Pi 400 and RF


Michael WA7SKG
 

Is anybody experiencing RF problems with the Raspberry Pi 400? I was recently gifted a Pi400 and loaded the HamPi distribution. I don't have RF problems with anything else in the shack, but when I transmit (so far only on 20 and 40 meters) the Pi400 goes nuts. Stuff jumps around on the screen, programs open and close and all matter of strange behavior. It's like there are multiple mouses screaming around randomly clicking on things. Nothing is connected to it, just the Pi400 with its stock mouse and power supply hooked to a generic monitor. It was on a small table several feet from the radio. There are four other computers in the shack and a variety of other things that are not affected at all.

Thought appreciated.


--
73,
Michael WA7SKG

"Any day you do not learn one new thing is a wasted day."


Kelly Keeton
 

Sounds like you have a harmonic or rf back into the touchpad. 

Move it, lengthen cable or choke it see if that helps. 

73


Excuse typos and brevity, sent from a mobile device.

On Saturday, November 27, 2021, 9:51 AM, Michael WA7SKG <wa7skg@...> wrote:

Is anybody experiencing RF problems with the Raspberry Pi 400? I was
recently gifted a Pi400 and loaded the HamPi distribution. I don't have
RF problems with anything else in the shack, but when I transmit (so far
only on 20 and 40 meters) the Pi400 goes nuts. Stuff jumps around on the
screen, programs open and close and all matter of strange behavior. It's
like there are multiple mouses screaming around randomly clicking on
things. Nothing is connected to it, just the Pi400 with its stock mouse
and power supply hooked to a generic monitor. It was on a small table
several feet from the radio. There are four other computers in the shack
and a variety of other things that are not affected at all.

Thought appreciated.


--
73,
Michael WA7SKG

"Any day you do not learn one new thing is a wasted day."






Mark Griffith
 

The Raspberry Pi's are very subseptible to RF.  The most likely way to correct it is RF chokes on the power supply cable and any cable between the Pi and the radio.  Maybe even the monitor cable although those are usually well shielded.  In my experience, the clamp on chokes don't seem to work very well, but the kind that you can split apart and wrap the cable around it to or three times has cleared up any problems I have seen.

If that doesn't work, maybe a metal case for the Pi and perhaps some sleuthing to find out where the RF leak is in your setup.

Good luck!

Mark
KD0QYN


On Saturday, November 27, 2021, 11:51:17 AM CST, Michael WA7SKG <wa7skg@...> wrote:


Is anybody experiencing RF problems with the Raspberry Pi 400? I was
recently gifted a Pi400 and loaded the HamPi distribution. I don't have
RF problems with anything else in the shack, but when I transmit (so far
only on 20 and 40 meters) the Pi400 goes nuts. Stuff jumps around on the
screen, programs open and close and all matter of strange behavior. It's
like there are multiple mouses screaming around randomly clicking on
things. Nothing is connected to it, just the Pi400 with its stock mouse
and power supply hooked to a generic monitor. It was on a small table
several feet from the radio. There are four other computers in the shack
and a variety of other things that are not affected at all.

Thought appreciated.


--
73,
Michael WA7SKG

"Any day you do not learn one new thing is a wasted day."






Dave R
 

Hello. I had similar issues and a couple of generic clamp-on ferrites fixed it for me. One on UTP ethernet cable, another on the 5Vdc power supply cable was all I needed. 73


On Sat, Nov 27, 2021, 09:51 Michael WA7SKG <wa7skg@...> wrote:
Is anybody experiencing RF problems with the Raspberry Pi 400? I was
recently gifted a Pi400 and loaded the HamPi distribution. I don't have
RF problems with anything else in the shack, but when I transmit (so far
only on 20 and 40 meters) the Pi400 goes nuts. Stuff jumps around on the
screen, programs open and close and all matter of strange behavior. It's
like there are multiple mouses screaming around randomly clicking on
things. Nothing is connected to it, just the Pi400 with its stock mouse
and power supply hooked to a generic monitor. It was on a small table
several feet from the radio. There are four other computers in the shack
and a variety of other things that are not affected at all.

Thought appreciated.


--
73,
Michael WA7SKG

"Any day you do not learn one new thing is a wasted day."






Dave R
 

No metal case a available for pi400. It's the pi4 built inside a keyboard.  It has a massive heatsink and no fans needed. 73


On Sat, Nov 27, 2021, 10:21 Mark Griffith via groups.io <mdgriffith2003=yahoo.com@groups.io> wrote:
The Raspberry Pi's are very subseptible to RF.  The most likely way to correct it is RF chokes on the power supply cable and any cable between the Pi and the radio.  Maybe even the monitor cable although those are usually well shielded.  In my experience, the clamp on chokes don't seem to work very well, but the kind that you can split apart and wrap the cable around it to or three times has cleared up any problems I have seen.

If that doesn't work, maybe a metal case for the Pi and perhaps some sleuthing to find out where the RF leak is in your setup.

Good luck!

