[TowerTalk] balanced line loss on a mismatched antenna

[Gene Fuller]

I think that Cebik's deal with 44 feet was to use it from 10-40 and keep the 
lobe splitting to a minimum on 10. If you want to play on the cmputer you 
could look at putting an about 11 foot stub, with a spst relay on the end, 
on the center of the 44 foot element.  Short the stub on 15 and 40 and  open 
on 20 and 10. That will phase the currents about right and give some 
compromise on the feed point Z.  I  once build a parasitic array using four 
of them on a 30 foot boom, tunig only 3 on 40, fed with 450 ohm line. With 
it up 100 feet the patterns looked reasonable and it performed fairly well. 
That was before any of the ham computer programs. Tuned it with a grid dip 
meter and it required a lot playing around with additional relays and little 
stubs to get the elements to resonate where I wanted them. But, bottom line, 
I have since gone to a 7-60 MHz log periodic  (15 elements on a 45 foot 
boom) and with the aide of a computer to optimize it on the ham bands, it 
certainly beats the old parasitic array. I've also had pretty good luck with 
a 44 foot vertical dipole fed with 450 ohm line and a little parrellel line 
tuner for portable operation.
Gene / W2LU

----- Original Message ----- 
From: "Paul Christensen" <w9ac at arrl.net>
To: <towertalk at contesting.com>
Sent: Tuesday, February 28, 2012 2:04 PM
Subject: Re: [TowerTalk] balanced line loss on a mismatched antenna


> >"You'd be way better off with just a dipole (EZNEC says 22 - j600 ohms 
> >for a 44 foot element) and either..."
>
> I agree with Dave's loss numbers for 44 ft element length.
>
> However, before giving up and using a shortened 44 ft. dipole, you may 
> want to see if there's a way get the elements lengthened close to a 
> halfwave and still keep spacing at 0.1 wavelength.   Perhaps bring the 
> ends down if you're maxed-out on horizontal space.  If you can, then you 
> can use my prior message as a guide for system loss.  I would still model 
> it with the hanging ends.  Otherwise, the 44 ft length on 40m is going to 
> be a real looser with the 8KJ as the added element really drives the 
> impedance down from mutual coupling and the short element length makes it 
> too reactive to keep losses low, even when trying to match at the 
> feedpoint.
>
> Paul, W9AC
>
>
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