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Re: Topband: Soliciting suggestions on our receive antennas for 5X8C

To: Dave <>,
Subject: Re: Topband: Soliciting suggestions on our receive antennas for 5X8C
From: Bert Barry <>
Date: Sun, 10 Feb 2013 11:20:52 -0500
List-post: <">>

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.

Bert,  VE3QAA

On 10/02/2013 4:05 AM, Dave wrote:
Hi All,

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
Topband Reflector

Topband Reflector

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