🚀 go-pugleaf

In article <35e6319c.53011606@news.lakwod1.co.home.com>,
Aaron Blosser <blosser@home.com> wrote:
>>  I'll inquire with my network staff for more research material, as
>>I'm curious as to why 75ohm cable would be that much of a problem?!?

>I wonder as well.

>For short runs of cable, I highly doubt that using 50ohm vs. 75ohm would
>make a difference.  That measurement is a measure of the cable's
>impedance over some distance (1000 ft?), so for a short bit of maybe
>50-100 ft, the difference *may* be neglible.

>Of course, this all depends on how senstive the receiving equipment is,
>and I can't make any claims to know how it would really affect the
>performance.

>The reason you *should* use properly rated cable is because with
>impedance matching you can achieve maximum power output.

And, as I wrote a few days ago in this thread, the basic issue isn't the
length of the cable -- that's a concern for other reasons -- but the
transition-points.

	You get reflections at the points where there's an
	impedance mismatch.

The same kind of effect may be seen by looking at an object with or
without a pane of glass intervening -- the thickness of the pane isn't
all that much at issue; that it's there at all, and has an index of
refraction different from the surrounding medium (air, usually), causes
observable reflections if there's a signal coming from the observer's
vantage-point.

Reflections not only represent some signal lost, but also increase the
probability of a reflection being interpreted as something that could
contribute to an Ethernet collision.

david
-- 
David H. Wolfskill				david@dhw.vip.best.com
As a computing professional, I believe it would be unethical for me to
advise, recommend, or support the use (save possibly for personal
amusement) of any product that is or depends on any Microsoft product.