Make It Tea - public:radio:topics:aprs

APRS

anonymous@undisclosed.example.com (Anonymous) — Thu, 04 Jun 2026 06:39:56 +0000

←APRS

APRS

VHF and HF APRS

VHF

FT8900 : 2m I-Gate GM4SLV-2 - Raspberry Pi, TNC-Pi and APRX I-Gate software
- UPDATE 6/4/24 : 2m APRS suspended. Coverage not adequate from low 2m antenna.
TM-D710 in van : GM4SLV-9 - will digipeat “WIDEn-N”
TH-D72 : GM4SLV-8
Anytone 878
- analogue : GM4SLV-7,
- DMR
  - Brandmeister → PC 234999 (Self-Care set to GM4SLV-7)
  - DMR+/Phoenix → PC 5057 → GM4SLV-7

HF

Occasional use of 30m AFSK 10,147.6kHz USB as GM4SLV-10
- IC-706 and Signalink-USB soundcard

Software

Direwolf
- HF (300 baud FSK) or VHF soundcard modem/TNC
- AGW Packet Engine TCP/IP interface to other software
- standalone iGate and Digipeater
Xastir
- Can use the Direwolf TCP/IP AGW TNC across network
WinRPR winrpr_075_2.zip
- Can act as TCP/IP KISS mode TNC providing 300 or 600 baud Robust Packet TX/RX and also simultaneous 300 baud FSK RX
APRSISCE32 aprsis32.zip
- Can use WinRPR's KISS mode TNC
UIView32 32full203.exe
- Needs to be registered first at https://www.apritch.co.uk/uiv32.htm
  - ••••••••••
- Can use Direwolf's AGW TNC across network

HF Frequencies

30m

300 Baud FSK RF centre 10149.3kHz
- 1700 Hz audio (1600/1800Hz tones)
- Dial = 10147.6kHz USB
  - alternative dial = 10151.0kHz LSB (signal can be inverted without issues)
300 baud RPR RF centre 10148.8kHz
- 1500 Hz audio
- Dial = 10147.3kHz USB
  - Normal 300 baud AFSK resolves at 2000Hz - and is decoded by WinRPR at this offset

Direwolf update : 10/04/24

Direwolf v1.6 in Debian has a minor annoyance - it decodes its own transmitted frames occasionally due to cross talk in the sound card
This is reported to be fixed in 1.7 release so I cloned the git repository and built the current 1.7 version
It has removed the annoyance of seeing (and reporting to APRS-IS) your own transmitted packets
There are other changes and improvements which I will investigate over time.
Steps to clone/build

sudo apt-get install libavahi-client-dev
git clone https://www.github.com/wb2osz/direwolf
cd direwolf
 
mkdir build && cd build
cmake ..
make -j4

Running the new version

cd src
./direwolf -c ~/direwolf.conf

A few red warnings due to changes for v1.7 not being fully compatible with the previous config options, but it runs and doesn't seem to decode its own transmissions any more.

A few tweaks to the config:

ADEVICE  plughw:2,0
 
CHANNEL 0
 
MYCALL GM4SLV-10
 
#MODEM 300 7@30
 
MODEM 300 B+
 
#FIX_BITS 1
 
TXDELAY 50
 
LOGDIR .
 
AGWPORT 8000
KISSPORT 8001
 
PBEACON sendto=0 via="WIDE1-1" delay=0:00 every=10:00 symbol="\-" lat=60^17.31N long=1^25.51W comment="30m HF Direwolf AFSK"
 
#FILTER 0 0 ( ! d/* )
#FILTER 0 0 (! b/GM4SLV-10 )
 
#IGSERVER euro.aprs2.net
 
#IGLOGIN GM4SLV-10 19626
 
#PBEACON sendto=IG delay=0:30 every=60:00 symbol="\-" lat=60^17.31N long=1^25.51W comment="30m AFSK RX Igate"
 
 
DIGIPEAT 0 0 ^WIDE[3-7]-[1-7]$|^TEST$ ^WIDE[12]-[12]$ PREEMPT
 
#IGTXLIMIT 6 10

I will remove the Debian version 1.6 and sudo make install the newly compiled v1.7 once I'm happy with it.
This version also decodes FX25 packets - which I don't fully understand yet

