[UK-CONTEST] Verticals

Wed Apr 1 01:59:45 PDT 2009

As this seems to have become a topic of more general interest, here's my 
reply to Mike a few days ago, which I did not post generally. MIke 
subsequently clarified the MFJ type number, which as far as I can see is the 
same unit as the HyGain.

Mike,

Depends what bands you want.

As I see it the HyGain is simply a rod (no traps) and needs a tuner near the
antenna to tune out the reactance.  I'm always wary of these, unless the
tuner is at the base of the antenna, as you get a whole load of radiation
from the feeder, and this can give EMC problems. As for the  MFJ, the 299 is
a microphone/equaliser so I think you may mean another model ??

I think for verticals there are two options:

Non-resonant (The HyGain you quote and Titanex are this sort) - my comment
above about the tuner is the point here. It's also worth modelling these on
EZNec, so see the effect of a multiple of wavelengths on some bands. It can
give rise to only high-angle radiation, so not good for DX. My Titanex has
this problem on 40m. But I agree about your Tiger beers. My first (and one
of the best) verticals I've ever used (at the previous QTH) was home brew.
It was a 33 ft vertical segment, with a 7 MHz trap at the top, and a 22ft
sloping section above that. Sort of half a W3DZZ, on its end. Worked a treat
on 80 and 40, and even allowed me to work VK9MM on Mellish in broad daylight
on 80 ! If I were considering a new vertical here, and was looking at the
commercial non-trapped  units, I'd not buy one, I'd build one. All you need
is a pole and a few bits of metal, and a local agricultural engineering
workshop which can do the metalwork. For up to about the top 20ft, I use
fibreglass/carbon fibre fishing poles with aluminium or copper wire up the
inside. Light, strong and cheap. You can then fit these to the top of 20ft
aluminium scaffold poles, and you have a 40-45ft vertical. If you go for the
half of a W3DZZ, you only need 33ft (I used a 20 and 12 ft scaffold pole
with a scaffold joint) and some wire and, of course, a trap (which I'd make,
to get a good power rating). This gives you 80 and 40 WITHOUT a tuner.

Resonant (and for multiband this means some form of trap): If I were buying
a trapped vertical for LF and wanted just 80 and 40, I'd go for the
Butternet HF2V. MUCH more efficient than any other trapped antenna. In fact,
apart from 80, the HF6V is almost as good, and you get an extra multi-band
antenna thrown in ! The HF2V is a great antenna for 40 and 80, but of course
you need an earth mat. My Butternut here (HF6V) is used as a spare antenna,
but as my principal antenna for 30m, and regularly busts the pile-ups. OK
it's on a  ridge, but it works very well. It is also excellent on 40, but
had the disadvantage of only about 30 kHZ bandwidth on 80. The HF2V is
better on 80.

Finally if I were going for 160 metres as well, and assuming you can't get
away with a 90ft vertical like the Titanex, I'd go for the W3DZZ vertical,
with a longer top section, or even an extra trap for 80m. You need the
vertical section for 160 DX. The commercial antennas that have "160" use
base loading, which is inefficient. Better to pull the current up the
vertical section by top loading.

Hope this helps. Happy to provide more info.

73

Don, G3BJ

----- Original Message ----- 
From: "Andy Swiffin" <a.l.swiffin at dundee.ac.uk>
To: <uk-contest at contesting.com>
Sent: Wednesday, April 01, 2009 9:45 AM
Subject: Re: [UK-CONTEST] Verticals

>>>> On 31/03/2009 at 14:11, in message 
>>>> <001301c9b202$4507d630$0200a8c0 at G3VAO>,
> "Mike Farmer" <G3VAO at ARRL.net> wrote:
>
>> Thanks for all the replies so far I have to correct a typo in my original
>> 73 all must get back to digesting the info recieved
>
> Hi
> I'd be interested to hear what the collective wisdom of "uk contest" has 
> to say, if you could post a precis to the list.
>
>
> Maybe I always think too simplistically about verticals, but I never 
> understand how they sell them for hundreds of pounds.
>
> Surely:
>
> <being simplistic>
>
> The whole point of (most) verticals is to get a resonant 1/4 wave 
> vertically into the air over a ground plane.   Where you want it to do 
> more than one band you either have
>
> i) traps   or(and?)
> ii) an ATU
>
> so it becomes a bit of a compromise.
>
> As in the MFJ/Hy Gain (sic)  offering it's a 43 foot scaffold pole with an 
> insulated base and a telescopic whip on top which is multiband because you 
> stick an ATU at the bottom.   It's 43 feet because if it was any longer 
> the vertical lobes at high HF would make it almost useless and if it was 
> any shorter the losses at low LF would make it almost useless?
>
> Wouldn't a vertical work just as well if you took one of these long 
> fibreglass poles and stuck some wire up it?  You could even make it a 
> resonant 1/4 wave of wire?
>
> </being simplistic>
>
> I expect the solid 43 foot poles or the Stepp-IR copper strip variable 1/4 
> wave takes away some of the hassle of making something, it just seems an 
> awful lot of money for 1/4 wave of wire stuck up in the air?  Or am I 
> missing something?
>
> 73
> Andy
> gm8oeg
>
>
>
> The University of Dundee is a registered Scottish charity, No: SC015096
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