As I explained in About SuperPacket, "Big Picture of Amateur Radio" articles like this will now be in my blog SuperPacket. This article has been copied there.
AREDN is useful enough that I think every ham that has a Go Kit with a computer, should have a few AREDN
Amateur Radio Emergency Digital Network (AREDN) is a firmware image for selected Wi-Fi access points and Wireless Internet Service Provider (WISP) units. AREDN's firmware adds various services such as Domain Name Service (DNS) and Dynamic Configuration Host Protocol (DHCP) and most notably, hands-off mesh networking (sometimes called peer to peer networking). As part of the AREDN firmware, it enables the Wi-Fi radio to use a portion of the 2.4 GHz band that is only legal for use by (licensed) Amateur Radio operators. You don't have to be an Amateur Radio operator to use the firmware, but you do have to be an Amateur Radio operator to make use of the additional channels.
AREDN is useful enough that I think every ham that has a Go Kit with a computer, should have a few AREDN nodes in their go kit. My rationale for making that statement is one of the issues that Amateur Radio operators have in responding to emergencies with their go kits (again, with a computer) is that there is no good, and certainly no easy way to have their computer communicate with other Amateur Radio operators. I've observed many, many times when computer-to-computer communication devolves to putting a file on a USB memory device that's then "sneakerneted" to another computer. AREDN units are a fix for that. AREDN is mostly "plug and play" to use, but some preparation is required.
The easiest way to understand and experiment with the potential of AREDN is the GL-iNet GL-AR150 shown above. It's around $25 on Amazon - buy two for your experimentation. The model in the photos above has an internal antenna. The GL-iNet GL-AR150-ext features an external antenna port and a small antenna. The big brother of the GL-150 is the GL-750, which is a bit more expensive, but has the benefit of a 5 Ghz radio in addition to the 2.4 GHz radio.
The best way, I think, to think of AREDN nodes for this use case is that they're the rough equivalent of an Ethernet switch and Ethernet cables connecting multiple computers together to share resources, such as a local web server, file sharing, or any other service we take for granted via the Internet - as long as it can be hosted locally. Think email via POP/SMTP, but not Gmail.
After it's flashed with the AREDN firmware, there is some minimal configuration required, including entering your callsign and setting up a password. I recommend installing the tunnel software (allows you to create a Virtual Private Network - VPN to other AREDN nodes via an Internet connection). The tunnel software doesn't take up much room and it's much, much easier to do it when you have a good Internet connection rather than adding it later on a marginal or no Internet connection. Unlike the initial firmware installation, the tunnel software must be done "live" - you can't download it for later installation.
(Apologies that I'm describing all of this with words rather than photos - a future version of this will include photos.)
Then it's as simple as providing the AR150 power via USB (it doesn't need much - a computer's USB port is adequate) and plug the AR150's LAN Ethernet port into the computer's Ethernet port. Assuming you select the default radio settings, any other AREDN node within range (with the same radio settings) will automatically connect into a mesh network.
The real power of AREDN is the services beyond the AREDN nodes. In my example above of multiple Amateur Radio operators in a shelter, one computer can be configured as a web server, advertise that server on that particular AREDN node, and then anyone else in the AREDN mesh can click on that advertised service and see the web page.
The use case I'm describing here hasn't been discussed much (that I've seen).
I have a mild criticism of AREDN that they posit its role as outdoor infrastructure, and in my opinion, that's somewhat impractical. 2.4 GHz is hard enough to make work, even with the "quiet" portion of spectrum that AREDN is using. The better model for Amateur Radio high-speed microwave infrastructure, in my opinion, is HamWAN. Alternatively to HamWAN's way of doing things, you can buy off-the-shelf Wireless Internet Service Provider (WISP) equipment designed for this purpose (thus, it's expensive). Vendors of WISP equipment include Cambium Networks, Ubiquiti Networks, and MikroTik. While this is equipment intended for WISPs, because it uses license-exempt spectrum (generally 5 GHz), it can be purchased and used by anyone. One good vendor of such equipment is Streakwave Wireless. It's a bit of work to get them to work with an individual, but they're willing to do so.
I'm now able to access two AREDN Virtual Private Network tunnels, one for my fellow Amateur Radio operators in Whatcom County, and another for my buddies in the Seattle area. One issue to be careful about is routing loops so I'm careful to keep the two networks segmented for now, as I want to experiment on both of them. I have two sets of AREDN nodes in my shop, and they don't interoperate with each other because of of unique radio configurations for each group.
My friend Bill Vodall W7NWP made a good set of notes on configuring the AR150s.
