Oh dear. It appears you may be right.
I've just checked with the suppliers and they tell me the plugs I
bought are 75 ohm ones. This really stinks as in their catalogue,
although they don't specifiy the impedance of these plugs, they do
clearly state that they're suitable for RG214 coax. AFAIK, RG214 is
only available in 50 ohm - if anyone knows otherwise please tell me. It
took me a good deal of time and trouble to make up these patch leads so
all in all, I ain't exactly pleased.
Here's the URL for the catalogue page so you guys can tell who's at
fault he

http://cpc.farnell.com/jsp/endecaSea...=CN06870&N=411