Monthly Archives: November 2016

1916 Spark Coil

One thing that sometimes mystifying when looking at diagrams of early spark transmitters is that the descriptions often lack much detail as to the most important component, the induction coil or spark coil. A good description can be found in Electrical Experimenter magazine, November, 1916, from which this illustration is taken.

The “coil” is really two coils, plus an interrupter, and the operation is described here:

When the primary switch of such a coil is closed, the battery current passes through the first winding on the core and magnetizes it. This attracts the iron armature on the vibrator spring, as shown in Fig. 1, and when this spring breaks contact with the platinum tipped screw in front of it, the circuit is opened. At this juncture there is induced in the secondary winding a very powerful current. The spring-actuated vibrator returns to its former position in the fraction of a second and the process is repeated all over again.

The referenced schematic diagram is shown here:

Battle of Moscow, 1941

7 November 1941 parade in Red Square, 1949 painting by Konstantin Yuon via Wikipedia.

Seventy-five years ago today, the Battle of Moscow was underway, with Nazi troops at the gates of the Soviet capital.

To boost morale and stiffen the Red Army’s resolve, Stalin ordered the traditional Revolution Day parade to take place as it traditionally did in Red Square. But this time, after the troops paraded past the Kremlin, the continued marching directly to the front.

The event is heroically depicted in the 1949 painting by Konstantin Yuon shown above. Film of the event can be seen here:

As the soldiers paraded to the front, Stalin charged them:

Comrades, men of the Red Army and Red Navy, commanders and political instructors, men and women guerillas, the whole world is looking to you as the force capable of destroying the plundering hordes of German invaders. The enslaved peoples of Europe who have fallen under the yoke of the German invaders look to you as their liberators. A great liberating mission has fallen to your lot. Be worthy of this mission! The war you are waging is a war of liberation, a just war. Let the manly images of our great ancestors inspire you in this war! May the victorious banner of the great Lenin be your lodestar!

For the complete destruction of the German invaders!

Death to the German invaders!

Long live our glorious Motherland, her liberty and her independence!

Under the banner of Lenin, forward to victory!

Radio Bargain House, Birmingham, AL, 1941

Seventy five years ago this month, Pearl Harbor was still a month away, and the end of civilian radio production was still five months away. But radio retailers were starting to feel shortages, since many parts were in short supply due to wartime material priorities, and in some cases, the numbers of new sets available didn’t meet demand.

This led many retailers to take a closer look at selling used sets. Trade-ins were often viewed as a headache, and little effort was made to realize a profit from them. But the wartime economy made many retailers consider selling used radios. The November 1941 issue of Radio Retailing carried advice from the experience of M.M. Law, the proprietor of Radio Bargain House of Birmingham. Law got into the radio business by accident when running a hotel. A hotel guest turned a radio over to him for sale, and he placed a classified ad in the paper. He received fifteen calls in response to the ad. When he eventually lost the lease on the hotel, he decided to get into the radio business.

Law typically made a net profit of about $2 on each set. He often bought in bulk from other dealers looking to unload their trade-ins, sometimes as low as $1 per set. He typically invested about $3 fixing up each set, and quickly sold many for $6.95. He estimated that his average sale was between $12 and $15.

He continued advertising in the classified ads, since his experience was that this was where bargain shoppers looked. He always kept a set outside his shop, marked “today’s special,” and reported that he would often sell this set, with the buyer not bothering to look for others. In other cases, however, the set outside would entice a buyer to come in the store to buy a better set on the floor.

1936 Two Tube AC-DC Regen

The plans for this simple two-tube set appeared eighty years ago this month in Radio Craft magazine, November, 1936.

With plug-in coils, the set tuned 10 to 600 meters, and the author reported picking up numerous European and other foreign stations in New York City with excellent volume. The set employed two tubes, either type 37 or 76. One served as rectifier, with the grid and plate terminals tied together. The other served as the regenerative detector which was “capable of picking up even the faintest of signals.” An antenna of 30-100 feet was recommended. No ground connection was necessary, since the house current took care of the ground.

1956 Boys’ Life Radio Contest

Sixty years ago this month, the Boys’ Life Radio contest was once again underway, and radio made the cover of the November 1956 issue of Boys’ Life, depicting a ham who took a break from his duties in the school Thanksgiving play to work some DX.

This cover was the work of frequent Boys’ Life artist Harold Eldridge. According to the magazine’s description:

Miles Standish thought he had it touch, having to defend the pilgrims with just a handful of soldiers armed with blunderbusses. But pity the poor dramatics coach who has his Indians better trained than his hams. That friendly Algonkian in the window probably pictures the coach back in the high school auditorium, sweaty hands clutching the curtain ropes, but not John Alden, no Priscilla Mullen, and no Miles Standish yet appearing in the wings.

According to the magazine, the artist never did tell whether the DX’ing ham ever got back in time to cut some turkey on stage.

1941 One Tube Broadcast Receiver

The duo shown here are putting together the one-tube receiver described in the November 1941 issue of Popular Mechanics.

The set was billed as being for the beginner who wanted to graduate from the crystal set stage, or for the radio experimenter who enjoyed pulling in some DX, an ability this set possessed. The single tube was a 117N7-GT, so it required no A battery. Instead, the filament was powered by the AC line. The set was so efficient that it would run on a 30 cent 4.5 volt battery supplying the B+ voltage. The required parts, including the tube and battery, but not including the headphones, priced out at about $4.50, even accounting for recent price increases.

Cpl. Maurice Masterson, 1895-1918

During the centennial of World War 1, this page periodically remembers American servicemen who gave their lives in that war.

Corporal Maurice Masterson, the son of Edward J. Masterson and Florence Dalton, was killed in action on this day 98 years ago. He was born on August 8, 1895, in Pomeroy, Iowa. The family moved to Barnesville, Minnesota, in 1905, where he and his brothers excelled in school. In 1917, the three brothers dropped out of college to join the Army. Maurice served in the 151st Field Artillery, Rainbow Division.

On September 18, 1918, Cpl. Masterson was severely wounded or gassed. He was killed in an artillery barrage in France on November 1, 1918. He is buried at Saint Mary’s Cemetery, Barnesville, Minnesota. American Legion Post 153, Barnesville, Minnesota, is named in his memory.

The photo here is from Soldiers of the Great War, Volume 2, Page 114.

References

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