K4KDR's GRC for SLEDGE

From: K4KDR
To: JE9PEL

Gladly!

I have a 'standard' that I use for just about everything - but of course with variations
where needed. You have input choices of a recorded I/Q file (w/ manual adjustment to center
the signal of interest), recorded AUDIO files (.wav or SatNogs .ogg), or 'live' audio from
some other source; in my case, GQRX.

Of course that is followed by demodulation & deframing.

Outputs are a hex dump to the lower monitor in GNU Radio, a KSS file, and a special KISS
output to pseudo-device '/tmp/kisstnc' which feeds an instance of Direwolf running w/ the
'-p' option to provide a display format that I like:


[2026-09-15 17:35:38] ------
[2026-09-15 17:35:38] U frame UI: p/f=0, No layer 3 protocol implemented., length = 39
[2026-09-15 17:35:38]  dest    SLEDGE  0 c/r=1 res=3 last=0
[2026-09-15 17:35:38]  source  TEST    0 c/r=1 res=3 last=1
[2026-09-15 17:35:38]   000:  a6 98 8a 88 8e 8a e0 a8 8a a6 a8 40 40 e1 03 f0  ...........@@...
[2026-09-15 17:35:38]   010:  53 4c 45 44 47 45 20 54 45 53 54 20 31 39 32 30  SLEDGE TEST 1920
[2026-09-15 17:35:38]   020:  30 20 47 33 52 55 48                             0 G3RUH
[2026-09-15 17:35:38] ------


Lastly (disabled for test files), is the ‘Telemetry Submit' block to upload decodes to SatNogs.
As I said, I used this over and over with changes to baud rate, demod, & deframing as needed.
Custom output destinations are added if a Team provides an upload proxy or decoder that is
listening on a UDP or TCP port.

Screenshot from 2026-09-15 17-43-21:



A copy of the .GRC is available at:

https://www.dropbox.com/scl/fi/c3rf10i2cw2oaaz7bthr0/sledge-k4kdr_test-file_shared.grc?rlkey=604j040scws5evoixf1hyjuee&dl=0
https://www.ne.jp/asahi/hamradio/je9pel/sledge--k4kdr_test-file_shared.grc
https://www.ne.jp/asahi/hamradio/je9pel/19k2_fixed6_48k-AUDIO.wav

(be sure to change the ‘Check AX.25 address' block for the satellite's actual call sign "FROM: ESGS01" after launch)


[2026-09-14 02:25:35] ------
[2026-09-14 02:25:35] U frame UI: p/f=0, No layer 3 protocol implemented., length = 94
[2026-09-14 02:25:35]  dest    ABCDEF  0 c/r=1 res=3 last=0
[2026-09-14 02:25:35]  source  ESGS01  0 c/r=1 res=3 last=1
[2026-09-14 02:25:35]   000:  82 84 86 88 8a 8c e0 8a a6 8e a6 60 62 e1 03 f0  ...........`b...
[2026-09-14 02:25:35]   010:  bc 62 a7 10 bc 7c 40 31 08 7c 41 01 01 00 00 00  .b...|@1.|A.....
[2026-09-14 02:25:35]   020:  00 00 00 00 00 00 00 08 01 75 0d 6d e7 7b 40 7f  .........u.m.{@.
[2026-09-14 02:25:35]   030:  6a 7c 40 0a d7 7b 40 1d 5a 7c 40 e7 fb 7b 41 00  j|@..{@.Z|@..{A.
[2026-09-14 02:25:35]   040:  00 00 00 00 00 80 3f 00 00 80 3f 00 01 ff 00 00  ......?...?.....
[2026-09-14 02:25:35]   050:  00 00 00 00 00 00 00 00 41 00 00 00 88 00        ........A.....
[2026-09-14 02:25:35] ------

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