[RFI] Decoupling small trailer to reduce RFI?

qrv at kd4e.com qrv at kd4e.com
Sun May 25 16:05:58 EDT 2014

OK, finally got outside with my small AM-SW handheld receiver.

The ferrite-bar antenna makes it semi bi-directional.

There is a field about 4' around the Prius (powered up) where
the RFI is significant on AM-BC and AM-SW.

Inside the Prius the worst area is in the front, esp. around
the dashboard, plus in the back storage area near the rear seat
(under which is some electronics), and drivers side rear where
the 12v battery is located.

BTW: Generally Hams & others add a second float-charged battery,
Optima deep-cycle is common, on the driver's side rear for use
in powering gear.

It did seem that some RFI was coupling into the short 2/440
antenna which sits on a 4-magnet mount and connects via coax
through the rear hatch then winds it's way to the console
(nothing was connected to that end at the time of my test).

4-6' behind the Prius the RFI appears to be very manageable.

My next test will be to hook up the 21' aluminum frame
trailer I own, mount an antenna on it, and see what I hear
on a rig inside the Prius.
[Note: I'll need to exclude RFI traveling via the hitch
and/or the trailer wiring, as well as DC and the coax.]

One key may include isolating the rig from noise on the
12vdc system and RFI from getting into the rig through the
mic and/or body.


FYI: I also narrowed the source of the RFI getting into my
43' vertical (previously fairly quiet) to two specific poles.
Our power company is a local cooperative & has been very

David KD4E


David Colburn, KD4E - Nevils, Georgia USA

Safe & Secure Search Engine: duckduckgo.com

Android for Hams: groups.yahoo.com/group/hamdroid
Creative Tech: groups.yahoo.com/group/ham-macguyver
Raspi Alternative: groups.yahoo.com/group/beagleboneblack/

Restored to design-spec at Heaven's gate 1Cor15:22

More information about the RFI mailing list