28 Jun
2023
28 Jun
'23
2:40 p.m.
On Jun 28, 2023, at 9:48 AM, Tony Duell via cctalk
<cctalk(a)classiccmp.org> wrote:
On Wed, Jun 28, 2023 at 6:00 AM Grant Taylor via cctalk
<cctalk(a)classiccmp.org> wrote:
Not for one meter. For 50 meters, sure, although a piece of Cat 5 Ethernet cable for the
signals along with a separate wire pair for power may well be an entirely adequate
substitute. The rule of thumb I would use is that any wrong-impedance connection shorter
than a 5 percent or so of the wavelength isn't a problem. For 10 Mb/s Ethernet that
translates to 1.5 to 2 meters.
This is also why "UHF" connectors are acceptable at RF frequencies (but not at
UHF frequencies, never mind what they call themselves).
paul
Tony's email makes me ask more questions than I have (smart alack)
answers to. Maybe ~> hopefully I can ~> will learn something.
I was being a bit of a smart alec too. The point I was making is that
a bit of normal IDC ribbon cable is not electrically the correct cable
for an AUI interface but it won't matter over a few inches.
The correct cable is 4 twisted pairs with a overall screen (shield).
One pair is thicker wires than the other 3 and is used for the power.
This cable was very hard to get by the metre when I needed some about
30 years ago, and a full reel was several hundred pounds. I was lucky
enough to be given a couple of metres as an 'offcut' by a gentleman
who worked in network support. You probably need something like that
if you're makng a 1m cable. But not for what the OP is trying to do.