[Hallicrafters] Ordered AES substitute antenna coils for SX-71

[Philip Atchley]

Hello All
Today I "bit the bullett" and ordered two coils for my SX-71.  (The one with
P-poor BCB sensitivity).  They said yes, these were for tube receivers, have
adjustable inductance (for tracking) etc.

I ordered both the antenna AND the RF amplifier coil as I thought I would
try replacing both units.  This will allow me to adjust the low to high end
of the BCB for best tracking.  One thing I did notice about this set was
that the BCB band "peaking" didn't track really well.  Instructions say to
tune the oscillator "padder" for maxmum gain at 600kHz (which peaked 600kHz
at about 580 on the dial and then it was still poor).  Of course that made
the dial calibrations off some from one end of the dial to the other.

Now, I really suspect that getting these coils to track properly (and
replacing what I'm sure is a bad input coil) will REALLY bring up the BCB
sensitivity.)  I will first take an AGC and S meter reading on a given
station (640kHz)  AND on the signal generator at 600kHz.  Then after doing
the coils I'll re-check.  IF, by any chance the gain is too high and I get
overloading on any local stations I can either reduce the RF gain or "swamp"
the RF amplifier coil with a resistor (as the factory did).

After this job is all finished I will post the results here for all to see
(Along with the AES part numbers).  At $7.75 each plus shipping they won't
break the bank.

73 de Phil  KO6BB
Loving home provided for wayward Boatanchor Receivers
k06bb at elite.net
Merced, Central California
37.18N  120.29W  CM97sh






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