Topband: A question of efficiency

[k3bu at optonline.net]

>>Now, my question it this:  Which is more efficient (less lossy)?

(A) Bringing the antenna to resonance with the loading section, and then 
matching to the line with the L-network?

Or,

(B) Matching the non-resonant antenna directly with the L-network, omitting 
the loading section altogether?

K5ZK - Charles<<


About the same.

Efficiency of the antenna is proportional to the area under the current distribution curve along the radiator.
That is from the tip down. In both cases you have the same situation, difference would be only proportional to differences in ohmic loses at the base, loading section or tuner.

If you want to have more efficient antenna, you need to "pull" the max current portion as high as you can, which can be done by the loading coil 2/3 up the radiator, or best, using the top loading hat/wires/L section.

I have used 3/8 wave resonant  radiator, 40 ft mast, with loading coil and L loading wire and 1/8 wave elevated radial at the beach with very good results. It gets max current along the vertical mast and gives around 50 ohms at the feedpoint, no matching (lossy) devices necessary.

More on loading coils, current distribution at
http://www.k3bu.us/loadingcoils.htm

Yuri Blanarovich, K3BU