Re: USB cable quality and QRM in a spyserver setup with an Airspy Hf+ and Raspberry PI3. 6 microUSB cable test. #airspyhfplus #bestpractice #raspberrypi

ea5ehs@...
 

Hello David,
I decided to go de Orange Pi UNO way for different reasons; low cost, Gigabit ethernet outside the usb bus, only one usb 2.0 port. 
My theory about the usb qrm from cables is that there is a RPI USB design allowing for this. I have tested one Rpi2B and two Rpi3B with identical results.
QRM is only generated when an active data connection is on, ie when a client connects to spyserver and start sdr#. 
When I connect the airspy HF+ to a usb port of my Laptop and rin SDR#, no noise is generated with any of the six tested cables' using the same antennas.
I was considering the Tinkerboard SBC but as I'm runing on solar power, every mW  of power consumption counts. Tinkerboard seems to draw more power than Rpi an Orange pi. Rpi3+airspy accounts for 630mA at 5V during an active connection. I have also taken additional power saving measures like turning off the on Board leds and the HDMI.

Best Ni
EA5ZL

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