Monthly Archives: September 2013

A little technical talk about WiFi

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Adam Gittins has published another terrific post on his Precision Ag Explained blog about problems he ran into getting his AyrMesh network up and running.

It reminds me that WiFi isn’t entirely straightforward, and some explanations of the vagaries are in order.

As Adam points out, interference is potentially a huge problem on WiFi. One problem is that the 2.4 GHz. WiFi band was partitioned out into 11 channels (in the U.S. and Canada), but most of those channels actually OVERLAP each other. There are only THREE DISTINCT CHANNELS: 1, 6, and 11 – all the other channels overlap at least one of these three (and each other). For a good explanation with graphics, I always recommend Wikipedia.

As he points out, if you have your “indoor” WiFi and your “outdoor” WiFi on the same channel, they’ll interfere with each other, reducing the range and bandwidth of both. Even if they are less than five channels apart this will happen to some degree. The AyrMesh network always comes by default on channel 6, so you can either change your home router’s channel to 1 or 11, or change the AyrMesh channel using your account on AyrMesh.com.

InSSIDer – courtesy of MetaGeek

We use and recommend a couple of tools to help discover WiFi interference. InSSIDer for Home is a free program that run on Windows, Mac, or Android, and shows all of the WiFi Access Points in range of the computer and a pretty good estimate of the signal strength of those Access Points. (NOTE: It has recently been pointed out that getting InSSIDer for Home from the Mac App Store actually costs $4.99)

WiFi Analyzer for Android, Courtesy of farproc

WiFi Analyzer is another free app that runs on Android. It’s a little simpler and quicker than InSSIDer, and has become my “go-to” solution for taking a “quick look around” on my phone.

It’s worth noting that there is no analogous app for the iPhone because Apple doesn’t allow direct access to the WiFi card. However, there are similar apps available if your iPhone is jailbroken.

Chanalyzer Spectrum Analysis, courtesy of Metageek

Just to make it a bit more interesting, however, I have to point out one more fact: WiFi is far from being the only thing using the 2.4 GHz radio band. Cordless phones, baby monitors, wireless surveillance cameras, certain radars, and microwave ovens all use the same spectrum, so they can all potentially interfere with your WiFi. This is, in fact, precisely why Metageek gives away InSSIDer – they sell tools called “Spectrum Analyzers” – their “Wi-Spy” Spectrum Analyzers are excellent and relatively inexpensive. They can show not just WiFi interference, but all the interference in the 2.4 GHz. band. They even offer a very nice “Wi-Spy mini” bundled with their “InSSIDer for Office” product for only $199.

You probably won’t need a spectrum analyzer for your AyrMesh network. Out in the country there’s very little interference, and it takes a while to learn how to use a spectrum analyzer effectively, even with Metageek’s excellent software.

However, getting a copy of InSSIDer and/or WiFi Analyzer is something I recommend to everyone who’s curious about their local WiFi environment.

Great post on “Precision Ag Explained”

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Not really Adam – just a picture I thought was funny.

Adam Gittins of HTS Ag got an AyrMesh Hub2n a few weeks back, and he has published a great post about it on the outstanding blog “Precision Ag Explained.” The post helps explain how Wireless Farm Networking is going to drive better and more efficient farm operations in his view.

Here’s hoping we can see a lot more from him in the future – we really appreciate having someone of his experience and expertise writing about Ayrstone.

New Ayrstone Product: the AyrMesh Hub2n

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Today is the second most exciting day of Ayrstone’s existence – second only to the day we started. The introduction of the Hub2n marks a new era in wireless farm networking – even though the white plastic case is exactly the same as the old Hub, and the electronics inside are fairly similar, the software running on those electronics make it truly revolutionary.

The most important and exciting thing about the new Hub2n is that it introduces the concept of the “transparent mesh.” This means that you can build out your AyrMesh network across your farm or other rural business or homestead, but all the devices attached to the Hubs and Receivers in your network get their IP addresses from the router your AyrMesh Gateway Hub2n is attached to. This means that building and managing your AyrMesh Network is no more difficult than building a home network with your home router. In particular:

  1. Devices attached to your AyrMesh network will be in the same IP subnet as your router. If your router, for instance, is configured to create a private network with addresses of the form 192.168.1.x, then everything on your AyrMesh network will have IP addresses in that same form.
  2. All devices on your network will appear in the DHCP table or client table of your router.
  3. You can port forward from your router to any device in your network, whether it’s plugged directly into your router or miles away connected via WiFi to an AyrMesh Hub.

This means that, using the new Hub2n, you can easily build a farm-wide network that can be used for:

  • Internet access – even in places with no cellular signal
  • A reliable, high-bandwidth local-area network for remote sensors like cameras, thermometers, and weather stations, and
  • A high-speed, internet-accessible network to control devices like web-controlled relays and thermostats.

With the new Hub2n available, the revolution in Wireless Farm Networking can really pick up steam! Now there’s no reason not to have a farm-wide network to gather information and start automating operations on your farm.