For many years, a standard feature of most radio and electronics magazines was the nomogram (or nomograph).  Before the days of the electronic calculator, it was a convenient way to do calculations of a given formula. The nomogram consisted of three or more scales with the values of a given equation. If you knew two values, you would place a straightedge between them, and the point where the straightedge intersected the third scale, that would be the answer.

The example at the top of the page is a nomogram of Ohm’s Law, from the April 1967 issue of Electronics World. It shows Ohm’s Law, and it also has superimposed another two scales for calculating the power rating of the resistor. Such graphs were very common. In fact, people cut them out of the magazines for future reference. At one hamfest, I once took home a thick binder labeled “charts and nomos,” in which the previous owner had amassed a large collection of such items.

A nomogram is essentially the same as a slide rule, preset for a particular equation. For recurring problems, even quite complex ones, it was a great time saver.

Seventy years ago, Radio Craft Magazine, in its June and July 1946 issues, ran a series on how to make your own nomogram. To illustrate the concept, it started with the simplest possible case, and addition nomograph:

As you can see, this version has three vertical scales, equally spaced. The outer scales have their values placed twice as far apart as the inner scale. To add numbers on the outside scales, you place the straightedge on them, and the point where it intersects the center line is the sum. The concept gets more useful when the linear scales are replaced with logarithmic scales. Now, the nomogram can be used for multiplication, as with a slide rule. The straightedge is placed over the values in the outer scales, and the intersection with the center scale represents the product. Similarly, division can be done by placing the straightedge over one outer scale and the center, and the other scale shows the quotient:

The article showed how to handle exponents by moving the center scale. For example, this graph calculates power from the formula P = I^2 R:

By moving the center scale closer to the current scale, more weight is given to the current. In this case, the current is raised to the power of 2.

The following month’s issue went on to show how to handle more complicated situations, such as reciprocals and square roots. We take for granted these days how easy it is to do calculations with a calculator. But in cases where the same equation had to be repeated over and over, the nomogram represented an easy way to do it with nothing but a straightedge. And making your own nomogram required little more than a few sheets of logarithmic graph paper.

Click Here For Today’s Ripley’s Believe It Or Not Cartoon

One hundred years ago today, the United States was close to declaring war, but it wasn’t the European war.  On March 9, 1916, Pancho Villa had raided Columbus, New Mexico.  Sixty to eighty of Villa’s men were killed, along with a dozen Americans.  President Wilson ordered 5000 American soldiers into Mexico as a punitive expedition to capture Villa.  By June, the state militias had been called up and sent to the border.

Among the skills desperately needed were telegraph operators, both landline and wireless. This item appeared in the Washington Times, June 19, 1916.

According to the article, the D.C. National Guard had a need for “men who can speak two languages that are not United States: the Morse code and the persuasive expletives that awaken the potential dynamic forces of the festive army mule.”

In other words, in addition to mule skinners, the Guard needed trained telegraphers. “The telegraph is playing an increasingly important part in the conduct of war, and the men in the telegraph corps of the signal company of the District national guard are given the best sort of inducements to join the organization.” The article noted that pay ran as high as $76 per month, “considerably more than men employed in similar work in civilian employments receive.”

In addition to landline telegraphers, the army needed radio men. “There are more than 250 amateur radio operators in Washington who are members of the national organization of wireless telegraph operators. Inducement have been offered a number of these men to join the national guard, and several inquiries were made today regarding the chances for radio work. It is understood that wireless equipment is much in use on the Mexican border.”

Click Here For Today’s Ripley’s Believe It Or Not Cartoon

Seventy-five years ago this month, QST carried plans for a two-tube “fool-proof rig for 80 and 40 meters.” The author, Don Mix, W1TS, noted that there were two competing factors in coming up with a design: On the one hand, the cost had to be kept low and the circuit be capable of easy construction. But on the other hand, ease of adjustment and operation was important for the beginner. Mix noted that many designs, usually one tube, had erred on the side of low cost, and could prove frustrating for the beginner to operate.

For that reason, Mix settled on this two-tube design using two 6V6’s, or two 6L6’s with a lower plate voltage. One was used as the oscillator with the second serving as final amplifier. This arrangement would keep the keying chirp-free, since the oscillator didn’t need to work at full power. And the final amplifier could be designed in such a way as to prevent parasitic oscillation without the need for the beginner to go through the process of neutralizing the final stage.

The resulting circuit is shown below. The author noted that construction on a metal chassis would be ideal, and took no more time or skill. However, metalwork might require tools not found in the average household, so he showed how to build the set with a wooden chasis, by mounting two 1×2 strips on top. They were spaced such that the sockets for the tubes, coils, and crystal could be mounted between them. The variable condensers could be mounted on the front panel.

He also included a diagram for a suitable power supply which could be built on a similar chassis.

The author was on the ARRL staff, and wrote a number of articles for QST. In 1968, he produced a somewhat updated version of a transmitter for the novice, and that design was later reprinted in “How To Become A Radio Amateur.”

Mix had been on the MacMillian polar expedition in 1923, operating station WNP aboard the Bowdoin. Commander McMillian had recognized the value of radio, but didn’t think that sufficient funds were available. At some point, he had spoken to Hiram Percy Maxim, who suggested that many amateurs would be eager to take part. Mix secured the slot, and operated a station provided by Zenith. On a weekly basis, he transmitted a 500 word press dispatch, handled other traffic, and transmitted a list of amateur calls heard from the Arctic.

As we recounted earlier, one staton who was able to maintain contact with the Bowdoin is a young Art Collins, 9CXX, of Cedar Rapids, Iowa.

Click Here For Today’s Ripley’s Believe It Or Not Cartoon

Shown here on this day’s issue of Radio Digest ninety years ago, June 15, 1926, is Miss Fredda Josephine Brown, who was heard over the airwaves of who was heard over the airwaves of WDAF, Kansas City, Missouri.  The magazine noted that her beauty was equalled only by her versatility, since she was accomplished as a violinist and pianist, and also gave readings over the station. She was apparently still in high school at the time, since she  graduated in 1927 from Westport High School in Kansas City, which closed in 2010.

The station, “The Kansas City Star” signed on originally as experimental station 9XAB in 1922 at 833 kHz, and assumed the WDAF call letters later that year. It moved around the dial in the 1920’s, making appearances at 750, 730, 680, 820, and 810 kHz. According to the magazine, its wavelength in 1926 was 365.6 meters, or 820 kHz. In 1928, it moved to 610 kHz, where it was an affiliate of NBC.

In 2003, the station changed to a sports format and changed its call letters to KCSP. The original call letters are still used on FM and TV.

Click Here For Today’s Ripley’s Believe It Or Not Cartoon