On 2/14/2014 2:17 PM, Carl wrote:
Isnt that what "lowest loss" means? At least that was my intention.
I must not have written clearly enough. I was not questioning the low loss, only that the high Vf was the way to get it.
You DO get the low loss by going to larger coax, (like the 7/8-in hard line), but it's the fact that it's LARGER and has lower RF resistance, NOT the higher Vf.
Think of it this way -- The higher Vf cable has less attenuation per ft because the higher Vf allows the center conductor to be larger. But a stub made with foam coax with Vf = 0.84 must be 27% longer than one with with a solid dielectric and Vf =.66. If those coaxes are the same diameter and of comparable quality, the stub attenuation and Q will be nearly the same.
73, Jim K9YC _________________ Topband Reflector Archives - http://www.contesting.com/_topband
