[NLRS] FunCube

[Doug Reed]

Using SDR as a panadapter is simply using SDR as a swept receiver at
the first IF frequency of another radio.

In a traditional panadapter, you tap the main receiver at the first IF
frequency, ahead of any narrow filters. Then you sweep the panadapter
receiver around the IF frequency and use the detected RF level to
drive an oscilloscope display to show where the signals are. All very
old school.

A modern panadapter uses SDR to get the same effect. You tune the SDR
device to receive the first IF frequency out of the main receiver and
use the SDR data to show a typical spectrum analyzer display. The only
difference between a SDR receiver program and a SDR panadapter display
is where the signal comes from. For 10GHz, the guys using a SDR
transceiver as their IF rig have a significant advantage over the
people who have to tune their IF rig to find other stations. This is
equally an advantage for people running moonbounce or simply watching
the band for an opening....

The only trick in using SDR for a panadapter is tapping the first IF
without loading it down or injecting noise. Finding a SDR receiver
that covers the required frequency range is the real trick. People
have been using the Softrock 40 series of HF SDR receivers for this
purpose for more than 5 years. They even sold specific models for
specific HF radios.

73, Doug Reed, N0NAS.