Just came across this on a newsgroup, thought y'all would like to have a
look!
After all, it's FREE! :-) 73, DavidC AA1FA
"RJELINE1.exe" - OPEN-WIRE ANTENNA FEEDERS & ETC.
This small computer program will tell you almost everything you ever wanted
to know about the operation and behaviour of balanced, open-wire
transmission lines from power frequencies to UHF. The program's basic input
data is the line's UHF impedance, conductor diameter and operating
frequency, followed by resistance and reactance of the termination.
Terminating impedance may be entered in terms of either the series or shunt
values of R and jX.
Performance is computed for ANY complex load impedance between a short and
open circuit. Input impedance is given in both series and shunt component
forms. Values of VSWR, line loss in dB and reflection coefficient, and most
important, the percentage of input power which is dissipated in the feeder,
are computed. When a line is to be used as a transmitter tuned tank circuit
or in a receiver front end, its resonant Q is computed. Exact mathematical
transmission line formulae are used throughout.
The program can be used to design a transmission line for a given
attenuation or power loss at a particular frequency. There is only one
simplifying assumption - at HF the dielectric loss is negligible compared
with conductor resistance loss. Conductor loss takes into account skin and
proximity effects and is therefore accurate from 50 Hz up to UHF. The
behaviour of open-wire phone lines and high power LF transmitter feeders
can all be studied if you are so inclined.
Designing 1/4-wave matching transformers is a doddle. Conjugate matches
between complex impedances can be achieved by using matching sections of
lengths other than a quarterwave.
Not zipped-up. Downloads in a few seconds. Can be run immediately. Free.
Click Below.
--
Reg G4FGQ
http://www.btinternet.com/~g4fgq.regp
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