The best place to study this is in the early chapters of the ON4UN book,
where he talks about situations like this.
Someone suggested HFTA. HFTA applies ONLY to horizontally polarized
antennas.
David is right -- NEC does allow two ground models. It would be tricky
though -- the key here is the sea water ending in the range of 1,000 ft.
So the model would have to start with sea water out to 1,000 ft, then
shift to land for the second media. That would yield an overly
optimistic view of ground losses, but would take the limited sea water
into account.
73, Jim K9YC
On Wed,8/12/2015 7:33 PM, David Gilbert wrote:
I don't remember for sure off the top of my head, but I think that
EZNEC+ has the capability of specifying two different areas of ground
conductivity surrounding the antenna. You could rather easily see the
impact of the nearby salt water if I'm correct.
Dave AB7E
On 8/12/2015 1:19 PM, Mike Smith VE9AA wrote:
As we continue to look for land around the Maritimes for a small weekend
cottage we occasionally come upon a location that has shorefront on
saltwater, which really is not completely open water all the way to
EU or
USA, so it's not ideal. The south coasts of VO1, VY2, VE9 and VE1
all kinda
point S/SE
I have found a couple with a clear shot to the Caribbean or Africa,
but with
so few contest stations there, it's really not very important, except
perhaps for that rare LP to JA...
A few spots have open salt water towards EU of around 1000', before
it hits
land again (opposite side of the harbour) then gently sloping up past
that.
(0-100/200 feet)
So my question is really, does 1000' of salt water make any
difference at
all, or not enough to make any difference and the 200' hills on the
other
side of the harbour would be more hindrance than the salt water would be
helping?
There must be stations all over the world with a short salt water
takeoff
who could comment?
Has anyone done any A/B comparisons or proof at all?
I have read N6LF's and K2KW's and most related stuff on the Internet,
but it
generally references DXpeditions in the Pacific or Caribbean with
completely
open water as far as the eye can see. I am just wanting to know about a
1000' salt water runway, then low land again.
Thanks,
Mike VE9AA/VE1TTT/VO1TTT/VO2DX
Mike, Coreen & Corey
Keswick Ridge, NB
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