Re: Hallicrafters Crystal Filter/Phasing Alignment... HELP!

The crystal provides very sharp selectivity.  If you tune a CW signal and
then adjust the crystal phasing control on the front panel you should be
able to find a null where the signal drops way down.  When you do this, tune
the slug to maximize the null so that the signal is as close to disappearing
as possible.

You may have to tune very slowly to find this null.  There may also be a
peak but that is to be ignored for this procedure.

The BFO pitch should be set so that a medium pitch tone is received so that
you can make minor adjustments and still hear it.

However, the null is sometimes so sharp that many signal generators are just
not stable enough to find and hold it.  Sometimes the radio itself drifts
enough so it's difficult to hold the notch.  Use a light touch and make sure
everything is fully warmed up, at least an hour, before attempting this.
Never move the band switch on either the radio or the signal generator
during this procedure, as that will start a new drift period.

When properly aligned it should be possible to get rid of any CW signal by
tuning the phasing control.  The best tuning for the receiver is to have the
desired signal at the peak, where the phasing control should have no effect,
and then null out any interfering signal with the phasing control.  The BFO
is set to any convenient pitch and has no bearing on the rest of this.

Perhaps this procedure isn't clear but it's the best I can do.  I used
crystal filters for years until I got a modern radio that didn't need it.
Unfortunately, many receivers weren't stable enough to make best use of
them.

When I align a receiver I seldom use a signal generator.  On the air signals
are more than adequate unless I am trying to measure audio distortion or
receiver sensitivity.  For most alignment, use a broadcast station.  They
are stable.

Good luck.

Bob