Struggling with automatic Meteor-M LRPT demodulation

PE0SAT · April 19, 2026, 2:57pm

Looking at the meta data from a previous obs:

enable-iq-dump: "1",
iq-file-path: "/tmp/.satnogs/iq.raw",

Is there enough free space at /tmp/.satnogs ?

Jan | PE0SAT

dl7ndr · April 19, 2026, 4:06pm

Cannot scroll to logs from previous observation.

dl7ndr · April 19, 2026, 4:08pm

There is no /tmp/.satnogs.

However, I’ve found the following in the log.

satnogs_client_1 | OSError: [Errno 28] No space left on device

But:

df
Filesystem     1K-blocks     Used Available Use% Mounted on
udev              193576        0    193576   0% /dev
tmpfs             185708    18132    167576  10% /run
/dev/mmcblk0p2  30096980 13042864  15506020  46% /
tmpfs             464264        0    464264   0% /dev/shm
tmpfs               5120       16      5104   1% /run/lock
/dev/mmcblk0p1    522230    67486    454744  13% /boot/firmware
tmpfs              92852        0     92852   0% /run/user/1000

PE0SAT · April 19, 2026, 5:05pm

Sorry for the confusion, but you need to check inside the container.

docker exec -ti <container name> ls -la /tmp/.satnogs
docker exec -ti <container name> df -h
docker exec -ti <container name> bash (will start a shell inside the container)

Looking at the logs inside the container:

docker logs -tf <container name>

Jan | PE0SAT

dl7ndr · April 19, 2026, 7:27pm

Filesystem      Size  Used Avail Use% Mounted on
tmpfs           454M  435M   20M  96% /tmp

satnogs-client@753ed2356c32:/tmp/.satnogs$ ls -l
total 416732                                                                                                         
drwxr-xr-x 4 satnogs-client satnogs-client       120 Apr 19 14:30 data                                               
-rw-r--r-- 1 satnogs-client satnogs-client        26 Apr 19 13:28 grsat_13856206.log                                 
-rw-r--r-- 1 satnogs-client satnogs-client        26 Apr 19 14:13 grsat_13856245.log                                 
-rw-r--r-- 1 satnogs-client satnogs-client 426721280 Apr 19 14:25 iq.raw                                             
-rw-r--r-- 1 satnogs-client satnogs-client      4096 Apr 19 14:28 iq.raw.meteor

PE0SAT · April 19, 2026, 7:39pm

And when this tmpfs is full all satnogs-client operation will fail, I would suggest to use another iq file location.

Jan | PE0SAT

bali · April 20, 2026, 5:51am

as jan recommend, you need change the iq file location, that have enough space. (ideally 1 gb for meteor m2-3/4)

edit your station.conf, and change this variable to:
IQ_DUMP_FILENAME=/var/lib/satnogs-client/iq.raw

or for best solution, just leave IQ_DUMP_FILENAME variable to /tmp/.satnogs/iq.raw,
but set your docker /tmp size, in your docker-compose.yml
so become like this (in this example i set my /tmp size to 3 gigabyte):

      - type: 'tmpfs'
        target: '/tmp'
        tmpfs:  
          size: 3g

restart docker:
sudo docker-compose down && sudo docker-compose up -d && sudo docker-compose logs -f

check new tmp size:
sudo docker-compose exec satnogs_client df -h

it should be 3 giga free:
tmpfs 3.0G 0 3.0G 0% /tmp

PE0SAT · April 20, 2026, 6:24am

Changing /tmp on this device to 3Gb will cause other problems, this seems to be a Pi with +/- 2Gb internal memory, so there isn’t enough memory available to create a tmpfs memory file system.

In this case we will need to save the IQ on a physical file system.

Jan | PE0SAT

dl7ndr · April 20, 2026, 8:02pm

That worked. Will try on another pass.

@PE0SAT My Pi has only 1 GB RAM.

dl7ndr · April 21, 2026, 5:07pm

It failed again.

2026-04-21T13:45:06.834018000Z DEBUG    satnogsclient.observer.worker   Tracking stopped.
2026-04-21T13:45:07.444222000Z DEBUG    satnogsclient.observer.worker   Tracking stopped.
2026-04-21T13:45:07.449543000Z INFO     satnogsclient.radio.grsat       Stopped gr_satellites
2026-04-21T13:45:07.451178000Z INFO     satnogsclient.observer.observer Observation 13868060 finished.
2026-04-21T13:45:07.451353000Z INFO     satnogsclient.observer.observer Executing post-observation script.
2026-04-21T13:45:22.700399000Z /opt/pipx/venvs/satnogs-client/lib/python3.11/site-packages/matplotlib/projections/__init__.py:63: UserWarning: Unable to import Axes3D. This may be due to multiple versions of Matplotlib being installed (e.g. as a system package and as a pip package). As a result, the 3D projection is not available.
2026-04-21T13:45:22.701208000Z   warnings.warn("Unable to import Axes3D. This may be due to multiple versions of "
2026-04-21T13:45:22.733067000Z INFO     satnogsclient                   Starting status listener thread...
2026-04-21T13:45:22.733281000Z DEBUG    satnogsclient.scheduler.tasks   Starting scheduler...

The now 3 GB tmp directory is empty.

PE0SAT · April 21, 2026, 5:55pm

tmpfs is a volatile file system in Unix-like operating systems that resides in RAM (or swap) rather than on persistent disk storage.

Your Pi doesn’t have enough internal memory for creating a 3Gb tmpfs please revert to the original config and save the IQ file to another location then /tmp/.satnogs.

Looking at the memory usage of my docker satnogs-client, it is 1.1 Gb, I even wonder if this Pi can run the client without problems.

Jan | PE0SAT

bali · April 21, 2026, 11:57pm

nah. undo docker-compose tmpfs size modification, and try this:

dl7ndr · April 22, 2026, 10:52am

It worked now.
However, since the signal was not strong enough for my horizontal HB9CV without preamp, there was nothing to decode.

dvdiyen · April 25, 2026, 1:02pm

I was struggling to automate the LRPT. I had to install multiple times. Finally, figured out the method that works. Thanks to @bali and @PE0SAT for the inputs. @bali your frequent inputs deserve to be highlighted.