18 Feb
2006
18 Feb
'06
12:20 a.m.
Sounds a little off. Cables are important, with
impedance varying
with diameter, _Terminators_ are important, coming in the 50, 75
Ohm varieties mentioned, but the connector itself being 50 or 75
Ohm? First I've heard of this.
True and important. Using the wrong impedance connector or cable end
will cause a (sometimes insignificant) missmatch. The bigger problem
though is that mating a low impadance plug with a high impedance socket,
e.g. 50 ohm -> 75 ohm, will probably damage the socket due to the larger
internal conductor diameter of the plug. Mating a high impedance plug
with a low impedance socket, e.g. 75 ohm -> 50 ohm, will probably give
a poor contact due to the smaller inner conductor diameter of the high
impedance plug.
Lee.
18 Feb
18 Feb
1:55 p.m.
Sounds a little off. Cables are important, with
impedance varying
with diameter, _Terminators_ are important, coming in the 50, 75
Ohm varieties mentioned, but the connector itself being 50 or 75
Ohm? First I've heard of this.
True and important. Using the wrong impedance connector or cable end
will cause a (sometimes insignificant) missmatch. The bigger problem
though is that mating a low impadance plug with a high impedance socket,
e.g. 50 ohm -> 75 ohm, will probably damage the socket due to the larger
internal conductor diameter of the plug. Mating a high impedance plug
with a low impedance socket, e.g. 75 ohm -> 50 ohm, will probably give
a poor contact due to the smaller inner conductor diameter of the high
impedance plug. 
2:38 p.m.
On 2/18/2006 at 6:55 PM ard at p850ug1.demon.co.uk wrote:
And therefore there's no mechancial problem in
inter-mating the wrong
connectors. And for this application there's no electrical problem either
(the other end of the cable has an RCA phono plug on it, well known for
not having a defined characteristic impedance). Any mismatch at the BNC
end would cause no problems.
Back when I was networking with 10B2, I picked up a quantity of 75ohm BNC
plugs for very cheap. The cable size mismatch was apparent, but not the
inner conductor as far as I could tell. I simply grabbled some soft
thinwall copper tubing and used it as a shim over the sheild braid. It
worked fine.
Cheers,
Chuck
6734
days inactive
6734
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2 comments
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