Not intending to diminish the excellent accomplishments at Mellish Reef at
all, I have certainly modeled a half-wave inverted L on 80m (80 HWL), and
was well aware of those results when I replied above. I have also modeled
the Mellish Reef antenna as well, both at edge of salt water and over
average ground, using NEC4.
I would have to say that the MR antenna made use of the edge-of-salt water
enhancement by utilizing what amounted to nearly vertical polarization.
It's particular advantage at the reef was giving a good multiband vertical
antenna without lossy shortening and other issues, with a decent feed Z and
at the same time obviating the need for radials on 80m. I have every
intention of using it sometime on the eastern edge of Pamlico Sound for a
USA Field Day.
The MR antenna on dry land presents all the issues of any vertical antennas
over land, but lacks the day-to-day usefulness of COMBINED vertical and
horizontal polarization on 80m.
The 80 HWL seems to gain some advantage by having the current maximum away
from ground. This can be seen somewhat by certain treatment of ground in
NEC4, but the ground calculation methods in the code make certain
assumptions about ground penetration losses. The MR antenna on the other
hand was on the edge of salt water and could make fabulous use of the lack
of those losses.
Some who have had an 80 HWL on dry land would argue with your assertion that
it was not a good DX antenna, finding them better for DX and local use than
any other single wire antenna that they could erect on 80m, including a
regular 1/4 wave vertical with whatever radial field they could accomplish.
So, with respect, I simply disagree.
73, Guy.
On Wed, Sep 30, 2009 at 1:45 PM, GEORGE WALLNER <gwallner@the-beach.net>wrote:
> On Tue, 29 Sep 2009 10:30:19 -0400
> Guy Olinger K2AV <olinger@bellsouth.net> wrote:
>
>> A 160 meter inverted L can be used quite successfully on 80 and 40.
>>
>
> Guy,
>
> You are correct to say that the 160 inv will have a high impedance feed
> point on 80 which is not as difficult to feed as some may think.
>
> However, the 160 inv L on 80 meters is a poor DX antenna. ...snip...
>
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