Broadcasting (July - Dec 1936)

Watch Our Smoke! Those big stacks that rare skyward up and down the Ohio Valley certainly bear watching these days. They are doing a bit of "sky writing" that spells business and plenty of it! Steel mills are going great guns — Potteries are beehives of activity — Glass Plants are humming — Coal Mines are making new records. All of which means that men are working and when men work they spend and when they spend it's time to advertise and when it's time to advertise in the Ohio Valley it's WWVA for results! Check our "smoke"! National Representatives JOHN BLAIR & CO. NEW YORK . . . CHICAGO DETROIT . . SAN FRANCISCO Columbia Station DR. PICKARD'S TECHNICAL CASE FOR REGIONALS TECHNICAL testimony to substantiate the NARBS plea for duplication on clear channels, horizontal increases for regionals to 5 kw. and opposition to superpower, were presented graphically by Dr. Greenleaf Whittier Pickard, Boston consulting engineer, on Oct. 8 and 9. Much of the research work for his calculations and deductions was undertaken by Paul F. Godley and John A. Barron, consulting engineers. Dr. Pickard began on the premise that with 500,000 watt operation, interference would be caused not only in the United States but with stations all over the world. Dr. Pickard used many hypothetical cases to support his contention that duplication on clear channels would not obliterate secondary service to the point where rural coverage would be destroyed. For example, he said, that if a station in Seattle was placed on the channel of WJZ in New York, using 5 kw. with a directional antenna, it would give full protection to WJZ. Another case he cited was that of a 5 kw. station in San Francisco on the clear channel of WCAU, Philadelphia. He employed coverage contours to show that in such a hypothetical case the number of listeners ^served would not be seriously curtailed. Dr. Pickard, projecting numerous charts and maps on the film screen, demonstrated to the Commission that his calculations disclosed that only a small addition to the potential audience to be served is in sight if all 50 kw. transmitters went up to 500 kw. Audience Coverage TODAY'S 50 kw. stations, he showed, with plants costing1 about $128,648. are capable of serving 22.819,000 radio homes. At 500 kw., with plants costing, according to his estimates, $328,500, these stations would serve only 22.869,000 homes — too slight an increase to be a weighing' factor. Dr. Pickard showed that with 50 kw. stations, service today is available from two networks in 22.492,000 radio homes; at 500 kw., these stations would serve only 22,869.000 homes, he estimated. Thus he concluded that 98.35% of the radio homes of the country already can secui'e service from two networks. Discussing international interference rangres. Dr. Pickard placed a theoretical 500 kw. station in Washington, which he said would deliver winter interfering signals at 25 microvolts per meter well down into South America, the radiating pattern also cutting througii Europe at a point not far from Berlin. A 5 microvolt signal, he added, would include the major part of Africa, some of Asia and most of the Pacific Ocean as well. Dr. Pickard asserted that many of our clear channels alreadv are heard clearly in Europe, which he interpreted as meaniner that thev are laving down so strong a field intensity there now that the international interference problem would be considerably aggravated with 500 kw. Attempting to show that manv of the clear channels are occupied by Mexican stations, Dr. Pickard projected a chart which showed that there are no less than 25 stations in Mexico which are using clear channel assignments. Dr. Pickard produced exhibits designed to show that regional stations do a sizeable job of covering the country both daytime and nighttime even at present. He said he found that at night the regional stations of the country cover to the 2.11 millivolt line an audience of more than 175,000,000 people. He pointed out, of course, that this is greater than the population of the country but that in many areas regional service is procured from more than one regional station and the totals were combined in such cases. At night, he said, these stations, again taking into account the overlapping of service, cover an audience of 245,000,000 people. Staggered Frequencies A NEW note in allocation technique was proposed by Dr. Pickard when he suggested that regional stations on the same channel should operate with slightly staggered frequencies of a separation of perhaps 17 cycles. In that way, he said, the service of these stations could be expanded by elimination of the signal of the undesired station in this "out of phase" operation. The reason for this, he said, lies in the character of receivers now being built and also because the human ear would not be able to pick up the offfrequency interference which would be created. He said this was not a "paper idea" but had been proved in actual operation. By staggering of frequencies within the 50 cycle tolerance now permitted, Dr. Pickard said that there would be an appreciable broadening of regional station coverage. For example, he said it would result in an increase of nighttime coverage by regional stations supplying service to 175,000,000 people to a figure of nearly 190,000,000 people. Dr. Pickard argued that if clear channel stations used effective antennas they would be able to increase their coverage appreciably without increasing power from 50 to 500 kw. He recommended use of a "one wave Franklin antenna" which he said in some instances would increase coverage from 70%. Analyses of reception of distant clear channel stations in Boston next were presented by Dr. Pickard to show that they do not put out a signal capable of good reception because of "seasonal effect." It should be remembered, he said, that in the case of the FCC's allocation survey the records were made during March, April and May and not during the months of June and July when the seasonal effect is most noticeable. Pickard's Cross-Examination ON cross-examination of Dr. Pickard by Chief Engineer Craven, the distinguished engineer was asked point-blank whether in his opinion there could be duplication on all clear channels. Dr. Pickard said he felt that the duplication could be effected on 5, 10, or 15 cj the channels described as clear, it J f erring to the total of 40 provide ' for in the 1928 allocations rathe than the 30 which are clear aj present. That is interpreted t '. mean that at the outside, Dr. Picl ard felt that five additional clea channels could be duplicated. TJrJ der further questioning Dr. Picl ard said he felt that in a genen way these channels could be dupl cated with stations separated th width of the country and also ontj half the width of the country, ij any closer duplication occurred, h" said, interference of an objectior able character would be created. To the hypothetical question a] to what he would do if he starte from scratch in allocations, D, Pickard said he would like to se< a reallocation on a frequency bas: which would give particular type ( of frequencies to areas depender , upon particular types of propag*. tion conditions. In other words, \ said, he would assign high pow« , to the stations dependent largel upon sky wave coverage of remol areas and the lower frequencies \ i those stations which serve prin arily because of their groun waves. Dr. Pickard said he was in f avc of full-time operation of statioi. and felt that time-sharing operatic proves a handicap. Asked what 1 . would recommend that the FCC cl in the event it decided upon clej channel duplication, Dr. Pickai' said he would first look out for ta present group of stations to pe mit them to render best servir and that he would take care q full time and half time existir } stations before considering any ne station grants. On Horizontal Boosts ON THE 5 kw. power increas < Comdr. Craven raised the questic' of interference that might 1] caused by the boosting of powe:: of 250-watt and 500-watt regional Dr. Pickard agreed that a pro] lem of large proportions was ij volved and said that he had dj voted his primary attention in cor sidering these horizontal boosts stations of 1,000 watts rather ths those of 250. He said he believf Canadian shared regionals cou use 5 kw. with proper direction ! antennas. Dr. Pickard also agrei with Comdr. Craven that the iJ creases of stations using 250 ai 500 watts would produce not on a serious engineering problem b also a serious allocation problei Asked what he would do if a atj tion on a regional channel did n wish to go to 5 kw. because of ec nomic reasons while others on tl wave proposed to increase, E Pickard said that the station r fusing the boost could be protect' through use of directive antenns Rural Service Now Good WHEN Comdr. Craven also rais j the question of local stations i channels adjacent to regionals a) of clear channels adjacent to i.j gionals, Dr. Pickard said that would advise that this engineerii development go slowly. He said recommended the use of direction antennas for all classes of statioi including locals. Summarizing this testimo: 5,000 WATTS WWVA II60 KILOCYCLES Page 76 • October 15, 1936 BROADCASTING • Broadcast Advertisir