The part that puzzles me Bob is that this is a new occurence.  So, 
something must have changed.  Chasing RFI is a wonderful thing!
Pat, K9JAUAt 11:14 PM 2/20/2016, you wrote:
>Tom,
>
>That means that RF is coming down your coax lines from your antennas,
>and that you have a long ground wire which will radiate that Rf.  You
>also could be having a ground loop between your electrical and RF ground
>rod.
>
>I would try a coax RF choke at each antenna and or connecting a second
>ground wire that is a few feet longer which should lower your RF ground
>reactance.
>
>Bob, K8LR, [log in to unmask]
>
>On 2/20/2016 11:41 PM, Tom Behler wrote:
> > Bob:
> >
> > I tried this on several bands (namely 40 and 160 meters), with an output
> > power of 100 watts, and no RFI was noticed.
> >
> > I can't try the dummy load with my ALS600, because my dummy load only
> > handles 300 watts.
> >
> > I think this is telling me that I am getting some sort of RF coming back
> > down through my antenna systems.
> >
> > Tom Behler: KB8TYJ
> >