1917 Spy Antennas Everywhere!

1917SepEEA hundred years ago this month, there might not have been a spy behind every tree. But there very well could have been German spies using those trees to conceal secret antennas, and the editors of Electrical Experimenter, in the September 1917 issue, were doing their public duty to warn Americans of the potential threat. Some possible secret spy antennas are shown here, along with the warning:

In preparing this article we have endeavored to show the unsuspecting
public how an enemy agent may either send or receive radio messages
by means of the most innocent appearing objects.

The Editors thought it best to give the article wide publicity, in order
that patriotic citizens may the better apprehend possible spies, who might be using secret aerials of the types illustrated.

The article is intended for public enlightenment, as well as for the
country’s safety.

According to the article, there could be a spy cleverly using your shade tree as an antenna, and it was a good idea to go out and check: “Have you examined your shade trees closely this summer? Don’t be surprised if you find a wire cleverly painted to match the bark on the tree and leading up to the various branches. It is readily possible for a persistent member of the enemy espionage squad to thus rig up a tree areial, and it is not necessary to travel very far to find a sufficiently large tree, which would serve as a framework for several hundred feet of insulated wire.”

A similar warning was warranted for those hanging their laundry out to dry: “If you live in the city (or even in the country) and have occasion to use a metal clothes-line of any appreciable size, it might pay you to closely scrutinize the supporting framework to see whether or not some alien enemy has been at work in an effort to use it for wireless communication purposes.”

These spy antennas could be anywhere, as shown in the illustration above.

Elsewhere in the same issue is the report of the U.S. Government blowing up the wireless tower at Shoreham, Long Island, erected at the cost of $200,000 by Nikola Tesla some twenty years earlier. The structure was no longer in use, but “during the past month several strangers had been seen lurking about the place.” Those lurking strangers could very well have been German spies, hanging around the 185 foot tower to use it as an antenna to contact Germany. Therefore, the Government blew it up.


Fun With Arsenic: 1927


What could possibly go wrong here?

Ninety years ago, the September 1927 issue of Science and Invention magazine carried this article for aspiring young chemists with some educational and fun experiments they could do with arsenic. After a brief historical introduction ot the element, the article jumped right in with some practical experiments the young chemist could do at home.

For example, the amateur chemist could take some arsenic, presumably procured from the friendly neighborhood pharmacist, and reduce it at home to produce a purer oxide of the element. This was done by placing it over a porous plug of asbestos (also presumably readily available from the local hardware store), putting it in a test tube with some charcoal, and then placing it over a bunsen burner. This produced a vapor of arsenic trioxide, which was captured in another test tube. “When cool, the arsenic can be shaken out upon a piece of paper.”

The article also showed how to conduct a test for arsenic, with which “amounts of arsenic as small as a fraction of a milligram can easily be detected.” Perhaps the author included this bit of information as a warning, lest the young chemist allow a fraction of a milligram to “accidentally” be ingested by someone.

It also showed how to make a lovely green dye, known as Scheele’s green. Apparently, political correctness had already made a foothold by 1927, since the article pointed out that this green dye had previously been used in wallpaper. According to the article, “this caused a great deal of unnecessary excitement, for it was thought that you could be poisoned from it.” But this concern was entirely unwarranted, since “unless some was rubbed off accidentally and eaten, there is absolutely no danger.”

The article did caution, however, that the young chemist should “be very careful with it, as it is very poisonous.”

Warning:  This article is from 90 years ago.  You can’t buy arsenic from your local pharmacist any more.  Even if you could, the experiments described in this article sound very dangerous, and I would not recommend attempting any of them.  Those arsenic vapors sound like a really bad idea.  Besides, you can’t get asbestos either.  So even though the only category I had to put this article under was “Science Fair Ideas,” I don’t think this is a good choice.  But for more science fair ideas, some of which are just dangerous enough to be fun, you can see them all at this link.

Eico 711 Space Ranger, 1967


Fifty years ago this month, the September 1967 issue of Electronics Illustrated carried a review for a handsome shortwave receiver that I had never seen before, the Eico 711 Space Ranger.

The set tuned 550 kHz to 30 MHz in four bands, and included a BFO, S-meter, and bandspread. The power supply included a transformer, making the set somewhat safer than the AC-DC supply included in many budget receivers of the day. It was available for $49.95 in kit form, or $69.95 assembled.

