Sparks's Journal

Applications for Ham Radio 802.11 Networks

Note	This article originally appeared on 2016-02-12 but has been revamped to better include amateur radio technologies that are present in 2020.

Digital wireless networks have been around for decades, now. In the last few years, amateur radio operators have been taking advantage of cheaper microwave gear that has allowed much higher bandwidth than was once even thought possible back in the days of packet radio. So what can we do once we’ve built our IP-based 802.11 network to supplant the Internet or other commercial networks? Here are just a few ideas.

Situational Awareness

Taking an existing technology and expanding its role in day-to-day operations, as well as during emergencies; Automatic Packet Reporting System (APRS) can easily be run on a hybrid network to pass short messages, show the location of resources (food, water, repeaters, infrastructure), display emergent issues such at road closures, damaged infrastructure, or persons in need of help, and who is on the air. By running a local server on the network, everyone can run an IP-based station on the network without fear of overloading the VHF network. With a couple of well-placed i-gates, needed information can seamlessly move between the two networks allowing users on both networks to have a view into what’s happening.

Linking Repeaters

AllStar

The AllStarLink network is an extension of the Asterisk PBX (see below) used to link repeaters over IP networks (e.g. the Internet). These links can be passed over your own network to a server on the network without any Internet connectivity required.

DMR

Digital Mobile Radio (DMR) repeaters already use IP connections to connect to their network servers. Using your wireless network to connect your repeaters together is a logical use (see Rocky Mountain Ham Radio’s Microwave Network and their DMR network) of your network and doesn’t require much bandwidth.

E-mail

You don’t need Winlink when you’re trying to pass messages to someone that’s already on your network!

E-mail is a simple, asynchronous method of communication that is familiar to most people. If you aren’t using a web client, the bandwidth required can be very minimal.

Network and system administrators should be familiar with the three protocols that make email work: SMTP, POP3, and IMAP.

SMTP

Simple Mail Transfer Protocol (SMTP) is an Internet standard for routing messages between e-mail servers. When you send an e-mail, your client connects to an SMTP server and sends the message. The SMTP server, after receiving the message from you, attempts to figure out how to deliver the message to the distant email server. If the message is being kept locally (e.g. the recipient is on the same server as where you delivered the message) then the message is filed for delivery when the recipient queries the server.

200 An often-used SMTP program is Postfix. It requires a little configuration but basically just works out of the box. Postfix will handle receipt of mail and delivery to the mail server where your recipient is without further action from the user.

POP3 and IMAP

Post Office Protocol version 3 (POP3) and Internet Message Access Protocol (IMAP) are on the message delivery side of the house. These are the protocols that allow a user to query the e-mail server for messages.

POP3 basically forces a user to collect their mail and then delete it from the server. By doing so, once downloaded, the user has the only copy of the message and the server is freed of the responsibility (and storage space) for handling the message.

IMAP, on the other hand, allows the user to download a copy of the message but, until deleted, the message remains on the server. This allows the user to utilize multiple computers and, be able to sort their messages into folders and have that organization synchronize among all the user’s computers.

Dovecot handles delivery of messages to clients using POP3 and IMAP. Again, the software requires a bit of configuration but generally just works out of the box.

Web Server

Have a website you want to publish on your network? Want to use a program to share files and other information? You’ll need a web server!

200 Apache’s http server, commonly known as httpd, is very easy to setup and use. Once installed, the server looks for files in your web folder (/var/www/html) and waits for a request from a client.

WordPress

WordPress can be used to create websites that can be updated in seconds from a web browser. WordPress uses a web server (like httpd) and a database (like mariadb) to function. Once you have everything up and running, you’ll be up and running!

NextCloud

Nextcloud Logo Nextcloud is a suite of client-server software that creates a file hosting service and also allows management and sharing of calendar information, contacts, and more. Because it’s far more efficient to share files using the http protocol, compared to email, and because files can be managed and synchronized among many computers through shares, using Nextcloud to manage files is far superior than using email for the same tasks.

Voice Communications (VoIP)

Using the session initiation protocol (SIP), one can handle VoIP "calls" over the network. This can be between VoIP phones or between AT conversion boxes linking analog repeaters. Unless you know exactly what phones are where, and your system isn’t growing, you likely don’t need a server. But, if you plan on expanding your network and wish to have dynamic routing (phone numbers) then you’ll likely need a centralized server.

Asterisk is a great private branch exchange (PBX) server allowing telephones to connect with each other. Connections between the server and the clients are generally done using SIP whereas connections between Asterisk servers use Inter-Asterisk eXchange (IAX).

Connecting LANs

All of this information has been presented absent the network management infrastructure that helps make communications between easier. Handling data on a single local area network (LAN) doesn’t necessarily require this kind of infrastructure but utilizing tools like DHCP, DNS, and others can be helpful.

Summary Conclusion

As you’ve seen, once you’ve built your network there are a few more steps to making your network work for you. You don’t need any fancy hardware, either, as these tools can easily work on a laptop connected to the network for easy deployment.

All the suggested software is free and open source software (FOSS) which allows anyone to deploy the software for free (and allows you to make changes to the software if needed).