SP6PGH-10 audio level = 53   FX.25   75_______
[0.1] SP6PGH-10>APWW11,WIDE1-1:>100639zTest HF APRS station
Status Report, APRSISCE win32 version
Test HF APRS station
[0H] SP6PGH-10>APWW11,GM4SLV-10*:>100639zTest HF APRS station

a normal AX25 packet

IW4EGP-10 audio level = 46    _|||_____
[0.2] IW4EGP-10>APU25N,WIDE2-2:=4403.57N/01233.72E&APRS HF 30m -/D R-I  H24 {UIV32}<0x0d>
Position, HF Gateway  <= the original primary table definition, UIview 32 bit apps
N 44 03.5700, E 012 33.7200
APRS HF 30m -/D R-I  H24 {UIV32}
[0H] IW4EGP-10>APU25N,GM4SLV-10*,WIDE2-1:=4403.57N/01233.72E&APRS HF 30m -/D R-I  H24 {UIV32}<0x0d>

both of these are also digipeated my me, shown on the last line is my outgoing digipeated packet:
- [0H] SP6PGH-10>APWW11,GM4SLV-10*:>100639zTest HF APRS station
- [0H] IW4EGP-10>APU25N,GM4SLV-10*,WIDE2-1:=4403.57N/01233.72E&APRS HF 30m -/D R-I H24 {UIV32}<0x0d>

— John Pumford-Green 21/03/24 16:14

Last Update : 04/06/26 07:39 BST

Further Information

Direwolf v1.7 User Manual	user-guide_1_.pdf
aprs.fi	https://aprs.fi/info/a/GM4SLV-10

radio, aprs

HF APRS Base Station

anonymous@undisclosed.example.com (Anonymous) — Thu, 04 Jun 2026 06:39:56 +0000

←APRS

HF APRS Base Station

Direwolf TNC iGate on 30m

Using Direwolf on HF

30m APRS frequency = 10.1476MHz USB / 10.151MHz LSB (using 1.7kHz modem frequency)
RF centre frequency = 10.1493MHz, tones ±100Hz
Direwolf acts as
- TNC/Modem to send and receive packets via HF transceiver
- Internet I-Gate
- Tracker, when configured to use gpsd to provide real time GPS position
- Network (AGWPE) TNC for other APRS client software

Direwolf config

~/direwolf.conf

#############################################################
#                                                           #
#               FIRST AUDIO DEVICE PROPERTIES               #
#               (Channel 0 + 1 if in stereo)                #
#                                                           #
#############################################################
 
ADEVICE  plughw:1,0
 
ACHANNELS 1
 
#############################################################
#                                                           #
#               CHANNEL 0 PROPERTIES                        #
#                                                           #
#############################################################
 
CHANNEL 0
 
MYCALL GM4SLV-10
 
MODEM 300 1600:1800 7@30 /4
 
TXDELAY 30
 
TXTAIL 10
 
#############################################################
#                                                           #
#               VIRTUAL TNC SERVER PROPERTIES               #
#                                                           #
#############################################################
 
AGWPORT 8000
KISSPORT 8001
 
FIX_BITS 1
 
#############################################################
#                                                           #
#               BEACONING PROPERTIES                        #
#                                                           #
#############################################################
 
PBEACON  every=15  symbol="\-" lat=60^17.31N long=001^25.49W comment="30m HF" via=WIDE1-1
 
#############################################################
#                                                           #
#               DIGIPEATER PROPERTIES                       #
#                                                           #
#############################################################
 
#DIGIPEAT 0 0 ^WIDE[3-7]-[1-7]$|^TEST$ ^WIDE[12]-[12]$ TRACE
 
#############################################################
#                                                           #
#               INTERNET GATEWAY                            #
#                                                           #
#############################################################
 
IGSERVER euro.aprs2.net
 
IGLOGIN GM4SLV-10 19626
 
PBEACON  sendto=IG every=60  symbol="\-" lat=60^17.31N long=001^25.49W comment="30m HF"
 
#IGTXVIA 0 WIDE1-1
 
IGTXLIMIT 6 10

Direwolf running (in a Tmux session)

Xastir using Direwolf as TNC

Direwolf can act as a network TNC for other clients
- Uses “AGWPE” protocol

Set Xastir on another PC to use Direwolf as TNC. This gives user access to APRS - map, messaging etc.

APRS.FI

GM4SLV-10 info at APRS.FI

List of stations who heard me, and stations I heard, after running overnight.

Further Information

radio, aprs

— John Pumford-Green 26/04/23 06:30

Mini Igate

anonymous@undisclosed.example.com (Anonymous) — Thu, 04 Jun 2026 21:04:19 +0000

←APRS

Mini Igate

A small portable fill-in iGate

Deployed to improve APRS coverage in Lerwick.

