Re: [WinMac] Cable Scanner?

John C. Welch(jwelch[at]aer.com)
Sun, 30 Jan 2000 14:50:25 -0500

What you want is a cable scanner with a coax adapter, and a Time Domain
Reflectometer function, (TDR). The TDR is what will tell you where a break
is. Actually, it gives you the electrical length of the cable. If that is
too short, you have an open, if it's too long, you have a short, or a cross
connect. The better ones will show you connection points. Both Fluke, and
Pentascanner can give you this ability.

john

who learned TDR usage on B-1B's, where physical access is not often
possible...

> From: Romeyn Prescott <prescor@potsdam.edu>
> Reply-To: winmac@lists.best.com
> Date: Sat, 29 Jan 2000 20:48:15 -0500
> To: winmac@lists.best.com
> Subject: Re: [WinMac] Cable Scanner?
>
> I should have mentioned that this scanner also pinpointed a fault
> (short or open) to within a foot from the scan point. No ohm meter's
> gonna do THAT!
>
> To those of you suggesting that we replace our entire campus
> infrastructure with 10BaseT, well, I echo the sentiment.
> Unfortunately, 10 years ago when the decision to wire our campus was
> made, Thin looked to be the way things were going. Or that's the way
> they were at the time. No matter what drove the decision, obviously
> no one was thinking scalability! So now we're stuck with it. We
> have a 155Mb ATM backbone, but with a few exceptions, most of the
> rest of our network is 10Base2 or 10BaseT. The fiber links from our
> DecSwitches are 10Mb also, to DEMPR Thin repeaters with daisy loop to
> all offices from wiring closets. A dog. Yes. But when you consider
> that 95% of our user base uses the technology for chacking E-mail
> (who needs to do THAT at 100Mb speed?) and Web surfing (with a huge
> bottleneck at the SUNYNet gateway in Syracuse and/or Buffalo) and not
> much in the way of local file transfer, it's not THAT bad.
>
> Yes, we're pretty entrenched in Thin Ethernet, and unless the
> governor sees fit to channel some lottery money into the SUNY system,
> it won't be changing any time soon!
>
> ...ROMeyn
>
>> Oops! I meant to write more than 22 ohms and less than about
>> 32 ohms. This
>> corresponds to 50 ohms/2 minus 10% (which is the two 50 ohm terminator
>> resistors in parallel - 10% tolerance).
>>
>> At 08:30 PM 1/28/00 -0500, I wrote:
>>>
>>> Analog VOM (Volt-Ohmmeter). Look for more than 35 ohms, and less than
>>> about 50 ohms.
>>
>>
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>
>
> signat-url: http://www2.potsdam.edu/dctm/prescor/signat-url.htm
> Calendar: http://rompc.potsdam.edu/calendar.htm
>
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This archive was generated by hypermail 2.0b2 on Sun Jan 30 2000 - 13:02:02 PST