TopBand: 160 Magic

[Bill Tippett]

K0HA wrote:

>  That make's me feel that some past 160 meter European contacts along with
>some on 15 meters (and tonight's to Japan) were made via a bent path...

        Bill, it certainly could have been a bent path...I was just suggesting
that you try a high angle antenna based on my experience.  There are two
aspects to signal arrival...azimuth and elevation.  There is NO substitute
for diversity in both areas for 160 DX'ers and there are NO simple rules of
thumb that work 100% of the time on Topband.  In Colorado, I had 8 Beverages
for azimuthal receive diversity as well as a high angle antenna.  Here are
my observations:

1.  Low elevation angles (verticals/Beverages) are superior to high angles
(dipoles) about 99% of the time on 160.  The exceptions are usually at
sunrise or sunset.

2.  When signals are low angle, verticals and Beverages work well and complement
each other since both are low angle antennas, but you need a full complement
of azimuthal angles for unusual (maybe more common than we think?) conditions.

3.  Signals are often skewed by geomagnetic disturbances away from polar areas.
Verticals/Beverages still work well in these conditions but you must be
listening
on a Beverage in the right azimuthal direction.  If you don't have a Beverage
in the right direction, you may copy the signal better on your vertical than
the Beverage.  There was a striking example of this just a few weeks ago which
I noticed and WW2Y confirmed.  I heard GM3POI, G3SED, etc very well on
my Delta loop (low angle radiator)...yet they were PUNY weak on my 30 degree
Beverage.  I switched to the one at 70 degrees and they had S9+ signals.  Oddly,
the geomagnetic field was fairly quiet so something else was going on.  I
only have 2 Beverages up at the moment so I guessed that the signal was actually
being skewed further South, and that the 70 degree one was catching the signal
on the southern part of its main lobe.  I recall WW2Y's main EU Beverage was at
40 degrees and the signal was best on his 100 degree Beverage.  Peter WW2Y is
on the reflector so correct me if I got the details wrong.  This was one of
the more striking examples of skewing that I ever recall in my 12 years on 160.

4.  High arrival angle signals sometimes occur around sunrise and sunset.  Since
Beverages/Verticals are low angle antennas, they will not work well or even
at all under these conditions.  You need a high angle antenna (it's azimuthal
orientation is not all that important due to the high elevation angle) for
both transmit and receive.  I used a dipole (not an inverted vee which has
more low angle components) in Colorado and it is one of my projects for my 
new QTH here.  The dipole will ususally out-receive and out-transmit a 
Beverage/Vertical under high angle conditions.  BTW, every dipole that we can
put up on 160 is by definition a high angle radiator.  Even one at 130 feet is
only 1/4 wavelength high and the pattern is maximum at 90 degrees elevation!

        To summarize, your feelings about skewing could be correct.  To really
know for sure, you probably need a high angle antenna.  I was simply giving
you my observations based on what I usually look for if I see signals peaking
on Beverages at 90 degrees to their great circle bearing.  Usually geomagnetic
disturbances do not skew the signals that far in my experience, although I do
recall that I once worked SM6CPY from Colorado peaking on my 110 degree
Beverage  
when the K index was 6, so anything is possible on 160.  More often, when I saw
a signal peak on a Beverage at 90 degrees to great circle, I would switch to
my dipole and the signal would be better on that than any of the 8 Beverages.
Since the beamwidth of a 1 wavelength Beverage is in the order of 60 degrees,
the minimum setup for someone serious on 160 is 6 Beverages (more is better!),
a vertical transmit antenna and a horizontal transmit/receive antenna.  Only
then can you cover all the possibilities on this most fascinating band!

                                        73,  Bill  W0ZV

P.S.  Yes, I had a ball at W3LPL's this weekend, mostly on 20, but had a chance
to listen to and use his new 4-square on 160.  Frank only has 2 elevated radials
per vertical and beat ALL the other multi-multi's on 160!  I hope this doesn't
start another lengthy debate about elevated radials....PLEASE!  :-)  


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