[UK-CONTEST] 20m vertical

[Callum M0MCX]

James, I can tell you've been off with the flu :). Yes, the 40m vertical
array was rather special and gave us a 10 hour pile-up from Dorridge.
Unfortunately it's not rotatable, as you say!

Mark,

I thoroughly recommend a vertical for playing with, certainly most excellent
for 40m - you'll love it down there. Try a loaded version for 80m too if you
like. Spiderbeam do a 12m mast (and an 18m version too which will tune on
80m by lengthening the radials a whisker). You can't get it wrong being so
close to salt water. 10m fishing poles can be bought for less than 30 pounds
so there's no excuse for not buying a pair. Initially, for 20m, go down the
route of using a pair of radials about a meter above the ground (that's the
feedpoint raised up a bit) and you'll find a near match to 50 ohms. Very
convenient. You may find it'll be excellent for general DX. But as James
says, you won't have any front-to-back ratio and the EU lot will bombard you
when you're trying to work the US etc. so as a contest antenna it won't be
so good however Tim (M0URX) worked 100 countries on 40m during CQWW with a
basic quarter-wave. Build one!

Here's pictures of a 40m vertical done on the cheap with a 10m fishing pole
at 3m above the ground using 4 radials sloping to about 50cms above ground
(although a pair should act the same. 4 looked better!). You can use a
dipole centre from Moonraker / W&S etc as the feepoint. Clamp some ferrites
on the coax to act as a type of balun by the feedpoint to be more pure. This
will deliver you a more accurate piece of research.

- http://www.m0mcx.co.uk/gallery/picture.php?/460/category/41

Build both and let us know how they worked..??!!

(and here's a yagi version:
http://www.m0mcx.co.uk/gallery/picture.php?/458/category/41 - difficult to
rotate as you say!!) 

Cheers,

Callum McCormick
http://www.m0mcx.co.uk/


-----Original Message-----
From: uk-contest-bounces at contesting.com
[mailto:uk-contest-bounces at contesting.com] On Behalf Of James Thresher
Sent: 12 November 2008 16:05
To: uk-contest at contesting.com
Subject: Re: [UK-CONTEST] 20m vertical

This was a 1/4 wave vertical with 4 radials, and another slightly larger 1/4
vertical (not driven in any way) acting as a reflector, again with 4
radials, they were about a 1/4 wave apart. It wasn't just a vertical yagi ;)
It was built for 40m so it was quite large, the modelling suggested pretty
good gain figures. We had planned to build a 4 or 5 element version for SSB
Field day this year but decided against it in the end. Not sure how you
would even get the 2 element version rotating on a mast complete with
radials.

73

-----Original Message-----
From: uk-contest-bounces at contesting.com
[mailto:uk-contest-bounces at contesting.com] On Behalf Of Ian Maude
Sent: 12 November 2008 15:53
To: UK-Contest
Subject: Re: [UK-CONTEST] 20m vertical

James Thresher wrote:
>
> We've actually played around with these, a couple of the others in our
club built one the other year for 40m, they had pretty good results with it.
The big disadvantage of course is that you can't rotate it.
>
Why ever not?  If you mount it as ours was on 1 mast, it rotates easily :)

73 Ian

--

Ian J Maude, G0VGS
SysOp GB7MBC DX Cluster
Member RSGB, GQRP
K2 #4044 |K3 #455
http://www.amateurradiotraining.org

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