Band plans delineate where different Amateur Radio activities co-exist concurrently. Our guidebook, the FCC Rules and Regulations (47 CFR 97.1) states are reason for existence of the Amateur Radio Service:
The rules and regulations in this part are designed to provide an amateur radio service having a fundamental purpose as expressed in the following principles:
(a) Recognition and enhancement of the value of the amateur service to the public as a voluntary noncommercial communication service, particularly with respect to providing emergency communications.
(b) Continuation and extension of the amateur's proven ability to contribute to the advancement of the radio art.
(c) Encouragement and improvement of the amateur service through rules which provide for advancing skills in both the communication and technical phases of the art.
(d) Expansion of the existing reservoir within the amateur radio service of trained operators, technicians, and electronics experts.
(e) Continuation and extension of the amateur's unique ability to enhance international goodwill.
Considering 47 CFR 97.1(b), the Amateur Radio experimental clause, let's take a look at the Minnesota Repeater Council's Band Plans. On 6 meters, 50.600 - 51.000 Mhz (400 Khz) is reserved for "Experimential(sic)/Special Modes"; 2 meters, 145.50 - 145.80 (300 Khz) for "Packet, misc and experimential(sic)"; 1.25 m, none; 420.10 - 420.20 Mhz (100 Khz) for "Auxiliary Links and experimental". For a total allocation of 44 Mhz, designated experimental purposes are assigned 800 Khz, or about 1.812%.
In comparison, the ARRL Band Plans allocates 6 meters with 50.30 - 50.60 Mhz for "All modes", 50.60 - 50.8 Mhz for "Nonvoice communications"; 2 meters, 145.50 - 145.80 (300 Khz) for "Miscellaneous and experimental modes"; 1.25 meters, 222.15 - 222.25 Mhz and 223.71 -223.85 Mhz for "Local coordinator's option; FM simplex, packet, repeater outputs"; 70 cm, 420.00 -426.00 Mhz for "ATV repeater or simplex with 421.25 MHz video carrier control links and experimental". For a total allocation of 44 Mhz, designated experimental purposes are assigned 6.3 Mhz, or 14.3%. unevenly distributed in favor of 70 cm. I need to write to the ARRL for clarification about the definition of "local coordination's option", if it includes experimental.
Question: how many coordination requests have there been for ATV repeaters? MRC lists only one in the entire state for 70cm and below: Wabasha 439.250/431.250 Mhz (uplink/downlink). If you're above Line A, you will be excluded from the 420 - 430 Mhz section of 70cm. This effectively destroys the sub-band, leaving 2 Mhz for ATV simplex from 430 - 432 Mhz, leaving no possibility for ATV repeater coordination north of Line A.
We also need to consider the local frequency coordinator. There are two FCC rules concerning this - 47 CFR 97.3(a)(22) and 47 CFR 97.201(c):
Frequency coordinator. An entity, recognized in a local or regional area by amateur operators whose stations are eligible to be auxiliary or repeater stations, that recommends transmit/receive channels and associated operating and technical parameters for such stations in order to avoid or minimize potential interference. 47 CFR 97.3(a)(22).
Where an auxiliary station causes harmful interference to another auxiliary station, the licensees are equally and fully responsible for resolving the interference unless one station's operation is recommended by a frequency coordinator and the other station's is not. In that case, the licensee of the non-coordinated auxiliary station has primary responsibilty(sic) to resolve the interference. 47 CFR 97.201(c).
Don't forget about good operating practice, 47 CFR 97.201(a)-(d):
(a) In all respects not specifically covered by FCC Rules each amateur station must be operated in accordance with good engineering and good amateur practice.
(b) Each station licensee and each control operator must cooperate in selecting transmitting channels and in making the most effective use of the amateur service frequencies. No frequency will be assigned for the exclusive use of any station.
(c) At all times and on all frequencies, each control operator must give priority to stations providing emergency communications, except to stations transmitting communications for training drills and tests in RACES.
(d) No amateur operator shall willfully or maliciously interfere with or cause interference to any radio communication or signal.
Band plans are entirely voluntary, however, if you deviate from "good amateur practice" (read: accepted amateur radio practice) , you will incur the wrath of your fellow operators in the Amateur Radio Service and the FCC will descendeth upon you in the form of a Notice of Violation.
Looking at it another way, each band plan is divided between coordinated and non-coordinated frequencies. For 6 meters, the MRC coordinates 4 Mhz (50%); 2 meters, 2.16 Mhz (54%); 1.25 cm, 2.24 Mhz (74.7%); 70 cm, 22.175 Mhz (73.9 %). Above Line A, the 70 cm total is 16.175 Mhz (53.9 %) with the ATV repeater sub-bands rendered effectively useless.
IMHO, the band plans need to be updated.