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For three years I have been using an  HP 8300 SFF  in the lab to play with BBRF013, RX888 etc. I have made many modifications to the PC. I added a second USB3.0 controller and about two weeks ago I replaced the system disk with an NVME disk. Almost every day I use BBRF103 or RX888. Suddenly yesterday I cannot connect BBRF103 to the original USB3.0 ports on the back of the PC. When I launch the application the message appears : Fortunately, I have two USB3.0 controllers installed . After trying to change cables and BBRF103 I noticed that everything worked consistently if I connected to the ports of the second USB3.0 controller. I tried resetting and switching off/on the PC several times without any success. The solution was:  - backup and make a restore point - in device management disable and uninstall the affected USB controller - shut down the PC - upon restarting the controller was detected and the driver reinstalled automatically and voila now it works again. Th...

Why Use Oversampling when Undersampling Can do the Job? - Texas Instruments  :    “..If we use the sampling frequency less than twice the maximum frequency component in the signal, then it is called undersampling. Undersampling is also known as band pass sampling, harmonic sampling or super-Nyquist sampling. Nyquist-Shannon Sampling theorem, which is the modified version of the Nyquist sampling theorem, says that the sampling frequency needs to be twice the signal bandwidth and not twice the maximum frequency component, in order to be able to reconstruct the original signal perfectly from the sampled version.“ Justin Peng tweeted the result of his RX888 undersampling the FM band on  https://twitter.com/fei666888/status/1363859596784267265 At my location the FM band stations are very strong and internal HF LPF of RX888 is not enough to cancel the FM band alias. I need to add an external HF Low Pass Filter with higher attenuation of FM band. So I decided to bypass the ...

The  osmo-fl2k project  shows how to use an USB 3.0 VGA adapter as SDR transmitter.  Many thanks to Steve Markgraf. He presented it at OsmoDefCon 2018  https://youtu.be/VRvLVjLQSaw  . I made a  console tool named fl2k_noise that generates white noise in the full HF band. You can buy Fresco Logic 2000 based USB to VGA adapter in Aliexpress or Ebay for some 5-10$ price. See more info and the adapter scheme on  https://gitlab.hamburg.ccc.de/MarBle/fl2k-liberation/tree/assets The adapter was laying in my shack when I decided to test it as wide band (white) noise generator for HF band.  I selected an old VGA to VGA cable quite long and flexible and I cut it in the middle,  I cabled it as in the following scheme to adapt the 3 *75 Ohm input to the 50 Ohm output. The capacitors remove the VGA DC component and in case isolates the ANT bias tee of the receiver. The tentative code is in my repository  https://github.com/ik1xpv/fl2k_win ...