Nearest I can determine, the last time ARRL bandplans were reviewed was nearly 20 years ago for 50 MHz and above.
There is some ARRL Microwave Band Planning in it's initial stages that I welcome as it's long overdue in my opinion. So I do look forward to reading other peoples thoughts on how to tackle the problem of promoting ultra wide band data modes and somehow keeping some harmony with any existing activity on these bands.
Chairman and Liaison Appointments: Microwave Band Planning Committee: Tom Clark, K3IO, Chairman.
I noticed that Will Payne, N4YWK is a part of some sort of active ARRL Microwave Band Planning. He has a help wanted thread on the LinkedIn ARRL Ham Radio Operators group. He appears to be surveying conventional repeater use. (He is seeking help fill in two "lost decades", the 1960's and the mid-70's to mid-80's, contact Will if anyone you know who may have old repeater listings.)
The historic growth of repeater populations on the lower bands might serve as a bellwether for future growth on the microwave bands. Historic growth graphs would also be informative for the ham community at large.
Also in the The ARRL Letter, Vol 27, No 29 (July 25, 2008), there is this interesting snippet:
* ARRL Board of Directors Plans the League's Future at Second 2008 Board Meeting
The Board voted to establish an ad hoc study committee to review Part 97 of the rules governing the Amateur Radio Service to ascertain what rule change(s) would be beneficial to promote wideband digital modes, while at the same time minimizing potential interference to narrowband modes.
And more recently:
It Seems to Us: Coexistence - Radio spectrum management is a difficult business. The most useful part of the spectrum has been fully allocated for decades, yet new uses continue to be developed. Where can they go? It's a question that requires ever more imaginative answers.
With those observations pointed out. Basically I feel investigating and possibly revising the bandplans is long over due.
I feel that 900 MHz and above are the future of ham radio. On SHF frequencies outside the ham realm, wide band modes are exploding. Such hardware can be adapted to the amateur service. Doing so (as the former HSMM WG showed) is probably the easiest way to populate these bands. Our SHF allocations have the band space to accommodate such modes so this is a natural fit.
Therefore I feel wide band (OFDM) modes should be promoted as first class modes of operation on these bands. Presently they are see by many hams as secondary to "conventional modes" like FM and analog ATV. The present voluntary band plans for 900 and above seem to detour ham from experimenting with these "futuristic" modes, as they are unsure how they fit into to the existing plan if at all. The other detriment of antique band plans is when (potential) manufactures look at is for reference on what would be a marketable ham line or product.
Bandplans for 900 MHz and above, unlike for below 900 MHz, need to have a futuristic theme in mind, to provide a path to the future. This futuristic thinking is also because one must realize it will take years to substantial SHF utilization to occur anyway.
One of the purposes of a frequency coordinator is to recommend standard operating procedures. The frequency coordinator's main job is to make sure your repeater will not interfere with nearby repeaters already established.
They have the duty to not only produce bandplans that satisfy the needs of repeater owners within its area but also to protect the interests of coordinated systems in adjacent areas, weak signal modes, digital communications, AM and FM simplex, and satellite uplinks and downlinks. They define the bandplan for both coordinated and non-coordinated activities within its territory.
In the event your coordination body's band plan is behind the times; Aside from the FCC's frequency limits spelled out in Part 97, everything else is technically a voluntary band plan.
From what I have observed, the frequency coordinator's job (at state, regional
and nation levels) isn't an on-the-air practice so it seems they are totally off
the hook when it comes to holding up their duties.
Until things are formally updated, just observe Good amateur practice . Make your best effort to check for other band use. And if you determine the conventional band use doesn't offset your experimentation, then I tend to think what you are doing on our underutilized SHF bands IS in the best interest of the amateur radio service.
(You can see this has been on the ARRL’s to-do-list for at least a year or better. But we are talking about the ARRL here.)