Jim, I have measured (Icom 7300) reduction of nearly 11 dB of noise pickup
from local sources by installing a bifilar wound common mode choke in the
shack to transition from common mode from the transceivers/amps to
differential mode of my antenna feedline. It is NOT a waste of energy,
time, and money (built and measured my own).
Dave - WØLEV
On Tue, Jan 3, 2023 at 7:23 PM Jim Brown <jim@audiosystemsgroup.com> wrote:
> On 1/3/2023 11:03 AM, Martin Kratoska wrote:
> > The attached picture displays my proposed CM choking scheme around the
> > antenna switch. Take a look at this and comment, please - what is
> > insufficient, what is an overkill etc.
> >
> > The pic is also here:
> >
> > https://ok1rr.com/public/choking.png
>
> Where is the switch located? The most critical location for a common
> mode choke is at the antenna feedpoint. Chokes elsewhere in the system
> are a waste of money, EXCEPT when they break up a vertical run of coax
> feeding a dipole to prevent it from acting as a parasitic element to a
> nearby vertical antenna.
>
> I know nothing about the Laird parts.
>
> 73, Jim K9YC
>
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--
*Dave - WØLEV*
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