[Hallicrafters] SX-28A Alignment

[John Schmitz]

I have mine aligned at 458KHz as that's what the crystal centered at and it
works great. I used the alignment procedure written up by Bill Feldmann
NP6Y. In his procedure he has you find the center freq of the crystal and
then do the alignment at that frequency. He has a very good procedure
written up that is much easier to follow (and I think a better procedure)
than what's in the SX-28 manual. Let me know if you need me to send you a
copy of it, it's in Word.

John


-----Original Message-----
From: hallicrafters-bounces at mailman.qth.net
[mailto:hallicrafters-bounces at mailman.qth.net]On Behalf Of Dream Lobo
Sent: Monday, March 07, 2005 11:19 AM
To: hallicrafters
Subject: [Hallicrafters] SX-28A Alignment

Greetings
I am currently restoring two SX-28A's and I situation came up with the first
one which is finished minus the alignment. The IF frequency of 455 khz is
what the manual says to set the signal generator at when beginning the
alignment which I did, but, the receiver seems to actually want a frequency
quite a bit removed from that for max gain. I have seen this before in other
receivers but the difference was slight so I used the slightly different
frequency as the one I set the signal generator on. Only a few hundred
cycles or so. In the case of this SX-28A, max gain seems to be around the
frequency 451 khz which is a much larger difference that I have encountered
before. I did the first part of the alignment using frequency 455 khz but I
am thinking that the gain doesn't seem to be what it should be. The question
is, have any of you encountered the same type of situation and if so, what
did you do about it. I am think that maybe I should use the frequency that
seems to be the actual frequency that the crystal filter wants to see. Any
thoughts on this matter would be most welcome. Also, I have need of a band
switching knob for an HT-37. If anybody has one they can part with please
let me know.

Regards & 73
Ae8o
Tom
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