Automated Maritime Telecommunications System (AMTS) is a commercial mobile radio service used within the United States. It operates within the VHF frequency range, just above the North American Band III television range, and offers both voice and data communications to maritime customers. The system is operated by a network of private carriers across the country, with coverage primarily including coastal and inland waterways.
In 1981, the FCC proposed the Inland Waterways Communication System (IWCS), a commercial maritime radio service with the proposed purpose of expanding private maritime communication and that was to operate from 216 to 220 MHz.[1] Earlier reports had studied the feasibility of using this frequency band, but warned of the high probability of adjacent-channel interference with TV channel 13.[2] However, by the early 1980s, it had been estimated that radio tuner technology had advanced to the point that such interference could be minimized.
Final approval for auctioning of AMTS spectrum did not come until almost two decades later with the approval of the Balanced Budget Act of 1997, which required that the FCC auction licenses for such spectrum.[3]
Technical specificationsedit
Maximum base station transmit power: 1,000 watts ERP[4]
Maximum mobile unit transmit power: 18 watts ERP[5]
The AMTS spectrum may be used in Land Mobile Radio Systems subject to the above-mentioned regulations and TV interference considerations. For example, under the conditions of the service, AMTS spectrum could be used in land-locked (e.g.) Denver to carry mobile radio traffic.
Bands bought at auction having Geographic licenses (use inside a defined region, vs. Site Licenses that are only for a point) may be divided into frequency channels per the owner or licensee's discretion. Thus, if the user chooses to use Narrow Band spacings, the number of channels per block is 500 kHz / 12.5 kHz= 40 channels; with Very Narrow Band spacings, the number of channels per block is 500 kHz / 6.25 kHz = 80 channels. Using technology that can support narrower bandwidths in general allows more efficient use of the licensed block. Note that spectra do not have to be purchased in 500 kHz. purchasing (e.g.) 375 kHz is allowed under FCC rules, although the seller may not be amenable to such a proposal.
Restrictionsedit
The AMTS is unique to U.S. waters, having no compatible counterpart in Canada or Mexico.[3] Use is limited to a maximum of 12 nautical miles off the US coast. Interference outside US territorial waters is possible.
When used within 105 miles (169 kilometers) of a TV transmitter operating on channel 13 or within 80 miles (129 kilometers) of a TV transmitter operating on channel 10, the FCC requires a plan to limit interference of such TV signals by both base stations and mobile units.[7] As such, maximum transmit power may be below 1,000 watts ERP.
Lastly, AMTS systems may not interfere with the SPASUR radar system which operates on the adjacent 216.88-217.08 MHz band.[6]
Referencesedit
^R. Eckert: Guidance for Evaluating the Potential for Interference to TV From Stations of Inland Waterways Communications Systems, Federal Communications Commission Office of Science and Technology, 1982
^L. Middlekamp, H. Davis: Interference to TV Channels 11 and 13 from Transmitters Operating at 216-225MHz, FCC Lab Division Report, Project No. 2229-71, 1975
^ ab"Auction of Automated Maritime Telecommunications System Licenses Scheduled For August 3, 2005", FCC DA 05-1047, 2005
automated, maritime, telecommunications, system, amts, commercial, mobile, radio, service, used, within, united, states, operates, within, frequency, range, just, above, north, american, band, television, range, offers, both, voice, data, communications, marit. Automated Maritime Telecommunications System AMTS is a commercial mobile radio service used within the United States It operates within the VHF frequency range just above the North American Band III television range and offers both voice and data communications to maritime customers The system is operated by a network of private carriers across the country with coverage primarily including coastal and inland waterways Contents 1 History 2 Technical specifications 3 Restrictions 4 ReferencesHistory editIn 1981 the FCC proposed the Inland Waterways Communication System IWCS a commercial maritime radio service with the proposed purpose of expanding private maritime communication and that was to operate from 216 to 220 MHz 1 Earlier reports had studied the feasibility of using this frequency band but warned of the high probability of adjacent channel interference with TV channel 13 2 However by the early 1980s it had been estimated that radio tuner technology had advanced to the point that such interference could be minimized Final approval for auctioning of AMTS spectrum did not come until almost two decades later with the approval of the Balanced Budget Act of 1997 which required that the FCC auction licenses for such spectrum 3 Technical specifications editMaximum base station transmit power 1 000 watts ERP 4 Maximum mobile unit transmit power 18 watts ERP 5 Block 6 Frequency Band uplink Frequency Band downlink Block Bandwidth Channels Channel Bandwidth per duplex Num of LicensesA 217 5 218 0 MHz 219 5 220 0 MHz 500 kHz 2 20 25 kHz 9B 217 0 217 5 MHz 219 0 219 5 MHz 500 kHz 2 20 25 kHz 1The AMTS spectrum may be used in Land Mobile Radio Systems subject to the above mentioned regulations and TV interference considerations For example under the conditions of the service AMTS spectrum could be used in land locked e g Denver to carry mobile radio traffic Bands bought at auction having Geographic licenses use inside a defined region vs Site Licenses that are only for a point may be divided into frequency channels per the owner or licensee s discretion Thus if the user chooses to use Narrow Band spacings the number of channels per block is 500 kHz 12 5 kHz 40 channels with Very Narrow Band spacings the number of channels per block is 500 kHz 6 25 kHz 80 channels Using technology that can support narrower bandwidths in general allows more efficient use of the licensed block Note that spectra do not have to be purchased in 500 kHz purchasing e g 375 kHz is allowed under FCC rules although the seller may not be amenable to such a proposal Restrictions editThe AMTS is unique to U S waters having no compatible counterpart in Canada or Mexico 3 Use is limited to a maximum of 12 nautical miles off the US coast Interference outside US territorial waters is possible When used within 105 miles 169 kilometers of a TV transmitter operating on channel 13 or within 80 miles 129 kilometers of a TV transmitter operating on channel 10 the FCC requires a plan to limit interference of such TV signals by both base stations and mobile units 7 As such maximum transmit power may be below 1 000 watts ERP Lastly AMTS systems may not interfere with the SPASUR radar system which operates on the adjacent 216 88 217 08 MHz band 6 References edit R Eckert Guidance for Evaluating the Potential for Interference to TV From Stations of Inland Waterways Communications Systems Federal Communications Commission Office of Science and Technology 1982 L Middlekamp H Davis Interference to TV Channels 11 and 13 from Transmitters Operating at 216 225MHz FCC Lab Division Report Project No 2229 71 1975 a b Auction of Automated Maritime Telecommunications System Licenses Scheduled For August 3 2005 FCC DA 05 1047 2005 FCC rule 80 215 h 1 2009 FCC rule 80 215 h 5 i 2009 a b FCC rule 80 385 a 2 2009 FCC rule 80 215 h 2 2009 Retrieved from https en wikipedia org w index php title Automated Maritime Telecommunications System amp oldid 961726144, wikipedia, wiki, book, books, library,