Next steps in experimenting with AREDN:
- Configure a Raspberry Pi as a web server and advertise that service via AREDN
- Configure my new TP-Link 2.4 GHz radio to try to connect with the nearby AREDN node,
- Learn more about advertising services, such as VOIP, email, etc. via AREDN
- Order more AR150s, get them configured into a Go Box configuration with their own battery packs, weatherproof boxes, and better antennas for better range.
Update 2 - 2021-02-23 - Displaying a web page on an AREDN Node, from the AREDN node
The one thing I wished was possible on the AREDN nodes was to display some custom text like a small web page. It would be ideal if this was automated, like a checkbox to display custom text. When I plainted this desire to my long-suffering techie buddy Bill Vodall W7NWP, he was completely puzzled - "Steve... it has a web server already running. You're looking at the status page in a web browser, aren't you?". That was my D'oh moment. So then Bill and I went on an hours-long quest to figure out how to access it. Turns out you can ssh and scp into your AREDN node - IF you know what you're doing.
Part 1 - Make a simple web page
You can't effectively make changes to a file from / on the AREDN node. Well, technically, you can, but you the only editor available on an AREDN node is the vi(le) editor. Life's too short.
So, compose a web page that you want to be resident on your AREDN node on your "big" computer. It needs to be "something".html. Keep it simple. Compose in an HTML editor or a text editor, and keep it to text only (no images). Save it as a simple text file. If you're rusty on your HTML, as I was, here's an HTML intro.
Save it as n8gnj-test1.html (whatever name makes sense to you). Make sure you can find this file when you're in the command line using SSH.
Be sure to view your file in a web browser:
http:///path/filename
Part 2 - SSH
ssh -p 2222 root@n8gnj-1
ssh is Secure SHell. -p specifies the port which on an AREDN node is 2222 for ssh and scp. root is the username on the AREDN node, and n8gnj-1 is the system name (technically, it's N8GNJ-1 but the system doesn't seem to mind, and it's easier not to shift to all caps.
Also, the system doesn't seem to care about using n8gnj-1 vs using n8gnj-1.local.mesh, so I used the former.
and you're prompted for the node's password, and you're in!
But that was only part of the battle, but at least I could look at the file system from the inside.
Part 2 - SCP
The beauty of UNIX / Linux is that the tools like SCP have been honed over decades. They work... you just have to know how to use them. The available documentation, especially on a system, like man scp are terse at best. So it took Bill and I hours to get this right. Well, to be fair to Bill, it took him tens of minutes to get it right (based on my feedback) and it took me hours of fiddling around.
scp -P 2222 n8gnj-test1.html root@n8gnj-1:/www/n8gnj-test1.html
scp is Secure CoPy. -P (note that for scp, it must be an uppercase P) specifies the port which on an AREDN node is 2222 for ssh and scp. root is the username on the AREDN node, and n8gnj-1 is the host name.
n8gnj-test1 is the file that I created on the "big" computer.
The fiddly bit was the :/www/n8gnj-test1.html. :/www/ specifies that the scp command copies the n8gnj-test1.html file into the /www directory of the AREDN node. (You have to know a valid directory in advance of this command, thus it's useful to know how to use ssh). something2.html is the name of that file when it's copied onto the AREDN node (in the /www directory).
and you're prompted for the node's password, and if everything is correct, scp terminates. Then go back to ssh, and look at the /www directory, and there should be a something2.html file there.
At this point, you've moved a file into the file system of the AREDN node. Then, you get to get to do configuration magic to display it from the main AREDN node status page.
Part 3 - Configuration of a link to display
(Apologies that this next part is terse - I want to capture it before I forget these fiddly bits.)
Go to Setup, Advertise a Service.
- Name Box: (what name you want to appear under the Services column next to your node in the Mesh Status page) I put N8GNJ Simple Web.
- Click the Link checkbox (it will appear as a clickable link)
- First box - HTTP (pulldown, I think)
- Second Box - select your node from the pulldown. In my case it's N8GNJ-1.
- Third box (after the :) 80 (port number, apparently; Port 80 is universal for HTTP).
- Fourth box is the name of the file in /www. In my case it's n8gnj-test1.html. (Apparently the /www is prepended and no need to have it in the string - just the filename.)
- Click the Add button. It'll take a few seconds for it to update.
- Click the Save Changes button (above). It'll take a few seconds to save this new configuration.
Normally, this capability is used to advertise a service on another system; there are dozens of examples. Mine was going to be a web server running on a Raspberry Pi, but what I wanted to display is pretty simple, and it seemed like this should be possible, but there were only the vaguest of hints that this was possible, and how to actually do it, on the AREDN pages and forums.
Part 4 - Display the Web page
Now, in the mesh status page, next to my node N8GNJ-1, there is an advertised service - N8GNJ Simple Web that is clickable. When clicked, it displays the very simple HTML text that I put in there. What's really unique about this is that it's a web page that's stored on the AREDN node, and it's being served by the AREDN node.
