[TenTec] 75 Ohm twin velocity factor ?

[Stuart Rohre]

That should be a good working number, 0.67 for Vp for 75 ohm or 72 ohm twin 
lead.

It is much more narrow than 300 or 450 ohm types, and thus has a differing 
characteristic.

There were two USA types made by Amphenol at one time:   "receiving" twin 
lead of 72 ohms, which was about 1/8 inch wide, and "transmitting" type 
which was wider.  The conductors on the "receiving" type were about 22 gauge 
stranded, and insulation was brown polyethylene.  It sold for 2 cents a foot 
in 1957, as I used it on my 50 watt Novice station.

Stuart
K5KVH