lunedì 1 luglio 2019

Shielding, Interference, Noise, Signal Source and more other of SDR System

Shielding, Interference, Noise, Signal Source and more other of SDR System



SDR systems are not perfect but you can live together and learn how to best exploit them.

a lot of material is present on the network that talks about issues related to:

  • Shielding
  • Interference
  • Noise
  • Signal Source


Perhaps some of these readings can come in handy:

https://github.com/cernohorsky/USB-EMI-Filter

https://www.rtl-sdr.com/reducing-interference-in-the-rtl-sdr/

https://www.rtl-sdr.com/reducing-usb-shield-interference-rtl-sdr-dongles/

https://www.rtl-sdr.com/tip-reduce-radio-interference-rtl-sdr/

https://www.rtl-sdr.com/shielding-rtl-sdr/


http://hackalizer.com/reducing-noise-rtl-sdr/


Video:

 RTL-SDR radio in a metal box | modification/noise reduction:

 https://www.youtube.com/watch?v=LnOvZqN-AAI


Airspy HF+ SDR Receiver with Mini-Whip Active Antenna and External Attenuator:

https://www.youtube.com/watch?v=4xhYoPrQffQ



During my tests with various SDR devices I encountered many types of interactions that can generate apparent interference:

  • interactions between software, drivers and firmware
  • interaction between the hardware of the receiver, the PC and any connected peripherals such as power supplies, ungrounded power grids, lack of alignment between the "earth connections" of all the devices to avoid generating potential difference
  • computer software processes that are reflected on the hardware and vice versa
  • dispersions of the electric current at 50Hz which can propagate on work surfaces
  • various devices operating nearby

You can try searching for the source of the hardware problem with:



EMI mapping with RTL-SDR and OpenCV:

https://github.com/CGrassin/EMI_mapper


Listening To Electromagnetic Interference With A RTLSDR Dongle:
 

https://hackaday.com/2014/03/18/listening-to-electromagnetic-interference-with-a-rtlsdr-dongle/
  



Below are some examples of noise sources inherent in an SDR system,

Some interception of signal generators inside computers:

Test - TempestRAM receive signal from clock bus RAM with HackRF and comparative from three computers:

https://www.youtube.com/edit?o=U&ar=3&video_id=M8MystC5RRU

Test - Tempest for Eliza: Generate radio modulation signal by showing patterns on your monitor:

https://www.youtube.com/edit?o=U&ar=3&video_id=CHV8wrorl70

Test - TempestSDR with RTL SDR on windows - Desktop DVI Monitor:

https://www.youtube.com/edit?o=U&ar=3&video_id=-V50plHPQpY

Test - TempestSDR with RTL SDR on windows - Desktop VGA Monito:

https://www.youtube.com/edit?o=U&ar=3&video_id=8wLhS5SgSX4

Test - TempestSDR with RTL SDR on windows - Laptop Monitor:

https://www.youtube.com/edit?o=U&ar=3&video_id=OK70F4RsLjw

Hackrf One detect signal from Ethernet cable LAN:

https://www.youtube.com/edit?ar=3&o=U&video_id=0JBPq0-Ww8k

HackRf One receives different signals from two notebooks with AM LOOP ANTENNA:

https://www.youtube.com/edit?ar=3&o=U&video_id=onO-xwnqv4w


Most communication, control and signal processing peripherals generate interference due to oscillators, clocks, multipliers, etc.