NOTES AND COMMENTS

Radio Record, Volume I, Issue 45, 25 May 1928, Page 8

NOTES AND COMMENTS

_ ad JR\UGENE F. GROSSMAN, operating "engineer of the United States National Broadcasting Company, has designed and built a new mixing panel that will permit simultaneous transmission over eighteen separate microphones. [= is reported that the United States Navy builds short-wave equipment that must be accurate to within 100 cycles at 30,000 ke. That is, they build a transmitter to this specification, and a receiver to go with it, and the sum of their percentage inaccuracies must not be over 200 cycles in ten million, or 100 eycles for the individual unit. This represents an accuracy of one part in one hundred thousand, or one ten thousandth of one per cent, an accurhey fifty times as great as that required of stations now operating within the broadcast band. These Navy units, it should be noted, are designed for Morse code transmission and reception. ORE than 1500 radio pirates were rounded up by the British police. in 1927. Pirates, that is, radio users who have not paid the Government license fee, are located by means of Post Office direction finding vans. Evidently the pirates operate "howling valve" sets, or they would not be located. GERMAN police systems have adopted the Korn system of picture transmission, which is built along lines which have become conventional, Korn is a pioneer in the field, having, as early as 1907, transmitted newspaper photographs between Paris and London. Synchronous motors and neon lights are used. [A SOUNDPROOF room has been de- | signed by Frank Andrea for the engineers of Fada Radio in New York. It has two walls, two eeilings, and two. floors. The space between is fillled with wood chips and the whole is supported on cork to remove vibrations of the building. | TA CONTROVERSY rages as to radio : concessions extended by various Chinese administrations. Japan has an agreement, negotiated by the Chinese Ministry of the Navy, which gives | it a monopoly for thirty years, In 1921, the Federal Telegraph Company made a contract with the Chinese Ministry of: Communications for five stations to be operated by the American company for twenty years. The British also obtained contracts on behalf of the Marconi Wireless Telegraph Company. Apparently an exclusive license in China is non-exclusive. THE use of a fixed condenser across the loudspeaker terminals on the get will help to increase the quality of tone,-whilst a fixed condenser across the loudspeaker connections will have the effect of eliminating diaphragm rattle and hand capacity noises, such as those produced by touching the speaker cords, POPULARITY of the alternating cur- ’ rent receiver is shawn by a survey completed by the United States National Electric Manufacturers’ As sociation. It was found that there are at least 1,000,000 such sets in daily use. The survey also noted a slight decrease in battery operated receivers, dry cells and direct current valves. (VW HEN using a long aerial the coils ‘" om your set should be loose coupled selectivity is desired. FP XPERIMENTS carried out in order to find the best wavelengths for different times of day show that wavelengths of 26 to 40 metrea are suit‘able when the path between ‘transmitter and receiver is in complete darkness; wavelengths of 20 to 26 metres are suitable at times of transmission from darkness to daylight and viceversa, or when the path is partly in -daylight and partly in darkness; and wavelengths of 15 to 20 metres are suitable for a total daylight path.

wrt is believed to be a unique \ record in direct long distance communication was established recently. when a message was transmitted almost from the South to the North Pole. It was a signal‘on 33 metre? from’ the 3 kilowatt transmitter of a whaling ship in the South Pacific, The Bergen radio station on the west coast of Norway received the message, It is figured that this message ‘travelled 7000 nautical miles, or more than 8000 jand miles. JACKS often give trouble due to poor connection at the projection prongs and it is a good plan to see that thev ‘are kept clean,, but do not wear them out by cleaning with sandpaper or : other rough material. Dust often gets between these contacts and im- : pairs volume, A little household : Jiquid ammonia on a rag will clean the points of the jacks. 7 THE power valve improves tone quality and may give slightly more yolume, because it can handle greater power output with less distortion than can the general purpose valve. The ower valve of the American type in the 135-volt class is genery demoted by 112-A,

— TH E Dvott expedition to South America is anxious to hear amate eur transmitters ot 27 metres. Sucli is the anuouncement of Eric Palmer, owner of amateur station 2ATZ, Brooke lyn, N.Y., who reported that he had been in communication with William DeMello, operator of amateur station sblIB at Rio Janeiro. "The expedition plans to transmit soon from Curaba, 3000 miles from Rio Janeiro, using the call letters GMD. TATION CFCA, Toronto, Canada, has succeeded in rebroadcasting programmes from Sydney Australia. ‘This achievement, similar to that of WMAK, Buffalo, station, recently, is believed to have been the first successful Canadian rebroadcasting of an Australian programme Station CFCA previously, had picked up broadcasts of English radio stations and had sent them ont again for Toronto listeners. NEW YORK CITY has about 600,000 receiving sets, or one tr every, ten persons, A WAVE-TRAP often is an importe +" ant factor in increasing the celecs tvity of a radio receiver. Such a trap may be made easily with a_ tuning condenser shunted across a coi]. ‘The trap is connected between the aerial and the antenna binding post on the receiver. PRE drum is the most difficult musis cal instrument to reproduce over the radio. BUSINESS man of Newark, N.J.g U.S.A., who is a radio enthusiast, has written the Federal Radio Coms mission that only three of forty-two listeners questioned by him could name ten or more of the fifty broad~° casting stations in the metropolitarg area of New York. The fan said hé presented the question, ‘How many, metropolitan stations can you name ?’* to the people who own good radio sets and who are not connected with any, phase of the radio industry. The majority could name seven or eight; eleven peisons could name but five, and two persons only four stations. a

