Hello Tim,
A few comments.
First, I once had a 2L Delta Loop suspended from a 20 ft alumunum
boom (2 inch O.D.) at 120 ft. I placed pulleys at each end of the boom
with a closed rope loop (closeline style) to allow me to attach the loops
at the tower and pull them out to the ends. I formed small rope loops
around the boom to hold the wires. It was a KILLER antenna !
At 80 ft, I would recommend inverted vee elements instead of loops,
to maintain as high an effective height as possible. I use a 2L
40M inverted vee beam at our Field Day site with a 70 ft reflector
at 50 ft. It plays very well for USA, but 80 ft would be better for DX.
I recommend pulling the ends out as far as possible with light nylon
cord to maximize the apex angle.
Another option would be to use two equal length elements fed with 3/8 WL
of coax and switch both sides of the coax, allowing for quick reversal.
The unfed element plus 3/8 WL coax stub acts as a decent reflector.
A single dipole could be placed perpendicular to those elements, under
the boom for plus / minus 90 degrees without having to rotate any
elements.
Tom N4KG
On Sun, 9 Jun 2002 "Tim Makins, EI8IC" <contesting@eircom.net> writes:
> I was thinking of suspending 2 40m diamond-configuration quad loops
> from the top of an 80' steel scaffold-pole mast.
>
> Option 1 is put a horizontal 20' length of timber with central
> pivot at the top of the mast, thus spacing the loops correctly,
> and allowing them to be 'walked around' to the desired direction.
>
> Option 2 is to mount the tops of both loops on insulators at the top
> of the mast, and pull the sides and bottoms of the loops away from the
> mast, pyramid-fashion.
>
> What are the pros and cons of both options, and which do you prefer
> for best DX performance ?
>
> 73s Tim EI8IC
> www.qsl.net/ei8ic/
> Irish and Budget Contesting
> Last Updated: 07Jun2002
>
>
>
>
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