View Single Post
  #16   Report Post  
Old September 20th 09, 09:43 PM posted to rec.radio.amateur.antenna
christofire christofire is offline
external usenet poster
 
First recorded activity by RadioBanter: Oct 2008
Posts: 173
Default Resaonance and minimum SWR


"Roy Lewallen" wrote in message
...
Antonio Vernucci wrote:
. . .
Under the assumption that dielectric loss is negligible, a permittivity
2.26 time higher than that of air results in a lower inner conductor
diameter, for a given outer diameter cable and a given impedance. . .


Yes, and this is why foamed dielectric cable has lower loss than solid
dielectric cable. Not because of lower dielectric loss (at least below a
few GHz), but because it has a larger center conductor for the same
impedance and outside diameter.

Roy Lewallen, W7EL



You've got it ... spread the word to all those amateurs who are hung up on
(negligible) dielectric loss!

Chris