[Elecraft] OT: Small Patio Vertical:

[Martin AC6RM]

Hi;

   I've been experimenting on my very small ground-floor cement patio with
vertical antennas and I am looking for some references on vertical
antenna design that would give me relative antenna receive performance
for two different designs.  My patio is about 10-feet by 8-feet.  I
can't put anything in to the air higher than about 10 feet.

   The "ground plane" for my antenna is a 6-foot by 9-foot chunk of
"hardware cloth" (which is a wire mesh) laid out on the cement patio. 
Not optimal, but I don't have room for radials.  And it's a "constant"
in the comparison, cuz it's about as good as it's gonna git!

   Three designs:

1.  nine-or-so-foot home-made "whip" (actually the tube sections of a
buddipole [http://www.biddipole.com -- which I don't have room to put up
in a dipole configuration] with one of the collapsible whips on top) with
a SGC239 providing matching services at the base;

2.  same as above, but with one of the buddipole coil forms performing
antenna "tuning" duty.  Essentially a centre-loaded vertical;

3.  a screwdriver-driven centre-loaded vertical (high sierra hs1500).  The
two main differences between this one and #2 above being (a) the diameter
of the lower section of the vertical element -- about 2 1/2 inches on the
screw driver and a little under an inch for #2 above) and (b) the diameter
of the coil -- about 2 1/2 inches for the screwdriver and about 1 3/4
inches on #2 above.

   I am able to a/b test #1 and #2 and I found that #1 seems to have
better receive (more S-meter action on my K2 on any given signal) but
not by much.  My recall tells me that #3 performed better than either
#1 or #2, but it was set up in March and April when the great sucking
sound currently on the bands wasn't quite as high and more signals were
making it through to my little tiny patio :)

   Thoughts / references?  I am really interested in why one design -- #1
would be better or worse than #2 or #3 for receiving.  I do understand
the concept of Q; I have a high-sierra on my truck and when it's not
adjusted right, signals are clearly much harder to hear (the
screwdriver antenna manufacturers all talk about their "high-Q coils"
being better than the other guy's).  I have the same effect occuring on
antenna #1 above (even though the inductors in the SGC239 certainly
aren't evenly-space "coils;" they're more like toroidal inductors akin
to those in the K2).  My ear, as I listen to ARRL on 14.0475, tells me
there's quite a bit of "Q" happening there.

   And is the idea of putting the matching components (inductor, etc.) in
the middle of the antenna section better than at the base, from a
"receive" perspective?

   Many thanks and 73,

   Martin AC6RM (k2/100 #3021)