Author Archives: clem.law@usa.net

1944 Two Tube Receiver

Eighty years ago this month, the October 1944 issue of QST showed how to build this two-tube regenerative receiver. The set was a good performer. The pentode detector provided great sensitivity, and the pentode audio amp was enough to drive a small speaker, or headphones. It even featured a volume control that, while not absolutely necessary, would prove helpful if you wanted to listen with headphones.

Plug-in coils covered the broadcast band up to 32 MHz, and the article boasted that, unlike many similar designs, a single coil would cover the entire broadcast band.

The magazine cover boasted that you could laugh at wartime parts shortages. The articles was a little unclear as to exactly how, but it was probably due to the fact that you could substitute various tubes. The set could be built for use on AC power, or with a 90 volt B battery.

1964 Six and Two Meter Transceivers

Sixty years ago this month, the October 1964 issue of Radio Experimenter reviews the large number of 6 and 2 meter transceivers available to the ham. The article is penned by Tom Kneitel. He begins by noting that even those who view CB radio as a blight on society have to admit that there was a bright side. The concept of the transceiver–a combination transmitter and receiver–predated the CB craze. But the idea really caught on after CB manufacturers started cranking them out.

Hams were the beneficiaries, since the article gave details of many such units in production, from manufacturers such as Clegg, Gonset, Heath, Lafayette, Olson, Utica, and World Radio.

1924 Diving Mask

We’re not sure this is a good idea. And even if it is, the young woman in the canoe ought to be wearing a Coast Guard approved personal floatation device, or at least have one on board.

But a hundred years ago, there were a lot of surplus gas masks available, and the October 1924 issue of Science and Invention gave this idea for making use of them for diving.

You simply selected a garden hose, one sufficiently rigid so it wouldn’t collapse under the pressure, and attach it to the gas mask. It supplied your fresh air while diving, and you simply exhaled bubbles into the water. The magazine suggested adding lead shot to the canister of the mask to help weight it down, and recommended weights on your feet and belt to keep you under water. But the system was said to be good for depths of up to 20 feet. It looks like the girl is listening to the hose for continued sounds of breathing, which is probably a good idea.

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1924 Boys’ Telegraph

A hundred years ago, these young men (Bill and Sam) kept in touch and built up their code speed with this telegraph system linking their houses. All they needed was two buzzers, two keys, two switches, and enough wire to connect their houses down the street. And, of course, they needed some batteries, but this ad warned them not to just walk into the store and ask for a dry cell. Instead, they were to ask for Columbia Eveready by name. Those peppy batteries made the buzzer yelp at the slightest touch of the key, allowing them to quickly build up their speed. And for easy connections, you could get the batteries with Fahnestock clips.

The ad appeared in the October 1924 issue of Boys’ Life.

October 2, 2024 Eclipse Report

Shown above, via Facebook, is the view I hoped to see for myself on October 2, 2024. There was an annular eclipse of the sun that day for Easter Island, and portions of southern Argentina and Chile. Other places, it was just a partial eclipse. And as any eclipse chaser will tell you, a partial eclipse really isn’t a very big deal. The sky doesn’t get dark, and you can really see anything special.

But there’s an exception, and that is if the eclipse takes place at sunrise (or sunset). As anyone who has ever watched a sunrise or sunset can tell you, it is safe to look at the sun momentarily. (Of course, if you do more than a momentary glance, then you should get some eclipse glasses from our sister site, MyEclipseGlasses.com.) And you can see it’s shape. Normally, that shape is a circle as the sun hits the horizon. But if the sunrise is in the middle of a solar eclipse, then it’s not round. The sun is instead a crescent. I tried to see one in 2021, and got clouded out. And, unfortunately, I’m now zero for two when it comes to sunrise eclipses. My family travelled to Hawaii to see it, and we viewed the sunrise at a beach near Laie, Hawaii. Unfortunately, the clouds were just a little too thick, and they obscured the crescent shape. Our view, while a beautiful sunrise over the Pacific, is shown at the left. We had a nice trip to Hawaii and saw a nice sunrise. But we’re still zero for two. Our next chance will be March 29, 2025, when the Northeastern U.S. and Maritime Provinces of Canada will experience a Sunrise Eclipse.

