Svxlink Update (Dual Gateway)

— John Pumford-Green 02/06/22 19:56

To allow testing and comparison between 2m and 70cm I've got two SVXLink gateways running.

MB7AZE : 70cm : 430.050MHz @ 3W using FT-60
GM4SLV : 2m : 144.625MHz @ ??W using FT-8900

Both feed the same dual band colinear via a duplexer.

Both are connected to G4NAB's SVXReflector http://svxportal-uk.ddns.net:81/index.php

(UPDATE — John Pumford-Green 03/06/22 09:05)

I now realize that the DTMF problems were due to setting de-emphasis ON while actually using the audio feed from the FT-8900 for 1200 packet, which already has de-emphasis applied. So I was doing double-de-emphasis.

No wonder the tones were being mangled.

The ~~deleted~~ section below shows what steps I took to restore the tone detection in this situation, but this isn't actually necessary if the correct audio feed is used. The quick-fix is to turn SVXLink's de-emphasis OFF and restore the DTMF twist to its normal value. The better fix will be to re-wire the interface to use the flat 9600 baud audio and restore SVXLink's de-emphasis.

Set up audio levels MB7AZE SvxLink Config

Some tweaks were necessary to get GM4SLV to work - DTMF detection was flaky on certain digits when RX de-emphasis was enabled - which is necessary when using the 9600 packet flat-audio feed from the FT-8900. The issue seems to be the roll-off of the de-emphasis affecting the DTMF digits that use the widest spaced tone-pairs. There's are configuration items that can fix the problem: DTMF_MAX_FWD_TWIST and DTMF_MAX_REV_TWIST in the [Local Receiver] section. I had to set DTMF_MAX_FWD_TWIST to 15 to fix the problem.

The GM4SLV gateway now uses the FT-8900 via an unmodified CM108 sound dongle.

The PTT is from GPIO25 and SQL is from CTCSS.

I've swapped the Echolink service from MB7AZE-L to GM4SLV-L.

For the next period of testing MB7AZE will be lower profile, and the FT-60 handheld can not handle long periods of transmitting (e.g. when set on HUBNET or similar).

The start-up script that also sets up GPIO (for PTT):

#!/bin/bash
 
CFG=/usr/local/etc/svxlink/svxlink.conf
LOG=/home/gm4slv/svxlink.log
 
sudo killall svxlink
sudo killall svxlink
sudo killall svxlink
 
echo "25" > /sys/class/gpio/export
 
sleep 2
 
echo "out" > /sys/class/gpio/gpio25/direction
 
sudo svxlink --daemon --logfile=$LOG --config=$CFG
exit 0

crontab to start it at reboot

@reboot sleep 30 && sudo -u gm4slv /home/gm4slv/svx_ref.sh >/dev/null 2>&1

Here is the current ''svxlink.conf'' for GM4SLV :

 
 
[GLOBAL]
LOGICS=SimplexLogic,ReflectorLogic
CFG_DIR=svxlink.d
TIMESTAMP_FORMAT="%c"
CARD_SAMPLE_RATE=48000
LOCATION_INFO=LocationInfo
LINKS=LinkToReflector
 
[SimplexLogic]
TYPE=Simplex
RX=Rx1
TX=Tx1
MODULES=ModuleHelp,ModuleParrot,ModuleEchoLink	
CALLSIGN=GM4SLV
SHORT_IDENT_INTERVAL=0
SHORT_CW_ID_ENABLE=0
SHORT_VOICE_ID_ENABLE=0
CW_AMP=-20
CW_PITCH=1000
CW_WPM=20
LONG_IDENT_INTERVAL=0
LONG_VOICE_ID_ENABLE=0
LONG_CW_ID_ENABLE=0
EVENT_HANDLER=/usr/local/share/svxlink/events.tcl
DEFAULT_LANG=en_GB
RGR_SOUND_DELAY=0
TX_CTCSS=ALWAYS
MACROS=Macros
FX_GAIN_NORMAL=0
FX_GAIN_LOW=-12
ONLINE_CMD=998877
TIME_FORMAT=24
RGR_SOUND_ALWAYS=1
 
