[Antennas] coax 'sweet lenght'

Mon Oct 11 13:34:52 EDT 2004

Re:
> ARRL hand book (or antenna book) had a small hard to read chart showing 
> good and bad lengths of coax for use on all of the then HF bands.

I am looking at the 1974 version of the ARRL Antenna Book wherein they show 
feedline lengths to detune the line for avoiding feedline-plus-antenna 
resonance, when the coupling apparatus is not grounded, and grounded is more 
complicated. This not just for coax. They are talking about currents 
induced in the feeder by the antenna due to not being brought from the 
antenna at right angles, or other assymetry. They also note that induced 
currents are entirely independent of normal operation as a transmission 
line. I am thinking this is not a serious problem, as they also say tuned 
lines can be any length. Maybe the Gurus can enlighten our ignorance.
Richard Brunner, AA1P 