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Author Topic: RF proof USB hub?  (Read 355 times)

NT6X

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RF proof USB hub?
« on: August 18, 2021, 05:48:34 PM »

Hello all,

My initial problem was RF getting into my computer, but only on 15m above 600w and only when my antenna was pointed around 300 deg. I spent hundreds of dollars on large mix 31 Snap-on and donut Ferrite from Palomar and used them on every cable going into my computer. It didn't help. I finally unplugged a USB Hub I was using and everything was good. I could run legal limit on 15m no problem.

Is there such a thing as an RF proof USB hub? If not, any recommendations of USB hubs that have worked for you would be great.

Mike, NT6X
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WB6CVR

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Re: RF proof USB hub?
« Reply #1 on: August 18, 2021, 07:19:22 PM »

If your computer is a desktop, you might consider getting a USB card that plugs into a slot on your motherboard.

 
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N8FVJ

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Re: RF proof USB hub?
« Reply #2 on: August 18, 2021, 09:10:21 PM »

Grounded tin foil around the hub is likely only solution.
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K0RDG

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Re: RF proof USB hub?
« Reply #3 on: August 19, 2021, 05:32:47 AM »

Was that a powered USB hub?  If so, the wall wart power source is probably the culprit rather than the hub itself.
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W1VT

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Re: RF proof USB hub?
« Reply #4 on: August 19, 2021, 05:57:45 AM »

http://www.righto.com/2012/05/apple-iphone-charger-teardown-quality.html
"Disassembling Apple's diminutive inch-cube iPhone charger reveals a technologically advanced flyback switching power supply that goes beyond the typical charger. It simply takes AC input (anything between 100 and 240 volts) and produce 5 watts of smooth 5 volt power, but the circuit to do this is surprisingly complex and innovative."


Apple's charger includes EMI filtering.
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K2AR

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Re: RF proof USB hub?
« Reply #5 on: August 19, 2021, 06:03:18 AM »

I had issues with cheap USB 2.0 and 3.0 hubs from RFI to power surges. I ended up replacing them with the industrial grade hubs from Triplite and Triplite clones and never had a problem since. I see them on eBay for a reasonable price.
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VE6MB

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Re: RF proof USB hub?
« Reply #6 on: August 19, 2021, 09:45:20 AM »

Just curious if you had tried a sufficient number of turns of cable through the donut ferrite? Also, type 31 is commonly used to attenuate the low bands....80-160m and type 43 used for helping on 40-10m. Perhaps a combination is needed for 31 & 43?


I spent hundreds of dollars on large mix 31 Snap-on and donut Ferrite from Palomar and used them on every cable going into my computer. It didn't help.

Mike, NT6X
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W9IQ

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Re: RF proof USB hub?
« Reply #7 on: August 19, 2021, 04:17:06 PM »

Ferrite mix 31 offers superior choking compared to mix 43 on all HF bands. Mix 31 was developed some time after mix 43.

- Glenn W9IQ

« Last Edit: August 19, 2021, 04:27:46 PM by W9IQ »
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- Glenn W9IQ

God runs electromagnetics on Monday, Wednesday and Friday by the wave theory and the devil runs it on Tuesday, Thursday and Saturday by the Quantum theory.

G8FXC

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Re: RF proof USB hub?
« Reply #8 on: August 20, 2021, 02:34:34 AM »

I've fought a running battle against RFI into the computer for years - there is no single answer! You've started right with lots of ironwork on every cable. Avoid snapons - they really cannot give you enough inductance for HF - you need decent size toroids and wind quite a few turns of cable through them.

I did all that and improved things a lot, but there were still frequencies and modes that took everything down. I then put a lot of effort into improving the station RF grounding and looked carefully at the PC and peripherals. I was unable to find any laptop that would reliably work there, so I put in a small tower PC. This has a metal case which I could bind to the shack RF ground system via a short, fairly thick copper braid. I fitted a spade connector on the end and caught it under one of the case screws of the tower. I also searched around and found a metal cased powered USB hub - again I earth the metal case with a copper braid to the RF ground bus-bar. The result is a system that allows me to operate all modes on all HF frequencies at the full 100W output of my radios.

Martin (G8FXC)
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