APRS: APRX Setup iGate dan Digipeater di Linux
As a long time Amateur Radio Operator (callsign: KB8MON), I recently explored more into APRS, the Automatic Packet Reporting System. This interest was driven by another interest in High Altitude Balloons (HAB), and how they might be tracked. I live in downtown Detroit, and found that there is a vacuum here of what are called “APRS digipeaters” and “APRS igates” in the area. APRS Digipeaters are stations that repeat the location beacons of other more mobile APRS stations (or balloons in my case), and igates, that serve a similar purpose toward relaying this digital APRS location information to the Internet via aprs2.net.
To get this going, you need:
An Amateur Radio (Ham) License 2 Meter Radio TNC Modem Computer (i.e. Internet Gateway)
Here is what I came up with:
An Amateur Radio (Ham) License
I happened to already have this, but to get a new ham license, you will need to study up on the FCC requirements for getting one, but the test is not very hard. Then you need to find a testing location in your area http://www.arrl.org/find-an-amateur-radio-license-exam-session
2 Meter Radio
Pretty much any 2 meter ham radio will work for this. You just need to find one that has a microphone and speaker jack that will be used to transmit and receive the radio beacons, and set it to the 144.390 frequency, which is generally used in the US for APRS. I used an old-school Icom 32-AT transceiver.
TNC Modem
The TNC modem is a device that translates the audio from the radio into digital data. Pretty much the only current manufacturer of these are from a company called Byonics. I purchased their TinyTrak4 device that cost around $75 assembled, and it works great.
Computer
Although you can use any computer for this, you probably don’t want a giant desktop or laptop, as the CPU and memory required are rather small. So, I went with a Raspberry Pi computer that runs on an ARM chip, and only costs around $35. This computer runs an OS based on Debian called Raspian, and is connected to the TNC modem via a USB to Serial adapter, and to the Internet via a USB 802.11 WiFi adapter. I set it up to automatically connect to my home’s WiFi, as well as to automatically start a program in Linux called APRX.
Results
So, after it is all setup and running, you can watch as you relay and record on the internet the location and tracking information of other APRS people around you. The output looks like:
2012-10-21 21:16:56.243 KB8MON R VE3KCR>APN383,MTCLMN*,KB8MON-1*,WIDE2*:!4226.14NS08206.23W#PHG7640/W2,SONTn,Chatham - ve3cih@rac.ca 2012-10-21 21:17:28.337 KB8MON R KB8MON-1>KB8MON,WIDE1,WIDE2:/000000h4222.75N008305.76WI000/000Downtown Detroit iGate/Digi rob@wayne.edu/A=003281 2012-10-21 21:18:28.380 KB8MON R KB8MON-1>KB8MON,WIDE1,WIDE2:/000000h4222.75N008305.76WI000/000Downtown Detroit iGate/Digi rob@wayne.edu/A=003281 2012-10-21 21:18:47.029 APRSIS R BANCFT>APRX22,TCPIP*,qAC,W8FSM-JS:W8FSM 2012-10-21 21:19:28.424 KB8MON R