Thanks again Bill!
Update 1 - 2021-02-22 - AR-750 can offer Wi-Fi on 5 GHz in addition to AREDN on 2.4 GHz
In a running conversation I'm having with another Amateur Radio operator, it occurred to me that the GL-iNet GL-AR750 has a unique capability vs other ARDEN nodes because it has a 2.4 GHz radio and a 5 GHz radio. When you flash an AR750 to AREDN firmware, the 2.4 GHz radio is reprogrammed into AREDN's configuration for meshing with other AREDN nodes. But the 5 GHz radio isn't reprogrammed - it remains compatible with Wi-Fi. That capability enables this (theoretical) scenario:
- The big one happens - earthquake, power failure, ice storm, etc. Cellular service is out. This isn't THAT theoretical; I was without cell service for a week in Woodinville WA in the aftermath of a severe winter storm that toppled MANY trees onto the power lines. Power was out for that week, and the small cell sites that service most of Woodinville didn't have standby generators, only batteries, and those were depleted after 12 hours or so.
- People need to communicate their status - email is the most practical.
- A "package" of an AREDN AR-750 with a high capacity battery pack, is put into a tree or other high, central point.
- The AR-750's 2.4 GHz radio meshes with others.
- The AR-750's 5 GHz radio is avilable for access by "civilians". (Yes, this is legal because a ham is in charge of the network - a "control operator".)
- Civilians are able to use their phones to connect to the 5 GHz Wi-Fi Access Point on the AR-750.
- Civilians then open the web browser on their phones and are greeted with a "splash page". That capability requires some development.
- Civilian fills out a form on the web page and then that's upload to a control operator on a laptop somewhere in the mesh.
- Civilian gates out the email into the Winlink system and Winlink handles delivery of the email.
Repeater Coordination Does Not Exclude Other Use of the Repeater's Frequencies
As I explained in About SuperPacket, "Big Picture of Amateur Radio" articles like this will now be in my blog SuperPacket. This article has been copied there.
In my earlier article The Puget Sound Amateur Radio TCP/IP Network (circa 1995) I said in passing:
The last bit regenerative 9600 bps repeater, on 146.98 MHz on Mt. Baldi fell victim to a "sneak attack" because its "coordination" with the Western Washington Amateur Repeater Association (WWARA) lapsed. The moment the coordination lapsed, WWARA gave the "coordination" for 146.98 to yet another "ego box" voice repeater. To this day, forcing the unique 146.98 9600 bps data repeater off the air is one of the stupidest things I've ever witnessed in Amateur Radio. For that reason I have a very dim view of the utility of "frequency coordination" for Amateur Radio in general, and the WWARA in particular.
The premise that "repeater coordination" is based upon is that (widely held) perception that portions of the Amateur Radio VHF / UHF bands are for the exclusive use of repeaters, and any other use of those portions of the Amateur Radio VHF / UHF bands is not allowed. It has happened that other use of a particular repeater's input or output frequencies have caused complaints to the "repeater coordination body" and sometimes escalated to a formal complaint to the Federal Communications Commission (FCC), mostly back decades ago when the FCC took Amateur Radio interference complaints seriously.
Even before the stupidity about "decoordinating" the unique Mt. Baldi 146.98 9600 bit-regent repeater, the "it's MY repeater frequency, dammit" attitude struck me as wrong. When I was learning about Amateur Radio, one of the tenets I was taught was that in operating, no Amateur Radio operator had a "right" or "claim" to a particular Amateur Radio frequency, and the "exclusivity" nature of repeater coordinations just seemed wrong. It's right there in the FCC rules - Part 97.101(b):
Each station licensee and each control operator must cooperate in selecting transmitting channels and in making the most effective use of the amateur service frequencies. No frequency will be assigned for the exclusive use of any station.
But that seems routinely ignored when "it's MY repeater frequency, dammit" is asserted.
In my opinion, the proper perspective of a "repeater coordination" is that it's a mild preference among equal peers - that all things being equal, this particular usage is preferred. No more than that.
Years afterward, I read an official opinion of the FCC that confirmed my perspective, that while coordinated repeaters are recognized as a "first among peers" designation if they have blessing from a "coordination body", that "coordination" does not extend to exclusive use of the frequencies the repeater is using, especially when the repeater is not in operation. I squirreled away that note... too well, apparently, because I could never find it again. I tried Google searches, to no avail, until a few days ago.
