Does the app support using a digipeater to connect to a station with packet
winlink?
Many thanks
Bob Richardson K1JOZ
Not currently. It's on the roadmap https://trello.com/b/prOVNzwA/radiomail-roadmap
One aspect I need to solve is coming up with a good UI for it. I'd like to understand better how digipeaters are used. Could you answer the following?
1) How do you discover the existence of a digipeater (callsign, frequency)? Are there directories? Listed on club pages?
2) How do you know which digipeater to use with which winlink gateway?
3) Do you think of the digipeater as a property of a given gateway or do you think of the digipeater as a global settings that you set and then try to reach different gateways?
4) Do you ever use more than one digipeater, meaning would you need store different digipeater settings so you can select a particular one when necessary?
I'm somewhat surprised by these questions!
I can certainly answer them though...
1. There is no automatic system in place for digipeater reporting. There never has been. Discovery has to be done by manually monitoring and navigating the local network, or by local knowledge of the operators of the network. In some ares there is good local documentation available, in other areas there is no documentation whatsoever. Also, it is simple to set up an ad-hoc digipeater, which of course is not discoverable. Unfortunately, digipeaters tend to come and go at the will of those who maintain them. Digipeaters are "dumb" devices, they do not store any information about the network. The only way to know if a digipeater can reach a destination station is by trying a connection through the digipeater.
2. Local knowledge of the network topography must be obtained from those who build and maintain it. Again, there is no process in place for automated reporting.
3. Digipeaters are network resources that are not necessarily tied to any gateway. They can also be used for peer-to-peer connections. You could build a local "favorites" list that could include digipeaters for specific gateways.
4. It is unlikely that more than one digipeater would service a given area, however, one digipeater may service multiple gateways. There are times when you may need to use more than one digipeater to connect to a distant station. This is very inefficient and not recommended, but it can be done. Winlink Express limits this to 2 digipeaters in the path to a destination station (the AX.25 protocol supports 8). Keep in mind, using a digipeater is a different form of connection than a direct connection. You establish the connection by entering the destination call via digi call (or digi call1, digi call2, etc.) This is recognized in the AX.25 protocol as a digipeated connection.
On the Winlink Express implementation, you enter the destination call (gateway or P2P) and optionally one or two digipeaters. The same is true for Vara FM connections, which also support digipeating.
You may as well ask about network nodes too. The answers are basically the same, there is no automatic reporting system available. Network nodes work differently than digipeaters. Digipeaters are supported in the AX.25 protocol. Network nodes use standard "connected" mode connections to navigate the network. You connect to a node, then send the node the commands needed to tell it to connect to the distant station, or to additional node segments. This requires a connection script to be executed, something that Radiomail needs to support as well. This also requires knowledge of the local network topology, which can be learned by manually connecting to nodes and using commands to interrogate their stored information on the network topology. Network nodes do broadcast their existence and node tables, but not what end point stations they can access.
It would certainly be beyond the scope of any Winlink Client application to monitor a network and determine its topology.
-Scott, NS7C
1) How do you discover the existence of a digipeater (callsign, frequency)? Are there directories? Listed on club pages?
There is no uniform way digipeaters are advertised or discovered. Some are part of a node or gateway and are identified by plain text in the node or gateway's beaconing signal. Such beacons do not necessarily use a consistent format and must be read by a human to discern the existence of a digipeater and its call sign and SSID. Other digipeaters might be listed in a club web page or other publications. Many digipeaters exist with little to no notice of their existence other than word of mouth or accidental discovery.
2) How do you know which digipeater to use with which winlink gateway?
A user needs to know the geography of they area and the relative locations of digipeaters for completing a usable path to a gateway. Winlink users and clubs often share this information.
3) Do you think of the digipeater as a property of a given gateway or do you think of the digipeater as a global settings that you set and then try to reach different gateways?
Digipeaters need to be thought of as the location where you would like to place your antenna to reach the gateway you want to connect to.
