A simple HF APRS Digipeater howto

Last updated: 2019-08-23 10:50

This is a simple howto on how to use Direwolf to set up an APRS digipeater on HF.

Warning! When your digipeater is working correctly, it will transmit at "random" times.
So before you run Direwolf, be sure that your antenna has low SWR, your radio is tuned correctly, that no-one is near the antenna, and that you're operating within the terms of your licence (bands, power, etc).

Most of this howto would repeat the simple receive-only HF APRS IGate howto I wrote earlier, so I won't repeat it here.
Follow those instructions, and when you have that working, continue here.
The only differences are:
You will need to get hold of, or compile a copy of Direwolf with hamlib support (so that Direwolf can activate the PTT for you).
You don't need to bother with the iGate stuff (IGSERVER and IGLOGIN) if you only want to be a pure digipeater. However, if you have an internet connection as well, you might as well report what you hear too.
I use separate config files for Igate and digipeater operation. This allows me to switch quickly.

Configure PTT

You need to find out what the ID hamlib has for your rig. For my TS 590SG, it's 237. The hamlib wiki can help you.
You'll also need to know what the serial port is for your radio. For mine, it's /dev/ttyUSB0. dmesg can show you.
Add the following line (substituting the correct information)

PTT RIG 237 /dev/ttyUSB0

Enable digipeating

Add the following lines to enable Digipeating

DIGIPEAT 0 0 ^WIDE[3-7]-[1-7]$|^TEST$ ^WIDE[12]-[12]$ TRACE
IGTXLIMIT 6 10

This should be all you need to digipeat APRS traffic. At this point, you can run direwolf like this:
direwolf -t 0 -p -B 300 -c /path/to/direwolf-digipeat.conf
and you should be working.

Beaconing

If you want to send a periodic beacon, you need three more lines.
These three lines will send a beacon every 10 minutes.
The first one can travel two other digipeater hops.
The other two will not be digipeated. This is to minimise traffic.
Use your lat/lon (why is it not in simple decimal format?), power, antenna height and gain, and comment

PBEACON delay=1  every=30 overlay=S symbol="digi" lat=42^37.14N long=071^20.83W power=50 height=20 gain=4 comment="Chelmsford MA" via=WIDE1-1,WIDE2-1
PBEACON delay=11 every=30 overlay=S symbol="digi" lat=42^37.14N long=071^20.83W power=50 height=20 gain=4 comment="Chelmsford MA"
PBEACON delay=21 every=30 overlay=S symbol="digi" lat=42^37.14N long=071^20.83W power=50 height=20 gain=4 comment="Chelmsford MA"

Remember: the APRS frequencies are a shared resource, so don't send too much traffic. A collision of packets will probably mean both of them aren't decoded.
If you experiment further, take care not to (accidentally or deliberately) enable VHF/UHF -> HF rebroadcasting. The amount of VHF/UHF traffic, plus the fact that it uses AFSK 1200 as opposed to HF's AFSK 300 means that the amount of traffic will be large.