Broadband RFI at 1420 MHz traced to USB-SATA SSD adapter

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Ayushman Tripathi

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Jun 12, 2026, 7:59:58 PM (9 days ago) Jun 12
to Society of Amateur Radio Astronomers

Hi, I spent the whole day fighting a broadband RFI forest across my whole H-line band, floor raised ~10dB, line completely buried. NESDR-BIAS-TEE + DD FEED + WIFI DISH + Pi 500, booting/recording off a 512GB SSD via USB-SATA adapter.

Turns out the SSD adapter was the culprit. Not discrete spikes, it was broadband "everything shrinks" noise from the bridge chip + its unshielded cable.

Stuff that did NOT fix it:

  • Foil wrap (ungrounded): barely helped, wind shifted it and noise came back

  • USB 3.0 → USB 2.0: helped ~10dB but residual stayed

  • Different power supplies : not the source

Holding the cable in my hand made it improve. So it seemed a grounding problem.

Partial fixes (helped, didn't fully solve): USB extension to move SSD far away + grounded metal mass. Got usable but fragile.

What actually killed it 100%: ditching the USB SSD entirely. Cloned my whole system to a microSD in the Pi's native slot - that uses SDIO, no USB bridge, and no noise source. RFI just disappeared. Clean floor.

Moved to the Pi's SD card now, and the band is clean. Before and after spectrum pics attached for comparison.
IMG_0286.PNG
Screenshot From 2026-06-12 19-31-39.png


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