Topband: tuning elevated radials

[Jim Jarvis]

Ford,

Questions and comments.

Q:  I like the rf probe idea...and I think I can draw the circuit
you created...but rather than speculate, can you either send me
something directly...or post here if easier... showing the 9 turn
windings and how you oriented and connected them to the bridge?

I'm assuming the coils are in series, and connected across 2 terminals,
with the meter across the opposing pair, bypassed with the cap.
The coils need to be wound in the same direction, correct?  What
ferrite did you use?

Comments:

1) I'm a fan of elevated GP's, whether folded in an ell or not.
I have tended to use 3 radials @ 120' spacing as well.  W1CX
convinced me that having 4 radials...two opposing pairs...would
produce a cleaner pattern, and less high-angle radiation. FWIW.

2)I can only speculate that your north radial is over earth which
is different from the other two, and that's the source of the imbalance.

3) As a practical matter, I have made several monobanders for 160, 80 and
40,
and one 160-80 dualbander, most with 3 radials per band.  In all cases,
I cut the vertical portion for the low end of the band, and cut radials
at 105%.  Then, I fold back the radials equally to bring vswr to target.
I just wrap them around themselves 2 to 3', and usually don't cut them.

This doesn't assure a balanced pattern, by any means, and I may explore
your approach at my new site, this winter.  Available trees lend themselves
to GP's.

Tnx.

N2EA
jimjarvis at ieee.org