Category Archives: Radio history

1941 “Prairie Dog Special” Transmitter

1941MarRadioNews

1941MarRadioNews2Seventy-five years ago this month, the March 1941 issue of Radio News carried the plans for the “Prairie Dog Special” transmitter, specially designed for Field Day or emergency use. The set was named after the Prairie Dogs, a Chicago area radio club, which had assembled a number of the transmitters, resulting in first place in the four transmitter category in the 1940 running of Field Day.

The transmitter covered 160 through 10 meters, and would put out about 24 watts on phone or 35 watts on CW. It had built-in power supplies for either AC or 6 volts DC, making use of a vibrator.

The circuit consisted of a 6V6G oscillator, with cathode keying for CW. The final amplifier was a HY60 tube, although the article noted that the venerable 807 could also be used. The modulator consiste of a 6C5 audio amplifier, followed by a 6V6 modulator. Two 6X5’s in the power supply did the rectification duties.

Portable operation required FCC notification, and the rules were somewhat complex:

A word about operation. The FCC regs specifically provide that portable operation can only be done on the week-end and then only on 48 hour’s notice to the Commission’s nearest office to your home QTH. Besides this the law provides that the transmissions MUST be from portable power sources. These are batteries, or some generator or another. The use of 155 v a.c. house lines even if they be strung out into a field is specifically prohibited; though a motor generator producing this voltage is not. So use your P.D. Special only on 115 v a.c. at home, or if in the field, then only from some motor-generator or battery. The provisions concerning reception are left open, and there is not any requirement that the receiver be battery or motor-generator powered.

The article’s author was Raymond Frank, W9JU.

Click Here For Today’s Ripley’s Believe It Or Not Cartoon



Lola Schofield, WMBB Chicago, 1926

LolaSchofieldIn an earlier post, we covered WMBB radio, which broadcast from the Trianon Ballroom, the “World’s Most Beautiful Ballroom” from 1925 to 1928. Shown here is more of the station’s on air talent, Lola Schofield. This picture appeared in the March 13, 1926, issue of Radio Digest, which noted that she helped make the station’s programs pleasant with her dramatic soprano voice. The station concluded its broadcasts with the cast singing, “W-M-B-B Chi-ca-go,” an early example of a station jingle.

Shown below is more of the station’s talent, “Dell Lampe’s Syncopators,” which, according to the caption, could always be depended upon to provide lively dance music.

wmbb

 

Click Here For Today’s Ripley’s Believe It Or Not Cartoon



Radio Scouting, 1916

9UZ1916Shown here in the March 1916 issue of Boys’ Life magazine is the wireless transmitting and receiving apparatus of Boy Scout Troop 4, Covington, Kentucky. According to the magazine, the station was owned and operated by the troop’s Senior Patrol Leader, Austin Edwards. The troop’s scoutmaster was listed as Mr. Nelson J. Edwards.

According to the 1916 Call Book, Austin N. Edwards of 99 East 4th Street, Covington, Kentucky, was the holder of call sign 9UZ.

Click Here For Today’s Ripley’s Believe It Or Not Cartoon



Meissner 9-1081 2-1/2 Meter Transceiver

Meissner91081The 1941 issue of the Radio Handbook carried this ad for the Meissner Model 9-1081 2-1/2 Meter Transceiver.

This portable transceiver covered the 2-1/2 meter band, 110-120 MHz, and was reportedly built to withstand the abuse of portable service. It contained a compartment for microphone, headphone, and log book, and ad a built-in telescoping antenna.

The set measured twelve inches high, eleven inches wide, and 6-1/4 inches deep. It weighed 13 pounds without batteries.

Few details were given in the ad, and I haven’t been able to find any reference to a surviving example of this early portable. I suspect that the set was similar to the 5 meter transceiver I wrote about earlier, in that it probably used the same tube as both a superregenerative receiver and transmitter.

A later ad shows the price as $34.50.

Click Here For Today’s Ripley’s Believe It Or Not Cartoon



1936 Zenith Car Radio

1936CarRadio

This advertisement from the March 1936 issue of Radio Today shows a Zenith car radio.

The ad touts Zenith as producing “America’s safest auto radio,” and details some of the safety features. The tuning and volume controls are mounted on the steering column to keep the driver from having to fumble with the actual radio, which would be mounted somewhere else under the dash.

The dial pointer on the large “safety dial” was illuminated, but only when the dial was actually being turned. The dial was viewable at any angle, with never any glare to blind the driver.

The ad in this trade publication was directed at dealers, and reminded them that this radio sold fast!

Click Here For Today’s Ripley’s Believe It Or Not Cartoon



1936 Tube Tester

1936TubeTester

Shown here is one of the tools of the trade of the radio serviceman 80 years ago, as shown in the March 1936 issue of Service magazine.

From the Precision Apparatus Corporation, this is the Electonometer Model 500 tube tester.

Click Here For Today’s Ripley’s Believe It Or Not Cartoon



1943 Wartime Intercom

1943RadioIntercom

This intercom from the March 1943 issue of Radio News shows the kind of ingenuity that was necessary in the face of wartime shortages on the home front.

The article notes that with defense priorities, many small business firms were in need of interoffice communications but unable to get them. The only immediate answer, according to the article, was to make a small radio do double duty.

The article describes a four-station intercom constructed with a six-tube table radio. The only additional parts, all of which were available at the “radio bargain counter” were nine switches, four speakers, and a roll of shielded cable. The hookup allowed for the station with the radio to serve as the master, able to call or receive calls from the other stations. As an added bonus, any of the four remotes could listen to the radio, but stil l make calls.

Click Here For Today’s Ripley’s Believe It Or Not Cartoon



1926 Popular Mechanics Crystal Set

1926MarPM

Ninety years ago, the March 1926 issue of Popular Mechanics carried the plans for this simple crystal set. The unique twist about this set was how it was tuned. Two metal plates (made from the lids of tin cans) were positioned such that the coil could be slid in and out. To tune the set, you simply slid it to the correct position.

The article noted that the set had selectivity sufficient to tune out a strong station a few miles away.  The total cost for the parts was fifty cents.

Click Here For Today’s Ripley’s Believe It Or Not Cartoon



RCA 56X5 “12,000 Miler” from 1946

RCA56X5Seventy years ago, this day’s issue of Life Magazine, March 4, 1946, carried this ad for the RCA model 56X5. The “12,000 Miler” covered standard broadcast and short wave with six tubes, including the rectifier.

I’ve always considered this set to be quite handsome, and it’s also a good performer on both AM and shortwave.  A nice example can be found at the Radio Attic Archives.  And you can see the set in action pulling in some Chicago stations at YouTube.

Click Here For Today’s Ripley’s Believe It Or Not Cartoon



1941 Bamboo Beam

BambooBeam1

Seventy-five years ago, the March 1941 issue of Radio and Television carried the plans for this two-element 20 meter beam in use by R.M. Blanchard, W4FIC. The antenna was constructed of bamboo, with the driven element and director consisting of wires taped to the bamboo. The rotor consisted of a bicycle chain connected to ropes, adjusted on the ground as shown in the diagram below.

BambooBeam2

Mr. Blanchard reported that the antenna performed well, logging contacts with the Philipines, Guam, and Little America. In addition, the antenna was used for numerous schedules with the Hawaiian Islands.

Click Here For Today’s Ripley’s Believe It Or Not Cartoon