[TowerTalk] More on Bobtails

L. B. Cebik cebik@utkux.utcc.utk.edu
Sat, 29 Aug 1998 10:56:40 -0400 (EDT)


> This is a drawing of what it looked like at FD.  I know one end had a
> capactitor tuning box on it. I'll try to contact the person and see if I
> cannot get the lengths and the values for the tuning box.

Most SCVs show a very slow rate of change in the source resistance and an
almost linear change in reactance across the ham band.  The patterns
appear not to change in any dramatic way.  Hence, what some folks have
done is purposely cut the antenna for the lowest end of the band or just
below.  For current feeding, this makes the antenna inductively reactive
across the band, and some variables (or, for very wide bands, a variable
and switched fixed capacitors) place a compensating series capacitive
reactance at the source, leaving a resistive source impedance that often
works well with coax.

Voltage feeding is a different matter with different requirements.

-73-

LB, W4RNL



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