[GCARC] High Pass Filter

[MARK]

Good Afternoon Everyone, 

First time for everything... I have had my rig up for about 6 months with no problems with an antenna in the attic in an attached town home. Today, I am getting slight QRM on all bands. It is enough interference to stop HRD from decoding PSK and RTTY although I can still hear the incoming signals. The Waterfall looks like a carpet weave, At first, I thought my antenna had fallen but that is not the case. I suspect my neighbor is running something in their home and generating this signal. Would a high pass filter, attached to the coax leading to the antenna be the solution or at least reduce the problem? 

Thanks 

Mark 
WA2DIY