I am mirroring the output from an HR24 to an SD TV in my kitchen. I have the composite out from the hr24 going into an RF modulator and then a very long run of rg6. Intermittently, I get faint diagonal or wavy interference lines. Not really hum bars. The hr24, rf modulator, and an appletv are all plugged into the same sure protector. What should be my troubleshooting steps? I'm thinking first replace the coax connector plugged into the modulator?