In message , Michael A. Terrell
writes
Ian Jackson wrote:


I'm in the CATV industry, and I've just remembered that, many years ago,
I did see reference to 'vampire taps' as being the latest and greatest
for coaxial ethernet. That took me back to the early 1960s, when similar
tap devices were manufactured in the UK (by Thorn, I think). I may still
have one somewhere. Nasty things!


They were real low grade ****. They were replaced by backmatched
taps when systems were extended past the original 12 channel systems in
the US. They caused mismatch problems, and wasted a lot of the signal
on the trunklines or feeders. They worked, more or less on systems with
just a few channels, and very few customers, but them, those people were
already used to ghosting and snow. They had all been pulled from the 17
systems around Ft Rucker by 1972, including a couple short haul feeds
that only had a couple channels.


Equally bad on ethernet I expect? Also, does ethernet require them to be
non-directional (ie just resistive tap-offs, with no directional
coupler)?
Ian.
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