2017-05-10 Digging for the source(s) of HF interference with a complete powerdown 8 months ago
Today I had planned to dig deep into the sources of the HF interference by switching off the electricity in the whole house and seeing what difference that would make and if it did, search for sources. I used the 10-20-40 meter band endfed outside, and the 10-20 meter dipole inside. The conclusions are mixed:
So for the 10 meter band and less for the 20 meter band it was good to search in the house for sources of the noise. Found:
- The 40 meter band (that I can only use on the endfed) is not influenced at all by switching off the power.
- The 20 meter band on the dipole gets somewhat less noise when the power is down.
- The 20 meter band on the endfed gets the same amount of noise when the power is down.
- The 10 meter band on the dipole gets no noise at all when the power is down. Change from S8 noise to S0 noise.
- The 10 meter band on the endfed gets 2-3 points less noise when the power is down.
So the problem sources that I can't switch off easily are all part of the home network. My current theory is that 10 meter seems to be affected by gigabit network. My experience is that transmitting on 10 meter indoors causes a network outage. The home network is all Cat-5E at the moment, unshielded twisted pair. It seems an upgrade to s/ftp is in order (with foil and braided wire, the same I do for antenna cable). The thing is that with the current solar cycle 10 meter use is very rare. I haven't made a contact yet in that band in 2017.
- The lights in the attic
- The UPS for the server
- The netgear switch downstairs when ports become active. The switch upstairs probably too, but it's behind the UPS, so interference from the UPS showed up first
- The wireless accesspoint downstairs