Category Archives: Radio history

Hammarlund Super Pro Console, 1937


The Hammarlund Super-Pro series of receivers represent one of the best performing prewar communications receivers. The line was first introduced in 1936, and when war came, they took the BC-779 nameplate for the military version.

Thousands of the models making up the series rolled off the Hammarlund assembly line over the years, but one of the rarest variations is shown here, and it appears that only about 70 were made.  Inspired, no doubt, by high-end home consoles such as the McMurdo Silver, Hammarlund decided to move the set from the ham shack to the living room.  So they put it in the cabinet shown here, as seen in the August 1937 issue of Radio World.

But it wasn’t just any cabinet that they slapped it into.  As the accompanying article explains, the cabinet was carefully designed for its audio qualities, particularly the bass response.  There’s no doubt that the set was a top performer, and I’m sure it sounded good.  Since it was destined for the living room, a few modifications were made.  For example, even though the set had a BFO for listening to code, the BFO pitch was not adjustable from the front panel.

But it was a flop as far as sales.  As the Radio Boulevard site explains, “it just wouldn’t do for hams – it had no BFO on the front and it was too big. It didn’t have the Scott or McMurdo chrome chassis – how could you impress your friends?”  The site does have a picture of a nicely restored specimen, owned by AA6S.  From the color picture, it does look like a communications receiver thinly disguised as a console.  The front panel is faux walnut, and just looks out of place.  It’s not quite a communications receiver, and it’s not quite a console.

I’d love to have one in my living room.  And as a loyal reader, you would love to have one.  But let’s face it, nobody else would want one!

Elizabeth Rickard, Radio Pioneer

1917NovElecExpShown here, from the November 1917 issue of Electrical Experimenter,
is Miss Elizabeth Rickard, the first woman to graduate as a radio operator from Hunter College, New York City. According to the magazine, she received her first grade commercial license.

The school had a “very enthusiastic wireless class who are blest with every provision for quickly assimilating the intricacies of radio telegraphy.” The Marconi company had presented the college with standard receiving and transmitting equipment, as well as instructors.

Miss Rickard entered the college’s wireless class in April 1917, and in May of that year, she was detailed to the Marconi school for intensive training. She passed her tests in July, with the highest scores of the class of 20 men and 3 women.

1937 Montgomery Ward Ham Station


Eighty years ago, the October  and November issues of Radio News carried a review of the model OR-5 transmitter for the 160 through 10 meter bands put out by an unlikely supplier for ham gear, namely Montgomery Ward & Company.

The reviewer, Everett Walker (whose call was, coincidentally, W2MW, whose 5 meter station we previously featured), posted an overall favorable review of the transmitter: “the small transmitter proved itself an excellent all-band unit on small power. On the higher frequencies it proved a good competitor for the 500 watt transmitter used at W2MW. On the lower-frequency bands it put out a signal that could compete with the normal QRM with more effectiveness than was expected. The transmitter also was tested on 160 meters, not at the writer’s station, but at a nearby station that was equipped with an adequate antenna. Here it put out a good signal and the operator who made the test reported local communication was excellent and more than six “out-of-the-district” stations were worked within a short time.”

He noted that the rig put out 60 watts CW on all bands but 10 meters, where it put out 40 watts.

The rig was geared mostly for the CW man, but the accompanying OR-7 modulator was also available for AM use. In the photo above, the transmitter is at the right, with the modulator in the middle. The accompanying receiver on the left, whose model number is not stated, is also from Montgomery Ward.

1937 Little Giant Cathedral Crystal Set


This ad for a “Cathedral” radio from the Little Giant Radio Company of 1166 Diversey Pky, Chicago appeared in Radio Guide 80 years ago today, November 20, 1937.

The ad praises the set in near miraculous terms, and contains a number of glowing endorsements. Of course, the set is a simple crystal set. The “cabinet”, it turns out, is made of cardboard, and the earphone is mounted permanently right on the back. So to listen, you have to hold the whole radio up to your head.  The set had two large alligator clips, presumably to attach to an antenna and ground.  But it’s just $2.95, they would send it C.O.D., and your satisfaction was guaranteed.

More informaton, and a picture of the set, can be found in Volume 2 of Crystal Clear: Vintage American Crystal Sets, Crystal Detectors, and Crystals.  (Volume 1 and Volume 2 of that set are both available on Amazon.) You can also see some more photos of the set at this link.

US Army Signal Corps, 1942

Signal Corps mobile radio unit.

Signal Corps mobile radio unit.

Seventy-five years ago this month, most of the November 1942 issue of Radio News was devoted to the U.S. Army Signal Corps, and included dozens of photographs, including the color photos shown here. The photos themselves were taken by Signal Corps photographers, which comprised a branch of the service.

Here are a few of them, showing various phases of both wireline and radio communications.

Command car equipped for both voice and code communication.

Command car equipped for both voice and code communication.

Operation of handheld radio from Jeep, probably around 50 MHz.

Operation of handheld radio from Jeep, probably around 50 MHz.

Radio-equipped halftrack.

Radio-equipped halftrack.

Students receiving instruction on portable transmitter.  Note operating frequencies of ___ kHz.

Students receiving instruction on portable transmitter. Note operating frequencies of 2300, 2900, and 3400 kHz.

Operating radio from concealed position with hand-driven generator.

Operating radio from concealed position with hand-driven generator.

Operating four-band portable field set.

Operating four-band portable field set.

Field telephone in operation.

Field telephone in operation.

