Hi Hans
The G8JCFSDR has a built-in signal generator when using the Elektor SDR Shield.
Enter Config, and click Calibrate, the SDR Shield Calibrate screen will be displayed - for the purposes of these tests IGNORE the Official/Actual Frequency boxes, do NOT click RESET or APPLY buttons.
Tune the G8JCFSDR to 14 000 000 Hz, ie 14 MHz, and check ON the IQ Cal Freq box as shown above
A carrier at 14 001 000 Hz, ie 14.001MHz will be generated, and should show up on the G8JCFSDR Spectrum Display
Set the Mode to USB and you will hear the 1KHz tone. To verify that this 14.001 MHz signal really is from your SDR Shield check off/on the IQ Cal check box.
You can try the same procedure at 16MHz, (18Mhz and so on) remembering each time to turn the IQ Cal check box OFF and then ON
If you have a V2 board, then attach a short piece of wire to the CLK0 pins for a much stronger signal and at lower frequencies - eg use a female Dupont cable - I have a V1 SDR Shield so the signal I am seeing is just the "leak" from the Si5351 track traces hence why I start at 14MHz and work up (higher frequencies=shorter wavelengths so short traces will radiate more signal).
If you don't see these calibration signals then it is likely that your SDR Shield AF (I/Q) output is not connected to your LINE-IN connector on your Soundcard, ie let's try and check that all the connections from your Computer to SDR Shield are all correct.
73
Peter - GM8JCF
