Observations of electromagnetic (radio) signals on very low frequencies, 0 KHz - 10 KHz. Observed 10 may 2008, approx. 23.00 hour on 4,5. KHz: next to the original radio resonance of 4,5 KHz there is another resonance (spectrum on approx. 10 KHz), that comes in and fades away after 30 minutes. Did not observe longer, so I could not see if it came back later at night. You could see in general (1-10 KHz) small lines on other frequency bands then the original resonance of the antenna, they come and go. Looks like sub-resonances (?), though the spectrum is not broad enough for a sub-resonance. Seen on 10 KHz (daylight, 11 may 2008, approx 11.00) that the "subresonances" came in the shape of curved lines, so moved over a certain (sub) frequency band. You can also see that there are broadband radio disturbancies going from 0 Hz to 10 KHz, like the "click" sounds you can hear over the mains voltage. If you watch this video on another channel as YouTube, please check YouTube for the original video (changes etc.). The software I use was found on the INTERNET and works under Windows 95 on an IBM thinkpad laptop with a sound card. The output of the receiver (the one with the 6088 tube) is connected to the microphone input of the sound card.