GPS, APRS and HAM Radio

[Emmbeedee]

This subject relates to the Data In and Out available on certain GPS units when used with appropriate cables and connections to APRS and Other technologies. The Garmin Montana Rugged Mount provides the connections needed through its Data cable. I think other models of gps like the 60/76 can also be made to work this way.

I know nothing about this but it looks like an interesting subject as described by Adrian Burg of Calgary Alberta in the GPSCentral February 2013 Newsletter: APRS and Ham Operations with the Garmin Montana GPS

Here's another description of the technology: http://www.gpscentral.ca/photos8.html

[Emmbeedee]

As I suspected, there's a long list of gps units which can be used with APRS.

Here's a list on eHam.net.

[Emmbeedee]

More info on APRS.

http://www.aprs.org/

[AVGeek94]

Boy, look what I started!

I've been researching APRS for use on my bike when traveling, since I first came across this as an option on Spotwalla. Basically, APRS is a means of automatically transmitting a message using amateur radio technology. In the US, APRS is transmitted on 144.300MHz. Using APRS requires an amateur radio (ham) license.

In the course of my research, I found that some GPS units have the capability of sharing data with a properly equipped radio or translation box using the NMEA serial protocol standard. I became interested in it when I found that the Garmin Montana is one of those units, and that the serial port is available on the Rugged Mount (meaning, I could mount some hardware hidden on my bike that would interface with the Garmin and a radio to broadcast my location when traveling).

I posed the question on the Montana thread about using the serial data lines to see if anyone here has done this before. I am by no means an expert in amateur radio (I've had my tech class license for over 10 years now, but haven't really kept up with the hobby), so I was looking for guidance.

[Emmbeedee]

Originally Posted by AVGeek94

Boy, look what I started!.

Thanks for bringing it up. It looks fascinating, though expensive, to me.

[stevenknapp]

I used my 276C, HT, and one of these: http://www.byonics.com/tinytrak/

Worked well enough, wasn't super reliable as your location being reported really depends on what APRS stations are nearby. Still neat.

[stevenknapp]

Pretty much any GPS with an NMEA output would work for this. You can even find some small standalone pucks.

I had the HT already, used a VX2R. It all fit in a handlebar bag on my Buell.

These days something like the Spot, Garmin GTU10, or Google Latitude seems to fit the bill just as well.

[AVGeek94]

Originally Posted by stevenknapp

Pretty much any GPS with an NMEA output would work for this. You can even find some small standalone pucks.

I had the HT already, used a VX2R. It all fit in a handlebar bag on my Buell.

These days something like the Spot, Garmin GTU10, or Google Latitude seems to fit the bill just as well.

I saw that Byonics unit you posted earlier, might go that route since I am radio-less at the moment. I tried Google Latitude on my SS1000, and it didn't automatically update my location, I wound up manually checking in at my fuel stops.

[stevenknapp]

The Tiny-Tracker I have still needs a radio. There is one that is self contained, but it ends up costing more: http://www.byonics.com/mt-aio

Did you see this about latitude? You need to jump through some hoops to share with the public, if that's what you were trying to do.

http://support.google.com/gmm/bin/an...&answer=144216

I've had very good luck with latitude, better than I had with APRS.

[lmychajluk]

You guys are killing me... I stumbled on this discussion from the Montana thread, and it just so happens that I also got an email the other day with an offer to take a free class to get a HAM license. I originally just ignored it, but now curiosity got the better of me and so now I'm signed up for a Ham oeprator class starting next week. Still not sure why...