Mark
KD0QYN


On Saturday, November 27, 2021, 11:51:17 AM CST, Michael WA7SKG <wa7skg@...> wrote:


Is anybody experiencing RF problems with the Raspberry Pi 400? I was
recently gifted a Pi400 and loaded the HamPi distribution. I don't have
RF problems with anything else in the shack, but when I transmit (so far
only on 20 and 40 meters) the Pi400 goes nuts. Stuff jumps around on the
screen, programs open and close and all matter of strange behavior. It's
like there are multiple mouses screaming around randomly clicking on
things. Nothing is connected to it, just the Pi400 with its stock mouse
and power supply hooked to a generic monitor. It was on a small table
several feet from the radio. There are four other computers in the shack
and a variety of other things that are not affected at all.

Thought appreciated.


--
73,
Michael WA7SKG

"Any day you do not learn one new thing is a wasted day."






Chuck K4RGN
 

Although it's not an issue for the OP, I found that the Pi's i2c bus is very susceptible to RF. Note that at VHF or UHF frequencies, an i2c ribbon cable of an unfortunate length can be especially troublesome. Since there was no good solution using a ferrite, I bought some fine copper mesh on eBay to put the Pi and its i2c-connected devices inside a Faraday cage. This worked. The long-term solution, though, was to use USB-connected devices instead of i2c-connected devices. USB isn't impervious to RF either, but its natural noise immunity appears to exceed i2c's. 

73 Chuck K4RGN


 

Consider the antennas and coax also. Try putting a dummy load on the radio and see if the problem goes away. You might have a common current problem.  Antennas that are in balanced or have an insufficient counterpoise can cause RFI to the equipment in the shack. The dead giveaway that it’s the antenna and not the coax is to put the dummy load out at the antenna.

Tadd - KA2DEW 

On Nov 28, 2021, at 12:06 PM, Chuck K4RGN <K4rgn@...> wrote:

Although it's not an issue for the OP, I found that the Pi's i2c bus is very susceptible to RF. Note that at VHF or UHF frequencies, an i2c ribbon cable of an unfortunate length can be especially troublesome. Since there was no good solution using a ferrite, I bought some fine copper mesh on eBay to put the Pi and its i2c-connected devices inside a Faraday cage. This worked. The long-term solution, though, was to use USB-connected devices instead of i2c-connected devices. USB isn't impervious to RF either, but its natural noise immunity appears to exceed i2c's. 

73 Chuck K4RGN


Charles Gallo
 

Yeah, EMI from large motors too

—  
Charlie
73 de KG2V
Http://www.thegallos.com


On Nov 28, 2021, at 12:06 PM, Chuck K4RGN <K4rgn@...> wrote:

Although it's not an issue for the OP, I found that the Pi's i2c bus is very susceptible to RF. Note that at VHF or UHF frequencies, an i2c ribbon cable of an unfortunate length can be especially troublesome. Since there was no good solution using a ferrite, I bought some fine copper mesh on eBay to put the Pi and its i2c-connected devices inside a Faraday cage. This worked. The long-term solution, though, was to use USB-connected devices instead of i2c-connected devices. USB isn't impervious to RF either, but its natural noise immunity appears to exceed i2c's. 

73 Chuck K4RGN


KJ7VID_Mike
 

Michael,
First thing I’d try is replacing the mouse. 
Mike KJ7VID

On Sat, Nov 27, 2021 at 10:51 Michael WA7SKG <wa7skg@...> wrote:
Is anybody experiencing RF problems with the Raspberry Pi 400? I was
recently gifted a Pi400 and loaded the HamPi distribution. I don't have
RF problems with anything else in the shack, but when I transmit (so far
only on 20 and 40 meters) the Pi400 goes nuts. Stuff jumps around on the
screen, programs open and close and all matter of strange behavior. It's
like there are multiple mouses screaming around randomly clicking on
things. Nothing is connected to it, just the Pi400 with its stock mouse
and power supply hooked to a generic monitor. It was on a small table
several feet from the radio. There are four other computers in the shack
and a variety of other things that are not affected at all.

Thought appreciated.


--
73,
Michael WA7SKG

"Any day you do not learn one new thing is a wasted day."





--
Sincerely,
Mike _ KJ7VID
73


Bill Cromwell
 

Hi,

Just for my own curiosity is the offending radio in a plastic box or in a grounded metal box?

7,

Bill KU8H

bark less - wag more

On 11/27/21 12:51 PM, Michael WA7SKG wrote:
Is anybody experiencing RF problems with the Raspberry Pi 400? I was recently gifted a Pi400 and loaded the HamPi distribution. I don't have RF problems with anything else in the shack, but when I transmit (so far only on 20 and 40 meters) the Pi400 goes nuts. Stuff jumps around on the screen, programs open and close and all matter of strange behavior. It's like there are multiple mouses screaming around randomly clicking on things. Nothing is connected to it, just the Pi400 with its stock mouse and power supply hooked to a generic monitor. It was on a small table several feet from the radio. There are four other computers in the shack and a variety of other things that are not affected at all.

Thought appreciated.


Mike - KG0P
 

I'm not sure a metal case would be the  answer. After all, the wires leading in and out of the case would just act as short antennas sending the RF to the Pi in spite of the case. I do like the idea of chokes, though.