View Single Post
  #8   Report Post  
Old May 12th 08, 12:53 PM posted to rec.radio.amateur.antenna
Highland Ham Highland Ham is offline
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 250
Default Coils getting hot in antennatuner. Is this normal ?

Dave Platt wrote:
snip
You might be able to reduce the losses and heating by changing the
length of the 300-wire line you are using, so that the antenna's
feedpoint impedance is transformed into an impedance at the tuner that
doesn't require extreme impedance transformation, and requires the use
of lower amounts of reactance during tuning.

========================================
With the velocity factor of 300 Ohms ribbon being 0.99 (take it as 1)
and using a symmetrical dipole (hence not a Windom type of antenna), to
get a low impedance at the matching unit (tuner if you like) the length
of half the dipole + the length of the feeder should be about an odd
number of quarter wavelengths.

Frank GM0CSZ / KN6WH