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projects:jimbob:frequency

Frequency Ramblings

Frequency range legally available is 434.04MHz - 434.79MHz according to IR2030.

Point in time analysis using SDR and external collinear:

  • 434.040MHz - Start of legal band
  • 434.046Mhz - Weak interference
  • 434.075Mhz - NTX2
  • 434.078Mhz - Weak interference
  • 434.099Mhz - Weak interference
  • 434.110Mhz - Weak interference
  • 434.112Mhz - Weak interference
  • 434.121Mhz - Weak interference
  • 434.127Mhz - Weak interference
  • 434.150Mhz - Good Frequency?
  • 434.169Mhz - Medium interference
  • 434.267Mhz - Weak interference
  • 434.320 to 434.330 - Strong interference
  • 434.330Mhz - Weak interference
  • 434.347Mhz - Weak interference
  • 434.361Mhz - Weak interference
  • 434.369 to 434.379 - Strong interference
  • 434.375Mhz - Emergency Comms
  • 434.392Mhz - Weak interference
  • 434.412Mhz - Good Frequency?
  • 434.475Mhz - Internet voice gateway, 25khz
  • 434.487Mhz - Good Frequency?
  • 434.500Mhz - Internet voice gateway, 25khz
  • 434.512Mhz - Good Frequency?
  • 434.518Mhz - Weak interference
  • 434.525Mhz - Internet voice gateway, 25khz
  • 434.550Mhz - Weak interference
  • 434.562Mhz - Good Frequency?
  • 434.581Mhz - Weak interference
  • 434.600Mhz - Repeater input, 25khz
  • 434.612Mhz - Good Frequency?
  • 434.613Mhz - Weak interference
  • 434.625Mhz - Repeater input, 25khz
  • 434.650Mhz - NTX2
  • 434.650Mhz - Repeater input, 25khz
  • 434.675Mhz - Repeater input, 25khz
  • 434.687Mhz - Good Frequency?
  • 434.700Mhz - Repeater input, 25khz
  • 434.725Mhz - Repeater input, 25khz
  • 434.737Mhz - Good Frequency?
  • 434.750Mhz - Repeater input, 25khz
  • 434.775Mhz - Repeater input, 25khz
  • 434.790Mhz - End of legal band

Thinking about frequency spacing, to be able to receive multiple transmissions with one dongle:

Typical RTTY bandwidth is 650Hz, we probably want at least 3,000Hz gap to keep audio spectrum separate.

Frequency drift research is very difficult, actual examples found are down at 1.1 or 5.7khz, advice is that they could drift 20khz. 50khz spacing seems a reasonable suggestion to allow for +20khz of one and -20khz of another.

We want to restrict the spacing to the FunCUBE Dongle bandwidth of 192,000hz, 50khz plus drift fits easily within this bandwidth.

projects/jimbob/frequency.txt ยท Last modified: 2013/09/04 14:26 by kevwal