On Sat, 25 Feb 2006 16:47:28 -0800, Roy Lewallen
wrote:

Owen Duffy wrote:

Beware of having 50 and 75 ohm versions of BNC and like around,
incorrect pairing risk damage to the female connector. Most 75 ohms
applications still use 50 ohm BNC connectors, even though 75 ohm
versions are available.

I keep reading this, and it puzzles me. I have a number of RG-59 patch

Roy,

I have clear recollection of 75 ohm BNCs (meaning a BNC connector
desiged for 75 ohm through impedance) that were incompatible in days
when I worked in communications facilities that used 75 ohms for IF
(70MHz) and baseband, and 50 ohms for RF (GHz).

However, I note on Amphenol's site:

"Two distinct types of 75 ? BNC's are available, and both mate with
each other and with 50 ? BNC's. Type 1 is designated 75 ? BNC-T1 and
provides constant 75 ? performance with low VSWR DC – 4 GHz. Type 2 is
designated 75 ? BNC-T2 and is usable with low reflection DC - 1 GHz.
For applications above 1 GHz, Type 1 is recommended. "

Though it is clear that Amphenol and probably some other manufacturers
produce compatible connectors, I am mindfull of earlier experience,
though I concede that it may have been the result of non standard 75
ohm BNCs.

Owen
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