Tony Renshaw wrote:
> Gidday,
> I am about to install my Europa dipole antenna to the back of my sternpost,
> and have a couple of questions regarding ideal length etc of each portion
> of antenna. Annex C at the end of the manaul outlines to make each portion
> 515 mm initially in length. The dimension in the schematic uses the
> dimension of 490*mm, so it is obvious to me there is a point somewhere
> within this range that is what I am after. Does anyone else have a more
> refined starting point?
Well it depends upon a "fudge factor" re the width of the copper strip you're
using.
According to Jim Weir's book, if 12mm or so wide, then 515mm should peak
at 126mHz, roughly mid-band; 490 at 133 mHz (too high). If unable to actually
tune it with a VSWR meter, it's best to err on the side of legs too long.
That peaks performance down lower on the radio dial, where at least here in the
U.S. common freqs used in VFR abound.
If a copper strip vs. wire, precise length is not that critical as the thing
will
be wide-band enough for practical use, as I found in actual testing.
Regards,
Fred F.
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