Sunday, April 11, 2010

APRS Embeded into Get-R-Done Horse Ride, Inyokern, CA


KG6STR Operating as Net Control

I embedded my MT-AIO tracker into a Horse Ride that the local club was providing communications for. I was also a volunteer for the event, I assumed Net Control at Base camp for a few Hours. This gave me the perfect opportunity to test my tracker in the field. I prepped my tracker (KI6PSP-3) with Energizer Lithium batteries. The higher voltage would provide a bit more power output, vise the rechargeable batteries that resulted in 3 watts of output while running off 10.5 volts.

The tracker was started early in the morning, with the first packet reaching the internet via my local digi (WI6RE) at 7:12AM, just as the rider, Sue Benson and her horse Rocky began Loop 1.

I quickly setup my low powered APRS computer station in the control booth at base camp. I soon realized that the El Paso Peak Digi was probably not hearing every packet the tracker was sending, so I enabled digipeating on my station, and set it for 10 watts. The antenna I was using was a 3db magnet mount, on top of a box fan.
As Horse 509 carrying my tracker and its rider crossed Brown Rd, heading South back to base camp, I picked it up on my computer. It was really interesting when I was able to see exactly where they were, then look out the window and saw them during their Vet Check.

The tracker has an SMA connector for the antenna. I picked up a $15 1/4 wave flexible antenna from Fry's Electronics (Premier Antenna RD-9), and used that on a SMA-BNC adapter. This allowed the antenna to stay vertical, and not get in the way of the rider. During their 30 minute hold, I inspected the antenna and snapped a few pictures. The antenna got slightly bent, but that was why I used the cheaper short antenna. The tracker was located on the front right pocket of the saddle, and you can see the antenna if you look closely at the picture.

Heading back out

Plot from Event
I was unable to attend the whole event, but I left my computer station to act as a fill-in digi. With the digi in operation, I was able to track horse 509 as it finished Loop 1, returned to camp, proceeded through Loop 2, completed its final Orange Short loop, then returning to base. The tracker shutdown around 5:22PM, operated for just over 10 hours, with a transmit interval of every 2 minutes. Distance traveled was about 55 miles. Top speed tracked was 9 MPH along a stretch of Loop 2. During this event, 7 packets were heard directly by WI6RE Digi, and 59 Packets were digi'd by my computer station.

I do still plan on building a new APRS Server for the Digi on El Paso Peak, with an alternate receive freq that we can operate on for events like this, as the MT-AIO doesn't listen for activity before transmitting. If I combine this with a better antenna at base camp, with slightly more elevation, I think this system will work well.

As the evening set in, I recovered my computer station with the assistance of my 2 year old daughter. She had fun telling me where every horse was that she could see. I am unsure if she would rather ride the horses or help with tracking them.