Yesterday, we showed a regenerative preamplifier from 1968, designed by Hartland B. Smith, W8VVD, currently licensed as W8QX.  We promised that we would bring you another article by this prolific writer which appeared ten years earlier, in the September 1958 issue of Radio Electronics.

Smith begins the 1958 article by pointing out that he had been a licensed ham for 18 years and had his share of exciting DX contacts, but that he could “honestly say that none of these gave me quite as much a thrill as when I first saw an indentifiable transmission directly from London on the screen of my own TV set.”

And as shown by these pictures, that’s exactly what he did. The winter of 1957-58 was at the peak of the greatest solar maximum in recorded history, meaning that the maximum usable frequency (MUF) was frequently going above 40 MHz. This opened the possibility of pulling in Transatlantic TV signals, which is exactly what Smith set out to do.

Receiving the audio of British and French television signals was a relatively simple matter. The London and Belfast stations were on 41.50 MHz, and Caen, France, was on 41.25 MHz. Armed with nothing more than a prewar FM receiver, he was easily able to hear the audio. (Indeed, it wasn’t uncommon for American hams to listen to British TV audio on their six meter receivers.)

But being able to watch the video posed a much greater challenge. European TV used both different frequencies and different standards from American TV, so an American TV could not be used without some modification. So Smith set out to make the modifications. He focused on trying to pull in the powerful London station, which transmitted on 45 MHz with 200 kilowatts. The French station’s video was on 52.4 MHz, which was likely to be above the MUF even if the audio were booming in.

The first relatively modest challenge was the frequency, which was lower than that tuned by American sets. This was accomplished with a simple converter consisting of a single 12AT7 tube. With an oscillator frequency of either 33 or 123 MHz, this would bring the British signal to American channel 5, which was unused in his area. The antenna consisted of a two-element beam in the attic for video, with a folded dipole for the audio receiver.

Lisajous pattern on scope showing equal frequencies. Wikipedia image.

Tuning in the signal was one thing, but getting a visible picture required that the set be modified internally. The first issue was the horizontal sweep frequency, which was 15,750 Hz in the American set, but 10,125 Hz on the British signal. He did this by using an audio oscillator to produce the required 10,125 Hz signal, and feeding this and the horizontal oscillator into a scope. He then adjusted the horizontal and added components until the frequencies matched, as shown by a circular lisajous pattern on the scope.

The British vertical frequency of 50 Hz was deemed close enough to the American 60 Hz to not require any modification.

The final problem was that the video carrier in Britain was opposite of that used in the U.S. To correct this, he modified the video detector by reversing the cathode and plate.

With the modifications made, it was just a matter of listening on 41 MHz and waiting for the audio of the European signals to appear. This meant that the band was open, and it was time to turn on the video receiver.

This was a fairly elaborate process. The first step was to turn on the converter, and adjust the converter frequency until the “familiar out-of-sync zig-zag lines denoting a video carrier” appeared on the screen. (Anyone who watched TV in the 1970’s or earlier knows exactly what he means. If you’re too young to remember, click here for an example.)  At that point, the vertical hold would stop the picture from moving vertically, and then the horizontal hold control was adjusted (which might require some internal adjustment to make sure the control was in range). As he put it, “TV dx tuning is an art that is a little hard to describe on paper. It is best learned by experiment.”

He pointed out that picture quality would never be perfect. For one thing, there would almost always be multipath interference, since signals through the ionosphere might travel numerous paths. He noted that the ghosting problem might sometimes be acute. During one televised tennis match, he reported seeing at least 30 players batting 15 balls back and forth. But occasionally, the ionosphere would settle down momentarily, resulting in the identifiable images shown here.

Sixty years ago, domestic tranquility was restored in this household, as shown in this picture from the October 1957 issue of Popular Science.  Dad and Junior can watch the fight, while Mom and Little Sister work on the piano lessons.

This major breakthrough was accomplished after extensive testing by the editors of the magazine. Every TV owner had been waiting for the good news: “a simple way for each member of the family to turn the sound off or on, to suit himself, without annoying anyone else.”

The magic that made this possible was the inductive loop. Because the headset was wireless, “there’s no dangling cord to tether you to the console.” The headsets could be made in a couple of hours, and the magazine proposed three varieties.

