{{tag>[radio dra 818 dra818vhf]}}
~~NOTOC~~

=====DRA818 VHF Voice Transceiver Module=====
  * Plug and play module [[https://www.sv1afn.com/dra818.html]]
  * Datasheet: {{ ::dra818v-datasheet.pdf |}}
  * VHF Schematic: {{ ::dra818-vhf-schematic.pdf |}}

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//DRA818 VHF Voice Transceiver Module//

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//DRA818 VHF Module connected to Raspberry Pi//

====Serial config with Python====
  * Modify if needed: <code>
#!/usr/bin/python3

import serial

serport = '/dev/ttyAMA0'
baud = '9600'

channelspace = '0'      # 0=12.5kHz, 1=25kHz

rxfreq = '144.8000'     # TX frequency
txfreq = rxfreq         # Same as rx freq.

squelch = '1'           # 0-8 (0 = open)

txcxcss = '0000'        # CTCSS / CDCSS
rxcxcss = txcxcss       # CTCSS / CDCSS


ser = serial.Serial(serport, baud, timeout=2)
print('Opening port: ' + ser.name) 

print ('\r\nConnecting...')
ser.write(b'AT+DMOCONNECT\r\n')

output = ser.readline()
print ('reply: ' + output.decode("utf-8"))

print ('\r\nConfiguring radio...')
config = 'AT+DMOSETGROUP={},{},{},{},{},{}\r\n'.format(channelspace, txfreq, rxfreq, txcxcss, squelch, rxcxcss)
ser.write(config.encode())
output = ser.readline()
print ('reply: ' + output.decode("utf-8"))

print ('\r\nDisabling filters...')
ser.write(b'AT+SETFILTER=0,0,0\r\n')
output = ser.readline()
print ('reply: ' + output.decode("utf-8"))

print ('\r\nSetting volume...')
ser.write(b'AT+DMOSETVOLUME=1\r\n')
output = ser.readline()
print ('reply: ' + output.decode("utf-8"))
</code> 

====Configuration for DireWolf souncard modem====
Dire Wolf is a software "soundcard" modem/TNC and APRS encoder/decoder. Source code: [[https://github.com/wb2osz/direwolf]]

  * Create ''~/.asoundrc'':<code>
pcm.!default {
        type plug
        slave {
                pcm "hw:1,0"
        }
}

ctl.!default {
        type hw
        card 1
}
</code>
  * Mixer settings:<code>
# Set Microphone levels, mute loopback
amixer -c1 sset Mic playback 0% cap mute
amixer -c1 sset Mic capture 75% cap mute

# Set Headphone level
amixer -c1 sset Headphone playback 70% cap unmute

# Disable auto gain control
amixer -c1 sset 'Auto Gain Control' cap mute
</code>
  * direwolf.conf:<code>
MYCALL <callsign>
MODEM 1200 E+ /3
TXDELAY 20
PTT GPIO -4         #RPI GPIO 4
</code>

====WAV  / audio test====
Configure the radio with pre/de-emphasis and filters, see script above.

  * Text-to-speech example:<code>
# Set pin 4 as output
raspi-gpio set 4 op

# Transmit
raspi-gpio set 4 dl

echo "<callsign>" | cwwav -f 700 -w 20 -o morse.wav && aplay morse.wav

/home/pi/.local/bin/google_speech -l nl "Dit is <callsign>, met een testuitzending."

# Receive
raspi-gpio set 4 dh

</code>