[ARC5] BC-453 B dynamotor hum
WA5CAB at cs.com
WA5CAB at cs.com
Sun Nov 1 00:48:25 EDT 2015
If the receiver still has its original RF coil set, aligning the tracking
of the HFO is usually pretty simple. Remove the tube cover and top cover.
Do NOT remove the capacitor cover. First align the IF's and the BFO at 85
KC. Then connect the signal generator to the antenna post and set it and the
tuning dial accurately to 520 KC. Adjust trimmer capacitor C4E for zero
beat. Re-tune the receiver and the signal generator to 210 KC and adjust
trimmer capacitor C9 for zero beat. Repeat these two steps until no further
adjustment is necessary. Tune receiver and sig gen to 365 KC and note frequency
of beat note. That is the tracking error. Unfortunately, the manuals do
not state the allowable maximum error here. What you have to do if you can't
live with the error is fairly complicated and quite time consuming.
While doing the above, you might as well tweak C4D at the high end. Tune
for maximum output amplitude. Unfortunately, there is no easily accessable
low-end adjustment for the RF stage.
Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480
In a message dated 10/31/2015 18:52:52 PM Central Daylight Time,
arc5 at mailman.qth.net writes:
> Hello all,
> Been tweaking this beacon receiver in preparation for the 600m event in
> November. Peaked the IF's , but the dial is off about 2khz or so.Is this
> going to be hard to calibrate/? Maybe I should leave it alone? I 'm wondering
> if it's worth the trouble. This radio is running on the original 24 V
> config.
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