QPSKRF or Ugly mode

The F5OEO software has a QPSKRF or “ugly” test mode which directly generates a DATV signal on 437 MHz using the internal RPi clocks. This facility is available in the Portsdown transmitter as it is very useful for initial across the shack testing but has limited functionality and as its name implies, is not suitable for putting on air even if bandpass filters are used.

Image of UGLY mode spectrum

Ugly mode also has a number of functional limitations:

• It will not work reliably above 333 Ksymbols

• It will not work reliably with the internal test patterns

• Connecting a 1/4 quarter wave of wire to pin x will increase the radiation but may also increase the multi-path and spectral impurities - experience has shown it is better to improve the receive pick up loop.