darryl ramm’s blog

I’ll write up some more comprehensive comments on the SPOT satellite messenger soon, but in the meantime I wanted to provide some screen shots of the SPOT web site showing what is available from the optional SPOT Track Progress service from SPOT. Overall I’m impressed by the SPOT messenger and I will be using it in my glider, particularly when flying in remote areas to automatically track my location and as a supplement to my existing McMurdo Personal Locator Beacon (PLB). I purchased my SPOT messenger from my local REI store, it is also available at REI online.

SPOT is a subsidiary of Globalstar, the satellite phone company. The SPOT satellite messenger has an internal GPS receiver and sends the GPS coordinates and message type info via the Globalstar L-band simplex data network. Message types available are an automatic tracking message, or manually triggered events - a “911″ distress alert, a less severe “help” message or just an “OK” message.

In the track progress (aka “SPOTcasting”) mode the SPOT messenger automatically sends latitude/longitude position reports every ten minutes for up to 24 hours, after which the automatic tracking needs to be reenabled. Enabling this mode involves holding down the “OK” button for 5 seconds or longer. This needs to be done carefully, if held down for too short a time the SPOT messenger will just send a single “OK” message and will not send subsequent tracking messages. While in track progress (”SPOTcasting”) mode the messenger cannot send single “OK” messages, but can send “Help” or “911″ messages by pressing the corresponding buttons. “OK”, “Help” and “911″ SPOT message types can be forwarded to email or cell phones as SMS messages, but automatic tracking messages can only be viewed by logging into the SPOT web account associated with the SPOT Messenger.

Click on the thumbnails above for full size images, the Message History page at the top left shows my SPOT user account message page that shows tracking messages from my SPOT messenger. Clicking in the check boxes next to each message or clicking “Select All” and then clicking on the “Show on Map” button will generate a Google Map with track points overlaid as shown in the two map screen shots. Importantly, the track points are numbered but this appears to be fairly uselessly just the sequence they were in the Message History page, and may not be the actual time sequence. The first track map shows only a few track points from a short flight from Williams gliderport in Northern California. The second track map shows what happened when I took the SPOT messenger and put it on the passenger seat of my SUV but forgot to turn it off then drove home to the San Francisco Bay Area. The SPOT messenger was able to acquire a GPS signal and transmit via the Globalstar satellites fairly reliably through the closed sunroof of my SUV, I was pretty impressed by that.

The final photo shows where I have the SPOT messenger installed on the canopy rail in my ASH-26E motorglider. It is just held in place with 3M adhesive dual-lock fastener tape. It will likely be moved to a more permanent mount on the instrument shroud and also be painted black to minimize reflections in the canopy.

I am concerned that the SPOT messenger does not end up being used instead of Personal Locator Beacons (PLBs) by glider pilots flying in remote areas. PLBs have a 406 MHz beacon that is monitored by SARSAT/COSPAR satellites, PLB units like mine relay their GPS coordinates over the 406 MHz signal, or alternately the satellites can doppler position the transmitter relatively accurately. PLBs also have a secondary 121.5 MHz homing beacons that CAP and other SAR organizations can home into. SPOT has no homing beacon and the “911″ escalation service they provide is through a commercial operation, not the standard US government SAR organizations, so it needs to be seen how well this works in practice. If I’m hanging under a parachute canopy after having bailed out of my glider, I want my PLB with me not SPOT. For other stuff the SPOT position tracking feature may provide rescuers my last know location without requiring manual PLB activation or an (unreliable) impact activation from an ELT. And SPOT is capable of sending ground crew and others non-critical messages, like where you have landed out, something you can’t do with a PLB or ELT.

See also the first look and an update on the SPOT messenger by Doug Ritter of Equipped to Survive.