Its a kind of magic, because SatNOGS was perviously configured (for 40069/44387) to start it’s I/Q recording with 144ksps when the transmitter mode was set to “LPRT*”. So, it has also been inherited by 57166 - but otherwise, we do the decoding completely independently from satnogs-client itself.
Interesting, as that functionality currently doesn’t exist. However, starting the IQ recorder with 144ksps would’ve been my preferred solution. Can you check how satnogs-client has been adapted on your end?
@PE0SAT has added an FSK transmitter to 57166 which allows IQ recording of 256ksps, and this also works.
I made it a bit smaller, it will now produce 128ksps and should be enough.
1 Like
Do you mean this “LRPT IQ recording usage” => “FSK 32000”? Would it be sufficient for a 72ksps symbol rate?
1 Like
The FSK baudrate results in a IQ sample rate that’s 4x larger, so in this case 128ksps.
What creates the iq.dat file?
Not having much luck.
https://network.satnogs.org/observations/7804770/
https://network.satnogs.org/observations/7804372/
You can enable the IQ file creation via sudo satnogs-setup and then the option advanced -> radio
There are two options that influence the behavior:
ENABLE_IQ_DUMP
Type
boolean
Default
False
Required
No
Description
Create I/Q data dumps for every observation. Use this feature with caution. Enabling this setting will store large amount of data on the file-system.
IQ_DUMP_FILENAME
Type
path
Default
None
Required
No
Description
Path to file for storing I/Q data dumps.
The files created are pretty big and if you use a Pi the writing of these files can wearout your SD card.
Thanks for the quick reply. On the last pass I did have these settings. SatNOGS Network - Observation 7804770
ENABLE_IQ_DUMP=“1”
IQ_DUMP_FILENAME=“/tmp/iq_vhf.raw”
After the pass I tried changing the name to iq.dat and then running the postob.sh with no luck.
#!/bin/bash
echo "POST OBSERVATION SCRIPT RUNNING"
#ID="$1"
ID="satnogs_7804770_2023-07-03T03-59-00"
DATE="$2"
demod=/usr/local/bin/meteor_demod
decode=/usr/local/bin/meteor_decode
cp /tmp/iq.dat /tmp/${ID}.dat
${demod} --batch --quiet -O 8 -f 128 -s 144000 -m oqpsk --bps 16 /tmp/${ID}.dat --stdout | \
${decode} --batch --quiet --diff -a 65,65,64 -o /tmp/.satnogs/data/data_${ID}_${DATE}.png -
rm -f /tmp/${ID}.dat
#old method
#python /home/pi/satnogs-extras/scripts/process_meteor.py "$1" "$2" "$3" "$4"
echo "POST OBSERVATION SCRIPT FINISHED"
SATNOGS_SOAPY_RX_DEVICE="driver=rtlsdr"
SATNOGS_RX_SAMP_RATE="2.048e6"
SATNOGS_ANTENNA="RX"
UDP_DUMP_HOST="127.0.0.1"
SATNOGS_RF_GAIN="8.7"
#SATNOGS_RF_GAIN="32.8"
#SATNOGS_RF_GAIN="16.6"
SATNOGS_GAIN_MODE="Overall"
# Black Nooelec SDR
# 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6
# Silver Nooelec SDR
# -1.0 1.5 4.0 6.5 9.0 11.5 14.0 16.5 19.0 21.5 24.0 29.0 34.0 42.0
ENABLE_IQ_DUMP="1"
IQ_DUMP_FILENAME="/tmp/iq_vhf.raw"
###Control the PSTROTATOR with this stuff
SATNOGS_ROT_MODEL="ROT_MODEL_NETROTCTL"
SATNOGS_ROT_BAUD="0"
SATNOGS_ROT_PORT="192.168.14.144:4533"
SATNOGS_PRE_OBSERVATION_SCRIPT="satnogs-pre {{ID}} {{FREQ}} {{TLE}} {{TIMESTAMP}} {{BAUD}} {{SCRIPT_NAME}}"
SATNOGS_POST_OBSERVATION_SCRIPT="/home/pi/postob.sh --id {{ID}} --tle{{TLE}}"
What information or error messages did you get?
Are the meteor_demod and meteor_decode build via github ?
Yes the meteor_demod and meteor_decode were just built from the github source today.
After the meteor_demod finished it had 00:00:00 for the time and no files generated. I will give it another try after the next good pass. Thanks again.
You need to set -s 128000 instead of -s 144000. But if you have individual saved I/Q files, try first to run manually on these dumps, then add the post-obs script if all works fine 
2 Likes
It looks like the VIT never drops below 1300 during the decode. I have a couple of METEOR M2-3 METEOR 2 2-3 METEOR-M N2-3 (whatever it is called) daylight passes coming and will try some more settings.
I had a good daytime pass over EM00 and have been playing around with the IQ file.
https://network.satnogs.org/observations/7805833/
So far I have found this to work but the $ID and $DATE were not coming over so the png file did not upload to the observation.
