At 11:42 AM 7/30/2003 -0400, you wrote:
>I am wondering what the impedance would be if two RG8X coax cables are
>right alongside each other...
100 ohms.. 2 * 50 (or 104 if RG-8X is 52 ohms.. it's probably not
controlled that well anyway)
>this would be easy to fabricate... either some tape or heat shrink every
>few feet would make a clean/neat bundle..
They actually make coax "zip cord". I don't recall the number, and it
might be more expensive than 2 RG-8X's, because the RG-8X, etc. are sold in
huge volumes. (Alpha 9845 is dual RG 59-B/U for instance) There's also some
funky dual 93 ohm stuff for networking (based on RG 62). Again, I
don't recall the numbers
There's a RG-63B/u which is 125 ohm, a pair for 250 ohms..(0.5 dB/100ft,
compared to 0.66 for the RG-8 family, and 1.1 dB/100ft for the dual RG-59)
From a fabrication standpoint, there are a number of wire and cable
companies around that will be happy to gang up a bunch of coaxes in one
jacket with appropriate filler material and so forth. It's not all that
expensive ($<0.50/ft back in 1990), and the minimum orders are in the 100
foot range. They have fairly generic machines that do this. (they can
also hotstamp your name on the coax... be sure you get your coax back after
field day... I worked for a company that had custom 12/3 extension cords
with the company name on them so they'd get them back (eventually)) I'll
look through my old notes to see if I can find the mfr. (Standard Wire and
Cable rings a bell, but that might not be it)
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