Since we got “proper” broadband in the village, I have been unable to use the 10MHz (30 metre) band for anything other than contacts with extremely loud stations. There is a wall of noise right across the HF band, particularly bad between 8MHz and 12MHz. The worst part is that if I transmit, the noise is replaced with some very loud training tones at 4kHz intervals. Not content with wrecking my enjoyment of the band, the broadband service then screams in agony when I spoil its fun.
In the first video, check the band noise in the first few seconds. It is way louder than it should be. The the video freezes for 6 seocnd while I transmit. Soon as I go back to receive, all hell breaks loose, with loud carriers at 4kHz spacing for about 100kHz around my transmit frequency. It them retrains and goes back to the wall of noise, but leaves the training tones at a high level for 15-30 mins.
They call is progress. Fibre service would be progress, this is just stone-age cheapo interference-making.
The training tones fire up a comb of carriers at 4kHz spacing. Note the dip in diginoise close to where I was transmitting.
This is the noise on 10MHz before I transmit. About 20-25dB over what the noise floor should be. 30m dipole up 30ft in a tree about 40m from the nearest phone pole. Elad FDM-DUO and SW2
The waterfall shows more clearly that the diginoise spectrum looks like a ploughed field at 4kHz spacing
On the higher bands, the xDSL is notched out. There is a sharp edge at 12MHz where the nature of the noise changes from solid mush to a pulsating 25Hz comb that sounds like a buzz on AM. Here’s the 12MHz edge and guard-band
The notched-out bands from 20m up are well-defined:
and the pumping buzzsaw noises stop at just over 27.7MHz
for info, the screen recordings were made using the Windows 10 built-in recorder, accessed using Win-G to load the games toolbar, then hit record. Much nicer than the freeware screen recorders with all the nasties they tend to install.