Topband: Help with RFI

[Mike Waters]

Jim's suggestion worked beautifully here! 14 turns of CAT5 cable on a
single 2.4" #31 core works much better than the old choke with 5 or 6 turns
through four stacked 2.4" #31 cores. It eliminated the last traces of RFI
coming through my computer speakers running 700w on 75 meters.

And three more turns of the line cord through the same core all but
eliminated it on 40 meters.

(If you haven't figured it out already, the dipole is much too close to the
house.)

73, Mike
www.w0btu.com

On Sun, Jan 13, 2013 at 10:34 AM, Jim Brown <jim at audiosystemsgroup.com>wrote:

> On 1/12/2013 7:38 PM, Mike Waters wrote:
>
>> I wrap a few turns of the CAT 5 Ethernet cable coming into the back of my
>> shack PC around a few stacked 2.4" diameter #31 ferrite cores.
>>
>
> For 160M, 14 turns on a single #31 core is a pretty good choke. Don't
> overlook power supply cables as a possible receiving or radiating antenna
> for RF.  A #43 core "works" at these frequencies, but not nearly as well.
>
> 73, Jim K9YC
> _________________
> Topband Reflector
>