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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 RX-888 mkII designed by Justin Peng and Howard Su  arrived!   It is an evolution of the first RX888. The curiosity won out and I opened it. Be careful if you decide to open your device because two heat pads are used to carry the heat from the R828D and the LTC2208 to the aluminium case. I managed to slide them out without damaging them by moving the PCB very gently. A plastic wide stick may help to push out the pads and after to reassemble the radio. The PCB layout is similar to RX888 In HF the input attenuator is a  PE4312   covering a 31.5 dB attenuation range. This replaces the 0, -10 ,-20 dB attenuator of RX888.  It is followed by the low pass filter at 64 MHz.  Then two switches PE4259   select the HF input or the VHF tuner R828D produced by Rafael Micro that replaces the R820T2. The added transformer connects in a balanced way to the R828D IF outputs. An AD8370  digitally controlled variable gain amplifier (VGA) pro...

It is a tentative version of ExtIO_sddc.dll  that can operate with BBRF103,  HF103, RX888 as the FX3 Arm code detects the hardware type used. The sources are at  https://github.com/ik1xpv/ExtIO_sddc/releases   a compiled dll is at  https://drive.google.com... MD5 ef1579eeb47ee1fc4f3c8ec45520d81c extio_sddc_v1.01.dll Copy the dll in a directory with HDSDR.exe and libfftw3f-3.dll. Here a summary of changes. - First, there are a lot of new bugs... I'm sure :-) - The SDDC_FX3.img arm program detects the radio hardware.      If there is not a programmable Si5351a  the radio is a HF103 and operates only in HF      else      if there is a pull up (led blue) on GPIO54 of FX3 the radio is a BBRF103      else      it is a RX888. -The control protocol in between FX3 and ExtIO_sddc.dll is redesigned and the programming of Si5351a and R820T2 is now made by the SDDC_FX3.img code. It obta...

Yesterday I received the RX888 designed by Justin Peng and Howard Su.  The first impression in o pening the shipping package  is that it is very small.    It is as big as the Cypress fx3 superspeed explorer kit ! Thanks to Guy Atkins'  SWLing post  I was able to resist the desire to open it right away to see the interior.   I started looking at HF. I connected it to my old I7-3770 pc and to the 10 meters wire antenna that I have on the balcony of my house.   My city is Turin and here the local transmitter in MW has frequency 999000 Hz synchronized to a high precision reference. I tuned this station and without calibration of the internal oscillator of R888 I measured an accuracy better than 1 ppm. This is not obvious after a transport of more than 10000 Km. In case there is the internal trimmer that allows you to calibrate the reference oscillator when you have a reliable reference. Frequency calibration test The ExtIO_RX888.dll v0.4 has...