Category Archives: Radio history

1927 Book and Piano Radios

Apparently, the big fad in radio 90 years ago was radios that didn’t look like radios. These examples come from the August 1927 issue of Popular Mechanics. The first, shown above, looks like a book, but it’s actually a crystal set. According to the magazine, the set had recently come on the market and was nicely constructed. It had enough space inside to accommodate the headphones, antenna, and ground lead. It was said to pull in stations within a radius of 20-30 miles.

The second example was a homemade six-tube set built in to a miniature baby grand piano. The speaker cone was mounted at the rear on the sounding board.

1942: Last of the Prewar Radios

75 years ago, many consumer products, such as radios, stoves, and vacuum cleaners were no longer rolling off the assembly lines now devoted to war production. Civilian radio production, for example, ended on April 22, 1942. But these items remained available, as retailers sold the last of the remaining stock.

This ad appeared in the August 27, 1942 issue of the Chicago Tribune and shows some of the last prewar versions of these items.

The model number of the Silvertone radio-phono is not shown, but according to the ad, the set was an $89.95 value selling for only $68.88. It featured an automatic record changer which could accommodate up to ten 12″ records or twelve 10″ records. The six-tube radio tuned both standard broadcast and shortwave.

1947 Crosley Spectator

Seventy years ago, television was finally becoming a reality. The war was over, stations were coming on the air, and the enlightened radio dealer was getting ready to move into television. Crosley, the pioneer in radio manufacturing and broadcasting, had also made the move to television. The Crosley Spectator is shown here, from the August 1947 issue of Radio & Appliance Journal.

The set boasted an image size of 6-3/8″ by 8-1/2″, had 27 tubes and three rectifiers, and tuned all 13 channels, 44-216 MHz, including the elusive channel 1, which was never put to use.

Those 27 tubes consumed 380 watts, and the set weighed in at 85 pounds.

The ad assured the dealer that the Spectator in the shop window as its own salesman, and each set sold would become the talk of the neighborhood and draw in even more business.

You can see a nicely restored example of this set in operation at this video:

Metal Tubes Go To War

Now that the excitement of the eclipse has passed, we will resume our normal programming, focusing mostly of the history of radio. We offer this advertisement from 75 years ago this month, showing the vacuum tube having gone off to war. But it’s not just any tube, it’s a Ken-Rad metal radio tube, made by the Ken-Rad Tube & Lamp Corporation of Owensboro, Kentucky, which assured that as soon as the war was over, metal tubes would be back for civilian customers.

Ken-Rad was founded in 1899 as the Kentucky Electrical Lamp Company. It was sold in 1918 and used to create the Kentucky Radio Corporation, later known as Ken-Rad. The company started making radio tubes in 1922, and also continued to make light bulbs. The company’s light bulbs were used to light the first Major League Baseball game played at night in 1935.

The lamp division was sold to Westinghouse in 1943. The tube division was sold to General Electric in 1945. The company’s building was torn down in 2007 and is now an Owensboro city park.

The ad appeared in the August 1942 issue of Radio Retailing.

The Dark Side of Sunspot Cycle 19

1967AugRadioElec Sixty years ago, solar activity was at an all-time high, and the sun was plastered with sunspots. This was good news for hams, who depend on this solar activity for ideal radio communications on the high frequency bands. But in addition to being literal dark spots, this was, figuratively a dark time for the hapless TV repairman in fringe areas, because it fell upon him to explain to his customers that their interference woes weren’t his fault, but were instead caused by blotches on the sun.

Fortunately, the TV repairman got some sympathetic advice from this article in the August 1957 issue of Radio Electronics.

It starts by noting that Sunspot Cycle 19 was about to reach a peak, which was good news for hams and shortwave listeners, for whom shortwave propagation would be better than at any other time in history.

But the average TV owner “probably does not care about receiving Havana, Cuba, or some other distant TV station over his favorite local channel,” which was a distinct possibility in fringe areas. The article noted that this would be particularly an issue for channels 2, 3, and 4.

The article counseled the serviceman on how to deal with these calls. And unfortunately, there was little that could be done, other than to “explain to the owner what is happeninng and that the condition will probably pass in a short while. Ask him to call the next day if the trouble is still there.”

The article suggested that a good way to educate the customer would be to draw a sketch of the earth and ionosphere as shown above. While reorienting the antenna might help in some cases, the best advice was to hope that the owner understood what was happening. If the customer understood, it would make him “less likely to call a service technician and thereby leave the technician more time to devote to true television troubles.”

1942 Mallory Wood Condensers

1942AugService With wartime material shortages, replacement radio parts were hard to come by. And even when parts were available, the manufacturers had to adapt to wartime conditions.

This is illustrated by this ad from the August 1942 issue of Service magazine, showing the Mallory “Wood Neck” condenser (what we would call a capacitor these days). Instead of an aluminum case and base, the capacitor had an impregnated paper case and a threaded wooden base. The ad noted that “they are designed for the emergency but we predict they will be popular long afterwards.”

1917 Wireless Telegraph

We’ve carried plans for other wireless telegraphs and telephones that relied upon ground conductivity, and here’s another one that comes from a hundred years ago this month, in the July 1917 issue of Electrical Experimenter.

This one is a bit mysterious for a couple of reasons. First of all, the receiver appears to contain a crystal detector wired in series. (At least I think that’s what the component to the left of the capacitor is.) Admittedly, I haven’t tried making one of these, but I can’t really see the purpose of it, since the signal transmitted through the ground is essentially an AF signal that the headphones would be able to pick up.

Second, I can’t see any real advantage in burying one of the ground electrodes so deep (10 feet). Doing so does achieve 9 feet of separation between the two grounds, and this separation is necessary. But it seems to me that this could be accomplished much more easily by placing both grounds near the surface, separated horizontally. This would avoid the necessity of having to dig a 10 foot hole, which seems like a lot of work.

