[ct-user] Networking CT over long distances

wheeler wheelerm@actrix.gen.nz (wheeler)
Fri, 29 Aug 1997 21:55:49 +1200 (NZST)

hi All

>>Brian, K2BJ, said:
>>Anybody out there have experience (a la field day) of networking CT over
>>long distances, ie 100-200 ft apart?...if you go apart this far serial
>>interfaces don't work so well.
>Tony ke6ynr said:
>RS232C voltage mode is guaranteed to 50 feet but generally works
>to 200 to 250 feet. RS232 current loop mode works to 1500 feet in
>an industrial environment. As it's a current mode/low impedance
>loop (4 and 20 mA), it is much less susceptible to common mode
>noise pickup. Voltage to current loop converters may be less 
>expensive than voltage to fiber optic connections (extremely 
>noise immune). 
At one operation we ran V.24 (RS-232) across a computer room floor down six
floors (stories/levels) [thats from 6  > 5>4>3>2>1>ground level] at 9600bps
alongside a lift (elevator) with no problems.
At the contest site we where running unshielded NULL Modem cables between
stations with some problem, suspect RF and the odd poor comms port, we have
now installed fixed shielded cable which was first used on IARU, reports were
operation a lot better.
CQWW will be the test, I suppose you want something for this ? We will let
you know how we go  ! ! !
If you can afford the cost check out the fiber optic meantioned.

>> Are my concerns unfounded? If so, who can
>>help with a good design out there that is stable in a high-power
>Sorry, I have no direct experience with this in a high rf power
>environment. It works great in an industrial control environment, 
see comments above

73 Malcolm  ZL2UDF

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