Seventy-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.

Fifty 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.

Eighty 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.

Another 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.

The November 1937 issue of Popular Science carried the plans for this midget one-tube regenerative receiver for the broadcast band using a dual-grid type 49 tube.  The notable feature of the tiny set was that it employed only a single battery, a 3 volt “A” battery that powered the filaments as well as supplying the modest B+ voltage.

The low power requirement apparently meant that the set was just a bit finicky, since the article cautioned that many of the parts had to be exactly as specified in the article.  But when done, the midget tube set was said to produce good headphone volume with 10-20 feet of insulated wire tossed on the floor as the antenna.

The modest battery requirement meant that the set was ideal of hikers and campers, or for use in isolated areas without electric power.

Midget tube receiver schematic

This ad from sixty years ago, in the November 1957 issue of Popular Electronics,  was for two little VHF rigs I had never seen before, from a company called Springfield Enterprises of Springfield Gardens, New York. The prices shown in bold print certainly look reasonable. The two-meter version is priced at $6.98, and the six-meter version is $14.98. But the fine print reveals that these are the prices for the chassis only. It is already assembled, but it doesn’t include the microphone, “miniature mike transformer,” headphones, or even the case. With these “accessories,” the price increases.

The description is lacking in details, but the two-meter version is a single tube with VFO. It’s probably similar to the transceiver shown previously at this link.

The six-meter version contains a crystal-controlled transmitter with variable frequency receiver, and uses multiple tubes. Both sets were billed as having a range of 1-5 miles with a built-in whip, and “much more with directional beam antenna.”

I’ve never seen any reference to either of these rigs, other than this K3DSM’s website, in which he states that he owned one of the two-meter versions.

Seventy years ago this month, the October 1947 issue of Popular Science carried the plans for this simple one-tube receiver mounted on a chassis the size of a matchbox.

The set used few parts beyond the 1S4 tube. Tuning was accomplished by a 175-500 pF trimmer capacitor. The article noted that the small capacitor might not cover the full broadcast band, but suggested small plug-in coils to extend the range.

The set required a 1.5 volt battery for the filament, in addition to a B battery, which could be as low as 4.5 volts.

Readers of this blog might remember the name Hartland Smith, W8VVD, currently licensed as W8QX.  We previously featured his steam powered transmitter, which appeared in Popular Electronics in 1965.  A number of his projects appeared in PE and other magazines, and the one showed here appeared in Popular Electronics 50 years ago this month, October 1967.

It was a transmitter for the novice which put out a very respectable 65 watts on 80 and 40 meters. It was an updated version of the author’s “Hart 25” transmitter which appeared in the magazine in 1955. Despite the increased power, the new version boasted the same price of about $20 for all of the parts.  The 1955 version had used a 6W6 tube to put out about 25 watts, along with a 5Y3 rectifier in the power supply.

The 1967 version employed a 6HB5 TV horizontal amplifier, which was said to be highly efficient at cranking out RF. Tuning was accomplished by the simple expedient of tuning the pi network for maximum brightness of the pilot lamp. Another pilot lamp was provided for monitoring the current to the crystal, since too much current could fracture it. The article noted that smaller HC6/U crystals (and almost any modern crystal designed for solid-state circuits) should not be used because they would overheat, drift, and possibly shatter.

Cathode keying was used, but since the would mean as much as 700 volts across the key, a 6 volt relay was used for safety. The built-in power supply used a semiconductor bridge rectifier.

Smith recommended a full-size dipole antenna for the transmitter, rather than trying to use it with a random wire or multi-band antenna. He did have one insight that I independently discovered years later: “If an 80-meter dipole is too long for your piece of real estate, don’t hesitate to bend it around corners, or even droop the ends. Whatever the final arrangement, make certain that you have a total of 125′ of wire in the air.”  As you can see from my fan dipole from the June 2010 issue of QST, I’m not adverse to introducing a few zig-zags into an 80 meter dipole in order to squeeze it only a city lot.

He notes that the pi network should be adequate for keeping harmonics to a minimum. However, he also advises that if TVI is a problem, a low-pass filter in line with the antenna is in order. With today’s more stringent requirements for spectral purity, it would probably be a good idea to add the extra filtering even in the absence of TVI reports.

He reported that on the air, he worked numerous stations throughout the U.S. and Canada on both 80 and 40 meters. The rig had a “click-free pure d.c. note that was a joy to copy.” It was reported to be “rock-steady” on 80 meters, and “its 40-meter stability compares favorably with that of many low-cost VFO transmitters presently on the market.”

Hart-75 Transmitter. QST photo.

In addition to writing articles, Hartland Smith was the proprietor of Hart Industries, which produced a number of kits (and a few wired sets), including the Hart 25.  The 1955 Popular Electronics article included the address for Hart Industries for the kit, which included the pre-punched chassis.  Another Hart Industries kit was the similarly named Hart-75 from 1956. That transmitter was reviewed by Lew McCoy, W1ICP, in the February 1956 issue of QST. Even though the basic circuit was quite different from the PE transmitter (it used a 6AG7 oscillator and 807 final), it did have one common design feature, namely, the use of the relay for keying.

The 1956 model had an interesting twist, in that a DPST relay was used, keying the oscillator and amplifier almost simultaneously. But the circuit used something called “differential keying.” The contacts of the relay were set so that the oscillator came on slightly before the amplifier, and stayed on longer. The result was that chirp was greatly reduced.