Finally, I can’t think of any good reason for making one electrode copper and the other zinc.

The accompanying text doesn’t answer any of these mysteries. The diagram was submitted by a reader, one O.M. Warren of Detroit, MI, who submitted it along with the question, “would it be possible to use the following scheme to telegraph a distance of a block or two?”

The editors answered merely: “Yes. You will have no trouble in transmitting considerably more than the distance you mention.” But they don’t even hint that Mr. Warren needn’t bother digging the two ten foot holes.

The reader also asked whether a tuning coil or loose coupler should be used, but the editors did say that they should not be used, since “it is impossible to tune any distant signal with this ground telegraph system, speaking generally.”

But since radio transmission or reception were forbidden during the war, Mr. Warren would be able to communicate. Let’s hope that nobody told him his ten foot holes were unnecessary.

Think It Over, 1942

This RCA ad, which appeared 75 years ago in the July 27, 1942, issue of Broadcasting, shows the warning label affixed to radios in Nazi Germany. It contains this warning:

Think it over. Receiving foreign broadcasts is a crime against the German State. By order of the Fuehrer, it will be severely punished.”

The ad goes goes on to say that most will think it over. And perhaps, like a sensible Nazi subject, the radio’s owner will take the warning to heart.

And maybe you don’t. Maybe there’s a hunger for truth in you, that no threats can suppress. Maybe you still retain some sense of the inalienable rights of a decent human being.

Maybe you tune in far-off America: to RCA-NBC International Shortwave Stations WRCA and WNBI, hearing truths that are flashes of light in a world of darkness and despair.

WJAZ and the Eclipse of 1925

Portable station WJAZ. Radio News, Jan. 1925.

During the August 21 solar eclipse, I’ll be contributing some radio propagation data by making beacon-style transmissions on 7 MHz from the path of totality. These will be picked up by the Reverse Beacon Network, and can be analyzed later to see how the eclipse affected radio signals traveling through the ionosphere.

Such experiments are nothing new, as shown by an article in the February 15, 1925, issue of Radio Progress. Radio station WJAZ was one of several portable radio stations licensed in the 1920’s. The station was owned by and licensed to Zenith Corporation, and was mounted on a one-ton truck chassis. It was originally built in 1924 for testing to determine the best location in Chicago for the company to build a permanent station. It continued service to promote Zenith radios by rolling into towns to provide something for local radio buyers to listen to. The station was equipped with a battery operated 100 watt transmitter, a generator, and 53 foot telescoping antenna masts.

In anticipation of the eclipse of January 24, 1925, the company brought the station to Escanaba, Michigan, which was on the center of the eclipse path of totality. This eclipse was visible along a path from northern Minnesota extending to the northeastern United States and then over the North Atlantic. WCCO in Minneapolis managed a live remote broadcast with a portable transmitter in an airplane.

After driving the 1120 kHz portable station to Escanaba, Zenith set it up at the rear of a garage building with a 100 foot antenna running almost straight up the mast. The studio was set up in the front show window. For the three nights preceeding the eclipse, the station ran a musical program from 10:00 PM to 1:00 AM and solicited reception reports. An average of 500 reports were received by telegram each night, since the station was awarding free Zenith receivers to those reporting from the greatest distance, as well as to listeners selected by drawing. The greatest distance covered during those tests was about 800 miles.

The night before the eclipse, the station was on the air from 10:00 PM until 1:30 AM. At 3:00 AM, the station was back on the air in advance of the 8:02 AM eclipse, and remained on the air until 9:00 AM.

The station reported that between 3:00 and 5:30 AM, only ordinary results were obtained, with a few telegrams coming in from Missouri, Kansas, and Nebraska. As the normal “gray line” propagation began at about 5:30 with the sun starting to rise, propagation was enhanced, and telegrams were received from as far away as Oklahoma. As the station began to go under the shadow of the moon, the station reported that the normal early morning enhancement of propagation continued, with reports being received from Nebraska, North Carolina, Ontario, Oklahoma, Kansas, and Iowa.

The article concludes that the tests “proved conclusively that the theory of ionization and absorption of radio waves due to the sun’s rays is no longer a theory only, but actually a fact.”

Making QSL’s With a Hectograph

The venerable hectograph made an appearance 80 years ago this month in the pages of the July 1937 issue of Shortwave and Television magazine. Today, it’s trivially simple to print numerous copies of a document at home with an inkjet or laser printer, or to go to the local copy store and print them there. But this hasn’t always been the case. 80 years ago, printing in quantity was more or less a secret art practiced only by professional print shops.

But there was one exception, and that exception was the hectograph, or gelatine duplicator as it’s called here. The desired image was drawn or typewritten onto paper using special ink, that ink was transferred to gelatine, and then copies could be made onto any paper. The hecto- prefix implies that a hundred copies could be made, although that’s more of an upper limit. Nonetheless, for small print jobs, the hectograph provided about the only method of home printing for many years.

This was not lost on one Miss M.E. Burke, who was apparently a shortwave listener in need of an inexpensive method to produce SWL or QSL cards. She used a gelatine duplicator, simply printed them at home, and then sent the idea to the magazine, which agreed that it was a good idea.

Back in the day, hectographs could be purchased wherever office supplies were sold. My own entry into the world of publishing came when I got a toy hectograph for Christmas. I soon graduated to a more professional model, on which I was able to prepare typewritten newspapers.

Since they are obsolete technology, you can’t buy a hectograph today. But fortunately, they are so simple that you can make one at home, and I have full instructions at my website. All of the materials you will need are readily obtainable, and you’ll be on your way to creating a vintage style QSL card or other printed item.

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