Sunday, June 08, 2014

Mobile Digital Communications

With a big part of my day spent away from home, I like to stay connected, and my mobile is equipped to make that happen.
One of the modes that I have available to me for communicating while mobile is APRS (Automatic Packet Reporting System)
APRS is a digital communications information channel for ham radio. As a single national channel, it gives the mobile ham a place to monitor in any area, at any time to capture what is happening in ham radio in the surrounding area. Announcements, Bulletins, Messages, Alerts, Weather, and of course a map of all this activity including objects, satellites, nets, meetings, Hamfests, etc.
With APRSIS running on my computer, and with telemetry being downloaded from my Kenwood TM-D710A, I have a birds-eye-view of the beaconing stations around my mobile.

I recently installed an APRS weather station, and the install was a bit of a challenge as the Argent Cable ADS-WS1 weather station was not designed for a mobile installation, but is meant to be installed in a fixed location.
Well that would be to easy, as I wanted a weather station that was first APRS capable, and second capable of being modified for mobile use.
One of the challenges I had to overcome was that the ADS-WS1 electronics module does not support a GPS receiver, as it is assumed that being it would normally be at a fixed location, you manually enter in the lat/long coordinates for your location and call it done.
Well that was not going to work for a weather station that is on a mobile, so I came up with a solution, and that is another Argent Cable device being my Opentracker OT3m.
The OT3M does support a GPS receiver, and fortunately there are two serial ports on the board of the OT3m, so I was able to connect both serial devices, that being the GPS receiver, and the ADS-WS1 weather module

I was a bit worried about how they would pass data to the OT3m, as it has only one external serial port, although there are two serial ports on the board.
However by using a serial splitter cable, and with my laptop and the config program for the OT3m, I set the A port for 4800 baud as required by the GPS receiver, and configured the B port for 2400 baud as required by the ADS-WS1 module.
Once I had the OT3m and ADS-WS1 configured, and holding my breath, I forced a beacon from the OT3m, and Eureka!
My ROVER-15 weather station was being decoded by my Kenwood TH-710A and the weather screen on my D710A with it weather symbols was reading out the temperature, humidity, barometric pressure, wind direction, wind speed, and the rainfall.  This information was also appearing on on the Internet as well.
With that out of the way for the moment, I proceeded to build a mount for the up top weather sensors with included mast to be mounted on my mobile.
Now there are times that I do not want my weather mast assembly on my mobile, so with that in mind, I built a mount that couples to my HF mount normally used with my HF antennas.
The mount took some design work, as remember the part about the fact this weather station is on a mobile that will be parked on inclines and pointing in various directions.
So the mount I came up with allows me to pivot the sensor array to position the anemometer/wind direction assembly on a East/West direction, with the anemometer on the West end of the boom as required for the wind direction sensor to report the proper information .
The mount also has an adjustment that allows for the mast assembly to be squared off. This is required for the self-emptying rain gauge to register correctly, as well as to allow the wind sensors to function correctly. Once the assembly is positioned on the mount of my mobile, It only takes seconds to make it plumb.

I am still fine-tuning my ROVER-15 weather station, and one of the things I have going on, is a small 40mm diameter aspiration fan as part of a 1.5 inch tube assembly, that draws outside air and passes it through a additional opening that I cut in the ADS-WS1 module, before exiting at the far end of the module where the temperature and humidity sensors are located on the board.
This allows the humidity sensor to report accurate readings as  to the humidity outside my mobile.
The on-board temperature sensor is no longer being utilized, as I have installed an external temperature sensor connected up to the 1-wire  data bus and is enabled in the ADS-WS1 software.
Also the air being sampled outside my mobile is in a sheltered area, my version of a Stevenson screen. The external temperature sensor is also located there.

While I am running on the fringes of the APRS Network, I change out my antennas for Larsen long-range NMO 150 VHF antennas.
If I am still having problems with my Rover-15 weather station being heard by digipeaters off in the distance, as it only has a 5 watt radio as part of the electronics package, I can then activate the digipeater in my D710, and then I have 50 watts available for my ROVER-15 weather station allowing it to be heard by distant digipeaters with a Internet connection.
Once I am back in Calgary, I then change out the two NMO 150's for my normal configuration of antennas, that being the Larsen dual band 2/70K on the front left, and my 2/70 dual band Tram at the right rear of my mobile, as my mobile then fits through the door of my garage better.

While I am away from my mobile, I carry my Kenwood D72 handi-talki with me, as it receives weather up-dates on the weather screen, direct from my ROVER-15 ADS-WS1weather station when the OT3m beacons.

This same information is also being uploaded to on the Internet.
If you wish to see what this information looks like on the Internet, once you click on the link below, on the right top enter "ROVER-15" in the "Track callsign" box.
Then in the "Show last" box, enter the hours or days you wish to look back.
Then in the "Track Tail length" box, enter the hours or days you wish to look back, and then click on search located just to the right of where you entered "ROVER-15" in the "Track callsign" box.
Once the panel with the information for my ROVER-15 floats in to view on google-maps, if you click on "info" you will see a whole lot more information, including weather graphs.
If I am out and about, you will see me moving in real-time, as I go on down the road.
Note...In actuality, you will find the page already loaded when clicking on this link. You can pull the page down to get a look at the route I travelled, which is highlighted in green.!mt=roadmap&z=11&call=a%2FROVER-15&timerange=43200&tail=43200 

Note...all photos expand.

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