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 Elevated vertical antenna radials 
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Post Elevated vertical antenna radials
Guys
I'm proposing to replace my windom with a non resonant vertical with a remote tuner. I am going to have the antenna mounted on the chimney at the back of my house as my back garden has been landscaped and a buried radial system is totally out of the question. The base of the antenna will be about 40' up and I will add some radials from the tuner. Now i fully understand these radials will need to be resonant but i don't want to make the property look a mess with radial wire everywhere. What I'm wondering is can you use something like a ribbon cable to make a multiband radial to save me having lots of radial wires everywhere? I appreciate one will probably detune the other somewhat does anyone have any sensible suggestions? I have looked at the butternut STR-II resonant radial kit which seems to be made out of twin feed but they want > £150 for this which seems rather too much!
Also I am currently looking at a few different tuners. The Icom AH-4 as it will interface with my 756pro very well and also the CG-3000 as it looks to be a little more versatile radio wise. Does anyone have any experience or recommendations? The CG-3000 is over £100 cheaper than the AH-4.

Thanks

Keiron M0HKB

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Keiron M0HKB


Sun Apr 08, 2012 7:52 pm
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 Elevated vertical antenna radials 
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Post Re: Elevated vertical antenna radials
Keiron,

Yes, you can use ribbon cable for resonant radials, although tuning them becomes a bit tricky in the same way that tuning a fan dipole with closely-spaced wire is.

However, I don't see much point in having resonant radials if the vertical is non-resonant. I'd use several radials cut to the same length as the vertical and place a tuner at the feedpoint.

73,
Steve G3TXQ


Sun Apr 08, 2012 8:18 pm
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 Elevated vertical antenna radials 
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Post Re: Elevated vertical antenna radials
That makes things easier Steve. Much of what I had read led me to believe that with the tuner the radials will still need to be resonant. Any experience with either of the aforementioned tuners?
Thanks for your prompt reply!

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Keiron M0HKB


Sun Apr 08, 2012 8:20 pm
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 Elevated vertical antenna radials 
Silent Key

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Post Re: Elevated vertical antenna radials
Let's say you had a 25ft non-resonant vertical and a single 25ft non-resonant radial; you can view it as a simple 50ft multiband doublet with one leg "bent round". As long as you put something at the feedpoint that will reduce the SWR on the coax, it will work.

Sorry, I've no experience of those tuners, but I'm sure others will comment.

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Steve G3TXQ


Sun Apr 08, 2012 8:34 pm
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 Elevated vertical antenna radials 
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Post Re: Elevated vertical antenna radials
Does the construction of your house allow you to have the antenna on the chimney, and the tuner and radials fanned-out beneath it inside the loft?

Multiple parallel radials of different lengths are fine, as long as you can spread the ends apart. A bit like half of a fan dipole.

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Chris, 'oop North.


Sun Apr 08, 2012 8:52 pm
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 Elevated vertical antenna radials 
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Post Re: Elevated vertical antenna radials
Chris
The chimney will allow the radials to be fanned out so that wont be a problem. Thanks for your reply.

Re a remote tuners: I found this whilst surfing. Made some interesting reading http://www.ad5x.com/images/Presentations/Remote%20Tuners.PDF

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Keiron M0HKB


Sun Apr 08, 2012 9:01 pm
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 Elevated vertical antenna radials 
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Post Re: Elevated vertical antenna radials
OK, if you do put the tuner and radials inside the loft, the tricky bit will be feeding the antenna wire through the roof tiles so that it will be insulated, especially when it is wet. But I have seen dummy roof tiles on sale which incorporate a pass-through for TV/FM downleads.

As the others say: If you are using a non-resonant whip with no traps, it's better to have many radials the same length as the radiator rather than one radial for each band.

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Chris, 'oop North.


Sun Apr 08, 2012 9:28 pm
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 Elevated vertical antenna radials 
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Post Re: Elevated vertical antenna radials
Chris
I am going to externally mount the tuner directly under the vertical section and run the radial wires down to various points on my property. I don't have a loft as my house is three storys and the upper floor is where the radio room is.

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Sun Apr 08, 2012 9:43 pm
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 Elevated vertical antenna radials 
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Post Re: Elevated vertical antenna radials
Three floors eh? ... nice. That bit of extra height should work just fine.
I used to regularly work a bloke in Poland on 80m QRP who had nothing more than a wire running around inside his flat. He was up on about the 15th floor though :-)
Good luck.

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Sun Apr 08, 2012 9:53 pm
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