I’ve recently been sinking a lot of time into recording all the remaining 6000KHz NHK World Radio broadcasts I can before NHK leave Nauen and move to using just the Yamata and Issodun transmitters which I wont be able to hear very well compared to the amazing signal I get of Nauen.
I’ve taken this as an opportunity to further experiment and fine tune my demodulation settings for the “High Quality” videos and I feel that I have managed to make significant improvements over my previous attempts.
I learnt that SDR#’s Sync modes seemingly have some form of AGC before SDR# passes the audio to the IF Noise Reduction system which finally explains the confusion I’ve had for years on why the noise floor rises during quiet moments!
Knowing this I experimented with using DSB without sync, which can have some very slow beating (a sort of throbbing effect with the volume) because SDR# can only tune it to the nearest Hz. With one of the broadcasts I got very, very lucky and NHK’s carrier was tuneable this way without any beating but it is usually not possible.
I then tried pure LSB or USB mode … and quickly found SDR# has a 100Hz high pass filter in SSB modes which is not usable for music!
I finally settled on using DSB mode combined with the IF Processor plugin to turn DSB into SSB which worked perfectly, fully removing the noise floor while keeping the bass and sounding wonderfully clear. I can hear the presenters rustling their papers while they talk!
I am currently experimenting with adding the bass notes (<200Hz) of the other sideband using DSB mode (technically called ‘VSB’) which, hopefully, means the throbbing effect would only occur on the bass and not the mids or highs. This seems to work well and having redundancy on the bass improves the bass more than any throbbing side effect would damage it!
Without any further ado I present you my NHK World Radio Shinyabin playlist. You can see the progress I’ve made as it starts with the latest video and goes back in time through all the revisions of the processing system I’m using.
Hopefully you enjoy listening to these videos of some amazing retro J-pop as much as I enjoyed making them.
I’ve been absolutely captivated by these shows and they have easily become my current favourite music broadcast on shortwave radio! I will miss being able to listen to Shinyabin a lot but, hopefully, it’ll make a comeback in the B22 schedules!
Until next time,