Hi Dave,
Glad to see you have the Beverages working.
> This morning T32MP was back on, although with a much, much weaker signal.
> The T32 signal was essentially equal from all four beverage directions.
If
> I were trying out my beverages this morning for the first time, I would
have
> never believed that they are working. It's a little hard to believe that
> the angle of the arriving signal from T32 is so high that the beverages
show
> no difference in signal strength. Is there something else to attribute
> phenomenon to or is it purely a high angle of the arriving signal.
I have no idea what causes that effect Dave, but IMHO it can come from more
than one effect.
That effect (but without the complete loss of directivity) happens to a
small extent quite often. Although it doesn't happen every day, when it
does happen it usually happens just after sunrise. The verticals, which
clearly dominate all night long, gradually fade out until they are all
done. They still retain some directivity, however. I might hear ZL2REX on
the northwest antennas, and VK6VZ on the southwest antennas along with the
normal directions. A brief (maybe twenty minute max) peak occurs on the
high dipoles.
Some rare days when that effect happens, my phased dipoles (at 250 feet)
work much better than any vertically polarized antenna I have, including
the Beverages. A low dipole "starts to work", but is never quite as good as
the high dipoles. The verticals and Beverages are all but dead, including
propagated noise, but the dipoles are really zinging. They can be as much
as two S units (about ten dB) above the verticals.
This off-sunrise effect usually accompanies poorer over-all signal levels,
but not always. It seems to occur when the magnetic field is disturbed.
At other extremely rare times the verticals AND the horiz will show almost
no directivity. This is a very rare one, and usually accompanies weak
watery signals and severe geomagnetic storms. I've only hear it three times
since June.
ZL2REX, VK3ZL, others and myself have been keeping tabs on this since
June. I try three antennas on transmit, the phased dipoles at 250 feet, the
four square, and a low dipole.. and several on receive. About 35% of the
time the Beverages and 4 square are better than the high phased dipoles for
any distance more than a few hundred miles, often by five or ten dB. About
3% of pre-sunrise time the high dipoles work better. About 30% of the days,
ONLY counting the period just after local sunrise, the high dipoles work
better than the four square. About 73% of my operating time the verticals
equal or beat the high horizontals, and the verticals so far beat the low
dipole about 99% of the time.
I think there is so much going on, it's hard to get a clear picture what
causes what. The other day (22 Oct) the effect was weak signals NE from
Europe, and strong signals due east. My dipoles were killer, I worked about
two dozen Europeans, some far east "Russians", and five Africans with S9
plus signals. That was the first day ever ( and the last day so far) the
dipoles soundly beat the four square into Europe. The low dipole was well
down, but better than it usually is and just as good as the Beverages for
receive.
Weird propagation. As they say..."stuff happens". I think the correct view
is that a lot of "stuff" goes on, although like anything in life we all
look for one simple answer of "one cause one cure". Saying "I don't know,
a lot of stuff happens" will never win the prize, even if it is true.
73 Tom
--
FAQ on WWW: http://www.contesting.com/topband.html
Submissions: topband@contesting.com
Administrative requests: topband-REQUEST@contesting.com
Problems: owner-topband@contesting.com
|