09-15-2009, 06:24 PM
Quote:My suspician is that this must be because the antenna tank trimmer needs tuning. I arrive at this conclusion through the idea that the oscillator should only adjust WHERE the stations are on the dial, but the antenna tank would control the spread of the band. I'm thinking that maybe the band pass of the antenna squeezes on the ends and it's currently adjusted so that it is above the middle so most of the dial is fine, but the top end is starting to get into the squeezed end.
The oscillator alone will determine the station locations on the dial. In a more sophisticated radio there would be two oscillator adjustments. A capacitor for the top end of the band and a coil or large padder capacitor for the bottom end. The combination of the two gives you the 'width' or spread. In this model you only have the top end adjustment. Thats not unusual and is generally effective enough.
Here's the alignment data in case you don't have it.
http://www.nostalgiaair.org/PagesByModel...013512.pdf
(skip that Part B about tightening the trimmers all the way down. You don't need to start from scratch on a working radio and that might cause you to get lost for sure!)
They have you aligning the dial pointer physically and setting the oscillator for correctness at 1600. Then they have you set the antenna trimmer while at 1500. You can do this with off air stations if you have something reasonably close. The antenna circuit trimmer will not affect the frequency.
Will your digital radio tune out of the BCB...up to 2055kc for example? If so you can use it just as you were describing and set the oscillator using that method if you don't have a local station handy.
Once it is set, and you've found a station to use to set the antenna trimmer, then go back and tweak the IF trimmers again. That's really all there is to it!