[RFI] SO2R and 2nd harmonic

[Jim Brown]

On 9/15/2017 11:20 AM, donovanf at starpower.net wrote:
> Your 1/2 mile RF flooding RFI experience is similar to mine. I've only
> been able to resolve a few RF flooding RFI cases from nearby homes.
> In each case the problem was a wall wart, especially Apple iPhone
> and iPad wall warts.

In my own home, I've replaced all SMPS wall warts with vintage linear 
wall warts. Those vintage supplies are often found in second hand stores 
and at hamfests for a buck or so each. In the "killing RX Noise" 
applications note, I outline methods for doing this that can be 
implemented if you can first make a survey of the offending home, then 
return with a suitable replacement. An important part of this is to 
learn how by doing it in your own home first.

Also -- ferrite chokes on wiring that receives our TX RF and re-radiates 
the distortion can also help, and are minimally invasive.

And thank you very much for publishing what you've learned on this 
issue.  I incorporated your work, with credit, into both the 2-part NCJ 
article and my talks at ham events. Visiting with N6TV at W7RN last fall 
during the last hours of CW SS, I observed the problem in Bob's 
headphones. Your posting of that was key to my identifying it.

> One of the worst unresolvable problems is smoke detectors permanently
> connected to AC power wiring. I can correct them in my own home,
> but for obvious reasons not in neighboring homes.

The "home security" and aftermarket telephone industries have long been 
among the most backward of all with respect to good engineering practice.

73, Jim