Interesting information Barry. Terrain plays a major role
in determining radiation angle so I need to know if your
terrain is level from your tower towards Europe and Africa.
Antenna heights need to be adjusted to accomodate
terrain effects.
Part of the answer of course is that for the past 4 years,
we have been in the bottom of the sunspot cycle.
>From W4, everyone* I have persuaded to put up high and low
antennas has found times when the LOW antenna is best
to Europe and especially Africa, usually in the early afternoon.
Also, during SS contests, the low antennas are always best
for closer in stations, say 500 to 800 miles or so on direct path.
As sunspots increase, I expect we will see more occasions
when the low antennas are best.
It makes sense that if the
DX stations are using low antennas which produce greater
radiation at the higher angles, that the highest angle which
propagates will yield the strongest signal. IF high antennas
are used at both ends of the path, they MAY still produce the
strongest signals, but that is only true if the antennas at
BOTH ends of the path are high.
Other factors may still
predominate which tend to favor high angle radiation.
These include ducting and E-layer effects which may
cause downward "bending" of the higher angles. It would
follow that stations closer to the equator would observe
this effect more than more northern stations.
de Tom N4KG
*everyone = AA4NU, K4AB / WZ4F, NN4T / WA4CTA, N4NO
K1VR and others have made similar observations as well.
................................................................................................................
On Mon, 28 Sep 1998 10:29:12 +0000 "Barry Kutner" <w2up@mindspring.com>
writes:
>On 28 Sep 98, T A RUSSELL <n4kg@juno.com> wrote:
>
>
>> You forgot to include the versitility provided by a
>switchable
>> stack. Having UPPER / LOWER / BOTH options, you can
>> better match the waveangles that are propagating to your
>> target at any given time. And YES, they do vary. During
>> high sunspot activity and daylight hours, the angles can
>> get quite high, much higher than most references indicate.
>> de N4KG
>>
>I've had a 2-stack of TH7s up for about 4 years (40 and 76 ft). I've
>never seen a time when the lower is better. Generally, the stack is
>best, upper second, lower third. I've heard this "folklore" about the
>lower one being better, but have never seen it. Is it that the
>sunspots
>aren't back yet, my location (EPA, abt 70 miles from ocean), or
>something else?
>73 Barry
>--
>Barry Kutner, W2UP Internet:
>w2up@mindspring.com
>Newtown, PA Frankford Radio Club
>
>
>
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