[Elecraft] Antenna Theory

Vic Rosenthal [email protected]
Thu Mar 25 12:35:01 2004


Mike McCoy wrote:

> Since there seems to be no clear advantage to using coax (other than the
> fact virtually every piece of equipment made has a SO-259 on the back) why
> then is coax THE most prevalent feedline in actual use?

1) It is unaffected by nearby conductors.  It can be run through metal 
conduits, taped to a tower, even buried (if you get the right kind of 
jacket).

2) An unbalanced tuner is much simpler and cheaper than a balanced 
tuner.  If the SWR is moderate, then losses are acceptable.

3) An unbalanced output circuit in a transmitter, especially a multiband 
transmitter, is much simpler than a balanced one.

4) Given 2 and 3 above, there is likely a need for a transition from 
unbalanced to balanced -- and as many have pointed out, this can be 
difficult to achieve efficiently in a multiband system.

-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco