Hallicrafters Model S-38 Communications Receiver (1946)
Adding an S-Meter
One of the most popular shortwave radios ever made, the charming Hallicrafters S-38
introduced many thousands of people to shortwave and CW listening. It appeared in 1946,
immediately after the World War II consumer radio hiatus, and was priced at only
$47.50, making it the entry-level receiver for the Hallicrafters line.
This advertisement from Radio News magazine of 1947
shows the S-38 along with two more expensive Hallicrafters
sets.
Description
Using six tubes, the S-38 is a transformerless AC/DC radio with a metal
cabinet and integrated speaker. Its compact size and low cost made it very attractive
to radio-hungry consumers in the postwar years. Following the original S-38 were
models S-38A through S-38E, remaining in production until 1961.
Despite its simplicity, the S-38 is a "hot" radio, offering good sensitivity.
Like more expensive shortwave receivers, it has a separate bandspread tuner,
automatic noise limiter (ANL), and beat frequency oscillator (BFO) for CW listening.
It covers frequencies from .54 Mhz to 32 Mhz in four bands.
Many collectors consider S-38 the most desirable model in this line, since
later models lack the BFO feature.
With distinctive semi-circular dials, the S-38 through S-38C models are
very recognizable. Models S-38
through S-38B are black, some with a wrinkle finish. The S-38C has gray
hammertone paint. The S-38D and S-38E have a rectangular dial but have the
same features as earlier models. The S-38E was offered in beige and mahogany
as well as gray.
Here is the lineup of the receiver's tubes:
Tube |
Type |
Function |
V1 |
12SA7GT |
Converter |
V2 |
12SA7GT |
IF amplifier |
V3 |
12SQ7GT |
Detector/AVC/AF |
V4 |
12SQ7GT |
BFO/ANL |
V5 |
35L6GT |
Audio output |
V6 |
35Z5GT |
Rectifier |
From a collecting standpoint, the S-38 line is a good way to get started with
"boatanchors." Manufactured in great numbers for more than a decade, they
are still plentiful, and you can often find a good one for less than $50.
I paid about $45 for mine.
A nice feature of the S-38 is its ability to flip quickly across the bands
to see what stations are on the air. But it does lack a couple of features that
I've grown to appreciate in my fancier boatanchors: an S-meter and
an antenna trimmer. An S-meter indicates the strength of the incoming
signal and a trimmer matches the impedance of your antenna,
both aids
to accurately tuning weak signals.
A friend recently sent me some
Hallicrafters literature that explains how to add an S-meter to the
S-38 and several other Hallicrafters models. Our resident engineer, Walter
Heskes, tried out the project, and provided an updated schematic.
Check out our S-38 S-meter page for
construction details.
First Look
My S-38 was complete but rough-looking when purchased. The following
photo shows the set before restoration.
As you can see, the black cabinet was splattered with paint specks
in two different colors (mostly white, but some red). Based on the paint,
and the amount of dirt found inside, I suspect that this was somebody's
shop radio.
If you look closely, you can see a large blob of dust in the middle of
the speaker. Although a top-mounted speaker conserves space, it also
serves as a wonderful dust-catcher!
Electronic Restoration
The radio had not been used for some time;
most of the slide switches on the front were frozen solid. The first thing
I did after removing the chassis from the case was to spray DeOxit inside
all the controls, freeing them up and cleaning out accumulated gunk.
After I slowly brought up the power on an autotransformer, the radio did
play, but the volume was very weak. Powering it down, I proceeded to replace
the old paper capacitors. (See Replacing
Capacitors in Old Radios.) I also cleaned the entire chassis and tested
the tubes, all of which were good.
As boatanchors go, this is an easy set to work on. The underside
of the chassis is uncluttered and there are only about ten paper
capacitors to replace.
After the recapping was finished, the radio played quite well, but the volume
was still weak. Looking for the source of the problem, I tested the voltages
of each tube, comparing them to the values given in the schematic. I also
tested the volume control's resistance. Everything checked out OK, so I
tried another shot of DeOxit inside the volume control.
To my delight, the set woke up and played with plenty of volume. Some times,
one cleaning is not enough!
Not much work had been done on the electronics before I got this set.
The only previous service, apart from replacing some tubes, was
to replace the filter capacitor in the power supply. Since the radio
played without any hum, and had no power-supply problems, I left that
filter capacitor in place. The next photo shows the underside of the
chassis after restoration.
Cosmetic Restoration
That left the cabinet, which looked pretty daunting at first. Soap and water
did nothing to remove the hundreds of paint specks, and scraping them off one
by one was not an appealing prospect. After a little investigation, I found a
product called Goof-Off 2, which claimed to remove latex paint specks. Available
in a spray bottle, this worked very well.
The trick is to spray on the cleaner
and let it soak for a few minutes, before rubbing the paint specks with a soft
rag. Within ten or fifteen minutes, the cabinet was completely clean. Unlike
some solvent-based cleaners, Goof-Off 2 is not stinky. That's a real bonus when
you're working indoors.
Use care when cleaning cabinets with painted lettering. Scraping or rubbing the
lettering too hard may damage it, no matter what sort of cleaner you use.
The upper left corner of the cabinet also had a rust spot about the size of
your thumb. To remove the
rust, I carefully applied some naval jelly with a Q-tip swab and let it
work for a few minutes. Then I wiped it off and cleaned that corner again
with Goof-Off 2. The paint on that corner was worn completely away,
so this treatment left a bare metal spot on the corner.
I haven't decided whether to repaint that bare spot. Some paint "touch-ups"
end up looking worse than the boo-boo that you're trying to cover up!
In present condition, the radio doesn't look like a museum piece, but
it's pretty presentable. And it performs like a new radio.
Safety Note: Like all "AC/DC" type radios, the S-38 presents the danger of
electric shock if you touch its chassis while plugged in. To minimize the risk, you
should always operate the radio from an isolation transformer rather than plugging
it directly into the wall. Isolation transformers are available from
Antique Electronic Supply and
many other sources.
I own several other Hallicrafters radios.
Click the Communications link at the top of this page to
read about them.
About one year after finding this S-38, I ran across another one in a thrift store.
The cabinet looked rough, but the price was right, so I brought it home. It performed very well after routine maintenance. Perhaps I'll put it in one of my
sons' bedrooms to get them interested in shortwave listening. (I won't forget to provide
an isolation transformer to ensure safe operation!)
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