There is a new-type cellphone available. It includes not only implementation of Windows Mobile 6.0 or equivalent advanced Pocket PC operating systems, but also a chipset that includes both GPS protocols, and A-GPS protocols (cellular/satellite fast fix coordination).
An example is the AT&T Tilt (HTC TyTN II-Kaiser), pictured in Figure 1. This phone is also available from other providers, different cellular protocols (e.g., Sprint on CDMA) and under different names. Packing a Qualcomm 400 MHz CPU with over 100 MB of RAM, the phone has the capability to access up to 32 GB of data via microSDHC (super high density media cards). This phone could have been purchased at AT&T stores for as little as $149 during Thanksgiving. It is a complete, networked mobile PC if purchased with a data plan. It has Bluetooth (BT) connectivity, and a specialty mini-USB port. Implemented at AT&T, it is EDGE/3G capable with up to seven frequency bands for operation in almost any country in the world.
So, what does this have to do with ham radio?
The Tilt has the ability to run such programs as PocketDigi, a mobile digital mode program that includes PSK-31/RTTY/CW send and receive.† Figure 2 shows an example of the PocketDigi in operation on 40m receiving a CQ de WA6OVP (The Tiltís front screen opens to expose its keyboard).† To connect the cellphone to the HF transceiverís audio, I used a BT headset that formerly made hands-free cellular calls. A quick removal of the headsetís microphone and speaker, a few careful solder joints, and an isolation BT interface for PSK31 is born.
For me, the internal GPS was of greatest interest. It could be used for APRS. As an active ham when I travel I am often confronted with MANY electronic devices to pack. The fewer devices needed the better. Having ham digital modes available in my cellphone is a great asset. Having a GPS unit in my cellphone is a boon.
How to access the GPS chipset in the phone for APRS?
I have been able to implement NMEA data flow from my cellphone internal GPS using the following procedure.† It should also work with the SiRFstar III chipset in similar cellphones equipped with BT. I use a Kenwood TH-D7(G), an HT that has a built-in TNC for packet or APRS. The Kenwood HT successfully transmits the GPS coordinates to the APRS network (in the US on 144.390 MHz).
The connectivity between the cellphone and TH-D7(G) was accomplished by using a Brainboxes' BL-830 female DB-9-to-Bluetooth adapter attached to a DB-9-to-3 conductor 2.5mm plug going to the Kenwood's GPS receptacle, as pictured in Figure 3.
On the AT&T Tilt, I use the client software from GPSGate.com for PocketPC ($19.95) to set up a connection between the output of the internal GPS on COM4 and the cellphoneís Bluetooth Server. An added bonus of this process is that one can place the HT for best transmission in one location and independently place the wireless GPS at another location within the 10m range of the BT units.
In Figure 4, you see the AT&T Tilt plotting my carís position (the Jogger icon) on Google Maps as I drive, along with a nearby APRS weather station. The camera was a little shaky, hi hi.†
Iím continuing to work on this process with the hope that waypoint data from the Kenwood HT (APRS Stations) can be passed to the AT&T Tilt so other GPS mapping programs (e.g., Garmin Mobile XT) will work without the need for external access to the cellular phone network.
---* Ken WI7B