[Hallicrafters] Correction: SX-101 difference from SX-101A

[Glen Zook]

The original SX-101 came out in 1956 and had 13 tubes
plus rectifier tube and voltage regulator tube.  It
covered 160 meters through 10 meters plus an
uncalibrated band with a "spot" on the dial marked for
WWV at 10 MHz.  It did not have a product detector. 
Sideband selection was controlled by the switching of
crystals in the 2nd conversion oscillator.  The BFO
was continuously tuneable.

The SX-101 Mark II was basically the same receiver as
the original (sometimes called the Mark I).  The Mark
II did have a "damp chaser" installed.

The SX-101 Mark III is a slightly "up graded" version
of the Mark I/Mark II.  This version has an additional
filament transformer added to keep the heater of the
1st conversion oscillator "on" at all times.  The Mark
III also has a "damp chaser".

The SX-101A has a product detector and the "damp
chaser" was "renamed" as a "heating element".  The 1st
conversion oscillator has the heater "on" at all
times.  One additional tube (for the product detector)
was added.  The 160 meter band was eliminated and a
band which covered 30.5 MHz to 34.5 MHz was added as a
"converter band".  This was calibrated with markings
for both 6 meters and 2 meters.  However, other VHF
bands (especially the 1.25 meter band and 70 cm band)
were often used with appropriate converters.

The manuals for all 4 versions are available on BAMA.

The only version of the SX-101 that I have owned was
the SX-101 Mark III which I had for a little while
back in the mid 1970s.  I do own working SX-100 Mark
I, S-85, S-107, and S-20R, and have S-40, S-40A,
S-40B, and S-19R ("Sky Buddy") that are in need of
restoration.


--- Greg <bluebirdtele at embarqmail.com> wrote:

Would you please tell use the differences between the
SX 101 variants?  This thread needs your TLC OM.

Tnx

Greg
WA7LYO









Glen, K9STH

Website:  http://k9sth.com


       
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