Field telephone switchboard.

Field telephone switchboard.

Placing telephone lines.

Placing telephone lines.




1933 One-Tube “Triflex” Shortwave Receiver

1933NovSWAs our loyal readers are aware, we often get off on tangents here at, but we always try to get back on track by showing actual One Tube Radios.  And the one we offer today has all the hallmarks of being an excellent performer, covering the range of 10-200 meters.

1933NovSW2This is a one tube radio, since it uses a single 6F7.  But we’re cheating a little bit, not only because it’s a dual tube, but because the two halves of the tube are actually doing the work of three tubes.  The 6F7, which is still readily available at a reasonable price, consists of a pentode and a triode in the same envelope.  In this circuit, the pentode is used as an RF amplifier, with the triode serving as the regenerative detector.  But through the magic of “reflexing,” the pentode is then used a second time to serve as an audio amplifier.  The result is that the set gives the performance of three tubes, while only using a single tube.

The circuit originally appeared in the November 1933 issue of Shortwave magazine, in an article written by “well known shortwave engineer” Clifford E. Denton, who dubbed the set the “Triflex.”

For those wishing to duplicate the circuit, parts, or reasonable substitutes, should be readily available.  The new-old-stock tube can be found at this link.  You’ll probably need to make the plug-in coils yourself, but you’ll find helpful hints at this post.  Most of the other parts can be tracked down at my parts page.


1942 RCA Shortwave Transmitters

1942Nov16BCSeventy-five years ago today, the November 16, 1942, issue of Broadcasting carried this ad with a story showing the importance of the nation’s shortwave broadcast transmitters.

When Herr Braun was ordered to report for farm work in the south of Germany, he made an arrangement with his brother who worked in the rail yards. No matter what happened, the brother promised to write from Cologne every week.

At first, Herr Braun received letters written on cheap thin paper. But one week, the letters stopped with no explanation. The local Nazi paper reported an ineffective British raid on Cologne, but with only small damage. The Luftwaffe was invincible, according to the paper, an the enemy could never reach Cologne in force.

But the letters never came. So one night, Herr Braun tuned to a forbidden station–an American shortwave station. “And there it was–the facts, the figures, the full grim story of the mighty German city blown to bits from the air. Yes, the railroad yards were destroyed.”

So Herr Braun started to wonder. The newspaper had lied. Thanks to the powerful shortwave transmitters using RCA equipment, Herr Braun’s faith began to fade.

Canadian Northern Radio

1942NovManitobaCallingSeventy-five years ago this month, the cover of the November, 1942, issue of Manitoba Calling, the program guide of CKY Winnipeg, carried this photo of two northern residents being kept company by their radio through the lonely winter.

With its 15,000 watt voice from Winnipeg, the station had become “one of the family” for many of those in Canada’s north, including missionaries, trappers, Mounties, doctors, nurses, and fur traders.

The magazine noted that during the First World War, many of these residents did not hear until the spring of 1915 that Canada was at war. But with radio, “a fur trader in his lonely cabin will hear the news and the latest developments on the war-fronts at the same instant that we in urban centres hear them.

The article noted that radio must still occasionally bow to atmospheric conditions, and the Aurora Borealis might occasionally wreak havoc on the standard broadcast band. But it also noted that when broadcast reception was poor, shortwave reception was frequently good, allowing northern residents to hear both American and overseas stations.

The service provided by CKY continues as part of CBC North.  While shortwave service ended in 2012, service is currently provided by a network of FM stations.

Ship Radio Operators Needed: 1967

1967NovEIFifty years ago, the November 1967 issue of Electronics Illustrated explained how the gentleman shown in this drawing could achieve his dream of seeing the world as a ship radio operator.

The article made clear that there were two conflicting priorities at work: The lines needed radio operators, but the unions had their own vested interest in keeping the supply tight.

Ships sailing under the American flag had to have a licensed radio officer aboard, and the lack of men sometimes meant sailing delays. One bottleneck was Vietnam. Two hundred ships had been called up from the reserve fleet. Many radio officers had been called back from retirement, and those on duty were being asked to forego vacations and leave.

Entry into the field wasn’t easy. Most American ships carried only one radio officer, but he had to hold a First Class license. But to get a First Class license, you had to have six months’ service at sea.

Because of the shortages, the Radio Officers Union recently started a limited training program. After six months, the man was ready to take an assignment on a one-man ship. After 18 months, he was entitled to full membership in the union. Base pay was $300 per month for the next six months, and then $600 per month for the next 18. After becoming a full member of the union, his pay shot up to $900-$1000 per month, with good benefits. Retirement, with about a third of the pay, was possible after just 20 years of service, regardless of age.

The magazine contained addresses of the union and companies for those interested in looking into a career at sea.

1937 Ground Rod and AC Powered Mini Trouble Lamp

1937NovPMEighty years ago, the November 1938 issue of Popular Mechanics showed this method of increasing your ground conductivity. The addition of water isn’t even mentioned in the text. But by adding the water, the ground near the rod becomes saturated, increasing the conductivity.

The actual hint being discussed is the use of a spark plug as a lightning arrestor. The lead-in is connected to one terminal of the spark plug, with the other end grounded.

1937NovPM2Another hint shown in the same issue is shown here. Batteries are cheap enough these days that I don’t think it would be worth trying to put together this contraption, which doesn’t look very safe. But if you really want to run your small flashlight off AC power, then wiring it in series with a 25 watt light bulb, as shown, would do the trick.