LignoSat uplink specs? (ISS deployment upcoming)

Satellites & Observations Launches
1

Greetings.

Reports indicate that LignoSat has been delivered to the ISS for future deployment.

Coordination particulars show that it will be listening for AX.25 packets at 4800 baud on 435.820 MHz.

https://iaru.amsat-uk.org/finished_detail.php?serialnum=847

… there is also a document with ‘some’ information about the format required:

… however, all required information has not been provided, so I post here to see if that information can be located.

#1, does the required AX.25 uplink packet use the same format as a standard APRS packet?

#2, what TO callsign should be used. And is a specific ‘VIA’ (digipeater) call sign required as well?

In the event that we get lucky and the format ends up matching our standard APRS packets, I’ve done an over-the-air test transmitting from the UISS app through one of the UZ7HO SoundModem variations that includes 4k8 FSK and that decoded fine on a separate receiver:

LignoSat_test-decode
LignoSat_test-decode969×566 205 KB

But now we need answers to the questions above to know how to proceed. I tried to email the contact listed on the IARU Coordination (after removing the ‘no-spam’), but that address was not valid. Does anyone have a contact in Japan that might be able to fill in the missing details here so that we can be ready before this sat is deployed?

Thanks!

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2

By accident, I noticed that Direwolf is also capable of transmitting and decoding at G3RUH scrambled 4k8 FSK.

Looking at the help of Direwolf, the option “-B 4800” is explained as 4800 bps uses 8PSK based on V.27 standard.
And if you enter
direwolf -B 4800 -r 48000
this will be displayed:

Channel 0: 4800 bps, 8PSK, TUVW, 48000 sample rate.

That sounds not good.

However, if you enter
direwolf -B 4800 -r 48000 -g
you will get

Channel 0: 4800 baud, K9NG/G3RUH, +, 48000 sample rate x 2.

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3

The particular .conf details that I used for Direwolf in my over-the-air decode test shown above are:

k4kdr@3010i5:~$ cat 4800.conf
ARATE 48000
ACHANNELS 1
MODEM 4800 0:0
TXDELAY 60
TXTAIL 120
KISSPORT 4000
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4

The output of your reception window looked very familiar to me, like Direwolf (:

You started direwolf with option -g, right?

5

Let’s see - I use scripts to run all my Direwolf variations; here is the one I’d put together some time ago for 4800 baud… no option “g”.

k4kdr@3010i5:~$ cat 4k8-direwolf.sh 
#!/bin/bash

clear

mkdir -p log

direwolf -c 4800.conf -dup -t 0 -qd | ts '[%Y-%m-%d %H:%M:%S]' | tee -a log/$(date +%Y-%m-%d--%H%M)
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6

Got it.
In your config file you are using

MODEM 4800 0:0

This is equivalent to option “-g”.

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7

Satellite and transmitters added to the database.

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