Telamon wrote:
I always thought it was because the impedance of basic antennas are
around 50 and 75 ohms. Here is another story I came across.

Another story I have heard is that at the begining of WWII, the development
of RADAR required a new type of feed line. Coaxial conductors were made of
copper pipe. The pipes used were standard pipe purchased at a plumbing store
and the ratio of inner conductor to shield was due to avaialble sizes.

Geoff.

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