Thread
:
Ladder line Vs. Coax
View Single Post
#
12
May 28th 08, 11:27 PM posted to rec.radio.amateur.antenna
Owen Duffy
external usenet poster
First recorded activity by RadioBanter: Dec 2006
Posts: 1,169
Ladder line Vs. Coax
(Dieter Kiel) wrote in news:1ihnz3n.wxm0z7nvxaivN%
:
http://www.w8ji.com/vswr_reactive_power.htm
I assume Dieter that this is your recommendation of the article.
That article uses the term 'reactive power' in a non-conventional way,
though the term is a well known one (ie has a conventional meaning).
Conventional use is that the term 'apparent power' is applied to the
product of RMS voltage and current flowing into a two terminal load, and
the units are VoltAmps (VA), not Watts as used in the article.
Reactive power is the reactive component of apparent power, and expressed
in units of 'VoltAmpsReactive' (VAR).
'Real power' is the real component of apparent power and expressed in
units of Watts (W).
The relationship is that
apparentpower = (realpower^2 + reactive power^2)^0.5 .
This is all basic lumped component AC circuit theory, and holds at RF.
However, basic lumped component AC circuit theory is not a good way to
analyse antenna systems, expecially to determine transmission line losses
cause by highly reactive loads (which is what that article tries to do).
Owen
Reply With Quote
Owen Duffy
View Public Profile
Find all posts by Owen Duffy