10base5 (Thick) Terminator ?

[Tom Peters]

No. Thicknet used N connectors.
It was (as someone else pointed out) not the one that used BNC connectors 
(That's thinnet or 10Base-2) nor Tees (Also 10Base-2).

It was (is-- I still have a spool of it!) 50 ohm coax with N connectors, 
and paint marks at every meter boundary. You had to terminate each run of 
thicknet end each end (that's two ends, for those who are counting).

You had to tap it with a vampire tap ONLY ON THE 1 METER MARKS using a tap 
drill tool that would core into the shield and expose the center conductor. 
You had to be very careful not to nick the center conductor too much, or 
you would cause an impedance "bump" at that point, and partial reflections. 
You also had to use a good tap tool, not a cheapo, so as to make clean 
holes, because god help you if you got stray braid in the hole and shorted it.

With the tap in place, a transceiver was bolted to it, usually I used 
Cabletron, Lantronix, or DEC. Then you carefully made sure the "heartbeat" 
switch was OFF, plugged in a 15-pin AUI ("DIX" = DEC Intel Xerox, I think) 
cable, which ran to a concentrator of some kind. We were using DEC DEQNA or 
DEMPR products, as I recall. One of them fanned out into a large number of 
thinnet runs.

I'm still looking for specs on thicknet cable-- I know the characteristic 
impedance is 50 ohms, but if I knew the velocity factor and losses at VHF 
(144 - 148 mhz) and UHF (430 - 450 MHz) I could use the stuff for my 
amateur radio hobby. As it is, it's gathering dust.

HTH,
Tom



At 01:16 PM 3/31/2005 -0500, you wrote:
> > Subject: 10base5 (Thick) Terminator ?
> >
> > This is probably gonna be a really easy question for you
> > guys; is this http://www.mansier.net/10base5terminator.jpg a
> > 10base5 (thick ethernet) terminator ?
>
>This is an "N" type connector. I thought 10base5 used PL259's (single
>unshielded pin in the center, screw shell).


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