On Mon, 22 Nov 2010 14:22:33 -0500, Bob wrote:

Hi,

Like I mentioned in a previous post, I have a WinRadio Excalibur SDR
being fed by a PAR EF-SWL antenna.

Would like to improve the S/N ratio a bit.

Noise is the ear of the be-hearer. Characterize your problem with
noise levels observed at what time of day and in which band. If the
noise is bothersome, it is worth starting a log just so that you don't
go chasing your tail when it is merely seasonal.

After the PAR Balun, I have the typical coax run to the house.

I will get some of those snap on ferrites, as suggested, and try them out.

I have tried unplugging just about all of my wall warts in the vicinity,
the LinkSys Router and the Comcast Modem.
Surprisingly, at least to me, no discernable changes.

Have you changed the source of power to your
WinRadio/Computer/what-ever? Use an extension cord to a power strip
that provides power to EVERY gizmo plugged into the computer
supporting your WinRadio. Plug the extension into every branch from
your breaker box.

Take note of the emphasis on EVERY! Any exception turns this exercise
into an useless endeavor. In the past when our Internet connection
went to a modem, the Telephone ground brought grief. Connections like
that can slip beneath the radar. EVERY means your antenna line too -
which is to mean it might pass through a grounded connection along the
way, and that is enough to scotch this deal.

I see WinRadio offers, for $50 (ugh), a Common Mode Choke to go on the
coax at its end, right where it joins the Excalibur module.
(see specs, below)

You can find the same thing for less. You can build it even cheaper.
Think it's worth a try ? Why ?

What's your time worth?

Thoughts on ?

Sink a ground rod at the far end of your transmission line where it
connects to the antenna. Connect the coax shield to that rod.
Remember to connect that rod to your service ground through a SEPARATE
wire. Using the coax shield to bring the far ground back to the shack
invites disaster.

73's
Richard Clark, KB7QHC