VHF APRS iGate

UPDATE June 29 2023

I've decided to stop all 2m (and 70cm) activity (which amounts only to APRS, really) as I seem to be simply creating traffic for myself, no-one else locally uses APRS, apart from GM7AFE who runs the other iGate locally, and then only rarely. It seems futile to keep a system operational when all it's used for is for the owner to use it occasionally to check it's operational.

From now on I'm HF ONLY on CW and Digimodes.

Hardware

Platform	Raspberry Pi
software	dixprs
Radio Hardware	TM-D710
Frequency	144.800MHz
Callsign	GM4SLV-2

Software

iGate Software : aprx or Dixprs

Using Linux AX25 network device

/etc/ax25/axports

# /etc/ax25/axports
#
# The format of this file is:
#
# name callsign speed paclen window description
#
1 GM4SLV-2 19200 236 2 VHF APRS (1200 bps)

Everything starts by a script, with options commented out as necessary to start whichever software is required. I'm currently (— John Pumford-Green 24/04/23 15:34) using Dixprs instead of aprx

Dixprs seems to be moribund, the google site where help and information was available is gone but Dixprs works well and has handy features - such as responding to ?APRSxxx queries.

ax_start.sh

#!/bin/bash
 
logger "AX-Start"
logger "kissattach..."
sudo /usr/sbin/kissattach /dev/ttyAMA0 1 10.0.0.1
#kissparms -p 1 -f n -l 50 -r 32 -s 320 -t 400
logger "kissattach ok"
logger "ifconfig"
sudo /sbin/ifconfig ax0 10.0.0.1 netmask 255.255.255.0
sudo /sbin/ifconfig ax0 hw ax25 GM4SLV up
logger "ifconfig ok"
logger "mheardd"
sudo /usr/sbin/mheardd
logger "mheard ok"
logger "ax25d"
sudo /usr/sbin/ax25d
logger "ax25d ok"
 
#logger "aprx"
#sudo /sbin/aprx
#logger "aprx ok"
 
screen -c /etc/screenrc -dmS dixprs /usr/local/dixprs/dixprs.py -c /usr/local/dixprs/config.txt
 
#sleep 10
#screen -S dixprs -x -X screen bash -c 'python /home/gm4slv/selcall.py; exec bash'

Aprx Config file :

#############################################################
#
#
 
mycall  GM4SLV-2
 
myloc lat 6017.31N lon 00125.51W
 
<aprsis>
#passcode 21424
passcode 19626
 
server   euro.aprs2.net
 
#server 192.168.21.101 2023
#filter "b/GM4WMM*"
#filter "b/G0RAS*"
#filter "b/G8YPK*"
#filter "t/*"
#filter "-t/t"
#filter "-b/KE8TCB-*"
#filter "-b/ASHIE*"
#filter "r/60.2885/-1.4252/80"
#filter "b/GM4SLV-13"
#filter "b/OM6ZB-7"
#filter "b/KD7LMN"
#filter "-b/GW4AMZ*"
#filter "b/GM4SLV*"
 
filter "m/150"
 
</aprsis>
 
<logging>
pidfile /var/run/aprx.pid
rflog /var/log/aprx/aprx-rf.log
aprxlog /var/log/aprx/aprx.log
</logging>
 
<interface>
ax25-device $mycall
tx-ok true 
</interface>
 
#<interface>
#serial-device /dev/ttyAMA0 19200 8n1 KISS
#tx-ok true
#</interface>
 
<beacon>
beaconmode radio
cycle-size  30m
#beacon dstcall BEACON interface $mycall via WIDE1-1 exec /usr/bin/uptime
beacon interface $mycall via WIDE1-1  symbol "/-" $myloc comment "APRX - R.Pi/TNC-Pi"
#beacon interface $mycall via WIDE1-1  symbol "/-" $myloc comment "VHF 144.800MHz"
#beacon interface $mycall via WIDE1-1 raw ">VHF 144.8MHz"
</beacon>
 
 
#<beacon>
#beaconmode radio
#cycle-size 60m
#beacon via WIDE1-1 object "GB3LU" symbol "/r" lat "6008.57N" lon "00112.29W" comment "145.675MHz T077 -060 Shetland Isles"
#beacon via WIDE1-1 object "GB3LER" symbol "/r" lat "6008.57N" lon "00112.29W" comment "50.064MHz *** Faulty *** OFF AIR *** Shetland Isles"
#</beacon>
 
<beacon>
beaconmode aprsis
cycle-size  60m
beacon dstcall BEACON exec /usr/bin/uptime
beacon  symbol "/-" $myloc comment "APRX - R.Pi/TNC-Pi"
#beacon raw ">VHF 144.8MHz"
#beacon  object "GB3LU" symbol "/r" lat "6008.57N" lon "00112.29W" comment "145.675MHz T077 -060 Shetland Isles"
#beacon  object "GB3LER" symbol "/r" lat "6008.57N" lon "00112.29W" comment "50.064MHz ***OFF AIR*** Shetland Isles"
</beacon>
 
<digipeater>
    transmitter     $mycall
    <source>
        source         $mycall
	filter "-t/t"
	filter "t/*"
    </source>
 
