Back To The Future With Packet Radio - Part 02

In part 1 of this 'back to the future' series, looking into packet radio using some retro equipment, we found a number of stations that had traffic flowing on 144.950MHz. We had set our TNC to monitor some of the packets that we could hear over the air by using some of the 'monitor' commands. Because of the way that we had set those, when we connect to another node, we would no longer see them... until we disconnect. This is really useful as it can be quite overwhelming to be trying to do something specific on a distant node and still see these messages.

Screenshot showing the results of traffic monitoring

For now, those settings have served their purpose, which was to find out who was on the network and therefore was potentially in range for us to connect to. With that decided, let's dive and see what we can find on packet radio in 2026...

To start with, let's try to connect to a repeater that does not have a mailbox (we'll save that for later). Looking down through the list of station callsigns from when we were monitoring, we can see MB7NSC. Connecting to a node is simple enough... we can use the CONNECT command, which can be shortened to just the letter C. Commands are not case-sensitive, by the way.

cmd: C MB7NSC

Now that we are on to the MB7NSC node (located in Bell Hill. Dorset), we have a range of options open to us. For now, let's assume that this node acts more like a gateway, rather than somewhere to stop and browse, so we want to find out where we can hop to next...

To do this, we can use the PORTS and ROUTES command to start building up a picture of our available network and we are also going to constrain ourselves to RF-only routes to begin with.

Just before we do that, something else has happened un-noticed perhaps..? When we typed in our original CONNECT command on our TNC, we were in COMMAND mode - we issued commands telling the TNC what we wanted it to do (i.e. setting the MONITOR, MCON, MCON states, asking it to CONNECT to another node); now that we have connected, we have automatically changed to CONVERSE mode. Now, whatever we type is just sent out when we hit the <ENTER> key. You can enter the CONVERSE mode whilst you are still at your TNC by typing K (then using <CTRL-C> to exit back to COMMAND mode).

Back to where we were though, on MB7NSC. Let's issue the PORTS command and ROUTES command and see what we get...

Connecting to MB7NSC and finding out the routes and ports available

We can see that the MB7NSC node has five ports (ways to connect to / from the node). Three of these (ports 1, 2 and 3) are RF ports, the fourth is an internet connection and the fifth is a local TELNET connection.

As we are using the 144.950MHz frequency, we have come in on Port 1, which is a 1200baud AX25 link.

The ROUTES command shows that there are currently six other nodes that we could connect directly to from MB7NSC - G0NZO, GB7GDT, GB7IOW, GB7NBW, GB7RWY and M0EYT.

• G0NZO, GB7RWY and M0EYT are on Port 1
• GB7GDT, GB7IOW and GB7NBH are on Port 2

The output also shows us that the ports are in use (this is the '>' symbol) and that they are good reliable links (indicated by 190 or 192). This route quality number ranges from 0 (non-existent) to 255 (the best possible); for RF links, 190-192 is about the best that you will see.

We now have a good idea of what is available on MB7NSC and which nodes we could move on to next... but how do we choose? How do we get an idea of where these nodes actually are?

That will be covered in the next part and we will continue to move through the network.