View Single Post
  #7   Report Post  
Old May 8th 04, 11:07 PM
Richard Fry
 
Posts: n/a
Default

"Reg Edwards" wrote
In any case an antenna can present a match to a line at only one frequency
in the band. The transmission line transforms the mismatch at the antenna
to something else at the tuner and something yet again at the transmitter.

__________________

Correction: some FM broadcast transmit antennas have an input VSWR less than
1.15:1 from 88 to 108 MHz (50 ohm coaxial environment). There IS no
significant mismatch at the antenna input requiring the use of a matching
network there.

It depends on the application as to what VSWR bandwidth is necessary, but
certainly it is not difficult or expensive in many antenna designs to span
several hundred kilohertz with a good match to the transmission line.

RF

Visit http://rfry.org for FM broadcast RF system papers.