DS3 Coax..

Sun Apr 20 03:11:47 UTC 2003

I not only agree with these guys but I can give you an example..

One upon a time in a job a long long time ago, I worked on a
data differential passing system based on Frequency Multiplexed 
microwave signaling to send information up to 1000 feet.
We had a special interface on both ends, and a ground potential 
leveling circuit. The coax was very similiar to what is used for
a DS3. In addition to the "data" coax we also ran a "grounding"
strap. 
A number of times in the service of this equipment we had lightning 
strikes, power surges, and grounding failures.
Everytime we had one of these events, there were major system failures.
Now this system was quite a bit more expensive than a DS3 mux, and 
as I recall, none of our failures were under a solid 5 figure level.

We finally retired this old animal in 1993 after 21 years of faithful
headches. Thank you Uncle Sam..... That is a different story...
It was replaced with a fiber system and a backup high-freq RF system.

So with that thought of nostalga, I would defiantely go with a fiber link.
Even if you have to put a DS3 router on the COLO side of the park and run 
Ethernet fiber across the parking lot.....

If you do this, it will be a much better idea. and much more expanable.
DS3 to a router- 100 Meg fiber...
This will even allow some monitoring for errors across the pipe...

Anyway...

Jim

> -----Original Message-----
> From: David Lesher [mailto:wb8foz at nrk.com]
> Sent: Saturday, April 19, 2003 9:20 PM
> To: nanog list
> Subject: Re: DS3 Coax..
> 
> 
> 
> Speaking on Deep Background, the Press Secretary whispered:
> > 
> > 
> > Definately.
> > 
> > You most emphatically do NOT want copper going across your 
> parking lot.
> > Besides the danger from lightning strikes and other 
> electrostatic discharges
> > you run the risk of ground potentials differing 
> significantly.  You could
> > wind up with a significant amount of current flowing across 
> the coax just to
> > balance building grounds.  (This is why telcos insist on a 
> single ground
> > point and have that point connected to an array of ground 
> rods driven deep
> > in the ground.)
> 
> Agreed.
> 
> Fiber is Your Friend [tm]. 
> 
> Ground loops and potential differences will not only have you
> ripping your hair out, but you stand to lose DS-3 ports. Now
> some guy told me that such costs a bit more than the RS-232 &
> Ethernet ports I regularly see die, but that's likely just a rumor.
> 
> 
> 
> 
> -- 
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> 