[RFI] Decoupling small trailer to reduce RFI?

Jim Brown jim at audiosystemsgroup.com
Mon May 26 14:58:15 EDT 2014

On 5/24/2014 3:09 PM, qrv at kd4e.com wrote:
> That said, what if I mount the HF antenna on a small
> trailer, electrically decoupling it from the frame of
> the Prius

Whatever you decide to do with any antenna, three things are VERY important.

1) SERIOUS ferrite choke on the antenna at the feedpoint, following the 
guidelines in my choke cookbook.

2) Home run of TWISTED PAIR from the rig to the battery with a SERIOUS 
ferrite choke on it, located near the battery.

3) SERIOUS counterpoise for the antenna. In many (most?) modern 
vehicles, this can be quite difficult, because pieces of the body are 
insulated from each other by paint. To solve this, one must bond those 
pieces together. BIG job.

Although my XYL just bought a Prius, she doesn't even let me drive it, 
let alone put a rig in it. :)

Another thing to watch out for with anything Toyota. I bought my 2006 
Sequoia (big SUV) when I began my move from Chicago in the fall of 2005, 
and tried HF mobile on some cross-country trips. That quickly ground to 
a halt when I learned that RF was getting into the car's computer and 
putting me in "limp home" mode. Since I was deep into moving, I had no 
time to troubleshoot it, and once I had moved, no longer wanted to do HF 
mobile. :) Items #1 and #2 are aimed both at this issue, and also at 
minimizing RX noise.

73, Jim K9YC

More information about the RFI mailing list