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Survive USB3 Interference
#1
USB3 circuitry is the source of annoying RF interference I badly experimented it, those past weeks, after moving my
system (boot & root) from an SD to an USB3.0 SSD. It became almost impossible to get any FIX !

When I saw that video  I knew I was getting close to the source of my  problems ...

Searching "USB3 interference"  in the Raspberry Pi org web forum returned 974 matches  !

The phenomenon is generic, not specific to the RPi4 : see this  Intel  whitepaper !
It affects many various domains : WiFi 2.4 GHz, Bluetooth, wireless keyboards & mice, and, of course GPS receivers !

How can we live with that ?
  1. Dont use USB 3 if  you are not obliged : Connecting my SSD to an USB2 port solved immediately the case.
    Knowing that  may save your boat and your life ...
  2. Move the receiver away from the RPi : moving from 0m90 to 1m80 was a significant relief in my case ...
    I use a very common combined receiver with antenna (Ublox M8)
  3. Hey, I bought an expensive RPi4 to benefits from its USB 3 !!! So, I further improved the relief obtained in above
    point 2 by an extra shielding of both the USB cable and SSD case with a chocolate aluminum foil (see picture)
The two above actions allowed to walk-around the problem. So far I have not (yet) experimented the other potential
troubles, though I use a wireless Logitech keyboard (unifying dongle) !

Any other solution or suggestion ? Please POST !


Attached Files Image(s)
   
Cordialement
Didier B
Pi4, SSD USB3, OP 2.7.0 OC  5.2.4




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#2
Excellent post! marked as sticked
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#3
I experienced another solution, having got hit again by the USB3 malediction (testing another USB3 SSD enclosure) ! 
I had in the amount of spare items "which may be usefull..." an active USB 2.0 extension cord of 5 meters.This allowed me to further increase the distance between the Pi4 and the GPS antenna, giving much better results (SNR), and immediate occurence of a FIX.
I also get good results using the latest Argon M.2 enclosure, with the internal USB3 SSD ...
I am waiting the delivery of a  10 m extension cable  for my on board installation !
Cordialement
Didier B
Pi4, SSD USB3, OP 2.7.0 OC  5.2.4




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#4
You may be aware of the high level of RF Interference caused by the very (too) high speed of USB3.0 circuitry.
https://www.intel.com/content/www/us/en/...paper.html  Angry

Such interference do jam the satellite signals aimed to GPS receiver (signal level around -162db !), when gps receiver is located in the vicinity of a Raspberry 4,
practically <= 2 m form an Argon40 M2 case (Argon M2)

I suspected the USB3 'bridge' of the Argon40 M2 to be the "escape way" used by the RFI to jam my GPS receiver.
So I tried to shield it (as suggested by the above linked white paper from Intel corp.), and ... it worked Exclamation

I tested using miscellaneous GNSS receivers, keeping any other condition strictly identical :
     - without shielding : no fix, even after a long wait ;

     - with shielding : instantaneous Fix, at each try !

Shielding is made of aluminum 'diaper' grounded by simple contact with the the USB male connectors and blocked with a small piece of adhesive tape.
Of course shield design could be improved, and mainly offering a better grounding ! But now, these bloody interference are gone ! Big Grin

Experimentation context : one Raspberry Pi 4 4GB ram, one SATA SSD 120GB, of course one Argon40 M.2 case, one raw USB3 bridge,

one shielded USB3 bridge, use of GPSD and GPSD clients, various USB GPS receivers based on UBlox 7 and UBlox 8 chips...

Attached pictures : Argon 40 M2 case with unshielded USB3 bridge, shielded USB3 bridge.
 


Attached Files Image(s)
           
Cordialement
Didier B
Pi4, SSD USB3, OP 2.7.0 OC  5.2.4




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