[Boatanchors] SX-115 Xtal oscillator question

[Bob Macklin]

You have a SX-115 that has been modified to cover part of the CB segment.

Bob Macklin
K5MYJ
Seattle, Wa,
----- Original Message ----- 
From: "Paul Vasek" <w2ec at bmjsports.com>
To: <hallicrafters at mailman.qth.net>; <boatanchors at mailman.qth.net>
Sent: Monday, October 15, 2007 6:47 PM
Subject: [Boatanchors] SX-115 Xtal oscillator question


> I'm just starting to work on an SX-115 that needs some cleanup and a
little TLC restoration. The oscillator crystals for WWV thru 10 meters were
not installed in their sockets but had come loose. In sorting them out in
order to ensure they were all there, I found a strange situation involving
one crystal. In the SX-115 there are four 10 meter band segments, each 500kc
wide, consisting of band 10-1 (28.0mc to 28.5mc), 10-2 (28.5mc-29.0mc), 10-3
(29.0mc-29.5mc) and 10-4 (29.5mc-30.0mc). According to the schematic, the
oscillator xtals should be: 10-1 = 34.505mc, 10-2 = 35.005mc, 10-3 =
35.505mc, 10-4 = 36.005mc.
>
>   Heres my problem, I found the correct crystals for bands WWV, 80, 40, 20
and 15 meters, plus those for 10-2, 10-3 and 10-4. I do have an additional
crystal left over for band 10-1, howevr it is 33.505mc, NOT 34.505 mc as
needed for band 10-1 (28.0mc to 28.5mc). Since I don't have the radio
working yet I can't just plug in the crystal and see what I get when I
select band 10-1. Doing the math it looks like a 33.505 crystal (assuming
the circuit will oscillate OK) will have band 10-1 operating on 27.0mc thru
27.5mc, which is pretty much the 11 meter CB band, what a co-incidence.
>
>   So I either have an SX-115 with a crystal that was mismarked 33.505mc
instead of 34.505mc 40 some years ago, or someone modified their SX-115 to
cover the 11 meter/CB frequencies. I'm guesing the latter, so does anyone
have a spare 34.505mc crystal for an SX-115 in case I need one?
>
>   73, Paul W2EC
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