On 3/25/2014 9:31 AM, Tom Osborne wrote:
I remember good old 'twisted pair' that we used 'back in the day.' I
had a Heathkit AT-1 and just bend one wire and stuck it inside the
coax jack and taped the other wire to the outside of the coax jack.
Who knew about PL-259's and SWR back then :-) Think the twisted pair
was about 75 ohms.
Hi Tom,
Twisted pair is great stuff, and far better at RF than most folks
realize. I'd guess Zo to be between 50 and 75 ohms, which makes it a
decent match to a dipole. Virtually all of the loss in transmission line
below VHF is due to copper loss, so big copper means low loss, and a
good twist minimizes both radiation and pickup on the feedline from
differential mode current. A good choke is still required to kill common
mode current.
73, Jim K9YC
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