Re: GPS and data transfer, I can tell you that one way that's used on a boat - Every modern marine radio in the US supports DSC (Digital Selective Calling), which, among other things, provides a 'panic button' on the radio that will automatically send out a distress call to the Coast Guard and whoever else is listening. The NMEA protocol (originally 0183, now 2000) is used for data transmission between the radio and GPS (as well as other shipboard devices). What this does is allows the current GPS position to be sent along with that distress call, and, if your radio and GPS support it, will automatically plot the location of a distress call recieved via VHF on the GPS. Some may even provide a way to automatically plot a course to that waypoint. Another similar use for AIS, which broadcasts the position of your vessel and allows the position of any ship broadcasting an AIS position to show on your GPS (along with some data like ship's name, speed, course, etc...), even when that ship may be out of sight or radar range. Here's a site that collects that info and overlays it on a Google Map:
http://www.marinetraffic.com/ais/

One cool thing that's up and coming with the AIS technology is 'virtual' navigation aids. If there's an obstruction in the water, an authority like the Coast Guard can broadcast the position via AIS and that can show up as a marker on your GPS. Or, boat races can have the courses defined on thier GPS without having any physical bouys in the water. There are even PLBs that are starting to incorporate AIS so if you go overboard, an alert with your position is transmitted to any nearby ship w/ a VHF radio. Some pretty cool stuff!

[stevenknapp]

If I understand DSC you can use it for non-emergencies as well. Hail a friend, or query their location.

I had it all wired up to my 276C when we had a small cruiser. Now with the jetski I picked up the Standard-Horizon w/ the GPS built in!

[lmychajluk]

Yes. DSC is 'enabled' by programming a freely-obtained MMSI # into your radio. This # becomes a unique identifier to the vessel (all radios on a vessel should use the same MMSI#). It's transmitted along with any DSC call, so that's how the Coast Guard knows who's issuing a distress call (they look up the registration data in a database). If you know the MMSI of another radio, you can use it to call that radio directly (and most radios will allow you to keep an 'address book' of MMSI numbers with user-friendly names). Depending on the features of your radios, there are also things like Position Tracking and Position Reporting that allow you to set up periodic, automated position reports or requests between radios, which, with the right GPS, will show your buddies' location on the screen. I have a handheld SH HX851 as a backup to my SH Matrix+ that's mounted on my boat.

[advNZer?]

Originally Posted by lmychajluk

Yes. DSC is 'enabled' by programming a freely-obtained MMSI # into your radio. This # becomes a unique identifier to the vessel (all radios on a vessel should use the same MMSI#). It's transmitted along with any DSC call, so that's how the Coast Guard knows who's issuing a distress call (they look up the registration data in a database). If you know the MMSI of another radio, you can use it to call that radio directly (and most radios will allow you to keep an 'address book' of MMSI numbers with user-friendly names). Depending on the features of your radios, there are also things like Position Tracking and Position Reporting that allow you to set up periodic, automated position reports or requests between radios, which, with the right GPS, will show your buddies' location on the screen. I have a handheld SH HX851 as a backup to my SH Matrix+ that's mounted on my boat.

that could be a handy feature on a group ride.Are there really compact radios that can do this?

[lmychajluk]

Originally Posted by advNZer?

that could be a handy feature on a group ride.Are there really compact radios that can do this?

Legally, you can't use a marine radio on land. But, in reading up on HAM / APRS, I think APRS can be used for similar functionality. You'll need a ham license, though...

Check out this link: http://aprs.fi

You can see all the APRS transmitters in an area. The trick would be to get the data your radio is recieving and display it on your GPS, which (I think) is what AVGeek94 was talking about.

Here's a compact radio w/ built in GPS that can be used for something like this (as far as I can tell):
http://www.amazon.com/Yaesu-VX-8GR-D...keywords=VX8GR
This one doesn't have the built in GPS, but seems to have the connectivity needed to connect an external GPS (possibly along with the previously-mentioned TinyTracker):
http://www.amazon.com/Quad-Band-Yaes...=IZ0VELTAA3NRO

Still not sure how one would get the incoming data from the 'other' riders output back to the GPS and displayed. In all honesty, though it sounds like a lot of fun to play with (to a geek like me, anyway), Google Latitude will probably do the same thing for free with 5 min of setup, providing you can get a cell signal.

[AVGeek94]

Someone posted over in the Montana thread that his displayed any received APRS beacons, so it appears that the communication with the Montana is bi-directional. I'm still in the research phase, so haven't yet made the plunge with any hardware.