The modification of the set and the installation of the loop was an almost trivial matter.  The magazine warned to unplug the set and let it sit for 15 minutes “for the tubes to cool off” (and hopefully for the electrolytics in the power supply to lose some of their charge).  Then, the lead to the speaker was snipped and hooked to the inductive loop, as shown here.  The magazine recommended adding the closed-circuit jack shown in the circuit here, so that the loop could be unplugged on those occasions when the speaker was desired.

The loop could be run under the carpet, as shown here, tucked away near the ceiling, or even placed in the joists in the basement below.  While reception was best when the headsets were at the same level as the loop, the magazine’s tests showed that any of these arrangements would work well.

This loop formed the primary winding of a room-sized audio transformer.  The secondary windings would be in the individual headsets.  For the kids, the magazine recommended the spaceman style shown here, with the assurance that the kids would love them.

As revealed by the diagram below, these headsets were simplicity itself.  The coil was worn around the head, and hooked directly to the headphones.  The magazine suggested that Mom should be put in charge of suitably decorating the loop with colored tape.  No other electronics were necessary for these headphones for the kids.  The output of the coil was sufficient to drive the headphones.

Mom and Dad warranted somewhat more discrete looking receivers, and these could be either of the models shown below.  Mom had a version similar to the kids’ version, but the loop was not worn.  It was apparently thought that she could set it in a convenient spot, and it was hooked directly to a small earphone.  The magazine noted that the earphone was so small that it could hardly be seen.  The only problem that might result would be forgetting to take it off before going to bed!

Dad is seen using a slightly more complicated version, but still easily within the capabilities of anyone able to wire up a lamp cord.  It used a much smaller coil, amplified with the venerable CK722 transistor.  It was the size of the proverbial pack of cigarettes, and the two penlight batteries would keep it running for a thousand hours.

Those wishing to duplicate this idea today can save a great deal of coil winding time by using a telephone pickup coil instead of winding the coils for the individual receivers.  If a set of high-impedance headphones is available, it could be fed without any electronics.  The CK722 is more or less unobtainium, except at very high prices.  But any small audio amplifier could be put into service.  If you want to make your own, hundreds of circuits are available using the readily available 2N2222 transistor.

Seventy years ago, television was finally becoming a reality. The war was over, stations were coming on the air, and the enlightened radio dealer was getting ready to move into television. Crosley, the pioneer in radio manufacturing and broadcasting, had also made the move to television.  The Crosley Spectator is shown here, from the August 1947 issue of Radio & Appliance Journal.

The set boasted an image size of 6-3/8″ by 8-1/2″, had 27 tubes and three rectifiers, and tuned all 13 channels, 44-216 MHz, including the elusive channel 1, which was never put to use.

Those 27 tubes consumed 380 watts, and the set weighed in at 85 pounds.

The ad assured the dealer that the Spectator in the shop window as its own salesman, and each set sold would become the talk of the neighborhood and draw in even more business.

You can see a nicely restored example of this set in operation at this video:

Sixty years ago, solar activity was at an all-time high, and the sun was plastered with sunspots. This was good news for hams, who depend on this solar activity for ideal radio communications on the high frequency bands. But in addition to being literal dark spots, this was, figuratively a dark time for the hapless TV repairman in fringe areas, because it fell upon him to explain to his customers that their interference woes weren’t his fault, but were instead caused by blotches on the sun.

Fortunately, the TV repairman got some sympathetic advice from this article in the August 1957 issue of Radio Electronics.

It starts by noting that Sunspot Cycle 19 was about to reach a peak, which was good news for hams and shortwave listeners, for whom shortwave propagation would be better than at any other time in history.

But the average TV owner “probably does not care about receiving Havana, Cuba, or some other distant TV station over his favorite local channel,” which was a distinct possibility in fringe areas. The article noted that this would be particularly an issue for channels 2, 3, and 4.

The article counseled the serviceman on how to deal with these calls. And unfortunately, there was little that could be done, other than to “explain to the owner what is happeninng and that the condition will probably pass in a short while. Ask him to call the next day if the trouble is still there.”

The article suggested that a good way to educate the customer would be to draw a sketch of the earth and ionosphere as shown above. While reorienting the antenna might help in some cases, the best advice was to hope that the owner understood what was happening. If the customer understood, it would make him “less likely to call a service technician and thereby leave the technician more time to devote to true television troubles.”