I would like to save the IQ-files from observations from my station. By enabling the iq-filedump and by giving a filename /tmp/iq, I am able to create one iq-file. So only the last observation is stored, but not the whole, unfortunately only something like to last 15 seconds or so, are stored. Filesize is about 100 MB, so a size limit from the filesystem is not reached in the moment.
I know that I need much file space, I have a 256 GB card for my raspi. Can I manage somehow to get the whole observation? I tried already to reduce sample rate but I cannot go down too far, as gnuradio starts to deliver errors (sample rate of 96000 does not work). Also the iq-file gets smaller with the reduction so I do not get more time into the file by the sample rate reduction. Has anybody some tips? Thanks in advance!
Yes it is possible to save and rename the observation IQ data.
You will need a SATNOGS_POST_OBSERVATION_SCRIPT that will take the ENABLE_IQ_DUMP=true and IQ_DUMP_FILENAME=/directory/iq-filename variables to move the received IQ to an obs related file and make room for the next observation.
Regarding your sample remark even with an old Pi it should be possible to use a 2.048e6 sample rate and would try to use that at least.
Just to add by transferring info from a related discussion in the matrix.org #satnogs-dev chatroom, the dev team works on getting read/write volume for the docker containers, to help solve similar issues.
I can access the /tmp-directory in the docker, so I was able to create a script there. It could of course be, that script gets deleted with next update …