Thread: Observations
View Single Post
  #5   Report Post  
Old September 27th 08, 06:31 PM posted to rec.radio.amateur.antenna
Frank[_5_] Frank[_5_] is offline
external usenet poster
 
First recorded activity by RadioBanter: Jun 2008
Posts: 38
Default Observations


"Richard Fry" wrote in message
...
"Art Unwin" wrote
... Now the antiresonant point will be between 100 and 200 ohms
resistive which allows me to feed it directly from a 50 ohm
transmission line (3/4 andrews) with negligable losses as
the mismatch is resistive.

__________

Art -

An antenna with an input impedance of 150 + j 0 ohms has a reflection
coefficient of 0.5 (50%), a return loss of 6.02 dB, and an SWR of 3:1 to a
50 ohm source. Probably not many transmitters would be happy with that
magnitude of load mismatch.

Do you maintain that the losses defined by these parameters are negligible
to amateur radio operators?

RF


In fact the losses are very low. 1000 ft of 7/8 hardline at 1.9 MHz has a
total loss of 0.68 db when terminated in 150 ohms. The total loss includes
0.26 db due to a the VSWR load of 3:1. Data from: "TLW, Transmission Line
Program for Windows", version 2.02.

73,

Frank