As anyone that has participated in a frequency coordinating organization can attest, finding an available packet frequency in our already crowded bands is a difficult and painful process. Trying to find a single national frequency is impossible! As a weak-signal operator, and ATV'er, I do not want to see any more encroachment on the 70 CM ATV frequencies and certainly not on the the weak signal bands. Also, as a member of the local Mid-Atlantic Repeater council, I have avidly defended the UHF FM voice frequencies from encroachment by packet operations.
GPS tracking does not act like the other packet applications, however, which always seem to need more and more spectrum. GPS tracking is a SINGLE FUNCTION, SINGLE FREQUENCY application. Conversly, all other packet applications such as BBS's and DX clusters, for example, are HUB or star based networks which operate most effectively when each major NODE or BBS has its own separate frequency. Due to the community nature of these beasts, there is always a crowding effect driving the users to find more and more frequencies.
The GPS reporting and tracking network, however, gains its advantage by having ALL mobile stations on one and only one frequency. Just as HAMS have 146.52 as a national calling frequency, and CB'ers have channel 19, the GPS application needs only a single calling frequency too.
Maybe it is time to allocate just a single one of the FM simplex channels near the 446.0 FM simplex calling channel as a mobile GPS calling channel. Just as 446.00 is recognized as the UHF calling frequency, there should be a comparable GPS status and calling frequency for mobiles nationwide. I anguished long and hard over this proposal, and I suspect that it will meet with a lot of emotional and idealogic controversy. But I think that anyone that is watching the trends in communications technology will certainly conclude that GPS position reporting of mobile radio operations WILL BE FUNDAMENTAL IN EVERY MOBILE NETWORK within 10 years. (Just witness the growth of APRS in only 4 years!) We either bite-the-bullet now and plan for the orderly development of GPS applications on the 70 cm band, or we will be fighting this same battle for the next ten years.
If you have any comments on this idea, or can see a better way, please contact your local frequency coordinating council. This is not a request for coordination, since it fits no established categories and simplex voice frequencies are not coordinated, but if your coordinating body does keep a "list" of common usage, then see if the 445.925 MHz simplex FM channel is available in your area. This is not a PACKET issue and should not just be relegated to the digital channels. It is a unique MOBILE application that should be addressed with primary consideration to its broad ranging and NON fixed application across coordination boundaries. On the other hand, typical packet applications are for FIXED links where frequency coordination and sharing are easy to accomodate by known fixed spatial separation. APRS UHF voice with GPS position reporting will be EVERYWHERE...
I just can't get over the excitement, of someday, being able to glance at your dash-board mounted full color map display and seeing the location of every mobile HAM within 30 miles! Setting aside a single GPS status and position reporting simplex VOICE frequency NOW, will make this happen!