Dave wrote:
now, someone please put a bird meter on a tdr and
see what the characteristic impedance of it is internally. then put it on a
network analyzer and see if it does indeed transform the 'environment' from
75 to 50 ohms in its 40mm length. oh and while you are at it calculate the
s factors for all the transitions, those will come up in the discussion here
shortly.

Probably all that is needed is to measure the Bird's s11
parameter while sitting in a 75 ohm environment. I'll
bet it's very close to zero.
--
73, Cecil, http://www.qsl.net/w5dxp