The review warned that the set probably wasn’t an easy project for someone who hadn’t built a kit before, and noted a few shortcomings in the assembly instructions. But for someone with some kit building experience, the set went together fairly easily, and the author reported that he had it assembled in about 20 hours.

The author did warn that the set was not aligned, and would require a signal generator for alignment. Performance was described as comparable with other receivers in the price class, with sensitivity dropping off sharply above 10 MHz.

I do agree with the author’s observation that the set “is smartly styled; you wouldn’t hesitate to leave it in your living room.”

You can find pictures and description of a nicely restored specimen of the set at this link.

How to Unplug Appliances, 1942 or 2017

1942SepPMToday, as a public service, we bring this illustration from the September 1942 issue of Popular Mechanics, which is just as relevant today as it was 75 years ago.

The drawing, which is clearly labeled “WRONG,” shows the housewife unplugging the radio by yanking on the cord.  The illustration in the lower left corner, shows the correct way, namely, by firmly grasping the plug.

The artist perfectly captures what appears to be a cavalier attitude on the woman’s part.  While she was probably otherwise the pinnacle of efficiency, the magazine pointed out that bad connections and broken power cords were the result of such treatment. It was a particularly bad idea in the case of the table radio, since it probably had a “curtain burner” cord, which would withstand few such jerks before causing the receiver to develop crackly noises or simply refuse to work. But even with plain line cords, then or now, the plug was easily damaged.

veracruzflagThe magazine even noted that rubber-covered plugs were not plentiful, so this woman’s treatment of the strategic material was practically unpatriotic in wartime.

As far as we’re concerned, it’s still unpatriotic.  If you love your country, then you should unplug appliances by firmly grasping the plug.

1942 Radio Census


Seventy-five years ago today, the September 7, 1942, issue of Broadcasting magazine included a supplement with the radio figures from the 1940 census, as well as a complete log of all U.S. broadcast stations as of 1942, and figures showing the numbers of radio retailers and sales figures. The map above shows the percentage of radio homes in 1940. Since there was a freeze on new stations during the War, and since no new radios were being produced, the issue provides an interesting snapshot of radio in the United States during the War years.

Massachussetts led the nation with 96.2% of its homes being equipped with a radio. Within that state, the county with the highest percentage of radio households was Norfolk County, with 98.1% of the households having at least one radio. The last place honors went to the State of Mississippi, with only 39.9% of homes having a radio, despite twelve broadcasting stations in the state. Within that state, the county with the lowest percentage of radio households was Issaquana County, where only 320 households out of 1779 had a radio, or only 18%.

Of Minnesota’s 728,359 households, 664,296 had at least one radio, for a percentage of 91.2. Lake of the Woods County had the lowest penetration of radio receivers, with 1150 radio households out of 1501 total, for a percentage of 76.6%. Minneapolis and St. Paul had very high percentages of radio households, 96.6% and 96.7% respectively. They were edged out, however, by Rochester, with 96.8% of the households having a radio. The other city included in the listing of cities over 25,000 was Duluth, with 95.7% of the households having a radio.

1942Sep7BC2The station listing shown here reveals that during the War years, Minneapolis and St. Paul were served by seven stations. Both KSTP, 1500 kHz, and WCCO, 830 kHz, had 50,000 watt signals full time.

Three stations had 5000 watt signals during the daytime: WDGY on 1130 kHz, reduced its power to 500 watts at night, but the hours were determined by local time in Albuquerque, since it protected a station there. WLB, which later became KUOM, was daytime only, and also shared time on its 770 kHz frequency with WCAL in Northfield, an arrangement that continued in later decades. WTCN reduced its power on 1280 kHz to 1000 watts at night.

WLOL on 1330 kHz was licensed for 1000 watts, and WMIN ran 250 watts at 1400 kHz.

Duluth was listed as the home to KDAL on 610 kHz and WEBC on 1320 kHz. The other station serving the Twin Ports, WDSM, was licensed to Superior, Wisconsin, and appeared in the Wisconsin listings.

Cities with 250 watt stations included Albert Lea (KATE, 1450 kHz), Fergus Falls (KGDE, 1230 kHz, with 100 watts nighttime power), Mankato (KYSM, 1230), Moorhead (KVOX, 1340), Rochester (KROC, 1340), St. Cloud (KFAM, 1450), Virginia (WHLB, 1400), Willmar (KWLM, 1340), and Winona (KWNO, 1230).

