SB-401 question

[Mark Graalman WB8JKR]

  I've got a couple questions for any SB-401 guru's
out there.

  I recently picked up a SB-401 to basically restore and
found first off on the Mixer/Bandpass circuit board there
is supposed to be a 21 Mhz trap, this trap is a series trap
to ground consisting of a inductor (#40-479) which is spec'd
as 3.5 uh, and the capacitor is a 180 pf mica, in the unit I have
this inductor is missing. My question is, is this inductor actually
a 3.5 uh or is it .35 uh, a .35 uh will resonate with 180 pf at about
20 Mhz, 3.5 uh is WAY too high!!! I'm thinking this may be a
misprint in the manual. Also don't understand the purpose of it,
it would only guard against the 4 th harmonic of the LMO output,
which seems unlikely anyway.

 Another question, under the alignment with the accessory
crystal pack installed (stand-alone-transmitter) on page 101,
under the 8.6 Mhz trap adjustment it tells you to remove the
15.895 crystal from the SB-301 receiver, needless to say if
I'm doing this alignment there may very well be no SB-301
receiver, so are they actually talking about removing the
15.895 Mhz crystal from the SB-401 and its a misprint?


 73 Mark WB8JKR

Novice 3/71, General 8/72, Advanced 6/80, Extra 8/88
Member Society of Cable Telecommunication Engineers
Member ARRL, DXCC, WAC, WAS, VUCC 2 meters, GJDXCC, OTC, RCC

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