Topband: Antenna in Bahrain

[Dave Court]

Hi All
I am now QRV on 160m in Bahrain as A92IO. As an antenna I am using the 
lower 15 metres of a spider beam fibreglass pole mounted on top of my 
roof which gives a vertical section of around 23 metres. I have two 18 
gauge wires taped to the fibre glass pole, joined at the top and 
currently have a top loaded inverted V arrangement with an end to end 
span of 10 metres. The lower section of the vertical comprises 400 ohm 
ladder line attached to the ends of the 18 gauge wires. the ground end 
of the ladder line is joined together. Natural resonance appears to 
occur at around 2.6 MHz. The ground system comprises two earth rods of 
around 5ft in length and 10 140ft radials. Ground conductivity is low 
due to the sandiness of the soil, however Bahrain floats over a lake of 
brackish salty water which is around 10 ft below ground level.

Originally I thought this arrangement could be tuned to resonance with a 
series capacitor but I believe the span needs to be around 20 metres to 
achieve a resonance lower than 1810 MHz. However this set me thinking. 
If I add 5 metres to each of the top loading wires because of the 
inverted V nature of the wires I will loose effective antenna height. So 
my basic question is - in my situation is it better 1) to use an L C 
matching arrangement at the base of the vertical which I currently have 
2) Extend the top loading wires in the inverted V arrangement and use a 
series C at the base or 3) use some centre loading in the vertical to 
take the resonant point below 1.8 MHz and then try to use a series 
capacitor to match the system at the base of the vertical?

All thoughts welcome.
73s Dave A92IO


-- 
This Email comes from Dave Court - A92IO, EI3IO, G3SDL, OZ3SDL
QTH (Grid) Locator - LL56fe (Bahrain) IO63wf (Ireland)
Web Site: http://A92.ath.cx or http://EI3IO.com
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