[RepeaterLogic]
 
[ReflectorLogic]
TYPE=Reflector
HOSTS=svxportal-uk.ddns.net
HOST_PORT=5300
CALLSIGN="change this"
AUTH_KEY="change this too"
JITTER_BUFFER_DELAY=0
DEFAULT_LANG=en_GB
DEFAULT_TG=0
MONITOR_TGS=8,91,235,2350,2351,23561
TG_SELECT_TIMEOUT=60
ANNOUNCE_REMOTE_MIN_INTERVAL=300
MUTE_FIRST_TX_LOC=0
MUTE_FIRST_TX_REM=0
TMP_MONITOR_TIMEOUT=3600
EVENT_HANDLER=/usr/local/share/svxlink/events.tcl
NODE_INFO_FILE=/usr/local/etc/svxlink/node_info.json
 
[LinkToReflector]
CONNECT_LOGICS=SimplexLogic:9:,ReflectorLogic
DEFAULT_ACTIVE=1
OPTIONS=DEFAULT_CONNECT,NO_DISCONNECT
 
[QsoRecorder]
REC_DIR=/var/spool/svxlink/qso_recorder
MAX_TIME=3600
SOFT_TIME=300
MAX_DIRSIZE=1024
 
[Voter]
 
[MultiTx]
 
[NetRx]
 
[NetTx]
 
[Rx1]
TYPE=Local
AUDIO_DEV=alsa:plughw:1,0
AUDIO_CHANNEL=0
SQL_DET=CTCSS
SQL_START_DELAY=0
SQL_DELAY=0
SQL_HANGTIME=200
VOX_FILTER_DEPTH=20
VOX_THRESH=1000
CTCSS_FQ=77.0
HID_DEVICE=/dev/hidraw0
HID_SQL_PIN=!VOL_DN
SIGLEV_SLOPE=1
SIGLEV_OFFSET=0
SIGLEV_OPEN_THRESH=30
SIGLEV_CLOSE_THRESH=10
DEEMPHASIS=0
PREAMP=0.0
DTMF_DEC_TYPE=INTERNAL
DTMF_MUTING=1
DTMF_HANGTIME=40
DTMF_SERIAL=/dev/ttyS0
#DTMF_MAX_FWD_TWIST=8
#DTMF_MAX_REV_TWIST=4
 
[WbRx1]
 
[Tx1]
TYPE=Local
AUDIO_DEV=alsa:plughw:1,0
AUDIO_CHANNEL=0
PTT_TYPE=GPIO
PTT_PIN=gpio25
HID_DEVICE=/dev/hidraw0
HID_PTT_PIN=GPIO3
PTT_HANGTIME=500
TIMEOUT=300
TX_DELAY=500
CTCSS_FQ=77.0
CTCSS_LEVEL=20
PREEMPHASIS=1
DTMF_TONE_LENGTH=100
DTMF_TONE_SPACING=50
DTMF_DIGIT_PWR=-15
MASTER_GAIN=0
 
[LocationInfo]
APRS_SERVER_LIST=euro.aprs2.net:14580
STATUS_SERVER_LIST=aprs.echolink.org:5199
LON_POSITION=1.25.30W
LAT_POSITION=60.17.18N
CALLSIGN=EL-GM4SLV
FREQUENCY=144.625
TX_POWER=2
ANTENNA_GAIN=3
ANTENNA_HEIGHT=5m
ANTENNA_DIR=-1
BEACON_INTERVAL=60
TONE=77
COMMENT=Connected to UK Svx Reflector
 
[Macros]
1=EchoLink:9999#
2=EchoLink:973498#
3=EchoLink:662666#
4=:91235#
5=:9123561#
9=:910#

overview of config

See MB7AZE SvxLink Config

Page Info

— John Pumford-Green 02/06/22 19:56

Page last updated: 06/03/25 06:49 GMT

echolink, svxlink, radio