Kudos to the ARRL for keeping this sort of vital information online!
http://www.arrl.org/news/fcc-dismisses-two-amateur-radio-related-petitions
But, just in case... https://web.archive.org/web/20100527003357/http://www.arrl.org/news/fcc-dismisses-two-amateur-radio-related-petitions
FCC Dismisses Two Amateur Radio-Related Petitions
On Wednesday, December 9, the Federal Communications Commission dismissed two separate Petitions for Rulemaking: One filed by Murray Green, K3BEQ, concerning the operation of repeater stations in the Amateur Service, and one filed by Glen Zook, K9STH, requesting amending Section 97.119(a) to change how often stations must identify themselves.
Murray Green, K3BEQ (DA 09-2559)
In his Petition, Green -- who filed his Petition on March 23, 2009 -- requested that the FCC amend Section 97.205(e) of its Rules "to prohibit a repeater station licensee or control operator from limiting the use of a repeater to only certain user stations, unless a user blatantly violates the Commission's Rules." Green argued that Section 97.205(e) -- which permits a repeater station licensee or control operator to limit the use of a repeater to certain user stations -- conflicts with Section 97.101(b) which states that no frequency is for the exclusive use of a particular amateur station, and each station's licensees must cooperate in selecting transmitting channels and in making the most effective use of the Amateur Service frequencies. In his Petition, Green argued that Section 97.205(e) permits "a pay for use policy in the Amateur Radio Service, enables user censorship and intimidation, breeds on the air inactivity by not using frequencies effectively and creates a negative public image."
In denying Green's Petition, the FCC concluded that Section 97.205(e) does not establish an exclusive assignment of a frequency to a repeater, saying that Green's contention that a coordinated closed repeater has "exclusive control of an Amateur Service frequency." The Commission noted that coordination is not required as a condition of operating a repeater: "Coordination does not and cannot result in assignment or establish control of an Amateur Service channel," the FCC said in its reply, "and nothing in the rules prohibits other amateur stations from using the channels for which a repeater has been coordinated when they are not being used by the repeater. Section 97.205(e) merely enables a repeater licensee or control operator to control the repeater so that he or she can ensure the repeater is properly operated as required by Section 97.105(a). Accordingly, there is no conflict between the rules, and no grounds for the Commission to propose to amend Section 97.105(a)."
The FCC advised Green that questions concerning the impact of the operational decisions of a repeater control operator, licensee or trustee -- such as limiting the repeater's use to certain stations -- should be addressed to the local frequency coordinator so that repeater problem can be "expeditiously dealt with at the local level by people with first-hand knowledge of the facts."
This phrase leapt out at me:
The Commission noted that coordination is not required as a condition of operating a repeater: "Coordination does not and cannot result in assignment or establish control of an Amateur Service channel," the FCC said in its reply, "and nothing in the rules prohibits other amateur stations from using the channels for which a repeater has been coordinated when they are not being used by the repeater.
Although this came too late to save the unique Mt. Baldi 146.98 9600 bit-regent repeater, it was something of a moral victory, at least to me. Armed with this, the fans and supporters of the unique Mt. Baldi 146.98 9600 bit-regent repeater could have argued that WWARA's new "coordination" of the "ego box" new 146.98 repeater was more of a gentle suggestion rather than effectively being "law of Amateur Radio in Western Washington".
Fast forward to 2021 and beyond. In my monitoring of the Amateur Radio VHF/UHF bands, the silence (unoccupied airtime) is deafening. Where is all the activity to justify the exclusion of every requested new "coordination" because "2 meters is full"?
I can also envision that based on this information, when a repeater is proposed for the 144-148 MHz band (2 meters) in Western Washington, instead of the WWARA essentially vetoing such a repeater ("2 meters is full. Go away.") that the new repeater "just do it". I think that especially applies to new data systems like the unique Mt. Baldi 146.98 9600 bit-regent repeater.
I've said that the entire function of Amateur Radio repeater coordination bodies should be, at most, a Wiki page where someone who wants to put up a repeater posts the basic information of the repeater:
That's it. Then, as the FCC suggests, any issues... can be "expeditiously dealt with at the local level by people with first-hand knowledge of the facts.
In a future post I'll discuss why all of the above is relevant - that new data modes such as VARA revive the discussion of using repeaters for data. Existing (voice) repeater owners are loathe to allow data usage of their (coordinated) existing "voice" repeaters, so those of us that want to use repeaters for data are just going to have to create new repeaters. For us "data first" enthusiasts, the situation K3BEQ describes with certain repeaters limiting usage for a select few users, we feel the same way about the exclusion of data. So, it's time to "route around those "voice only" repeaters. Likely they won't notice because their usage is so light.
The above is "cover" for putting up those new repeaters even though "2 meters is full".
There is now funding available to try interesting new things.
Thanks for reading!
Steve Stroh N8GNJ
Bellingham, Washington, USA
Posted by Steve Stroh on March 15, 2021 at 11:44 in Amateur Radio General Commentary, Speculations On Amateur Radio Futures, Useful Reference | Permalink