Category Archives: Radio history

Taking Requests by Signal Lamp: 1946

1946Jan21BC

WW2-era signal lamp. Wikipedia photo.

The taking of requests has been a long-standing tradition in the broadcasting industry. Most typically, the requests come in by phone, but other methods are possible, as shown in this item from Broadcasting magazine 75 years ago today, January 21, 1946.

WXLH, the Armed Forces Radio Service station in Okinawa, which had come on the air on May 17, 1945, carried a request program, originally slated to run 45 minutes six nights a week. The program was widely popular with servicemen, and requests poured in by telephone, teletype, mail, and in person.

Awase Mudflat Okinawa.jpg

Buckner Bay. Wikipedia image.

Left out, however, were the sailors on the hundred or more ships anchored in Buckner Bay. To accommodate them, on Christmas, some of the station’s engineers rigged up a 500 watt bulb on a stand and pointed it toward the bay. They blinked out a message that the station would be happy to take Navy requests as well.

The sky lit up within minutes with beams of light crisscrossing the horizon. AFRS and Signal Corps men dotted the hillsides and took down the requests.



1941 Inagural

1941InnaguralParade1941Innagural2Eighty years ago today, NBC Radio covered the third inagural of FDR with the help of a 25 watt FM transmitter. During the parade, receivers atop the Washington Monument and the dome of the Capitol. The pickup at the Washington Monument is pictured here, and clearly features a National HRO receiver not unlike the model we previously showed.

This item appeared in the January 27, 1941, issue of Broadcasting, which also carried the item at left detailing the work of radio amateurs from the Washington Radio Club. The hams handled 509 pieces of traffic for Red Cross first aid teams with battery-powered 2-1/2 meter radios.



1930 Car Radio

1930JanPMIn 1930, this gentleman, Popular Mechanics writer Allen C. Forbes, was undoubtedly the first on his block to have a car radio in his 1929 Nash. It took him two years of experimentation to finally succeed, but succeed he did, and he reported that the set furnished pleasure to himself during the day and to his family when out for an evening ride.

He reported that the biggest problems were ignition noise and lack of a good antenna and ground. Ignition noise was solved by suppressors in the ignition line and a well shielded set. For an antenna, he settled upon a screen mounted under the car’s fabric roof. He reported that with a set of six or more tubes, he could get good loudspeaker volume 100-150 miles away from a station.

Grounding was very difficult, because he used the car’s battery as the A battery, but the car had a positive ground, while the radio had negative ground. The set’s ground connection was not used, and the set was mounted with great care so that no part of the metal chassis or case touched the car chassis. The B and C batteries were mounted in an extra battery box. A plug-in cable was fabricated to facilitate easy removal of the radio from the car.

The radio was an Atwater-Kent model 35 with 3 RF stages, detector, and 2 audio stages. He noted that it was essential that a set with a metal cabinet be used, and that the set needed plenty of RF stages to offset the short antenna. Tet was mounted in the car upside down, and he noted that it was a good idea to solder the tubes into their sockets, especially if the car wasn’t equipped with shock absorbers.

The article appeared in the January 1930 issue of Popular Mechanics.



1921: New Transcontinental Radio Record

1921Jan19WashStarThis item appeared a hundred years ago today, January 19, 1921, in the Washington Evening Star:

RADIO RECORD IS MADE.

Civilian Message, Coast to Coast, and Reply in 6 1-2 Minutes.

HARTFORD, Conn., January 19.–A new civilian wireless record was established when Hiram Percy Maxim sent a message from his station here to Los Angeles, Calif., and received a reply 6-1/2 minutes later. The messages were relayed by stations at Chicago and Roswell. N. M.

Tests under the auspices or the American Radio Relay League, of which Mr. Maxim is president, have been made for four nights. It was announced the preceding day that a message had been sent to Los Angeles from this city and a reply received in 1 hour and 8 minutes, a new civilian mark for cross-continent wireless relay. The former record was said to have been 1 hour and 20 minutes, established four years ago by the Maxim station.

Amateur radio operators In all parts of the country sent messages of congratulations to Maxim when they learned through their wireless sets of the new record.

 



Heath Parasol: 1931

1931JanPMMost of our readers are quite familiar with Heathkits, since starting in 1947, the Heath Company sold kits for a wide variety of electronic devices. But the company actually got its start in 1926 with the product shown here, a Heathkit airplane, namely, the Heath Parasol.  About a thousand of the kits were sold in the late 1920s and early 1930s.

The ad here appeared 90 years ago this month in the January 1931 issue of Popular Mechanics.



1941 Sonora Radios

1941JanRadioRetailingAEighty years ago this month, the January 1941 issue of Radio Retailing carried this ad showing the 1941 lineup from Sonora Radio. With one exception, all of the sets shown cover the broadcast band only. Two are portables, and one, the model KNF-148 also includes a phonograph.

The six-tube model KXF-95 was a console which also tuned shortwave and included a phonograph. The company was based at 2626 Washington Blvd., Chicago.



1941 One Tube Regen

1941JanRadioTVEighty years ago this month, someone wrote in to the January 1941 issue of Radio & Television
magazine requesting plans for a one-tube set which would cover the broadcast bands and the shortwaves. The editors obliged with this simple circuit.

Coil winding data was included, and the editors noted that with the capacitor shown, one coil would cover the entire broadcast band. On the shortwaves, they noted that tuning would be very sharp, and recommended a smaller bandspread capacitor in parallel with the main tuning.



Hallicrafters HT-40 Transmitter & SX-140 Receiver, 1961

1961JanElecWorldSixty years ago this month, the January 1961 issue of Electronics World carried this ad for the Hallicrafters HT-40 transmitter and SX-140 receiver for the 80-6 meter amateur bands. They were available assembled or in kit form. As a kit, the transmitter retailed for $79.95, and the receiver, $94.95. Assembled, the prices were $99.95 for the transmitter and $109.95 for the receiver.

The five-tube receiver was billed as the lowest-priced amateur band receiver available. The transmitter had a DC input power of 75 watts to a 6DQ5 power amplifier, with a 6CX8 serving as crystal oscillator and driver. For AM, it used a 12AX7 audio amplifier and 6DE7 modulator. Both units featured silicon high voltage rectifiers.

I’ve never seen the receiver in operation, but the HT-40 was my first transmitter as a novice, and I used it to burn up the ether on 40 meters in 1974. I used that transmitter for my first few months as a novice before upgrading to a Viking Ranger with VFO. When the transmitter first came out, novices were limited to crystal control, and it made an ideal novice rig. When the licensee upgraded to general (or even technician, thanks to the presence of 6 meters), the new licensee could get right to work on AM.



Answers to Yesterday’s Quiz

1961JanPE2As promised, here are the answers to yesterday’s quiz, from the January 1971 issue of Popular Electronics.

The one on the left is 12 pF.  The center one is 6 pF, and the one on the right is 10 pF.



Capacitor Quiz

1961JanPE2This quiz appeared in Popular Electronics 50 years ago this month, January 1971. With a little bit of re-drawing and some basic math, you should be able to come up with the answers. If not, we’ll post them here tomorrow.