[TenTec] O2 AC line noise mainRX subRX???

[george]

I have torturing myself for the past 8 months with a AC arcing sound in the 
main receiver on 160 meters. This evening I listened to the sub receiver and 
WOW I can copy a weak CW signal on 160 meters where the main receiver 
exhibits an arcing insulator sound that masks the signal???
Anyone notice this?
Is it a fact that I have to use my sub receiver on topband for better 
results?
I also noticed that above 1.857mhz the AC arcing noise
I hope for the price of the O2 this isn't true!
George W2YJ