Some time back (April 7, to be a little more precise), I placed some notes
on antenna traps at the site--mainly on how to calculate the equivalent
R-L-C circuit values for each band in use.
I have added some further notes on trap placement using both conventional
(lumped component) traps and traps using linear (transmission line stub)
inductors. It is a long note (too long for one entry, too short for 2),
but has some pictures (not nearly as exciting as the pathfinder pix coming
through) to break the text monotony.
The key concept is to treat traps as a load at the end of but within the
higher frequency antenna length, not as an appendage to it (as is commonly
done with more traditional treatments of traps). The exercise uses a
10-20 meter dipole, but can be extrapolated to any trap antenna system.
You may be surprised to discover the length of the 10-meter portion of the
antenna when using stub inductors as part of the trap compared to a
standard 10-meter dipole.
Hope the notes prove useful to someone.
-73-
LB, W4RNL
Incidentally, I receive a large volume of replies to my note on
prunes--too many to relay (mercifully). Needless to say, they were, in
sum, the pits.
L. B. Cebik, W4RNL /\ /\ * / / / (Off)(423) 974-7215
1434 High Mesa Drive / \/ \/\ ----/\--- (Hm) (423) 938-6335
Knoxville, Tennessee /\ \ \ \ / / || / (FAX)(423) 974-3509
37938-4443 USA / \ \ \ \ || cebik@utk.edu
URL: http://funnelweb.utcc.utk.edu/~cebik/radio.html
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