Blog or Die!

I am happy to report that the signal general generator does work (turns on and outputs RF), despite all the YouTube repair videos.

My first experiment was to hook up the Signal Generator to an SDR, the RTL-SDR Blog V4, controlled by SDR++. I more or less randomly picked 17 MHz for the frequency.

I pressed the F1 button until the “<” sign appeared on the top row. In the preceding photo it’s after “017.0000.” It points to the parameter being set, in this case the frequency. To directly enter this frequency requires keying all 7 digits, “0170000.” Once you start keying a number, you must finish before going on. When the 7th digit is keyed, the frequency changes.

The number on the upper right is the signal strength in dB. The number lower left is a subcarrier tone frequency used by some devices (turned off here). The middle bottom number is the modulation frequency (0 for no modulation), and finally on the bottom right is what looks like a firmware version that hasn’t changed for a couple of years at least.

Here’s what the signal looks like on the SDR++ display.

When I take the generator setting of -71 dB and add the gain setting on SDR++, the result is -37.2, which is pretty close to what SDR++ shows using the scale on the left.

This generator only does FM modulation, narrow band FM in particular. That’s not my target use, testing portable shortwave radios, but AM radios do attempt to decode signals of all types, and a pure tone FM signal is detected, sort of. I heard a “warbling” tone when I set SDR++ to AM, and a similar sound from the Qodosen DX-286.