Tag Archives: Networks

SBARC Telecom Group Meets for First Time

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The new, and improved SBARC Telecom Group met Saturday June 4th for the first time. The Telecom Group is led by Bill W1UUQ and Levi K6LCM (co-chairs) and composed of members of the repeater and microwave crew that has maintained our infrastructure for years, and several members of the digital operations and mesh network group. Many members of the digital group have skills that will enable more people to share the load in maintaining and improving SBARC’s already amazing infrastructure. The SBARC digital group will be able to assume more responsibility for day-to-day repeater operations and programming, packet radio and APRS, weather stations, and other things that have overburdoned the telecom group for years. In the very near future, we will have some very powerful new repeater features available to the club, and this collaboration will ensure that the talents and skills available to the club are most efficiently utilized. Note: Missing from the picture is Brian K6BPM because he was taking it! Post expires at 6:53am on Friday August 5th, 2016 but will still be available in the archives.

Keeping Time on the Mesh Network

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These days we’re all used to our computers always having the correct time. Periodically, they simply connect to the Internet and get the correct time from an Internet time (NTP) server. Our local mesh network is designed to work “off-the-grid” without an Internet connection. This is a problem. All of our nodes and devices running services need to know the correct time. MeshChat servers record the date and time anyone posts a message. So does the SBARC mesh website. So how do we keep all these devices synchronized with the correct time? To address this problem, I am building a Raspberry Pi (RPi) based stand-alone NTP Stratum 1 server. Since it cannot connect to the Internet to update the time, I decided to synchronize it using GPS. Adafruit makes a perfect add-on board for this that plugs into the GPIO header that offers full access to GPS signals including the time. So every few seconds, the Raspberry “reads” the incoming GPS signals from whatever satellites it can “see” and adjusts it’s internal time. Normally, to get a good GPS “fix”, we need to connect to at least 5 or more satellites. However we can get an extremely accurate time reading from just one satellite. To allow other devices on the mesh to synchronize the time, a little programming is required on the RPi so it can be used as an NTP Stratum 1 server. It operates exactly the same as a time server does on the Internet. So instead of using something like time.windows.com as a time server, we can use k6bpm-ntp.local.mesh as the time server for our mesh connected devices. Connection speeds will vary node to node. While the RPi will be accurate to the millisecond, the various nodes using it may be off by a second or two because of latency delays due to connection speeds. But that’s okay. We don’t need millisecond accuracy for our purposes. In fact, we can be a minute off and it won’t hurt anything. I will probably locate this at my house when I am through testing it. I have a very fast connection (25Mbps+) to the Gibraltar nodes there. Everyone is free to use it for their “NTP Server” when setting up their local nodes.

Ubiquiti Videos

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I found some great videos at the Ubiquiti site that cover a lot of interesting topics about using AirMax equipment. Our Nanostations and Rockets are “AirMax” products. Although these videos are not specifically about devices using the AREDN firmware, they still explain a lot of concepts we share with the factory firmware equipped nodes. https://www.ubnt.com/videos/#airmax-videos

Mesh Network Status – April 9th, 2016

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Our three nodes at Gibralter Peak are working extremely well. We have members linking up from Goleta to Carpinteria and several points in-between. There are about 5 nodes online now and another 5 or so coming up soon! The node for the club station is programmed and ready to go, but installation on the mast was delayed because of rain. We still need to raise funds to build out the La Vigia site on the Mesa. We need 2 or 3 Ubiquiti Nanostation nodes there and a ToughSwitch network switch. All the equipment will cost us about $400 and any help our members can offer will be greatly appreciated. If you can help with a donation please click here. Our next step will be to connect over the mountain to the Santa Ynez Valley. We’re very lucky to have access to all the great repeater sites that Bill W1UUQ has spent many years cultuivating. This enables is to to some great things with emergency and general communications of all kinds and we hope to utilize these assets wisely to enhance our communications abilities.

Help Support our New Emergency Mesh Network

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SBARC members are launching a new club project to install a multiple node mesh network system in Santa Barbara. In simple terms, a mesh network is a lot like a wide area, long range WiFi network for amateur radio operators. Any licensed ham can participate and all the hardware needed costs less than $100. To get the project off the ground, SBARC needs to install some initial nodes at strategic locations. Participating users will be able to connect from their stations to these nodes. This will be a tremendous asset to the club and to the community in general in the event of an emergency. To read more about it, and learn how you can help, please click here.