From: jimlux <jimlux@earthlink.net>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Fair rite materials for choke baluns
On 7/4/16 12:26 PM, Jim Brown wrote:
> An easy to build test fixture would be to use the choke as the end
> insulator of an end-fed center-fed dipole, as I've shown a couple of
> places, and shove high power at a high duty cycle into the dipole.
end-fed center-fed? What's that? Do you mean coax into one side of UUT,
then of the two leads on the other side, connect one to "half
wavelength" of wire, and then what does the other side go to? The
antenna support? Or, since you're looking at common mode, both "output"
wires of the choke go to the same place?
> http://k9yc.com/VerticalDipole.pdf
## Look at the PDF. Think of a dipole.. but turned vertical.
With coax going to center, and center conductor bonded to upper wire half,
BUT, the lower wire leg, is replaced by the braid of the coax itself.
A CMC is inserted where the lower insulator would normally be placed on a wire
dipole.
Below the coax CMC... is just a continuation of the same coax... all the way
back to the xcvr.
## it’s a unique way to build a vertically polarized dipole...using a coaxial
CMC as the lower
insulator. It also places the CMC at an extreme high V / high Z point...and Im
surprised the
CMC actually survives.
Jim VE7RF
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