Another station covering Minnesota but not listed was WDAY in Fargo, which corrected the oversight by purchasing two full-page ads, one in the Minnesota listing and another in the North Dakota section, pointing out that it had a large service area in both states, and including a story, that must have seemed just a bit risque in 1942, about a traveling soap salesman and a farmer’s daughter.



1977 President CB


Forty years ago this month, the September-October 1977 issue of Elementary Electronics carried this ad showing a typical CB’er at the mike of her President CB rig, from President Electronics, Inc., of Irvine, California. While the ad doesn’t tell why she’s on the radio, she’s undoubtedly engaged in some form of public service, such as providing motorist assistance as a REACT member. But the ad makes clear that she does know that every single President radio is thoroughly tested, and doesn’t leave the factory if not working perfectly. She also knows that the radio was engineered with quality features such as variable mike gain and a sophisticated compression circuit to give her maximum “talk power.”

According to the ad, the set contains a gigantic “100 mm” digital channel readout. It’s unclear exactly how they are measuring this, since the digits don’t look four inches tall.

Radio/PA For Cyclists, 1937

1937SepRadioCraftEighty years ago this month, the September 1937 issue of Radio Craft shows this idea to combine a public address amplifier and radio to “produce a useful adjunct to itinerant groups.” The tour guide, who may either be the driver of the lead vehicle or in the side car, can augment “the pleasures of a jaunt through the countryside” by serving as a “guide well acquainted with the route.”  Judging from the cover photo, it appears that having the tour guide in the side car would be a better idea, so that the driver could keep his eyes on the road.

Between pointing out points of interest, he could flip a simple two-way switch to play the radio. The same idea could be used for groups of motorcyclists, but this would require “a power amplifier with somewhat higher output in order to overcome the increased noise level.”

According to the magazine, “it seems rather odd that no one has thought to put this idea into practice.”

Staples, MN, Earthquake of Sept. 3, 1917

1917MNEarthquakeIf you don’t like earthquakes, then Minnesota is about the best place on earth, since earthquakes are extremely rare.  However, they’re not unheard of, and today marks the 100th anniversary of one of the largest, the Staples Earthquake of September 3, 1917.

The earthquake was described by geology Professor C.J. Posey of the University of Minnesota in an article in the November, 1917 issue of Monthly Weather Review. According to Prof. Posey, the earthquake, the exact causes of which were obscure, hit at about 3:30 PM and was felt in central Minnesota. While there were no written accounts of earlier earthquakes, after the quake, pioneers came forward with reports of smaller earthquakes in 1860 and 1870.

The 1917 quake was felt in places approximately 110 miles apart, over an area of about 10,000 square miles. The duration was about 10 seconds, and observers reported a rumbling noise similar to an incoming train. Dishes and pans were rattled in Alexandria, and bricks fell from a chimney in Brainerd. In Staples, where the earthquake was strongest, walls were cracked and a cement floor cracked. Despite earlier press reports, no windows were broken by the quake.

The quake is estimated to have measured 4.3 on the modern Richter scale.



KSTP, St. Paul, MN, 1937


Eighty years ago today, the September 1, 1937, issue of Broadcasting magazine carried this ad for KSTP, St. Paul, Minnesota. The station was boasting its then 25,000 watt signal, and noted that it had received fan mail from 42 states and 8 foreign countries. While the station acknowledged that it did not suggest that it could deliver sales messages to Shanghai, China, it did have a loyal following in the nation’s 7th largest retail market.

Radio Constructor, 1947-1981

1947AugRadioConstructorSeventy years ago this month, August 1947, the first issue of the British magazine Radio Constructor rolled off the presses, with the matshead bearing the names of editors Arthur C. Gee, G2UK, and W. Norman Stevens, G3AKA, and business manager C.W.C. Overland, G2ATV. According to the introductory editorial, postwar Britain was seeing a boom in short wave listening almost as big as the boom in broadcast listening after the first war.

1947AugRadioConstructor1The first of many receiver plans to be published by the magazine was a four tube (or three tubes, plus selenium rectifier) AC-DC broadcast set shown here. The first issue also carried a few theoretical articles, as well as the plans for one transmitter.

The magazine continued until September 1981, when the final issue was published.