M0LTE

RFC- DAPPS on-air protocol

DAPPS is "Distributed Asynchronous Packet Pub/Sub", a proposed overlay over amateur packet radio, with the intention of making it easier for application developers to leverage "the network" without having to solve many of the same problems again and again.

In a nutshell, DAPPS discards the concept of a "connected session" between two stations potentially separated by multiple unreliable hops, and instead facilitates "eventual delivery" message passing. The application interface at each end is MQTT, facilitated either by installation of a DAPPS instance alongside the existing packet node software, or perhaps in future by the node software itself.

(Its implementation can still make use of AX.25 connected sessions to pass messages between neighbour nodes, but there is no session

M0LTE

Create a file named user userconf (or userconf.txt) containing the following:
pi:$6$c70VpvPsVNCG0YR5$l5vWWLsLko9Kj65gcQ8qvMkuOoRkEagI90qi3F/Y7rm8eNYZHW8CY6BOIKwMH7a3YYzZYL90zf304cAHLFaZE0
Place userconf (or userconf.txt) plus an empty file named ssh (or ssh.txt) in the BOOT (FAT32) partition of the SD card.
Insert the SD card in the Raspberry Pi and it should boot with access to user 'pi' (password : raspberry) via SSH.

M0LTE

sudo su
echo "IPQoS 0x00" >> /etc/ssh/sshd_config
sudo systemctl restart sshd
echo "IPQoS 0x00" >> /etc/ssh/ssh_config

M0LTE

SIMPLE
NODECALL=MB7NAA
NODEALIAS=AANODE
LOCATOR=AA00aa
EnableM0LTEMap=1
PASSWORD=xxxxxxxx
AUTOSAVE=1
NODESINTERVAL=10
MINQUAL=10
CTEXT:

M0LTE

SIMPLE
NODECALL=MB7NGP
NODEALIAS=GILWEL
LOCATOR=JO01ap
PASSWORD=xxxxxxxx
AUTOSAVE=1
NODESINTERVAL=10
MINQUAL=10
IDINTERVAL=15
IDMSG:

M0LTE

KISS is a super simple framing technique for packet radio TNCs.

Simplistically, a KISS TNC can be commanded to send an AX.25 frame out of its first (or only) port by prefixing it with 0xC0 0x00. See http://www.symek.com/g/smack.html

As well as KISS over serial, BPQ can do KISS over TCP or UDP. I assume the Linux kernel can too.

FreeDV (codec2) has a data transmission API. Codec2 ships with a pair of minimalistic demo programs for transmitting and receiving arbitrary data through FreeDV via stdin/out. The transmit program takes data on stdin and outputs audio bytes to stdout. The receive program takes audio bytes on stdin and outputs the original data on stdout.

Source of the two programs:

M0LTE

SIMPLE                  ; sets a lot of defaults
NODECALL=GB7RDG         ; Node callsign
NODEALIAS=THURST        ; Node alias (6 characters max)
LOCATOR=IO91lk          ; Maidenhead locator
MAPCOMMENT=40m, 6m, 2m, 70cm

PASSWORD=xxxxxxxx
AUTOSAVE=1
EnableEvents=1
EnableM0LTEMap=1

M0LTE

#(as non-root, on a Pi 2B, Raspbian 11)
mkdir linbpq
cd linbpq
wget https://www.cantab.net/users/john.wiseman/Downloads/pilinbpq
mv pilinbpq linbpq
chmod +x linbpq
sudo setcap "CAP_NET_ADMIN=ep CAP_NET_RAW=ep CAP_NET_BIND_SERVICE=ep" linbpq
mkdir HTML
cd HTML
wget http://www.cantab.net/users/john.wiseman/Downloads/HTMLPages.zip

M0LTE

using System;
using System.Linq;
using System.Net;

/// <summary>
/// A .NET type which parses the format of UDP datagrams emitted from WSJT-X on UDP port 2237,
/// for the Decode message type (the type emitted when WSJT-X decodes an FT8 frame)
/// </summary>
public class DecodeMessage
{

M0LTE

4.2V
3.7V
3.0V

5s = 21.0V -> 18.5V -> 15V
4s = 16.8V -> 14.8V -> 12V
3s = 12.6V -> 11.1V -> 9V

13.8V + 10% = 15.18V
13.8V - 10% = 12.42V