Results tagged “transmitter”

Radio 1946

Radio - Design, Production Operation, a technical magazine from 1946

I've always liked collecting old radio books and magazines, from kid's science project books to Popular Electronics.


I enjoy reading the scans done by other radio freaks trying to preserve history, so here's a contribution from me, scanned several years ago. It's a trade magazine called Radio, with 56 pages, written for engineers and technical people. One could say it's like a 1940s version of Radio World.

I believe that this magazine came from the trash of Peter Granba here in Pittsburgh. In the 1980s there was a big curb side trash pile on a main road nearby, and the trove was so good that I asked my dad to drive me there so that I could pick up some of the radio-related items. Granba was apparently a Ham radio operator and electronics experimenter.

April 1946 contents include:

  • Cover: Western Electric's 'Clover-Leaf' FM broadcasting antenna
  • Inductive Tuned Loop Circuits
  • IF Amplifier Stability Factors
  • Electro-Mechanical Analogy In Acoustic Design
  • AM Transmitter Design
  • D-F For Static Pulses
  • Recent Radio Inventions
  • Bridged T And H Attenuators, Diode Conduction
  • Loss Due To Shunt Or Series Resistance
  • Capacitor Machine, Co-ax And TV, FM With Non-Linear L

In 1946, television and FM seemed to be well on their way, with the FM antenna tower on the cover, and high power FM, VHF, UHF and microwave tubes for airplane instrument landing being detailed. One advertisement is for the Eimac 3X2500A3 external anode tube, capable of 3500 watts output from 88-108 mhz, the modern FM band.

My favorite article is Modern AM Transmitter Design starting on page 30, which is about the latest 250 watt broadcast transmitter, as used in many communities across the country. It's fan-less, so it can be placed right in the studio, uses motorized final amplifier tuning, a high level plate modulator, and has a frequency response from 30 to 10,000 hertz.

250 watt AM band transmitter

Get the full draft quality but readable PDF scan here:



Nice packing comrade!

I'm on the way to building an AM broadcast band synthesized PLL oscillator. What that means is I'll be able to choose a frequency between 530 and 1700 khz, set some little switches, and the oscillator will put out a stable signal at the chosen frequency. This small signal will feed a power amplifier to boost the signal, with a modulator attached to give it sound, making a small broadcast transmitter, an advanced version of the Radio Shack AM kit that I had.

I started to order parts for this project last month, and I was surprised at how these chips came packed. These are CD4060 oscillator/divider ICs, and are CMOS chips, which should be kept away from static electricity, yet these are packed in what appears to be a plain poly bag! They're probably okay, with protection diodes on their inputs, but I'll put the tea kettle on and make sure to open the bags in the presence of steam, to kill any static that might be generated, then put them into anti-static bags or foam. It's the dead of winter here, very dry air and the worst time to be handling static-sensitive parts.