Your difficulty may be the result of expecting vertical polarization to
work well an low geomagnetic latitudes. In his " Big Gun's Guide to Low
Band Propagation", the late Bob Brown, NM7M, described how the resonance
effect of the proximity of 1.8 MHz to the gyrofrequencies of electrons
in the ionosphere can increase absorbtion of top band signals at low
geomagnetic latitudes. Conversely, at high magnetic latitudes the roles
are reversed. The gigantic 160m horizontal yagi of OH8X was apparently
a huge disappointment, probably for this reason.
You might want to try inverted L's or T's, as high as possible.
On 10/02/2013 4:05 AM, Dave wrote:
My team is currently on DXpedition to Uganda 5X8C
We have erected receive antennas here in 5X with very poor success. W e have
used the same antennas at other places with great success. Please read below
and if you can offer some constructive suggestions please reply to me and copy
We are experiencing some weird problems with our receive antennas. We have a
beverage about 540 feet long, terminated properly about 5 to 6 feet over the
ground. I have built plenty of these at my house, they all work. This one
here does not. It hears noise but no signals. Once In a while you can hears
So put you're receive antenna hat on. We suspect the ground is the problem.
We are located on the shore of Victoria Lake at a resort. The soil appears to
be sandy but with fresh water lake nearby. 200 feet. The beverage is in the
clear away from large metal objects.
With a 510 ohm termination we measure about 235 ohms when looking across the
termination resistor. Using resistor theory essentially we have two
resistances in parallel. The wire , termination transformer, ground rods and
ground are about 500 ohms. Having not measured this at home I'm not sure if
this is too low or too high of resistance.
We erected a Flag 29x14 feet mounted just above the ground. This is purported
to be ground independent. Our tests last night indicate this antenna is not
hearing very well either.
We are soliciting suggestions. We only have a small amount of wire and other
antenna stuff, no Home Depot or Radio Shack around. Perhaps we can build a
ground independent antenna that does not care what it sits on.
We have or can source some wooden poles to make wire radiators.
The 5X8C team thanks you in I
Thank You in Advance,
Dave Anderson, 5X/K4SV
Sent from my iPad in Uganda