Topband: March LBM Article on Polarization

[Bill Tippett]

Hello All!

        W1FV's recent reference to K9LA's article in the March 2002
Low Band Monitor caused me to take another look at it.  Carl shows 
azimuthal plots of vertical antenna patterns (with the Earth's magnetic 
field taken into account) from VK6VZ, W8JI, IV3PRK and D44 (Cape Verde 
Islands).  The first 3 are essentially omnidirectional but Figure 4 
shows a dip of -10 dB for E/W directions from D44.  This would imply 
that NA would be a poor direction for anyone using a vertical from D44 
(true bearing 300 degrees to W4 from D44).

        But here's where I have an "anecdotal" problem...  Do you all
remember the 160 signals of C56CW/C56DX in March 1996?  These guys had 
a tremendous signal all across NA using the Titanex vertical.  In fact
I recall that this was one of the first expeditions to use it and I 
started asking around to find out what it was because their signal was 
so remarkable!  C56 is only 900 km East of D44 and I would imagine that
any polarization effects would be quite similar.

        Without C56CW/DX having isolated horizontal and vertical antennas 
to instantly compare, we can't say anything conclusively.  However I 
personally cannot imagine their signal being any stronger than it was. 
It was truly one of the strongest signals I've EVER heard from that area 
of the world.  Maybe Carl, Bob or someone has an explanation for this 
apparent inconsistency.  As I said before, I think polarization may be 
a 3rd-order effect compared to takeoff angles, near-field and far-field 
ground conductivity, etc. but it is difficult to say conclusively since
these factors all interact even for "pure" horizontal and vertical antennas,
not to mention the problem of sorting out hybrid antennas like Inverted-V's 
of various included angles and heights, Inverted-L's of various total 
lengths, etc.

        Last comment on this topic from me...I'll let you experts
debate it while I try to find another new one to work.  It's been a 
slim year for new ones here with XU7ACB being the only other new one
besides ET3PMW...the good news is that sunspots are definitely heading
down so next year should be better...hang in there!
 
                                          73,  Bill  W4ZV

P.S.  I totally agree with K1ZM that having diversity in antennas is
desirable which is exactly why I had both in Colorado.  I may try to
put up a flat dipole at ~120' here this summer since I do find myself 
occasionally missing the one I had at W0ZV.  I also agree with W7DD that 
an Inverted-V is not purely a horizontal antenna but a hybrid.  That
is why I mentioned the EZNEC model showed my W0ZV "droopy" dipole 
(ends pulled out >600' to each side of the tower) behaved more like 
a dipole than an inverted-V.