4) Do you ever use more than one digipeater, meaning would you need store different digipeater settings so you can select a particular one when necessary?
It may be necessary to use different digipeater for different gateways, and it may also be necessary to use a series of several digitpeaters to create a several hop path to a gateway. It all depends on geography and the locations of digipeaters and gateways.
Nodes are another and often better way to make such multi hop gateway connections.
Don N7WTR
From "Georges WH6AZ" <g@islandmagic.co>
To radiomail@groups.io
Date 1/3/2023 9:35:45 AM
Subject Re: [radiomail] Digipeater support with packet
I would second Scott, to follow the winlink express method of digipeating.
I have a follow-up question for the group or someone who understands digipeating better than me: Any reason you couldn’t just throw WIDE2-2 in there? Or is that more of an APRS specific thing?
Best Regards,
Scott
K0SHD
The WIDEn-N paradigm is specific to APRS, which uses all UI frames for communication. This is a very different kind of digipeating. Winlink packet uses "connected" mode frames for communications, which is an ARQ protocol. In APRS, we send a packet and maybe someone hears it, maybe not. That doesn't work for Winlink, where we want to know the data was received 100%, or that the link failed.
-Scott, NS7C
Thanks, appreciate everybody's input, it helps me form a better picture of use cases. In case you're wondering, being relatively new to ham radio and living on an island with no packet or APRS presence, I have very limited hands-on knowledge of the topic. Most of what I know is from reading specs and setting up my own test bench, and well, imagine trying to learn what the web is about by reading HTTP specs, without ever using a browser 
Here's my current thinking on design:
1) Offer some way to save digipeater info, perhaps as a station in the directory. This way users could save essential information like callsign and frequency for that station in the app as oppose to keep it somewhere else. Might make sense to add location too so users could see best digipeaters based their location.
2) Add UI to select digipeater when connecting to a packet station. Need to work on this as the screen real estate is limited there. Alternatively, I'm thinking this could be a global setting for packet, like setting up a proxy on your tcp connection so that all future packet connection use that digipeater?
3) Maybe remember what digipeater were used when connecting to a station so they can be selected again by default? Would have to be location aware as the user may have moved and is now closer to the gateway and could go direct.
4) Maybe in the future there could be a way for people to publish their digipeater to a central directory and it could be retrieved in the app?
I'm going to work on the protocol support first to see if I can get the functionality in the app. I was able to setup a digipeater with Dire Wolf so I think I can now experiment with this.
I've simplified my original design as it felt overcomplicated to keep track of digipeaters. Current approach is to have a global settings for digipeaters that you can turn on/off with a simple toggle. When on, the digipeater are displayed in the connection window if you're connecting to a station in packet mode.
I'm looking for a few volunteer to help test a new build that supports digipeating. I need people who can test with real live digipeaters, ideally up to 2 digipeaters if possible.
Please contact me directly if you'd like to participate and I'll add you to the TestFlight for that build.
Thanks for the great app. Just got Dire Wolf running today on packet and have VARA FM working as well. Using an ICOM 705 with only one com port. Both cannot be on Com 3 simultaneously. Looking for port sharing options. Advice??
I primarily use digipeating on VARA FM but willing to try your experimental build for packet. Hope to see digi on VARA FM as well.
Let me know if I can assist.
Cheers.., John KX7YT. Portland.
I run two Digirigs, one for Winlink (vara FM /soundmodem), the second for Pinpoint APRS.
Each one is on it’s own COM port so I can run both programs at the same time.
Good suggestion John. Vara FM digipeating should be pretty straight forward to add at this point.
Support for digipeater is working well. Both packet and VARA FM mode, up to 2 digipeaters.
Could still use a few more people to test the dev build in the field, specially on the packet side.
Please contact me if you'd like to help out.
Hey George...
I got my setup working. The New TNC4, UV-5R, and an iPhone. I sent/received message using a digipeater just fine.