[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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