The S-20R was a popular shortwave receiver prior to WWII
judging by the many seen to this day. It was a single conversion superhet with
no frills, but a good basic design for the casual listener.
The SX-25 "Super Defiant" was a pretty decent shortwave and amateur receiver
from the pre-war years. Stability and dial calibration was good and after
replacing a bad tube and all the paper and electrolytic capacitors, I gained a
useful receiver for the shack. Another SX-25 was acquired recently, but will
require a bit more work to restore because the previous owner painted it blue.
Hallicrafters developed the S-36 VHF receiver
toward the end of WWII. The styling was typically pre-war and the design
resembled the SX-24,25,28 series. It is a single conversion superhet with a
5.2 MHz. I.F. covering 27-145 Mhz. Both AM and FM modes are available and a
BFO was provided for CW reception.
S-36A was produced in 1946 and is in excellent condition for its age.
I only had to blow out the dust and replace a broken fuse holder. I also added
a three-wire power cord, then plugged it in.
After several decades on the
shelf, it lit up in good vacuum tube fashion. After some knob-twisting to wipe
the switch contacts, I was able to tune some FM broadcast stations in the 88-108
MHz. range. There may be some capacitor issues, but the push-pull audio output
sounds pretty good.
The S-40A was sold by Hallicrafters between 1947 and 1949. It was a step up
from the AC-DC S-38 series of shortwave receivers and an extension of the
pre-war S-20. The S-40A used metal receiving tubes except for the rectifier
tube which was a glass "80." The parts were of better quality than the later
S-40B units which makes this a desirable collectible.
This is the S-40B. I replaced the frayed power cord and
plugged it in not expecting much because the wax-covered paper capacitors looked
like they all had melted. To my surprise, it powered up and played beautifully.
A good cleanup and replacement of all the capacitors will restore it to like-new
The S-53A is a good tabletop shortwave receiver from the
early to mid-1950's which doesn't take up as much space as equivalent models.
Although it is slightly larger than the S-38 series, it boasts a
tranformer-operated power supply, eliminating the potential shock hazard
associated with less-expensive AC-DC models. I saw an S-53 that was in mint
condition go for almost $400 on E-Bay recently, but they normally don't command
much more than $50-$100 if in good condition.
The SX-71 was a pretty decent receiver from the early 1950's.
It offers double conversion with resulting good selectivity at the low I.F.
frequency. The mechanical stability exceeds that of the less expensive models
from the era.
When I first became a radio amateur in 1959, I had a Heathkit
AT-1 transmitter and a Hallicrafters S-38 receiver. I fruitlessly called "CQ"
for several months but couldn't copy anything through the QRM on the 40 meter
novice band using the S-38. I think the band took up only a quarter of an inch
of bandspread dial space. Some ham friends from school took pity and arranged
some QSO's with me. I was invited to the Four Lakes Amateur Radio Club for
Field Day in June and was able to operate the novice station with some good
tutors and excellent equipment. Immediately afterward, I took my savings to
Satterfield Electronics in Madison and with the help of my Dad, traded in the
S-38 for an S-85. From then on, it was relatively easy to make some contacts
and after switching to 80 meters, I was able to become proficient enough with
CW to pass the General Class license that Fall.
By today's standards the S-85 wasn't much of a receiver due to the broad I.F.
and mechanical instability, but to me it made the difference between giving up
amateur radio or moving ahead to what became a career in communications.
The next step up from the S-85 was the SX-99 with a crystal
filter and S-Meter. Although basically an S-85 with a few frills, it actually seemed to be a little more mechanically stable than the economy version. My friend Roy, KN9UWY, had one of these and seemed to hear more DX than I could on 40 meters. Maybe his vertical with a metal mobile home for ground near the swamp by Interlake helped.
Hallicrafters produced the SX-96 as a high-end version of
the S-85/SX-99 general coverage receivers. Although it looks outwardly like
its economy-priced cousins, it features double-conversion and much improved
mechanical stability. The SX-96 was followed by the SX-100 which is still a
desirable model for collectors and resultantly high priced on the used market.
The original SX-101 appeared in the late 1950's. It was a double conversion design with a 50 KHz. low
I. F. which provided an effective passband characteristic for both `phone and CW. The heavy duty
construction of chassis and case made it a hazard to carry around the shack. The early model included
the 160 meter band, but the "A" models eliminated 160 meters and added tunable range for VHF converters.
At the time, the LORAN navigation system effectively made 160 meters useless so many manufacturers didn't
include the band on their equipment.
In the 1960's, Hallicrafters changed the physical design of
their equipment which gave it a more comtemporary look. The slide rule dial
was adopted to replace the circular ones that had persisted since the 1930's.
The SX-111 was a very good double-conversion ham band receiver which was
similar to the more expensive SX-101. Although not as mechanically robust as
the '101, it wasn't far behind in performance. If you want a usable, but
relatively inexpensive boat anchor receiver for your 60's ham station, try one
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