Telamon wrote:

What are you looking for? Do you want an explanation of why the
connector does not have a big effect on a 100MHz signal and yet has a
great effect on a 1 GHz signal for the same impedance mismatch?


Have you ever used a TDR to look at a transmission line? A 1.5:1
impedance bump can cause problems and the more impedance bumps in the
path the more it degrades the signal.

The techs at Microdyne had both 50 and 75 ohm cables and adapters
available. I had someone tell me the video boards i had just tested and
calibrated were all bad. He was trying to use 50 Ohm cables in a 75 ohm
video test which caused the bandwidth to roll off to -3 dB at 16 Mhz
instead of 20 Mhz. It took all day to convince the old timers that they
had to use the right cables, because they had got away with the wrong
coax on the older, 5 Mhz systems for years.

--
Former professional electron wrangler.

Michael A. Terrell
Central Florida