Packet Radio Upgrades

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We’ve recently upgraded our packet radio capabilities here in Santa Barbara. Very popular back in the 80’s, packet lost much of it’s appeal with the advent of the Internet and email. However, for those of us interested in digital modes, packet radio is making a comeback. Unlike out normal HF oriented digital modes, packet lets us communicate with email like messages between users locally, and users of other packet systems around Southern California and beyond.

thThe K6TZ-3 packet station on La Cumbre Peak offers a PBBS (SBPBBS) system for messages and a Digipeater (SBDIGI) for relaying packet messages to other systems. It runs on a Kantronics KPC3 TNC and broadcasts on 145.050 at 25w. It has incredible reach easily reaching other packet stations down the coast of California. Recent modifications were to add KA-Node capability. This allows us to connect to out KN-Node (SBNODE) and connect to other KA-Nodes. You can connect from node to node to “chain” a connection from here to almost anywhere within a reasonable distance. Similarly, others can reach us from remote locations the same way.

I also installed two of my own packet stations here locally. They are mostly for fun and have nowhere near the coverage the La Cumbre Peak station has. However, they allow me to have my own mailbox system and people can leave me a message on my own systems.

Packet radio is far from dead. In a SHTF emergency, packet capabilities will allow 100% accurate text based messages to be sent quickly and easily. In my opinion, this is an extremely valuable skill to have and even if its popularity is not what it once was, it enhances our capabilities as individual amateurs as well as a club. It isn’t as complicated as it may seem, and is actually fun and challenging.

We discuss and operate packet on the Tuesday night SBARC Digital Modes Net, so if you have an interest, be sure to check in.

– Brian K6BPM

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.

Raspberry Pi 2 with GPS add-on board installed

Raspberry Pi 2 with GPS add-on board installed

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.

Technical Mentoring and Elmering Net – Thursday April 21, 2016

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The audio archive can best followed by downloading the .mp3 file for the appropriate date here and listening with the media player of your choice. You can move the progress slider forward or backward to the subject of interest to you.

Tonight’s net had 7 check-ins and some chat room visitors, Levi (K6LCM) was net control. Topics discussed were:

  • Repeater courtesy tone, what is it and how is it used? (Current stand in K6TZ repeater doesn’t have one).
  • What are the extra characters being transmitted in the repeater CW ID?
  • Continental Bio-Fuel airplane trip from Rhode Island to Santa Monica.

Tune in to the SBARC TM&E Net next Thursday at 8:00 PM (2000 Hrs) and see what interesting questions will arise or ask some of your own! All club members and visitors are encouraged to check in to the TM&E net each week and join in with questions and /or answers to and contribute the knowledge of new and seasoned amateur radio operators alike.

Nanostation Shielding and Mounting

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2016-04-16_21-53-12I installed my NanoStation today at my home QTH using one of these kits from RFArmor. I was really impressed with the build quality and general utility. Not only does if provide RF shielding for your Nanostation, it is also a mounting system with options for mast mount (which I used) or wall mount. All mounting hardware is included.

According to the manufacturer, these shields provide a lower noise floor, cleaner signal, superior signal to noise ratio, fewer wireless retries and errors, higher sustainable air rates, and up to 50% increase in performance.

They are $27.95 and available here: https://www.rfarmor.com/index.php/nanostation-kits.html.

Repeater Updates From Our Trustee

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A file photo of the La Vigia communications site atop the Mesa.

A file photo of the La Vigia communications site atop the Mesa.

Effective April 15, the former GE Mstr II repeater and its associated ACC RC-850 on 146.790 at the La Vigia site has been decommissioned. In its place is a GE MSTR III which will act as a surrogate system without any bells and whistles. It has the required time out timer and a CW ID. All synthesized voice announcements, autopatch and macro functions are disabled for the time being. The remote 2-meter receiver at UCSB and voter will be temporarily offline.

