Circular-Type Radio Antenna (Dec, 1942)

Circular-Type Radio Antenna

Designed for mobile use, this General Electric “doughnut” antenna shown at the recent convention of the Institute of Radio Engineers, can be installed directly above the roof of an automobile and is claimed to give the same results as the tall whip-type (vertical) antennas commonly seen on police squad cars. Efficient for both receiving and transmitting, it provides equal radiation of radio waves in all directions horizontally. The demonstration model was mounted on a toy train.

  1. blast says: January 25, 201211:37 pm

    Emmett “Doc” Brown would be proud. Perhaps they could get it to catch fire as it rolls on its way to the edge of the table and beyond…

  2. Orv says: January 30, 201211:58 am

    That looks like a DDRR (Directional Discontinuity Ring Radiator) antenna. They theoretically perform just like a 1/4-wave whip, with a much lower profile. The problem is the word “theoretically.” The current in the ring turns out to be very high, so unless the resistance of the ring is extremely low a lot of power is wasted in heating up the antenna. Practical ones are usually made of copper pipe. This is a common tradeoff for most small antennas.

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