Shown here 85 years ago this month in the February 1941 issue of Practical Wireless is the receiving station of Ronald Rose of Birmingham, England. At the left is a five-tube superhet, and at the right is a four-tube set. It also includes a wavemeter and speaker.
With a 75 foot inverted L, Rose routinely tuned in stations in America, Australia, and Panama.
Sixty years ago, the February 1966 issue of the British Radio Constructor showed a refinement in light beam communication. As we’ve shown previously, it can be done with a normal incandescent bulb. But there were two disadvantages. First, the bandwidth was quite low. And because the light source was spread out along the filament, it wasn’t possible to concentrate the light into an extremely narrow beam.
These problems were solved by the use of an arc lamp, specifically, a Sylvania Concentrated-Arc Lamp type A2, was used. The bulb necessitated a pulse of about 1000 volts, so some additional circuitry is required. The transmitter is shown here. The transistorized receiver is typical of other receivers, and is transistorized.
During daylight, the set was said to have a range of at least a quarter mile, and the bandwidth was 1000 Hz.
In what is, in our opinion, a shortsighted decision, Environment Canada announced recently that its VHF weather broadcasts will go dark starting March 16. Like in the United States, Weatheradio Canada broadcasts on 162 MHz frequencies from over 200 locations across Canada. In addition to weather conditions and forecasts in a computer-generated voice (in English and French), it uses SAME technology to activate alerts on radios. If there is a weather warning, your receiver will set off an alarm and wake you up.
For many people, this technology is obsolete, since their cell phone can do the same thing. But, in both the U.S. and Canada, there are many areas where cell phones do not work. But with an inexpensive receiver, the rather primitive technology employed by weather radios can provide a vital service to most of the continent. And weather radio can provide service to deaf persons, which might be problematic with other technologies.
Canada doesn’t seem to have a coverage map, and with 200 stations, the coverage probably isn’t quite as good as in the United States, where only a handful of truly remote places lack coverage. But the vast majority of the population has access to this service, even though many of those people don’t have cell service. And the cost is nominal. Each transmitter needs a few hundred watts of electricity to operate. The weather data is being generated anyway, and the system to broadcast it in two languages is completely automated.
You can read more about how weather radios save lives at our earlier post. And for specific information about how this technology can serve deaf persons, see this post. And Mexico also has its SARMEX network, which also includes earthquake warnings.
Unfortunately, I’m afraid that lives will be lost because of this unfortunate decision. I hope the United States, with its robust network of NOAA weather radio stations, will not make the same bad decision.
Seventy years ago this month, the February 1956 issue of QST showed this circuit for a very simple code oscillator, using the venerable CK722 transistor. This was actually a simplification of an earlier circuit, which had been updated by George Carson, W0JV. The oscillator runs on 1.5 volts, but for greater volume, that could be upped to 3 volts.
Carson was a professor at the University of Iowa, and his call is still held by the Iowa City Amateur Radio Club.
Seventy years ago, the British radio enthusiast who wanted to be the first on his block to own a transistor radio could do so, thanks to the plans contained in the February 1956 issue of Radio Constructor.
The portable set, dubbed the “Transistorette,” had been on display at a national radio show, where it had great interest. As soon as transistors became available in Britain, the editors of the magazine got to work coming up with a practical circuit. With a short antenna and ground connection, the set provided good loudspeaker volume on the medium wave band. It was essentially a crystal set, with a three-transistor audio amplifier. It ran off a 22.5 volt battery, and since transistors were new, the magazine contained a stern warning of the consequences of hooking the battery up with the wrong polarity.
This cyclist appeared seventy years ago on the cover of the February 1956 issue of Radio Electronics. She is described by the magazine as a “typical Southern university coed,” and she is
listening to a favorite program on her Darb Holiday radio, a four-tube portable that could be powered three ways. With separate power packs, it could operate from AC power, 6 volts DC, or dry cells. It featured pushbutton tuning of three preset stations, with no variable tuning.
Another installation by another cyclist is shown at right. The set was manufactured by S.C. Ryan. Co., 1316 Yale Place, Minneapolis.
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Eighty-five years ago, the February 1941 issue of QST carried the plans for this two-tube receiver which covered 1.4 through 14.5 MHz. The construction article, which carried no byline, noted that it was customary for beginners to start with a two-tube regenerative receiver. This one, however, was a superheterodyne. Since it contained no IF amplifier, the detector stage was actually regenerative.
The article conceded that this seemingly combines the disadvantages of both. But this wasn’t really the case. By having the detector set to a fixed frequency, it could be optimized for stability, particularly because the frequency was low, the set using an IF of about 1600 kHz.
The total cost was $11, $1.50 of which was for the most expensive component, the dial. A 45-volt battery supplied the B+, and a filament transformer was used to provide the 6.3 volts. The article noted that both the battery and the transformer could be had for about $2.
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If you were in the market for a radio in Milwaukee a hundred years ago today, you could take home this set from Schuster’s department store for only $69.50, a price which included the set, speaker, batteries, antenna, and tubes. You could be listening right away. The set was a Music Master model 60, and this ad appeared in the February 20, 1926 issue of the Milwaukee Leader.
Eighty-five years ago this month, the February 1941 issue of Practical Wireless showed how to build this two-tube receiver . It was specifically designed for use in an air raid shelter from which a reasonable external antenna had been mounted. It could be pre-set to either the Home
Service or the Forces program, and once the tuning was set, it needed no further adjustment.
It boasted long battery life for both the filament and high tension batteries. The set could drive a loudspeaker, and the completed project was mounted in the case shown at right.
