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About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024

Webmaster:

    Kirt Blattenberger,

    BSEE - KB3UON

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

My Hobby Website:

AirplanesAndRockets.com

everythingRF RF & Microwave Parts Database (h1) - RF Cafe

DIY Airplane Detector
May 1942 Popular Science

RF Cafe - May 1942 Popular Science CoverDuring World War II, Americans, Britains, Frenchmen, and other civilians were seriously engaged in helping to defend their homeland. Those who were not in the military gathered bottles, tin cans, tires, and clothing to use in the war effort. Others volunteered at the Red Cross, veterans' hospitals, and USO offices. Some stood guard at their nation's seashores and land borders, both as armed sentries and as troop and aircraft spotters. As part of the civil defense effort, listening devices were built to help detect the sound of approaching airplanes.

In patriotic tradition, magazines like Popular Science  published many articles to assist the population contribute. Here is a plan for a "Homemade Plane Detector." It used a horn "antenna" that fed into a 3-stage tube-based (1H5GT) amplifier + 1G4G headset driver circuit. You could build and power one today with a couple 1.5 V batteries - oh, and a 90 V and a 135 V battery.

RF Cafe - Homemade Pane Detector - May 1942 Popular Science, p71

 

RF Cafe - Homemade Pane Detector - May 1942 Popular Science - p72

See also Aircraft Detection Prior to the Invention of Radar

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