Hi Edu
As I said to you personally yesterday in a quick reply, both Salva EA5DY and
myself have done a bit of work in this field. As I think you know, I do a LOT
of mobile operating on the seaside and have done numerous contests as well. I
learned a long time ago that verticals and salt water are a good match, but I
guess it's something you have to experience for yourself before you can see
just to what extent.
Just for you to get a quick idea, I made first place in Spain in CQWW SOSB10 HP
in 2003. Admittedly conditions were good so getting 35 zones and 120 odd
countries wasn't entirely unexpected. But, if you take into consideration that
I was using a TS140, a 1.5m long helical whip, and 400w (in fact half of the
contest I just used 100 since I ran out of battery power), and that I was
competing with fixed stations with big yagis and full power amps, then it puts
it in a slightly different perspective.
A big yagi will do well next to the seaside too, and in some cases better than
vertical arrays, but as Stan has alluded, this will depend on the height you
can get your yagi up. In a temporary situation such as you are planning on, on
40m, it's almost certain that your best bet will be some kind of vertical.
Last year, I was contacted by EC5EC and EA5KB to see if I was interested in
operating in the IOTA contest from Tabarca island. The dates were bad, but
nevertheless I jumped in to help them with the antennas. This brought about a
long series of discussion, in which we also had some input from Kenny K2KW.
To cut a long story short we came up with a KISS design for a 2 element phased
array based on coax phasing lines which I think will be perfect for what you
want. On 40m, we made it out of two 12m long collapsable spiderpoles
(www.spiderbeam.net). When the beam is set up pointing north, it has two lobes,
one at approx 315º and the other at 45º. For us that is USA and EU/JA, the main
QSO areas, and I suppose that although you're a fair way south-west of me, it
should be more or less the same. That way, with one FIXED antenna you get to
cover the vast majority of your QSOs. Suggest you also take along a wire dipole
though.
To make it work, the element spacing is (from memory) 19.5m and the 3/4 phasing
line is 21m (for RG213). Both antennas are identical quarter wave verticals
using two elevated radials, which is probably the simplest for a temporary
setup.
I also built an 80m version for last years CQWW but unfortunately it didn't
work out (see my article on http://www.contesting.com/articles/905). I do plan
to have it active in this year's CQWW though :.)
If you want to see photos of the 20 and 40m arrays on Tabarca, go to
http://cq.uv.es/ee5kb/IOTA2007_FOTOS/ . The 20m antennas are aluminium, made by
Salva, the 40m antennas are spiderpoles, made by me.
In case you are still wondering as to whether they work, I met Pepe EA5KB last
week at the Torrent swapmeet. Pepe was so enthusiastic, and reminded me that
even though the generator had failed, they were still able to RUN JA with 100w
on 40m phone. No mean feat....
If you want any further details then just let me know.
73
Duncan EA5ON
From: cq-contest-bounces@contesting.com
[mailto:cq-contest-bounces@contesting.com] On Behalf Of ea8auw@cidxs.com
Sent: jueves, 24 de abril de 2008 23:19
To: CQ-Contest@contesting.com
Subject: [CQ-Contest] 40 Meters Antennes - Yaguis - Verticals -
rigiddipole...solutions pse.]
Hi Stan !
thanks you for your quickly answer.-
good questions, I think....
Well, the principal direction would USA and EU, In this way I have ocean
only, not montains in this 2 ways. possibly the salt water it's separate
of the antenna arround 10 meters possibly less if I want it..... if it's
better that the matils touch it the salt water, not problems.
This plan not it's for an antenna fixed, it's for contest or dx'p. I think
then that the maximum height would be 10 or 11 meters of some mastils, not
more...
TNX Stan !
73 EA8AUW
> How close to the salt water would the
> antenna be?. What would the elevation
> above sea level be for the 2 element
> yagi? Do you have a clear shot in
> preferred directions or are there
> mountains in the way?
>
> Stan, K5GO
>
> ----- Original Message -----
> From: <ea8auw@cidxs.com>
> To: <CQ-Contest@contesting.com>
> Sent: Thursday, April 24, 2008 3:18 PM
> Subject: [CQ-Contest] 40 Meters
> Antennes - Yaguis - Verticals - rigid
> dipole...solutions pse.
>
>
>> Hello friends!
>>
>> I want to make an effective antenna
>> for 40 meters for to use it near of
>> the salt water in contest, not for
>> everydays qso. sometimes the valid
>> antennes for everydays not running
>> well in contest..... I think.-
>>
>> Well, My first thought was to make a 2
>> elm. full size with 4 fishing rod
>> of 8.00 meters of large plus 3.00
>> meters of aluminium tube to each side
>> of
>> the boom. The central boom would be of
>> aluminium and 6 meters of large
>> more o less. the rest of the antenna
>> it's with fine wire 1,5 or 2
>> milimeters on the fishing rod tuned to
>> his size.
>>
>> Yestarday, I can to read an article of
>> Kenneth K2KW named DXpedition
>> Antennas for Salt Water Locations A
>> study on 20m Antennas and he says that
>> it is better 2-element vertical array
>> using vertical dipoles that yagis
>> antennes.-
>>
>> Now, I think many in this, Because I
>> have many doubts, I want to make 2
>> elem. vertical array, sometimes I am
>> thinking in to make 4 square for 40
>> meters, But I cannot delete of my mind
>> the 2 elem. full size yagi.
>>
>> I have many time now for to make
>> several antennes testing and for to
>> make
>> several antennes also. but I need some
>> schematics with size, connections,
>> space, separations between verticals
>> and more details, if you have some
>> schematic of some antenna system valid
>> and effective for contest, and
>> dxpeditions please send me at
>> ea8auw@gmail.com or write to me and
>> say me
>> where I can see them.
>>
>> Also, you can write me to comment on
>> your experiences with these types of
>> antennas, if you know as working 2
>> elem array vertical dipole, 2 elem.
>> parasitic vertical dipole, 4 square, 2
>> phasing vertical or 2 elem. yagui.
>> what it's the best for you....
>>
>> I am not electronic, Possibly I could
>> not it makes the relay or phasing
>> box for 4 square, if it's
>> difficult....
>>
>> this is all, for teh moments.....
>>
>> Thanks you to all in advanced, any
>> news it's very appreciated.
>>
>> Big 73 de Edu EA8AUW.-
>>
>>
>>
>>
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>>
>>
>> --
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>>
>
>
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