The Use of Rpi4 and SSD and RFI

[Jack Lobingier]

I thought there might be some interest in seeing the result of using two different SBC's as far as RFI is concerned.  In my setup I have a 3 meter dish looking at H1 emissions.  For sometime I have been using an AtomicPi computer to collect data, located at the antenna.  Reciently, I thought I would 'upgrade' to a Raspberry Pi 4 with a SSD.  Both are in a gounded steel box.  3m_H1_spec.csv.png is a plot of the RPi4 collected data, and 3m_H1_spec.csv.png is from the AtomicPi SBC.  I'm not really sure the reason for the bad RFI in the RPi 4, but it may be connected to the use of the SSD drive.  Part of the learning curve!

Jack

[Bogdan Vacaliuc]

Hi Jack,

That's a striking difference.  It would be good to get to the bottom of it.  You say you suspect the SSD on the Pi?  Is that because you don't see the RFI when you use the Pi's micro SD to save data?

Can you share some photos of the inside of the metal boxes for both systems?

Thanks!

-bogdan

On Sun, Apr 24, 2022, 12:39 PM Jack Lobingier <49j...@gmail.com> wrote:

I thought there might be some interest in seeing the result of using two different SBC's as far as RFI is concerned.  In my setup I have a 3 meter dish looking at H1 emissions.  For sometime I have been using an AtomicPi computer to collect data, located at the antenna.  Reciently, I thought I would 'upgrade' to a Raspberry Pi 4 with a SSD.  Both are in a gounded steel box.  3m_H1_spec.csv.png is a plot of the RPi4 collected data, and 3m_H1_spec.csv.png is from the AtomicPi SBC.  I'm not really sure the reason for the bad RFI in the RPi 4, but it may be connected to the use of the SSD drive.  Part of the learning curve!

Jack

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[Alex P]

Hello Jack,

I've been fighting RFI from USB<> Cat5 cable extenders for months. Tried 3 and using the best.

I made a 21cm loop probe to identify the location of the highest radiation. it also allows quick comparisons in the effectiveness of

 different shielding / ferrite combinations.

 My Solution : a remote aluminum box with internal ferrite on the cat5 cable.. Distance from the antenna being the best solution.

Cheers,

Alex KK4VB

[Jack Lobingier]

Alex, thank you for your reply.  Fortunately, I had the option of going back to my previous SBC, the AtomicPi, which for whatever reason does not generate this level of RFI.  In the future I will use the loop to check out anything new.

Thanks,

Jack

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[shefro...@gmail.com]

All,,, My Phase Shift Interferometer write up... I used a RPI and rtl-sdr.. powered using POE in ammo can... I saw garbage in the data which was caused by the phase shift signal to a LNA.. I used ferrite cores on the phase shift signal which choked the noise off... I never saw RFI due to the POE... The RPI was housed in a metal enclosure with the shell halves paint removed in an attempt to make a shielded housing.. All the I/o was done using capacitor feedthrus..... Check out the write up and pix..

73  wa1rht  Shef

[Jack Lobingier]

Bogdan, thank you  for your response.  Somehow it got lost in my system until now.  The main reason that I suspected the SSD is that I have used an RPi4 before and I have not seen this level of RFI until now.  Also, the SSD is connected by a 2 foot USB 3 cable.  The same box was used for both SBC’s.

Jack

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