#!/bin/bash
echo "POST OBSERVATION SCRIPT RUNNING"
ID="$1"
DATE="$2"
demod=/usr/local/bin/meteor_demod
decode=/usr/local/bin/meteor_decode
${demod} --batch --quiet -s 144000 -m oqpsk /tmp/iq.dat --stdout | \
${decode} --batch --quiet --diff -o /tmp/.satnogs/data/data_${ID}_${DATE}.png -
#rm -f /tmp/iq.dat
echo "POST OBSERVATION SCRIPT FINISHED"
Thanks for the help everyone that contributed to the thread. I have finished the work to automate the METEOR M2 2-3 observations and then upload the results including the decoded graphic.
https://network.satnogs.org/observations/7805833/
For the satnogs-client configuration I change the client file by hand and here is the code that I am using. SatNOGs version 1.8.1
sudo nano /etc/default/satnogs-client
SATNOGS_API_TOKEN="xxxx....."
SATNOGS_DB_API_TOKEN="xxxx....."
SATNOGS_STATION_ID="xxxx"
SATNOGS_STATION_LAT="30xx"
SATNOGS_STATION_LON="-99xx"
SATNOGS_STATION_ELEV="500"
SATNOGS_SOAPY_RX_DEVICE="driver=rtlsdr"
SATNOGS_RX_SAMP_RATE="2.048e6"
SATNOGS_ANTENNA="RX"
UDP_DUMP_HOST="127.0.0.1"
SATNOGS_RF_GAIN="8.7"
#SATNOGS_RF_GAIN="32.8"
#SATNOGS_RF_GAIN="16.6"
SATNOGS_GAIN_MODE="Overall"
# Black Nooelec SDR
# 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6
# Silver Nooelec SDR
# -1.0 1.5 4.0 6.5 9.0 11.5 14.0 16.5 19.0 21.5 24.0 29.0 34.0 42.0
#METEOR The IQ file is huge so it goes to an external drive with satnogs:satnogs ownership
ENABLE_IQ_DUMP="1"
IQ_DUMP_FILENAME="/media/usb/satnogs/iq.dat"
###Control the PSTROTATOR with this stuff
SATNOGS_ROT_MODEL="ROT_MODEL_NETROTCTL"
SATNOGS_ROT_BAUD="0"
SATNOGS_ROT_PORT="192.168.14.144:4533"
SATNOGS_PRE_OBSERVATION_SCRIPT="satnogs-pre {{ID}} {{FREQ}} {{TLE}} {{TIMESTAMP}} {{BAUD}} {{SCRIPT_NAME}}"
#METEOR Run this script after the observation
SATNOGS_POST_OBSERVATION_SCRIPT="/home/pi/postob.sh {{ID}} {{TIMESTAMP}}"
The post observation script postob.sh
Again I am storing the IQ file on an external drive to avoid wearing out the Raspberry Pi SD Card
#!/bin/bash
echo "POST OBSERVATION SCRIPT RUNNING"
ID="$1"
DATE="$2"
demod=/usr/local/bin/meteor_demod
decode=/usr/local/bin/meteor_decode
${demod} --batch --quiet -s 144000 -m oqpsk /media/usb/satnogs/iq.dat --stdout | \
${decode} --batch --quiet --diff -o /tmp/.satnogs/data/data_${ID}_${DATE}.png -
#rm -f /tmp/${ID}.dat
echo "POST OBSERVATION SCRIPT FINISHED"
Again I am storing the IQ file on an external drive to avoid wearing out the Raspberry Pi SD Card
If you have sufficient amount of RAM, you can also store these I/Qs in /dev/shm. Those (i mean, I/Qs) can be rather big, 1/2 gigabytes or so, so check it in advance.
So, if we do an FSK 32000 recording, just change the above -s 144000 to -s 128000. And then all will work automatically: SatNOGS Network - Observation 7823743. It seems that now Meteor M2-3 is transmitting the 72ksps OQPSK images at 137.1MHz and not at 137.9MHz.
2 Likes
@bcsak, yes the FSK32000 IQ recordings can be used and I am successful as can be seen by looking at this observation SatNOGS Network - Observation 7803282
I haven’t fully automated the demod → decode → upload yet.
Here is the script that I use for now.
#!/usr/bin/env bash
#
# Upload to the network:
#
# ${SATNOGS_OUTPUT_PATH}/data_<obsid>_YYYY-MM-DDTHH-MM-SS.png
if [ -z "${1}" ]; then
echo "Input variable missing."
echo "Syntax: $0 input file sample rate (default 128e3)"
exit 1
fi
SPS="${2:-128000}"
echo "Decode ${1} at a ${SPS} sample rate"
meteor_demod -O 8 -f 128 --batch --quiet --bps 16 -s "${SPS}" \
--mode oqpsk "${1}" --stdout - | \
meteor_decode -o "${1}".png --diff -a 65,65,64 -
I changed to using the 137.1 IQ Transmitter and had to change to 128000 for the demod. Also did the post processing with SmoothMeteor Smooth Meteor. Much better that my earlier results.
SatNOGS Network - Observation 7829917