I have designed this little USB Device supported by Windows/Linux GUI , Python /Matlab Programmable over libusb ,
Not really a precision test Equipment in terms of output amplitude but rather just a Programmable RF source.
Available on
https://www.circuitvalley.de/CircuitValley RFGEN44 Programmable USB RF Signal Generator
Output Frequency range 35Mhz to 4.4Ghz with 10khz Step
Output Amplitude 35 to 300Mhz 1 dBm 300Mhz to 1Ghz -10 dBm 1Ghz to 4.4Ghz -18 dBm
Features Automatic frequency sweep and Hop
Support Multiple Device on same PC, also support Identification using LED
Standalone Operation Automatic Configuration Load from High endurance flash
Driver Freee operation over USB HID, No driver or no special permissions needed on any Generic OS
Fully Programmable with Cross Platform (Win/Linux/MacOS) GUI or Python
Function and test Video