[NLRS] Two Meter Aurora Observations using Vertical Polarization (long)

[jcplatt1@mmm.com]

Terry, the question about vertical polarization is actually three questions
(at least !).

One question is what happens with polarity during AU propagation  .... is
it preserved ?   Most VHFers are using horizontal polarization.   I think
your earlier post goes towards addressing that.

A second question may be would vertical polarization propagate via the
aurora better than horizontal polarization ?   I haven't a clue, but I have
heard of some east coast stations doing some work on this some years back
and finding that there was basically no difference .... that as long as
both stations were using the same polarity that the signal strengths via AU
were the same (of course, this is all hearsay on my part, because that's
all I remember !).    I'm not sure if they tried any really long paths.
Does anyone know of any papers on this question ?

The third question is given any fixed antenna at a fixed height, for best
performance, should it be horizontal or vertical ?    Due to ground
interaction when vertically polarized, a yagi will have more gain in its
first main lobe when its horizontal.   If "performance" is gain, then
horizontal is better.

However, because of that ground interaction for vertical polarized
antennas, the nulls between the lobes is smaller (ie; filled) for vertical
polarized antennas.    For example, a 5 ele 2m yagi that I modeled using
EZNEC mounted at 20' above real ground has a first null of only -6 dB down
while the same antenna mounted horizontally and at the same height above
ground has a first null of -27 dB.     When the antenna is mounted higher
the null on both antennas deepens but the null on the horizontal antenna is
always deeper.    What this might mean is that for large AU events like we
had last night, as the AU moves south and elevates for us, that for an
antenna at a given height above ground it may be better to be vertically
polarized from the standpoint of staying out of the first null (which is
very deep on the horizontal polarized antenna).   Another alternative is to
have a lower horizontal antenna that has a higher take-off angle.

I think that the aurora was pretty far south last night.   I noticed that
N0UK thought that it was going pretty good, and I heard him working a bunch
of stuff on 2m, but I thought it was kind of hard to work people .... I
called CQ and with few takers, and I would call people who were calling CQ
who were S5 to S7 and get CQ'ed in the face again.   I run 800 watts out
and my single 2m yagi is at 50'.   I think N0UK runs about 400 watts but
his antenna is lower .... perhaps having a lower antenna was an advantage
this time (due to the higher take off angle and the higher first null)

The other thing that makes me think that the AU was south (elevated) for us
was that signals peaked on a very broad heading for me ..... I think this
is a sign that the signal is arriving at a high take off angle where the
antennas performance is degraded.   The bearing is broad because the
antenna performance at those high angles is broad and nothing like what we
normally experience for normal low take-off signals.

Regarding what I worked, I spent some time on 6, 2, and 222 and did a lot
of tuning around.   On 6m the best DX was to VE9 (NS) .... the interesting
thing about this contact was that it was on SSB with no distortion (no Au
tone).   On 2m I worked from NE & KS thru KY to NY and PA.   On 222 I only
worked two stations, one in IN and one in IL.    I did hear K1TEO weakly on
222 and gave him a call but no contact was made ..... I suspect that he may
have been running more power than my 100 watts.

Should be some more Au action for the next day or two.

73, Jon
W0ZQ