Quote:
Originally Posted by YT2095UK
Now it makes sense why the outer blades on a variable cap are often bent outwards slightly in some positions!
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Just a side-comment on that remark.
The usual practice of s/het tracking is to get the difference in the resonant freqs. of the RF stages and the oscillator to be the intermediate freq. Unfortunately, this difference cannot be maintained at all freqs. across the RF tuning range, so it is usual to get this required difference to be exact at 3 freq. points - a.k.a. "3-point tracking". At its optimum, there will still be small errors between these tracking points, so the idea is to adjust the cut outer blades (inwards or outwards) of the tuning capacitor to minimise these errors.
Al. / Skywave.