[R-390] 51J-3 500 kcs IF Questions

[Tom M.]

I'd like to swap notes with anyone who has mastered this.

Here is the issue.

As I see it, one can either align the IF at 500 kcs exactly, or align the IF at
the frequency of the xtal filter (might be a tad off of 500).

On mine, if you align at 500 exactly, the xtal filter does not work as
advertised (not a big deal for AM broadcasts) but the dial error from band to
band, every other band, ping pongs from +2 to -2 kcs, etc.

If I align the IF right at the center of the xtal filter,  the dial error is
greatly reduced (probably band xtal pluses and minuses only) and the xtal
filter works.

This is not by-the-book but the results seem to be better.  Still trying to get
symetry of the shape around the center freq.

Does anyone have experience with this alternate method?

Also, when picking diode load signal off of R511 as advertised, signal is
absent the BFO injection.

Has anyone hooked up an alternate detector signal which has the BFO injection
present?  Where is a good location to pluck this?

Regards
Tom



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