Robb,
I assume you do not have a 130 foot support at the edge of the cliff. Perhaps
you have a loaded dipole? If you think the cliff will block your signal in the
most desired directions, you will have to do something different but if not, I
would suggest you put two radials in line with each other with short supports
every 25 feet or so above ground by 2-3 feet as near the edge as you dare go
and hang the vertical element over the cliff. It would look like an upside
down vertical with a short feedline and surely a good performer at least in the
directions that cliff is not blocking. If the cliff blocks important
directions I would go for a vertical as you have described with the shield side
of the coax hanging down the side and the portion above the edge of the cliff
vertical even if it had to be loaded. 40-50 feet vertical with two inverted V
looking top loading wires to make it resonant on about 1830 will work well.
73...Stan, K5GO
> On Dec 3, 2015, at 7:07 AM, Robb Webb Proprietor of Robb Webb Photography
> <robb@robbwebbphotography.co.uk> wrote:
>
> Good day fellow Topband Experimenters.
> When it comes to antennas I am a keen experimenter but technically a suck it
> and see merchant rather than a design pro so I ask for your expert opinions.
> I live near a high cliff overlooking the sea. The cliff faces south, is a
> good 100ft high and is made up of mud and clay that over the years has been
> collapsing into the sea. I am considering mounting my Topband dipole as a
> vertical antenna above the cliff edge with the ground portion of the antenna
> going down the cliff edge below the vertical portion. I'm aware I may need to
> add radials but is there anything else I should need to consider. This is in
> preparation for the Boxing Day Stew Perry contest.
> Thanks for your help.
> Robb
> G0URR
>
>
> Robb Webb Photography
> Bringing Photography to life
> Mobile: 07891 575892
>
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