In 2019 K3LR presented such a test at the Dayton Contest University.
Tim describes it @ 15:30 into the presentation.
Here is the YouTube link: https://www.youtube.com/watch?v=wd5B5qPHI_U
The relevant slides are at pages 41050 of his Power Point presentation.
CTU 2019 14-K3LR-Contest-Station-Optimization-PLUSROTATOR.pdf
73, Alan K0AV
On Thu, Apr 8, 2021 at 7:47 AM Dave Cole <dave@nk7z.net> wrote:
> ....and look for a reduction in noise. That is what the data now suggests.
>
> 73, and thanks,
> Dave (NK7Z)
> https://www.nk7z.net
> ARRL Volunteer Examiner
> ARRL Technical Specialist, RFI
> ARRL Asst. Director, NW Division, Technical Resources
>
> On 4/8/21 6:01 AM, David Gottschalk wrote:
> > Interesting, I wondered about the validity of this "test"
> >
> > So really the only way to know for sure if you have common mode noise on
> > the coax, is to put a filter in place?
> >
> > 73,
> > David
> > KN4ZKT
> >
> > On Thu, Apr 8, 2021 at 1:36 AM Jim Brown <jim@audiosystemsgroup.com>
> wrote:
> >
> >> On 4/7/2021 7:38 PM, Dave Cole wrote:
> >>> Is this true, and if so, why?
> >>
> >> No. With the shield disconnected, the antenna is different -- if there's
> >> an effective choke at the top, it's now a long wire ending at the choke,
> >> because the shield and the center are capacity-coupled together. And if
> >> there's no choke at the top, it's a top-loaded long wire.
> >>
> >> 73, Jim K9YC
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> >>
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