Foresail-1p - Skylink Digipeater

1

Foresail-1p’s Skylink Digipeater is now ready to use!

The Modem needs to speak the Skylink Protocol.
Therefore, choose one of these three options.

.
See your digipeated packet on Foresail-1p’s Dashboard.

Dashboard
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Don’t forget to upload your received data.

Have fun and don’t hesitate to ask questions.

73
Daniel

5 Likes
2

Andy (UZ7HO) updated his SoundModem to version 0.06.

It now shows transmitted and received packets in the usual format.

SoundModem Ver 0.06
SoundModem Ver 0.06691×594 73.4 KB

2 Likes
3

I’ve updated my GNU Radio flowgraph skylink_repeater.grc skylink_repeater.zip (82.5 KB)

It’s now fully operational!

skylink_repeater
skylink_repeater7044×667 463 KB

Features:

  • listens on audio in with gr-satellites satellite decoder
  • uploads digipeated and telemetry packets to SatNOGS (others are discarded)
  • counts digipeated and telemetry packets
  • stores both packet types in separate files (each .kss and .hex)
  • forwards digipeated packets to PyttiAPRS (KISS client)
  • constructs skylink repeater packets from PyttiAPRS message input and outputs it via audio
  • executes TX ‘on’ and ‘off’ command for CM108 sound cards when new repeater message from PyttiAPRS arrives
  • allows to generate WAV files for single messages to be sent manually without GNU Radio

Use it together with PyttiAPRS (included in .zip) to transmit messages to the digipeater or just for receiving and uploading packets to SatNOGS.

Digipeater usage hint:
If the UHF module resets, the repeater is switched off automatically and needs to be switched on again manually.
Check uhf uptime for it.

I’ve also added Foresail-1p to the Digipeater Dashboard.

digipeater dashboard
digipeater dashboard1743×401 17.6 KB

Looking forward to see your message live on Foresail-1p or on its dashboard.

73
Daniel

4

Because FORSAIL-1P isn’t using the “standard” AX100 Mode 5 framing, we can only decode the frames using the gr-satellites integration.

For the new docker based clients this can be done by running sudo satnogs-setup choose Advanded - > Addons and set GR_SATELLITES_ENABLED to True

Run docker exec -ti satnogs_satnogs-client gr_satellites --list_satellites | grep FORESAIL-1P to see if the FORESAIL-1P Yaml file is available.

* FORESAIL-1P (NORAD 98467)

As you can see this Yaml is still using the temporary NoradID set by SatNOGS, when the identification is definite this will change.

The file is located in /usr/lib/python3/dist-packages/satellites/satyaml and this is its current config.

cat FORESAIL-1P.yml 

name: FORESAIL-1P
norad: 98467
data:
  &tlm Telemetry:
    unknown
transmitters:
  9k6 FSK downlink:
    frequency: 437.125e+6
    modulation: FSK
    baudrate: 9600
    framing: FORESAIL-1
    data:
    - *tlm

Jan | PE0SAT

2 Likes
5

I have been trying to utilize the sound modem method and not sure I am getting much luck with it. I am definitely getting usable packets out of the sound modem (did a loopback test and it decoded it) but I have not been able to receive any digipeated packets back. Do the DCDs need to be different?

image
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6

Hi Christopher,

Thanks for your interest in Foresail-1p digipeater.

DCD means Data Carrier Detect.
DCD A and DCD B only represent the dection of data for Modem A and Modem B.
Since Foresail-1p has only 9600bd, you need only one Modem. Therefore you may untick “Dual channel” under Settings - Devices.

The SoundModem has never been tested yet successfully on Foresail-1p.
I can only speak for my GNU Radio flowgraph. That works.

However, between 02/26 and 03/07 none of my packets got digipeated. Just today on 03/08 it started digipeating again (with the same settings as before).

What is your equipment (antenna, rig, power)?

73
Daniel

7

Gotcha thanks for clarifying that the DCD bit and not getting sound modem working yet (I took one your later screenshot as showing that it did work via sound modem).

Right now my Transmit setup is the following:

UISS → SoundModem (latest one you posted in this forum) →Sdrangel → plutosdr → driver amp →430mhz bpf→ PA → 50ft coax → 7dB Vertically Polarized Yagi antenna. I have measured before and get around 50Ws at the antenna input which should be fine to close a link.

I might be able to get your gnuradio script to work with sdrangel since I am just using audio sinks and sources to sdrangel but initially it seemed like the sound modem would be easier to get running.

8

Did you mount your Yagi on a rotator?

How do you do PTT? What did you set up in the SoundModem?
By the way, the GNU Radio flowgraph needs a cm108 chip to toggle a pin for TX
I don’t know if this would also work with Pluto’s GPIOs.

Did you use this setup already successfully on other 9k6 digipeaters?

9

Ptt I handle in sdrangel (serial device that disables or enables the Driver amp to the PA).

I also should have clarified it is on az el rotor. But otherwise I haven’t had any luck with lasarsat or crocube with getting digipeater working (tried multiple passes and not much luck). Have mostly used sound modem for both lasarsat and crocube and can clearly decode packets.

10

Thanks for the details.

At first to make sure that your rig works for 9k6, could you try GRBBeta on VHF?
Its receiver is very sensitive and it waits for about 1 second before it repeats the received packet. Should be enough to disable the driver amp to the PA and switch back to RX.

11

Unfortunately I only have uhf and not vhf setup so can’t try grb beta .

Do you know how long crocube, lasarsat and others typically wait before repeating the packet? I can probably improve my ptt time if that is the problem.

12

I’ll contact you via email.

13

My suggestion for updating the NoradID to 66778 was approved.

If you want to use the GNU Radio flowgraph, please update …

Telemetry Forwarder
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Press F5 to also update the python file if you start the flowgraph directly via python3 ...py.