<source>
   source        APRSIS
   relay-type    third-party
   viscous-delay  5
#   ratelimit      10 20
   via-path  WIDE2-2
   msg-path  WIDE2-2
 
   filter "-t/t"
   filter "t/*"
   regex-filter data ISBeacon
#   filter "b/GM4SLV-13"
#   filter "b/OM6ZB-7"
#   filter "b/GM4WMM*"  
 
</source>
</digipeater>

Dixprs Config File

[GENERAL]

# Mandatory parameters

# Your callsign with SSID
CALLSIGN=GM4SLV-2

# Degrees; West is negative, East is positive
LONGITUDE=-1.4251

# Degrees; South is negative, North is posittive
LATITUDE=60.2885

# Optional parameters

# Station height abvove the see level in meters; no default
#ASL=<fv>

# Owner name and contact; no default
OWNER=John GM4SLV

# Spool directory to import packets; no default
SPOOL=/home/gm4slv/spool

# Station symbol; default is S#
SYMBOL=/-

# UDP port base number; default is 31110
#UDPBASE=<n>

# Beacon frequency in minutes; default is 30
#BCNTIME=<n>

# Beacon text; %v replaced with actual version string; default is %v
# Used as default for ISGW and RADIO
BCNTXT= %v

# Select km/mi on monitor and in DX list; default is y (km)
METRIC=n

# Max number of digis passed for local stations
# Used as message gating condition for gating to Rf
# Default value is 2
#LOCALHOPS=<n>

# Range in km within messages gated to Rf
# If defined, checked after hop count (local) check
# No default
#MSGRANGE=<fv>
#################################################################
#                                                               #
# IS gateway settings; remove this section to disable GW        #
#                                                               #
#################################################################

[ISGW]

# Mandatory parameters

# Domain name of IS server to connect
host=rotate.aprs2.net
#host = 192.168.21.101
# Optional parameters

# Port number; default is 14580
#PORT=2023

# Filter; default is r/@/150
# @ is replaced with station position
FILTER=m/200

#################################################################
#                                                               #
# WRB server settings; remove this section to disable it        #
#                                                               #
#################################################################

[WEBSERVER]

# Mandatory parameters

# WEB server port, no default
port=9999

#################################################################                                                               #
#                                                               #
# Radio port configuration settings; repeat section for         #
# multiple ports                                                #
#                                                               #
#################################################################

[RADIO]

# Mandatory parameters

# Interface type
INTERFACE=AX25

# Device; as listed by ifconfig; it is nbot the ax.25 port name!
DEVICE=ax0
# Optional parameters

# Modem speed, default is 1200
#SIGNALRATE=1200

# Enable/disable NWS WX bulletin and object gating from IS to Rf
# Disabled by default
#GATENWS=<y/n>

# Enable/disable BOM WX bulletin and object gating from IS to Rf
# Disabled by default
#GATEBOM=<y/n>

# Descripton of port; no default
DESCRIPTION=144.800MHz VHF 1200bd

# Via used to send locally generated packets; default is WIDE1-1,WIDE2-2
AXVIA=WIDE2-2

# Digipeaters processed with WIDEn-n algorithm; default is WIDE1,WIDE2
WIDEN=WIDE1,WIDE2

# Blacklisted stations; they are not digipeated, not gated; default is NOCALL,N0CALL
#BLACKLIST=<lst>

# PHG string, do not mix with range; no default
#PHG=4137/

# Range value in miles, do not mix with PHG; no default
#RNG=<n>

# Enable/disable transmission; change it to PTTON=1 to enable trasmission; default is no
PTTON=1

# Gate locally generated frames to IS gateway; default is no
# Useful for rx-only radio ports
# Experimental, use carefully
#GATELOCAL=<y/n>

# Gate digipeated frames to IS gateway; default is no
# Experimental, use carefully
#GATEDIGI=<y/n>

# Beacon text; %v replaced with actual version string; default is %v
#BCNTXT=<str>

# Enable/disable digipeater; default is enabled
#DIGIPEATER=<y/n>

# Modem/TNC setup parameters 0...255; no defaults
# Use to setup modem/TNC by DIXPRS
#TXD=<n>

#PPERSIST=<n>

#SLOTTIME=<n>

#TXTAIL=<n>

#DUPLEX=<n>

# Below these are the traffic shaping settings for gating messages
# From IS to Rf
#
# For advanced users only; do not change if you do not know how
# traffic shaping works and if you do not have good reason !!!

# Traffic shaping high treshold, default is 0.75
#TRAFFICHIGH=<fv>

# Traffic shaping low treshold, default is 0.5
#TRAFFIClow=<fv>

# Traffic shaping transmission delay, default is 5.0 sec
#TRAFFICDELAY=<fv>

# Comma separated list of addresses to send receveid/transmitted frames
# in hostip:port format. No default.
UDPCC=192.168.21.107:5050

Hardware

I use a TNC-Pi attached via the GPIO serial port connections. Something had to be done to stop the serial port having a Linux Console attached, in the boot configuration, but it's been many years and I can't remember the details.

John's Vademecum

Table of Contents

VHF APRS iGate

UPDATE June 29 2023

Hardware

Software

Hardware

See Also