Television digest with electronic reports (Jan-Dec 1956)

mine the limitation of the Grade B contour of Station A in the presence of noise and interference from Station B. These additional two points may be located from Table IV. Fix)m this Table find the pertinent distance da. The required points will be this distance from Station B — the undesired station — and will lie on the 70% location noiselimited contour of Station A, i.e., at points x and y in the diagram. In the example da is 208 miles. These points will be positioned symmetrically with relation to the point already determined above and will indicate where noise will limit service to 70% of the locations and the interfering signal will limit service to 70% of the locations. The cumulative effect would thus be a limitation of service to 50% of the locations. The Grade B contour of Station A as limited by noise, and interference from Station B -will be determined by an arc of a circle drawn through the three points which have been located. The above procedure should be repeated for Station C. The Grade B contour limitations for Station A are shown in the figure as indicated by the arrows. TABLE I Distance to Noise Limited Contour for Locations Indicated Low VHF High VHF UHF At 50% Locations 78 Miles 70 Miles 49 Miles At 70% Locations 71 Miles 66 Miles 45 Miles TABLE II Minimum Spacing Required So That Grade B Service Contour Is Limited by Noise Only Low VHF High VHF UHF Offset 271 Miles 247 Miles 155 Miles Non-Offset 364 Miles 326 Miles 239 Miles TABLE III Distance (di in Miles) to Grade B Interference Free Service Contour in the Direction of an Interfering Station at Spacing Indicated Spacing Low VHF High VHF UHF (Miles) Offset Non-Offset Offset Non-Offset Offset Non-Of 100 26.5 31.0 37.0 110 30.0 34.0 40.5 120 32.5 37.5 43.0 130 35.5 40.0 45.0 140 38.5 43.0 47.0 150 41.0 46.0 48.0 155 49.0 160 44.0 48.5 170 47.0 51.0 180 50.0 53.5 190 52.5 56.5 41.5 200 55.5 37.5 58.5 42.5 43.0 210 58.5 40.0 61.0 45.5 44.5 220 61.5 42.5 63.5 48.0 46.5 230 64.5 45.0 66.0 51.0 48.0 240 67.5 48.0 68.5 53.5 49.0 250 70.5 50.5 70.0 55.0 260 74.0 53.0 57.0 270 77.5 55.5 59.0 280 78.0 57.5 61.0 290 60.0 63.0 300 62.0 65.0 310 65.0 67.0 320 67.0 69.0 330 69.0 70.0 340 72.0 350 74.0 360 77.0 370 78.0 Example of Service Computation — Low VHF L»-«« ■■ I 1 1 1 1 , I o so too /so Jioo zso Scale Im hlucs the nationwide television system. The Commission, by this Report and Order, expresses its growing concern in regard to the rapidly increasing needs of other radio services for additional spectrum space and points out that the transfer of television broadcasting to the UHF band would provide accommodations for the expanding requirements of industry in the lower part of the VHF spectrum which is well suited to the needs of the land mobile services. However, it does not appear that there is any inclination on the part of the Commission to reexamine the spectrum for this purpose at any time in the near future. While it is true that the conclusions to be reached as a result of such an examination would be tempered by the accomplishments of the expedited research program; nevertheless, it is my opinion that an examination of the lower VHF band should be conducted simultaneously therewith so that findings in each case could conceivably be reached at approximately the same time. Accordingly, I believe the Commission should immediately issue a notice of proposed rule making for the purpose of developing such data as it may need in determining the best use to be made of the lower VHF spectrum. CONCURRING STATEMENT OF COMRS. HYDE AND BARTLEY We concur in the adoption of the order, although we do not agree with discussion in the report regarding the disposition of certain prior TV allocation proceedings on which we have previously stated our views. TABLE IV Distance (d^) from Undesired Station at Which Interfering Signal Will Reduce the 70% Location Noise Limitation of Desired Station to an Overall Grade B Limitation Low VHF High VHF UHF Offset 208 Miles 188 Miles 124 Miles Non-Offset 307 Miles 274 Miles 210 Miles CONCURRING STATEMENT OF COMR. WEBSTER I concur in the thinking of a majority of the Commission that ultimately commercial television broadcasting may have to be moved to the UHF band. But, like my colleagues, I am of the opinion that a decision to make such a shift at this time would be premature in view of the present status of this phase of the radio art. Therefore, I am in accord with the Commission’s desire and suggestion that the industry immediately launch an expedited research and development program designed to hasten the day when UHF will be able to assume its proper role in STATEMENT OF COMMISSIONER MACK The Commission’s Sixth Report and Order (FCC 52294; April 14, 1952) adopted channel assignment principles and standards for Television broadcasting which have afforded a sound legal guide for the public and industry and which have promoted the rapid development of television in the United States. Today more than 90% of the homes in the United States are within range of at least one station and the great majority can receive 2 or more stations. The construction of additional stations already approved by this Commission will bring still more service. Consequently, it appears highly speculative, on the record in this proceeding, that any changes should be undertaken at this time to alter the principles set forth in the Sixth Report and Order prior to the adoption of a long-range program. To the contrary, the growth of the television industry is real evidence of the value of the 9