[TowerTalk] Butternut HF2V 'Top Hat Wires' Question

telegrapher9 at aol.com telegrapher9 at aol.com
Tue Jan 23 12:00:28 EST 2007

Adding the top hat wires will increase the radiation resistance. If the VSWR was 1:1 before it will be higher after the wires are added. The wires should just about triple the radiation resistance. Given a high ground resistance the radiation efficiency will triple. 
Running the top hat wires horizontal is the best. Angling them downward cancels some of the current-area of the antenna and results in a lower radiation resistance. 
Recommendation: Run the top hat wires as horizontal as you can. Tune the antenna to resonance. Adjust the VSWR at the shack using a good tuner. 
   Dave WX7G 
-----Original Message-----
From: tyron at globalnet.co.uk
To: mryan001 at tampabay.rr.com
Cc: towertalk at contesting.com
Sent: Mon, 22 Jan 2007 1:44 PM
Subject: Re: [TowerTalk] Butternut HF2V 'Top Hat Wires' Question

Hi Mike,

Have you tried adjusting the shorting straps on the coils to reduce 
inductance? I have no experience of this myself but have read the 
instructions having recently bought the remains of a wrecked one - it is 
missing the sections above the coils (parts G to M according to 
instructions). I hope to find the length these sections make up to 
source replacement parts, or perhaps an accurate overall length if 
anyone can help please? The instructions don't unfortunately give 
accurate assembled length - guess I could experiment but it'd be nice to 
get it right from the off! Also I intend mounting it above ground with 
raised radials so will be tricky to keep taking it up and down.

Interested in your experiences Mike, are you using the 160M add-on I 
wonder? That would further complicate setting up I suppose.

If anyone needs instructions I think I got them from Butternut website 
or I'm happy to email to whomever needs.

Regards to all,

Tyron, M1AQV

mryan001 wrote:

>Has anyone put top hat wires on an HF2V?  Having done so has adversely
>effected the swr curve and efficiency of the antenna to some extent. Before
>adding the wires the standing wave was near flat in the dx window. After
>adding the wires the standing wave is just below 2:1 at the resonant point
>but I would like to drop it below 1:5 if possible.  Will changing the angle
>of the top hat wires from the radiator do this in the way that changing the
>angle of or trimming a sloper wire does? Should the recommended length of
>25ft for the top hat wires be shortened or lengthened per wire to adjust the
>swr in some way?  Would attaching the top hat wires to the VERY TOP instead
>of about 5ft below the top as indicated by Butternut effect this?  Any
>suggestions?  - Mike
>TowerTalk mailing list
>TowerTalk at contesting.com

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