In message , Geoffrey S.
Mendelson writes
phaedrus wrote:

So the obvious question is: why are transmitters normalised to 50 ohms
when clearly 450 ohms would enable us to enjoy cheaper, do-it-
yourself, lower loss feeders? Was this some oversight at the time, or
good practice for some obscure reason that I simply cannot think of?


One story is that when radar was first developed coaxial feed lines were
made by buying copper pipe at the local plumbing supply and the
impedance resulting from using two standard sizes (one as the center
conductor and one as the shield was 50 ohms.

Well I've made 50 ohm line samplers ( Bird 43 lookalikes) with standard
UK copper tee pipe fittings and pipe.

Brian GM4DIJ
--
Brian Howie