capacitance for
the band spread capacitor. The main dial will not calibrate
at any other value of capacitance. The trouble is that you
are suggesting a sort of makeshift which would prevent the
radio from working properly. The question is why was the
capacitor made in such a way that it could not work properly
if the dial stringing instructions for the receiver were
followed and why some receivers of this model are one way
and some another. Tha last two questions are probably beyond
answering. Its possible that some person wanted the
bandspread dial to start at 100 as it does for other brands
of receivers and delibrately changed the position of the
stop peg on the capacitor so that it rotates the wrong way.
Its also possible there was some change made in production
although I doubt that. In any case, since I have been unable
to knock the peg out to replace it the other way. I will
restring the dial system to reverse the rotation of the band
spread capacitor. That will have the cap at minimum value
when the dial indicates zero. The dial says on it to set at
0. So, even though I could simply calibrate it with the dial
at 100 the markings would mislead someone else trying to use
it.
While makeshifts are sometimes necessary I really hate
having to use them. Even the crossed stringing is a
makeshift but I am afraid of damaging the capacitor and
making the whole thing unusable if I apply too much force in
trying to remove the stop peg.


--

--
Richard Knoppow
Los Angeles
WB6KBL