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Does RPi have an RF sensitivity issue?

Michael WA7SKG
 

I'm setting up an RPi for APRS. Loaded Raspbian and YAAC onto my RPi connected to a TNC-Pi and MoPi board. GPS connected an looking good. Everything seemed fine until I connected my handheld for testing. As soon as I connected the radio, it went into transmit sending out garbage audio. Then the screen went all fuzzy and everything seemed to lock up. I could still SSH into it, but couldn't seem to get the screen to work again. I shut it down and on reboot, I get a bunch of text scroll be I cannot read. The last line says something about end kernel panic.

I'm guessing the RF may have corrupted my SD card somehow. I am using the cable that came with the TNC-Pi, so the HT is only about a foot away from the RPi. I've not seen anything like this before. I guess I have to build a new SD card and start over from scratch. Going to be a long day as I was supposed to use this in a presentation tomorrow.

I'm looking for my 10 foot serial cable to get the radio farther away from the RPi. But I am worried how this will work in my truck with a 30 watt radio for APRS, but also 50 watt VHF/UHF radios and 100 watt HF also in the truck

Thanks for any ideas.

Michael WA7SKG

Max
 

I would bet that it's not the distance between the radio and the pi, but the fact that you're using an HT that is probability not actually being held. You have common mode current on the interface cable. Put that ht on a dummy load or a proper antenna. A piece of wire connected at the base of the rubber duct 19" or so inches long and pointing straight down (otherwise know as a 'rat tail') also works well. 

A longer interface cable with the proper choke(s) would most likely also work. But fix the problem, not cure the symptoms. Stop the common mode current.

Max KG4PID

On Saturday, February 22, 2020, 11:22:33 AM CST, Michael WA7SKG <wa7skg@...> wrote:


I'm setting up an RPi for APRS. Loaded Raspbian and YAAC onto my RPi
connected to a TNC-Pi and MoPi board. GPS connected an looking good.
Everything seemed fine until I connected my handheld for testing. As
soon as I connected the radio, it went into transmit sending out garbage
audio. Then the screen went all fuzzy and everything seemed to lock up.
I could still SSH into it, but couldn't seem to get the screen to work
again. I shut it down and on reboot, I get a bunch of text scroll be I
cannot read. The last line says something about end kernel panic.

I'm guessing the RF may have corrupted my SD card somehow. I am using
the cable that came with the TNC-Pi, so the HT is only about a foot away
from the RPi. I've not seen anything like this before. I guess I have to
build a new SD card and start over from scratch. Going to be a long day
as I was supposed to use this in a presentation tomorrow.

I'm looking for my 10 foot serial cable to get the radio farther away
from the RPi. But I am worried how this will work in my truck with a 30
watt radio for APRS, but also 50 watt VHF/UHF radios and 100 watt HF
also in the truck

Thanks for any ideas.

Michael WA7SKG



David Ranch
 


Hello Michael,

Bummer to hear about the corruption issue.  To avoid it in the future, consider:

   1. Make sure you're using a quality, name brand microSD card that is LARGER than you need.  The larger card will help minimize flash cells being overwritten many times and getting worn out

   2. Consider making use of RAM drives vs. writing data to the SD card.  There are lots of great guides out on the Internet on how to do this but here is mine:
     http://www.trinityos.com/HAM/CentosDigitalModes/RPi/rpi2-setup.html#6.ram-fs-to-minimize-sd-writes

   3. Once your SD card is working you like it.. back it up for easy restores:
     http://www.trinityos.com/HAM/CentosDigitalModes/RPi/rpi2-setup.html#49.backup-the-sd-card

--David
KI6ZHD


On 02/22/2020 09:22 AM, Michael WA7SKG wrote:
I'm setting up an RPi for APRS. Loaded Raspbian and YAAC onto my RPi connected to a TNC-Pi and MoPi board. GPS connected an looking good. Everything seemed fine until I connected my handheld for testing. As soon as I connected the radio, it went into transmit sending out garbage audio. Then the screen went all fuzzy and everything seemed to lock up. I could still SSH into it, but couldn't seem to get the screen to work again. I shut it down and on reboot, I get a bunch of text scroll be I cannot read. The last line says something about end kernel panic.

I'm guessing the RF may have corrupted my SD card somehow. I am using the cable that came with the TNC-Pi, so the HT is only about a foot away from the RPi. I've not seen anything like this before. I guess I have to build a new SD card and start over from scratch. Going to be a long day as I was supposed to use this in a presentation tomorrow.

I'm looking for my 10 foot serial cable to get the radio farther away from the RPi. But I am worried how this will work in my truck with a 30 watt radio for APRS, but also 50 watt VHF/UHF radios and 100 watt HF also in the truck

Thanks for any ideas.

Michael WA7SKG