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Old February 23rd 05, 07:16 PM
Mark Zenier
 
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In article .com,
bpnjensen wrote:
Mark and Frank - the frequency aligns correctly near the lower end of
each band - for example, on the 4-12 MHz band, WWV shows up at
virtually dead-on 5 MHz. At the upper end of the band, however, WWV is
off by *about* .6 MHz from 10 MHZ (depending on what the radio ate for
breakfast), and things are a bit worse on signals near 12 MHz. The
same is proportionally true for each of the other bands.


The fact that all the bands are off the same amount is a bit strange,
as (according to the schematic) the LO coil for each band has both a
coil adjustment and a trimmer capacitor.

I can think of a few things.

1) The main dial and the band spread will interact, so that the main
dial is accurate only when the bandspread is at some position.

2) Somebody realigned the radio with the bandspread at the wrong
position.

3) There's a "global" adjustment for the main or bandspread capacitors.
For a lot of radios, there were some mica compression trimmer capacitors
built into the main capacitor to adjust the top end tuning. (But this
doesn't show in the schematic so this may not exist).

The bandspread dial, when used, is off by varying degrees from one end
to the other, ranging from nil to about 15 or 20 khz.


That's pretty good, actually. There don't seem to be any adjustments
for the bandspread.

Mark Zenier Washington State resident