Seventy years ago this month, the April 1955 issue of Popular Electronics showed how to put together this simple two-tube (including rectifier) transmitter for the 80 and 40 meter bands. It was dubbed the Hart-25 and designed by Hartland Smith, W8VVD (later W8QX), whose later Hart-65 transmitter we’ve previously seen.

Smith was a prolific writer and kit designer, and you can find a number of his other projects on this site at this link.

This transmitter had about 25 watts input, and delivered about 9 watts to the antenna. Tune up was accomplished by observing a pilot light in series with the antenna while adjusting the output capacitor, as well as a trimmer in line with the antenna. There was a switch for shorting out the lamp. The article noted that you could turn it on occasionally to check the output, but it should be left shorted out most of the time, as it would consume power that would otherwise go to the antenna.

This video shows the transmitter in action:

Sixty years ago this month, the April 1965 issue of Popular Electronics showed the simple process for converting a Knight Kit C-100 walkie talkie to the ham bands. The author, Harland Smith, W8VVD, later W8QX, noted that a walkie talkie is handy for hams in many situations, such as staying in touch with friends at a hamfest, adjusting an antenna, or tracking down TV interference. But there were no low-cost units available for the ham bands.

He showed how simple it was to convert the $9.95 C-100 to 10, 6, or 15 meters. For ten meters, the set needed only a new crystal and a bit of retuning. For 15 or 6, it required rewinding a couple of coils.

One hundred years ago today, President Calvin Coolidge opened the Chicago Woman’s World Fair by Radio, as shown here in the Washington Evening Star, April 19, 1925.

The event, held at the Chicago Furniture Mart, spanned a week, and was attended by over 180,000, and celebrated women’s achievements in science, art, and business.  In his opening remarks, Coolidge proclaimed that “for long ages past, men have gone forth into the world, more recently they have been followed by women. Each are endowed with the same desire, each attempting to contribute to the satisfaction of the universal longing of the human race to bring something better home. ”

According to the event’s program, among the occupations represented was that of Radio Broadcaster.

Sixty years ago today, “Conditional Territory” in the United States got smaller.

The Conditional Class amateur radio license had privileges identical to the General Class. But instead of taking the exam in front of FCC employees, prospective licensees living far away from FCC exam locations could take it through a volunteer examiner. Until 1965, this applied to those who lived 75 miles away from an exam location. But starting on April 15, 1965, the distance was changed to 175 airline miles. And as long as an exam was given at least semi-annually, that location qualified. As a result, the areas eligible for a Conditional license got much smaller, as shown on the map above. The majority of the population was now ineligible.

The FCC realized that this might be a particular hardship in some cases, and they would entertain requests for waivers. But in most cases, rural hams now needed to make a trip to the closest FCC exam location.

The map appeared in the April 1965 issue of QST.