The photo above was taken by Stan Honda, October’s artist-in-residence at Hawaii Volcanoes National Park.

Mississippi Mobile Communications Center, 1954

Seventy years ago, the Mississippi Highway Safety Patrol and Civil Defense Council operated this state-of-the-art mobile communications center. The need for such a facility had been shown by recent disasters such as the Gulf Coast hurricane of 1949, the severe ice storm of 1951, and the December 1953 Vicksburg tornado.

The state’s basic police radio network consisted of nine 3000 watt stations, and this one would be the tenth, ready to roll at 60 MPH to wherever disaster struck. In addition to the state radio, the van was equipped with VHF low-band and high-band stations, complete with crystals for local departments. At the scene of the disaster, the correct crystals could be installed, and that station manned by personnel from that department. The van included a conference room and bunkroom with six bunks. A power generator was in a trailer. With the exception of the antennas, everything was operational while in motion.

The amateur station consisted of a Johnson Viking 2 transmitter and National NC-125 receiver. Six separate booths were available for the radio operators.

The photo is from the cover of Radio News, October 1954.

1939 One Tube Loudspeaker Receiver

Eighty-five years ago, this young man is making the final tuning adjustments for the one-tube radio he built from plans in the October 1939 issue of Popular Mechanics.

The set was simplicity itself, but it boasted a loudspeaker and AC power, so there was no need to mess around with headphones or a B battery. It was really a crystal set, with a fixed crystal detector. The single tube was a 25A7GT, which combined a pentode AF amplifier with a rectifier. Of course, it had a hot chassis and the familiar “curtain burner” cord to power the filaments.

It was best suited to tune permanently to the same local station. It wouldn’t tune the entire broadcast band without changing the fixed capacitor in parallel with the tuning capacitor, and tuning was very broad. But if you wanted to listen to a local station with loudspeaker volume, the simple design couldn’t be beat.

Happy Birthday, President Carter

Today is the 100th birthday of the 39th President of the United States, Jimmy Carter, the first former president to become a centenarian.

I never voted for Jimmy Carter. In 1976, I was too young to vote, and if I had been able to vote, I would have voted for Ford. And in 1980, I proudly cast my vote for Ronald Reagan, and would do so again.

But we have long admired President Carter. He is clearly a patriot and loves his country. He was appointed in 1943 to the Naval Academy, making him a veteran of the Second World War and the Korean War. He went on to serve honorably. He was undoubtedly the most intelligent person to ever serve as president, his credentials including that of a nuclear engineer.

In addition to being the oldest living former president, he is also the oldest living former governor. He achieved that position upon the death of former Minnesota Governor Al Quie (another statesman we admire) in 2023.

Happy Birthday, Mr. President.

1939 Three Tube Receiver

Eighty-five years ago this month, the September 1939 issue of Radio Craft carried the plans for this receiver, which the magazine dubbed the tiniest ham receiver.

The three-tube (including rectifier) set had a regenerative detector and one stage of audio amplification to drive a set of headphones. It tuned 9.5 through 700 meters with a set of six coils, meaning that it tuned the entire shortwave spectrum, the broadcast band, and could even pull in SOS calls on 600 meters (500 kHz).

As with many of these designs, it featured a hot chassis, so care must be taken before plugging it in to the power socket.

1924 Underground Antenna

A hundred years ago this month, the September 1924 issue of Amazing Stories carried this ad for an amazing product, namely this underground antenna from the Curtan Mfg. Co., 154 E. Erie Street, Chicago, the Ground Antenna promised loud and clear reception, regardless of static conditions. You would get better long-distance reception, freedom from static, far greater selectivity, and marvelously clear and sweet tone.

By writing to the company, you would get more details of their risk-free trial offer. It seems like a safe bet. If you decided it wasn’t living up to the promises, you probabaly had to go outside and dig it up to get your money back. This was probably safer for the company than its earlier endeavor, shown in the 1927 ad shown here from National Republic magazine. That miraculous product promised 120 miles on a gallon of gas, as well as instant starts in zero degree weather.

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