Re: Adding a second radio


Thanks for these ideas everyone.  I’m just in the middle of setting up my DRAWS Pi with two radios, one doing APRS and the other running LinBPQ for a BBS.  Very interested to hear about APRX and LinFBB, neither of which I had heard of before.

I would also be interested to hear in the reasoning behind the two different philosophies, advantages and disadvantages.  I’m currently doing it all through Direwolf as that’s the only way I know how, but have been dipping my toes in to the AX.25 stack as I’ve been playing with LinBPQ.

So much to learn and so much to read.  I appreciate all the work done and would also appreciate any other resources regarding these two different methods of doing packet radio with a Raspberry Pi.

VA7SHG - Phone
VE7TGZ - Other

On Oct 10, 2019, at 09:16, Basil Gunn <basil@...> wrote:

Hi J P,

Thank you for your reply. John Hays means well, but his reply did not
get me the traction that I expected.

John & I have 2 different philosophies regarding packet. He gave advice
on how to do everything in direwolf and I like to keep direwolf as a
sound modem only & use the AX.25 functionality of Linux.
John has done some great work on configuring virtual sound card interfaces so
that you can do 1200 baud & 9600 baud packet on the same radio.

And Yes I have a service monitor to set the deviation. It makes it alot easier :)


Another Topic will be the FBB that is installed as part of the BETA14
Build. Where is the FBB documentation? The FBB install script?

So this is a project I briefly got working but don't use day to day. I
think BBS are useful so that is on my list of things for permanent
infrastructure. The latest version (7.08-beta8 from SourceForge) is
built & installed on the image.

The documentation I have been using is here:

BTW we edited the URONODE config file and ran the install, an it appears to work.

Great to hear!

I think that direwolf.conf edits are all that are needed.

Depends on your philosophy.

How do we enable the APRS Gateway? I think it is just the list of attributes for “Channel 1"
Only on the second channel?

I use APRX for APRS embedded systems. ie. no monitor
See: 4.5 A Bi-Directional Cross-band Digipeater in this manual

You can just use Direwolf but I won't be able to help you with that. The
direwolf documentation is very good & if you go that route I recommend
you read the entire manual carefully.

Our Statewide only will permit digipeating, winlink, FBB messaging on the first Channel. (FBB install another challenge that we will make later.)
They only support 1200baud on the first channel. Our club will support 9600baud on the other channel.

ADEVICE plughw:CARD=udrc,DEV=0
ARATE 48000
MODEM 1200
MODEM 9600
PBEACON delay=1 every=10 overlay=S symbol="digi" lat=41^20.68734N long=88^28.39224W power=100 height=20 gain=6 comment="UDRC" via=WIDE1-1,WIDE2-1
DIGIPEAT 0 0 ^WIDE[3-7]-[1-7]$|^TEST$ ^WIDE[12]-[12]$ TRACE
PBEACON sendto=IG delay=0:30 every=60:00 symbol="igate" overlay=R lat=41^20.68734N long=88^28.39224W

One of the things that I don’t understand is how an instance running on a raspberry pi with two changes knows how to route traffic from Channel 0 (ie 1200 baud )
to Channel 1 ( 9600 baud ).

See: 4.5 A Bi-Directional Cross-band Digipeater in this manual

At our tower site, we have a pair of radios one on 145.610 and 147.555 and a Raspberry PI running a DRAWS with 2 channels.
Our State Packet Team insists on 145.610 running 1200baud, and only Digipeating, FBB Access and Winlink Client access.
For the tower site
KB9SZK-7 X.25
KB9SZK-10 Winlink RMS (Telnet access to WinLink CMS servers)
The Tower site has a Sprint internet connection to provide APRS Server access and Winlink Telnet access.

At our EOC we are running 147.555, a HF rig for ARDOP access to Winlink, and a raspberry PI

For the EOC site 9600baud on 147.555
KB9SZK-8 X.25
KB9SZK-11 Winlink RMS (Telnet access to WinLink CMS servers or ARDOP access via HF if needed)

Questions are:
How do we configure routing such that a station connecting on 145.610 at 1200baud, digipeats the packets on the 147.555 so that the the station can find the FBB server at the EOC.

Need more detailed explanation (maybe a diagram) of what you want to do. Just describe a
scenario. I believe Uronode will provide the functionality that you want.

How do we limit the Raspberry PI’s so that we don’t have APRS traffic on the 145.610 channel. ie the Tower Site Raspberry PI.

And then how do we configure the FBB that is in the build. Can we install FBB so messages are automatically copied from the EOC raspberry PI to the Tower Site Raspberry PI,

There are ways available to sync BBS's. I haven't done it but I know
it's possible.

Again Thanks!!!!
An Extra Thank you for your efforts. Most do not have any idea of how hard you have to work to keep up with the masses. :)

..jpw J P Watters
Morris, IL

On Oct 9, 2019, at 11:27 PM, Basil Gunn <basil@...> wrote:

I think you want a second ax.25 channel, which should already be

In a console run this:

ip a show

You should see ax0, your first ax.25 channel on the left connector & ax1
the second ax.25 channel on the right connector.
You need to set the baud rate you want (9600) in /etc/direwolf.conf
under "Channel 1 Properties". Change the MODEM 1200 line to MODEM 9600.

By default the left & right channels are always configured so it
shouldn't be too difficult to get the second channel going. The hard
part is that 9600 baud packet requires you to set deviation more
precisely than 1200 baud packet. Having access to a service monitor

Let me know how you make out.


J P Watters via Groups.Io <kc9kko@...> writes:

Our club has a DRAWS using a single radio that we have configured to
run as a digipeater and Winlink X.25 access using telnet to the CMS

The single radio is configured for 1200 baud X.25 Packet Digipeating
with access to a Winlink RMS. Our affiliation with the statewide
packet network limits that channel to 1200 baud digipeating and
Winlink X.25 access. They also exclude APRS data on that channel. We
can specify in the Winlink client a VIA to connect to another site
with HF access to Winlink.

We would like to add a second radio on the second DRAWS interface to
support 9600 baud, APRS Data and possibly a FBB instance.

Is there information on adding a second interface?

..jpw J P Watters
Morris, IL

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