KB8MON-1>KB8MON,WIDE1,WIDE2:/000000h4222.75N008305.76WI000/000Downtown Detroit iGate/Digi rob@wayne.edu/A=003281 2012-10-21 21:19:28.990 APRSIS R LANSNG>APRX21,TCPIP*,qAC,W8FSM-JS:!4245.28NS08431.53W#W2,MIn W8FSM Lansing Digi/IGATE 2012-10-21 21:20:18.134 KB8MON R VA3OT>CQ,VE3KCR*,MTCLMN*,WIDE2*:> " Maple City Weather " 2012-10-21 21:20:20.504 KB8MON R SHLBTP>APOT21,MTCLMN*,WIDE2*:!S8vEy9NF4# stPHG3170 W2,MIn Grid EN82lp WF5X 2012-10-21 21:20:27.560 APRSIS R JAMTWP>APRX23,TCPIP*,qAC,W8FSM-JS:W8FSM 2012-10-21 21:20:28.468 KB8MON R KB8MON-1>KB8MON,WIDE1,WIDE2:/000000h4222.75N008305.76WI000/000Downtown Detroit iGate/Digi rob@wayne.edu/A=003281 2012-10-21 21:20:35.070 KB8MON R VA3OT>CQ,VE3KCR*,MTCLMN*,WIDE2*:@212122z4224.00N/08210.00W_208/001g008t059r000p000P000h00b10166.DsVP
In case you are interested in what settings/configuration I used for the Bionics TinyTrak 4 Device, here they are:
BANK is 0 P300 is FALSE TXTDISP is FALSE NODISP is FALSE PPATHING is FALSE DMSDISP is FALSE MICETMV is FALSE ENTS is FALSE TELHIRES is FALSE TELVOLT is TRUE TELTEMP is TRUE PREEMPT is TRUE DIGIID is TRUE WXPOS is TRUE TELREAD is TRUE FRAWDISP is FALSE HRAWDISP is FALSE WYPTXT is FALSE PKTICOM is TRUE PKTOCOM is TRUE RPATHDISP is FALSE LEDS is TRUE PAVPEN is FALSE DEC96 is FALSE DDIST is FALSE HEADERLN is FALSE DMETRIC is FALSE SOFTRST is TRUE MSGCMD is TRUE MSGCAP is FALSE LRNTPS is FALSE GPSCHK is FALSE INTCLK is FALSE TOSV is FALSE TALT is TRUE TSPEED is TRUE TIMESTAMP is TRUE TIMEHMS is TRUE SBEN is FALSE TSWPT is TRUE AMODE is KISS BMODE is GPS ABAUD is 19200 BBAUD is 4800 BNKMODE is 0 SSIDROUTE is 0 ALTNET is KB8MON MYCALL is KB8MON-1 PATH1 is WIDE1 PATH2 is WIDE2 PATH3 is TSTAT is Downtown Detroit iGate/Digi rob@wayne.edu BTEXT is >Downtown Detroit iGate/Digi rob@wayne.edu BPERIOD is 900 TXD is 100 MTXD is 10 PERSIST is 0 SLOTTIME is 0 QUIET is 0 TRNKMODE is 0 CDMODE is TONES CDLEVEL is 20 TXLEVEL is 90 TXTWIST is 50 RXAMP is 13 GWAYLEN is 232 GWAYMODE is NMEA GRELAYBITS is 1 GRELAYRATE is 1 GKRELAY is 0 LOCATION is 4222.7500N 08305.7600W GALT is 1000 TSYMCODE is I TSYMTABLE is 0 STATUSRATE is 1 PPERIOD is 60 MPPERIOD is 0 SBSSPEED is 5 SBFSPEED is 60 SBSPERIOD is 1800 SBFPERIOD is 90 SBTANGLE is 27 SBTSLOPE is 255 SBTTIME is 5 MMSG is 2 TSOFFSET is 17 TDAO is 0 TPROTOCOL is APRS TPSWITCH is 0 TPERIOD is 0 TVOLTTWK is 128 TTEMPTWK is 128 WPERIOD is 0 ALIAS1 is WIDE1 ALIAS2 is WIDE2 ALIAS3 is WIDE3 DUPETIME is 30 FILTERCALL is
Also, if you are interested in the configuration file (/etc/aprx.conf) for APRX, here it is:
mycall KB8MON <aprsis> server noam.aprs2.net 14580 </aprsis> <logging> pidfile /var/run/aprx.pid rflog /var/log/aprx/aprx-rf.log aprxlog /var/log/aprx/aprx.log </logging> <interface> serial-device /dev/ttyUSB0 19200 8n1 KISS tx-ok true </interface> <digipeater>
transmitter $mycall
<source>
source APRSIS
relay-type third-party
via-path WIDE1-1
msg-path WIDE1-1
</source>
</digipeater>
Here is what the whole thing looks like closed in an Ikea box ;)