The ARRL just filed a Petition for Rule Making with the FCC concerning a specific modulation format called TDMA (Time Division Multiple Access). This issue has been simmering in the community of repeater operators but I suspect that most hams have no idea what this is about. It so happens that the land mobile industry (most notably, Motorola) has developed a very efficient and cost-effective digital standard called DMR (Digital Mobile Radio). Motorola markets this technology under the name MOTOTRBO.
As often happens, some radio amateurs deployed this new Part 90 radio technology on the ham bands. Along the way, people started looking carefully at the emission designator that Motorola was using for MOTOTRBO and began to question whether it was allowed under Part 97. I won’t go into the gory details as it makes my head hurt :-). My brief look at this concluded that there is definitely an issue here but I am not completely convinced that DMR is illegal under Part 97. If you want to dig into this, read the petition in detail with a copy of Part 97 and a few aspirin in hand.
The ARRL probably did the right thing by requesting a very focused rule change which should remove any ambiguity from Part 97. (I know this will disappoint the arm-chair lawyers who make a so-called life out of debating these issues to death.) The ARRL also asked for an immediate temporary waiver from the FCC to allow for DMR operation while the rule making proceeds…another good move.
It is unfortunate that the FCC amateur rules were written in a way that (potentially) disallowed the use of the latest land mobile radio system. This is exactly what we don’t want to have happen in the Amateur Radio Service, as it should be a place for easy adoption of new technology. Future FCC rule making should keep this in mind, always erring on the side of flexibility.
– 73, Bob K0NR
Update on 25 Mar 2011:
The ARRL reports that the FCC is seeking comments on this petition, now designated RM-11625. Comments can be filed electronically here.