[Antennas] Common-Mode choke at 430 MHz.

[Larry Bush]

The RG-58 is only 3 feet long terminated into type N female.
I'm well versed with loss of different types of coaxial cable.
What I really wanted was an answer to my specific questions.

<:-)  LB





----- Original Message -----
From: "Robert S. Stein" <w6nbi@earthlink.net>
To: "Larry Bush" <w5ncd@bigfoot.com>
Sent: Saturday, April 20, 2002 1:16 PM
Subject: Re: [Antennas] Common-Mode choke at 430 MHz.


> Obviously you are interested in antenna gain if you are going to use a
> couple of 8-element Yagis.  If so, why in the world would you use
> RG-58A/U?  Its loss at 430 MHz is over 10 dB/100 ft.  The loss in
> RG-213/U, or good RG-8 type, is about 4.8 dB/100 ft.
>
> Bob, W6NBI
>
> Larry Bush wrote:
> > Am building a couple of 8 element 430 MHz Yagi on 1 inch PVC boom.
> >
> > The driven element is a dipole with direct feed RG-58A. I thought a
> > common-mode balun wound with the RG-58 around the 1 inch OD PVC boom
would
> > be neat so I computed the reactance needed was .4 micro-Henry, which is
five
> > turns on the boom. During my research I was could not find the use of
> > common-mode baluns on frequencies higher than 6 meters. I have three
> > questions:
> >
> >
> >
> > 1                     Will a common-mode choke work on 430 MHz?
> >
> > 2                   Will the capacity coupling between turns of the
balun at
> > 430 MHz make the choke ineffective and if so would winding the balun by
> > spacing the turns the diameter of the RG-58 help?
> >
> > 3                   How would one check the common-mode currents on the
yagi
> > models?
> >
> >
> >
> >
> >
> > Larry Bush, W5NCD
> >
> >
> > - - -
> >
> > Your moderator for this list is:
> > Larry Wilson KE1HZ antennas-owner@mailman.qth.net
> > _______________________________________________
> > Antennas mailing list
> > Antennas@mailman.qth.net
> > http://mailman.qth.net/mailman/listinfo/antennas
> >
>
>