As explained by Matt Lechliter, W6KGB, at last months club meeting, the Mstr II will be converted to a uMstr with the addition of a new RLC Club Controller. Essentially the former repeater retains the same electronic design configuration. However, all the mixed cabling used for multiple variants will be discarded which will make the system easier to maintain by improving the common interconnections. A single RLC controller is now capable of handling six serial interfaced independent systems, multiple macros, and planned system interfaces tailored to the needs of emergency services and daily users. Commonality of a single controller will have the capability to interface the six-meter repeater, 440 IRLP repeater, the UCSB remote link and voter, ELT receiver, NWS warning system, etc. Command integration of the 146.79 (at La Vigia) and 145.18 (at Santa Ynez Peak) repeaters will be possible via ethernet controls over the club’s microwave data system. Most importantly the controller will be ethernet capable which will ease the load on control operators through remote computer-enabled configuration. We shall try to maintain the basic configuration of the previous club and ARES net functions as best possible. But no two systems have the same design features and capabilities so we must adjust and learn. As we move forward the first task is to upgrade the MSTR II to a uMstr. This should take about 2 months. Meanwhile the task of interfacing the six-meter and 440 system will be on-going. In time you shall see a much more capable system.

Mstr III mounted on top in rack above the Mstr II. Mstr II and controller has been removed for modification to a Micro-Mstr.

Mstr III mounted on top in rack above the Mstr II. Mstr
II and controller has been removed for modification to a Micro-Mstr.

A last word about the RC-850. The controller was way ahead of its time in the 70’s. It has served the club extremely well by performing a myriad of timed macro’s, voice synthesizer, paging variants, auto-patch capabilities, plus many control bells and whistles as a single system controller. The limitation of the 850 was interfacing of remotes or additional functions plus finding personnel who wanted to spend their time understanding the unique command software controls and becoming a good control operator-engineer. Hat’s-off to the ACC people. They designed a controller that worked flawlessly for over 35 years. But time moves on. Hopefully the new system will attract competent technical people who love to work with systems integration.

–Bill Talanian, Trustee
K6TZ & W6YJO Repeater Systems

Technical Mentoring and Elmering Net – Thursday April 14, 2016

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The audio archive can best followed by downloading the .mp3 file for the appropriate date here and listening with the media player of your choice. You can move the progress slider forward or backward to the subject of interest to you.

Tonight’s net had 9 Check-ins plus net control, Frank (K6FLD). Topics discussed were:

  • RG8U Coax, is it 50Ω and how can you check to be sure?
  • Single Loop Antenna, what gauge wire should be used to ground the rotor control box, linear amp, etc.?
  • Why am I hearing the remote base at USCB ID over the K6TZ frequency?
  • Mesh networking and two 90º antennas, will they interfere with each other?

Tune in to the SBARC TM&E Net next Thursday at 8:00 PM (2000 Hrs) and see what interesting questions will arise or ask some of your own! All club members and visitors are encouraged to check in to the TM&E net each week and join in with questions and /or answers to and contribute the knowledge of new and seasoned amateur radio operators alike.

Employment Opportunity At UCSB

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Bob Pizzi AC6PZ ( rpizzi@physics.ucsb.edu) has asked us to post this job opportunity available now at UCSB. It is for an Instructional Laboratory Assistant. It would be an interesting job for an amateur radio operator interested in science and physics. For more information, follow the instructions below:

Step 1: Go to : http://www.hr.ucsb.edu/
Step 2: Upper left hand corner Click “PROSPECTIVE EMPLOYEES”
Step 3: Lower right side click “Apply for a UCSB Job”
Step 4. Go to upper left corner. Click “SEARCH POSITIONS”
Step 5: Right hand side Department, select PHYS from scroll down list.
Step 6: Click SEARCH
Step 7: Select Job Number 20160152 (View/Apply)

Post expires at 10:22am on Saturday April 30th, 2016 but will still be available in the archives.