Hardware

Raspberry Pi
- Raspberry Pi 3 Model B Rev 1.2g
CM108 Sound card, modified for GPIO in/out
IC-2E
TP-Link MiFi router

Software

direwolf
autossh
tmux

Config & scripts

direwolf.conf

ADEVICE  plughw:1,0
 
#GPSD
 
 
CHANNEL 0
 
MYCALL GM4SLV-11
 
MODEM 1200
 
FIX_BITS 1
 
PTT GPIO 25
 
AGWPORT 8000
KISSPORT 8001
 
#TBEACON EVERY=15 SYMBOL="igate" overlay="T" comment="Mini IGate
#TBEACON sendto=IG EVERY=30 SYMBOL="igate" overlay="T" comment="Mini IGate
 
IBEACON every=30 via=WIDE1-1
IBEACON sendto=IG every=60
 
PBEACON every=10 overlay=T symbol="igate" lat=60^09.33N long=001^08.76W comment="Mini IGate" via=WIDE1-1,WIDE2-1
 
DIGIPEAT 0 0 ^WIDE[3-7]-[1-7]$|^TEST$ ^WIDE[12]-[12]$ TRACE
 
FILTER IG 0 r/60.2/-1.4/150 | ( ! t/t )
 
IGSERVER euro.aprs2.net
 
IGLOGIN GM4SLV-11 19626
 
IGFILTER m/150
 
PBEACON sendto=IG every=15:00 symbol="igate" overlay=T lat=60^09.33N long=001^08.76W comment="Mini IGate"
 
IGTXVIA 0 WIDE1-1,WIDE2-1
 
IGMSP 10
IGTXLIMIT 12 20

start_direwolf.sh

#!/bin/bash
 
session="Igate"
 
tmux start-server
 
tmux new-session -d -s $session
 
tmux rename-window "direwolf"
 
tmux selectp -t 0
tmux send-keys "direwolf -t 1 -T "%c" -c /home/gm4slv/direwolf.conf" C-m

crontab entry @reboot sleep 60 && sudo -u gm4slv /home/gm4slv/start_direwolf.sh >/dev/null 2>&1

autossh tunnel

see svxlink hotspot for details

#!/bin/bash
 
autossh -M 20000 -N -T gm4slv_tunnel

ssh config

Host gm4slv_tunnel
        HostName gm4slv.plus.com
        User xxxxx
        Port xxxxx
        RemoteForward 4446 localhost:22
        RemoteForward 8080 192.168.0.1:80

crontab entry : @reboot sleep 60 && sudo -u gm4slv /home/gm4slv/tunnel.sh 2>&1

Page created Thu May 26 12:41:10 2022 by John Pumford-Green

Page last updated: 04/06/26 22:04 BST

aprs, pi, radio

HF APRS Mobile/Portable

anonymous@undisclosed.example.com (Anonymous) — Thu, 04 Jun 2026 06:54:52 +0000

←APRS

HF APRS Mobile/Portable

Initial Thoughts

My plan is to use either of

TinyTrak3 + serial GPS as a one-way tracker
Netbook with direwolf and a USB GPS
1. a tracker
2. xastir for maps etc

Either of these will interface with a Xiegu G90 and some form of mobile whip.

I may use 30m hoping to get packets directly to other iGates in Europe or use 10m and run an iGate on 10m at home. It's all on the drawing board at the moment. It will be interesting to compare local coverage between 30m and 10m as well as seeing how well 30m mobile with a short whip can perform.

Tiny Trak 3

Uses serial GPS to provide position data
Only transmits, no receive/decode
Can transmit VHF (1200bd) or HF (300bd) APRS

HF APRS configuration settings

Date	Config.
April 2023	xxxx

Firmware/Docs

Firmware	tinytrak3_v1.42.zip
User Guide	tinytrak3plus_v1.03.pdf
Configuration Utility	tinytrak3_config_v1.4.6.zip

Test and Setup

First Reception

From aprs.fi - packets being received in Germany at DK4XI

https://aprs.fi/?c=raw&call=GM4SLV-11

2023-04-29 07:47:49 BST: GM4SLV-11>APT311,qAR,DK4XI-30:>John on HF
2023-04-29 07:47:52 BST: GM4SLV-11>V0QWRY,qAR,DK4XI-30:`w5Nl  j/"3x}
2023-04-29 07:52:50 BST: GM4SLV-11>V0QWSP,qAR,DK4XI-30:`w5Nl ^j/"4+}

Mobile Journey #1 on 30m

02/05/23:

using 10m “stinger” mobile whip and G90's internal ATU / 20W
not very encouraging local coverage between mobile and home QTH
large gap in coverage - journey actually went to Lerwick and back….
next experiment will be to use 10m - hopefully antenna is more efficient on that band

03/05/12

found that the antenna used yesterday was tuned to 31MHz… short whip
swapped for 2nd whip and this is tuned to 28.2MHz…. longer whip. More efficient?

— John Pumford-Green 26/04/23 15:02

Further Information

TinyTrak3 website : https://www.byonics.com/tinytrak3

radio, aprs

APRS

anonymous@undisclosed.example.com (Anonymous) — Thu, 04 Jun 2026 20:35:23 +0000

←Radio Topics

APRS

I've used APRS on both VHF and HF on and off for several years.

This is a small collection of information about various APRS related projects.

— John Pumford-Green 26/04/23 13:41