19 Apr
2013
19 Apr
'13
8 a.m.
On 19/04/2013 01:01, Dave McGuire wrote:
On 04/18/2013 05:13 PM, David Riley wrote:
All 3270 stuff uses BNC connectors. I don't know offhand which
impedance of BNCs they use (they look like 50-ohm to me) but at those
frequencies, a few MHz, the impedance bump really is minimal.
50ohn and 75Ohm BNC look much the same to me. At one time the pins were
different sizes but you needed a micrometer to tell. I think since 1978
they are the same size...
NO NO NO
NO NO! RG58 is 50ohm, 3270 is 93 Ohm so RG63....
What's the BNC for, then? As far as I knew, they only made
50 and 75-ohm BNC jacks. Or did they just use 75 ohm ones
and hope the brief blip on the TDR didn't do too much to
the signal? -Dave