Internal GPS Functionality
Like the Yaesu VX-8Gr, the GPS is built into the TH-D72 and obviously factored into the market price of the rig. Obviously, you need the GPS to make the APRS functions effective, but it does offer stand-alone functionality. Like the basic radio screens, the GPS screens are simple and easy to read. Rather than attempting to cram all of the GPS information onto one screen, the designers chose to put it on several screens requiring you to use the left and right navigation buttons to move between the screens. Some people will prefer the Kenwood's design; others will prefer the more cluttered but everything-at-a-glance presentation of the Yaesu design. I like both display designs and understand the merits of each.
One nice, well thought-out feature is the ability to turn the GPS on and off. It also has a GPS battery saver feature that turns the gps on and off based on the user selected timer and whether or not it has been able to lock onto your position. Here are a few shots of the various of the GPS screens that become active once you have turned the GPS on and it has locked onto your position:
GPS coordinates with Grid-Square indicator:
Altitude, bearing, time and speed:
The TH-D72 has GPS functionality is useful to those interested in geocaching, orienteering, or other such activities. You can enter up to 5 "target points" and then use the GPS to direct you to that point. Here is the screen that shows the distance and bearing to a target point off the coast of Africa in the Gulf of Guinea (00.000, 00.000):
Here is the screen that shows you the radio's current GPS acquisition status:
You can save 100 waypoints into the radio by using the "MARK" function. This is accomplished by pressing and holding the MARK button, after which you can edit the name and symbol used to recall the marked location. To recall the waypoints, you press the MARK button quickly, which results in this screen:
You can then use either the dial on top or the up/down buttons to select the waypoint, hitting the right arrow button to see the details like this:
Repeatedly pressing the right arrow button will also show you the altitude, bearing, and date/time the waypoint was saved. Pressing the MENU button brings up the naming options and also gives you an option to copy the waypoint to a "target point" for navigation. Even though the radio only allows 5 active "target points", the ability to save 100 waypoints should give you plenty of memory slots to play with.
The waypoint functions are not all that intuitive, unfortunately. Without reading the manual, there is really no way to figure out how to do certain things by relying solely on the the information labeled on the buttons. For example, if you want to delete a waypoint, you press the A/B button after highlighting the saved waypoint in the list. However, there is no way you will ever figure that out on your own and if you miss that one line in the manual, you'll end up frustrated.
An interesting GPS function is the ability to perform GPS logging. This feature saves a log of where you have traveled over a period of time. You must first configure how you want the log function to work by going into the menu labeled "LOG SETUP". You can select between three different methods: Time, Distance, or Beacon. Selecting Time or Distance allows you to set either a fixed time interval or distance change that you want to use to trigger the radio to record your GPS data. The manual does not say how the "Beacon" setting works and I haven't had a chance to test it yet. I assume it will record the GPS data every time your radio beacons the APRS info. I'll report back on that setting later.
Starting and stopping the logging function is a little tricky and not fully explained by the manual. If you want to perform logging while using the normal radio functions, you must be on the main frequency display screen
(this is the part the manual leaves out). You press F then 2 to start or stop logging. The screen will indicate at the top that the logger is starting or stopping. The other method is to put the radio into "GPS ONLY" mode and using the F-2 button. When you do this, you get the resulting screen:
When in this mode, you have no radio or APRS functionality; only GPS functions are enabled.
The logger saves the GPS information into an internal stored memory. You can see both the status of the logger and the amount of memory used by hitting the POS (position) button and then using the right arrow to select the logging status screen that looks like this:
If the logger is active, screen displays "Logging..." in the center.
Once you've recorded a GPS log, you need to use the Kenwood software to retrieve it to your PC. You can also clear the GPS log at this time. The file is saved in standard NMEA format. I use Microsoft MapPoint which does not support importing NMEA files, but instead expects the GPX format. Fortunately, the free GPSBabel software (GPSBabel: convert, upload, download data from GPS and Map programs
) can convert between any GPS file formats and allowed me to quickly import my test GPS log for display in the software.
Here is a screen capture of part of my test route today:
I didn't have a chance to test out live tracking with MapPoint using the radio's GPS today, but I will do that soon and report the results. I'm hopeful that it will work fine.
As you can tell, the GPS functions are very full featured. The ability to copy a trip log to a PC in a standard format is a really neat feature. Saving waypoints and then navigating to them is very straight forward. Some of the GPS functions are not very intuitive to figure out, but once you understand how to activate them, they work well.
Next, I'll start reporting on the APRS functionality.