>>"kinking" cat 5 doesn't hurt anything unless you mess up the insulation in
>>the process.
>WRONG! Ethernet traffic is broadband data, with components well into the
>tens of MHz. CAT5 cable is four parallel transmission lines with twist
>ratios that are offset from each other to minimize crosstalk from one pair
>to another. Kinking puts discontinuities in the cable, which can degrade
>the data waveform. It can also degrade noise immunity and crosstalk, and
>increase leakage from the cable (to your radio). You may not notice the
>data degradation, because Ethernet includes error correction and re-sends
>when data is corrupted. The effect is slower data exchange.
The theory is good, but in the field, I'd have to say there is a fair amount
of overhead built into the product and certification process. I've
installed literally thousands of drops in locations like Intel, IBM, Verizon
switching centers, etc. and tested them with expensive Fluke test equipment.
IMHO, if the $7,000 fluke says it passes the required tests, then the cable
is fine. I've kinked it, ripped the jacket, wrapped it around florescent
light fixtures, tied it to romex for 40-50 feet, and worse just for fun. It
passed every single time. I wouldn't install cable for a customer with
those problems, but, I venture to guess that if my $7,000 fluke equipment
says the cable is ok, my $25 network interface card is going to be able to
do fine with it.
I'm not recommending it be installed substandard, but in testing real life
'installation errors', the system has a lot of overhead and can tolerate a
LOT of damage and still meet certification. I don't have any equipment to
determine if the kink 'increased leakage from the cable to your radio", but
it would have to be pretty severe to be of interest. If you accidently get
a kink in the wire getting it out of the box, gently massage it back into
place and 99% of the time there is literally no issue with the run.
73
N7HQR
Daron
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|