APRS

VHF and HF APRS

• 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

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

• 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

• 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 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 : 06/03/25 06:49 GMT