Alternate Spectrum for Broadcasting: 1705~1800 kHz
This is the spectrum located between the AM broadcast band and the 160 meter amateur radio service band. It has been suggested in previous proceedings that this spectrum be used as an expansion for the broadcast band.
Who uses it?
Domestic incumbent users: There is one traveler's information station operating on 1710 kHz on a waiver, Two Alaska Fixed service licensees and one multiple site radiolocation licensee supporting the petroleum industry. There are some unlicensed 100 milliwatt (and some higher) operations on 1710 kHz. Unlike other so-called "Part 15 broadcasting", operations on 1710 kHz do not fall under the more liberal allowances for power and antenna length under §15.219.
Foreign incumbent users: Unknown.
How do they use it?
ITU Region 2 allocation: 1705~1800 kHz is allocated to fixed, mobile, radiolocation and aeronautical radionavigation on a co-primary basis.
Federal Government and FCC allocations: 1705~1800 kHz is allocated to the fixed, mobile and radiolocation services on a co-primary basis. The FCC has allocations in the Alaska Fixed Service (part 80) and the Private Land Mobile (part 90) radio services. The bands 1715~1725 and 1740~1750 kHz are allocated on a primary basis and the bands 1705~1715 and 1725~1740 kHz on a secondary basis to the aeronautical radionavigation service (radiobeacons).
Canada/Mexico allocations: Canada follows the Region 2 allocations. Mexico classifies this as protected spectrum for the aeronautical radionavigation service. Fixed, mobile and radiolocation service shall not cause interference to the operation of the aeronautical radionavigation service, no shall it claim protection against harmful interference from aeronautical radionavigation.
REC analysis and opinion for use as alternative spectrum
Worldwide, this spectrum is used for aeronautical non-directional beacons (NDB) however in North America, the spectrum below 530 kHz is used for NDBs and as much in North America. Historically, this spectrum has also been used for one way police radio calls even though a majority of those fixed stations were in the 1600~1700 kHz range. This spectrum has not been allocated anywhere in the world for broadcasting and despite the low power of alternative spectrum services, it's "legitimate" use as a broadcast service may require a change of the table of allocations or at least the addition of a national footnote through the auspices of a World Radio Conference (WRC). Like with the AM broadcast band, this spectrum may have propagation characteristics at night.
Using 10 kHz spacing, 9 channels could be accommodated (1710~1790 kHz). Using 9 kHz spacing, 10 channels cound be accomodated (1710, 1719, 1728, 1737, 1746, 1755, 1764, 1773, 1782, 1791). There appears to be a considerable number of consumer grade AM broadcast receivers that will tune the carrier frequency of 1710 kHz analog and possibly HD Radio. Reception of the rest of the band would be limited to general coverage receivers and software defined radios.
The use of this spectrum would probably be limited to very low power operations in the United States and would likely not trigger a market for manufacturers to invest in new receiver designs that would cover these frequencies, especially those with a digital mode such as DRM or HD Radio.