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Hi Martin,
I was not aware about your postings on this topic. Excuse me for that, you are ahead of me in technology. I read them with great interest. I will add them to the links in my article. Yes GPS sync is a need if a "noise" map? must be drawn but I have made these recordings just of curiosity to see? what is going on with the man made noise in my county. The most important result was that I compared? the minimal recorded noise with the noise at my house - so now I know "where I am" . The VDSL systems are very rarely used here.- most common are LAN cables and cable TV. The telephone lines do not exist here any more - everything is GSM.? I choose 3.5 MHz as a center frequency? because in semi-urban areas I have noticed that there the noise level has a peak (between 2 - 4 MHz) I do not have an explanation for that.? It will be interesting? for someone else to make similar recordings in order to compare the noise pollution.? We do not need? precise calibration - the level of the noise in quiet places is a good reference point. The merit of pollution will be? Nc/Nq?? where Nc is the current noise level? and? Nq is a quiet place noise level measured in the same date and time(approximately) . (or Nc-Nq in dBm). This can be done by car (or bicycle? : -)
Chavdar lz1aq