RADIO amateur in Belvedere, a -* little Kentish town, regularly invites his friends’ on Sundays to listen to the Monday morning broadcasts from 3L4), Melbourne’s short-wave station, 18,000 miles away in Australia. He uses a six-valve superheterodyne, and Melbourne comes in at good ioudspeaker strength, A feature of this radio fan’s activities is his claim that when he removed the aerial and carth Melbourne was still faintly audible. The number of licensed Jistencrs in. Germany reached 2,000,000 on December 15, 1927. ‘fhe number at the end vf September was 1,757,688, and the increase, Which is partly ‘due to the removal of the Inter-Allied restricitons in tne Rhine and Ruhr districts and the spening of the Rhineland high-power station at Langenberg has exceeded expectations, A further rise m the license fee, now 21 marks, will, it is thought, be necessary, andl it is cven possible that later on the amount of the fee may be reciuced.

In deference to revnests from Lab. our members of the official Radio Council of Austria, on which sit representatives of every class of subscriber, special features are shortly to be introduced into Ravug programmes which Will anneal directly to tewn and country artisans and labourers ‘The Latbour organisations are to he consulted, for, naturally, the selection of such features is not cass. The proposal now under consideration is for a monthiv lecture, on a werkers’ topic, such as food or clothing or recreation-non-wolitical, of course. Pur following which appeared in the Chicago "Evening Post" shows how they criticise studio singers in the Press of that city: "There should be a law against the unmerciful butchering of "Binne,’ one of the prettiest tunes te make an appearance in many no month, at the hands of divers persons whe are physically unable to sing the song us it was written. The latest xutrocity was at WC, where a Mir. Petersen mide a valiant but fruitless effort to do the number. bryidently the pienist tried to help out by transposing, but the upshot of the whole thine Was a strong resemblance to the ‘proceedings’ of the Nutty Club, With the ‘Unwasked Barytone’ as chief exevutioner." fete serin| lead-in wire should always be well insulated and should be kept as free of walls. trees, ete. as couveniently possible. Tacking the Wire to the walls will decrease the resistunce and will increase the losses. The resistance-at radio-frequencies-will even Le slightly ie reased if the Wire is close to the walls, although this is not generally For ul practical purposes no deleterious effects will result if joints are firmly spliced and soldered, If they are not soldered. lowever, the resistance of the joint will seon increase as cerrosiouw effects take place.

N Durepe the Luternational Radiophone Union regulates the frequencies wud time assiguments of broad‘nsting stutions. The Hungarian Covernment has been barred from adimission to this organisation at the plea of Czecho-Slovakian delegates, The Iinngnrians have been accused of using their stations to spread propa--ganda, attacking the Treaty of Trianon, thereby cndangering the integrity of Czecho-Slovakia. PRESENT estimates indicate that the American radio manufacturing industry will have a bumper year in 1928, The total receipts are expected to go over 600,000,000 dollars (£120,000,000), TPUERE wre all kinds of radio fans, but here ix a new one, A woman has been discovered in America who evidently believes her pet turkey gobbler listens-in. She infers that much, at least, in a letter to KOA at Denver. Her gobbler disappeared from its eoop one night, she said. and since nll other methods for finding it had fniled she requested KOA to broadcast for it.

eS connection with a. scheme for the investigation of the upper atimosphere, now being carried out by the University of Queensland, the authorities at that institution intend liberating from time to time small balloons filled with hydrogen. These balloons will rise to a height of from 10 to 15 miles, and then, after bursting, will fall slowly to the ground. A posteard will be attached to each balloon asking the finder to fill in particulars as to where found, ete, and then return it to the University. The principle of the experiment is similar to that of throwing bottles containing messages into the sea, and the information regarding winds in the upper atmosphere. The balloons may fall within a radius of 50 miles of Brisbane or may go further afield. The success of the experiment depends upon the number of cards returned, and in order to acquaint as many people as possible with full information 4QG, Brisbane, is broadcasting from time to time statements regarding the liberation of these balloons. "THE first direct wireless messages between England and Australia were transmitted from Carnaryon on September 22, 1918, and were picked up in Sydnee, 0 ‘

N Ohio radio fan, who is confined to his home in a small town, has written the U.S.A. Government federal yadio commission that he spends an average of twelve hours daily with the radio and that he finds little or no station interference in the 600 to 1000 kilocycle band. He wrote that he had eighteen different makes of receiving sets, ranging from two to ten tubes, but that in making his tests he got the best results from an inexpensive set. His Hotel Robert Morris, in Philadelphia, in common with many other hotels in the United States, has provided its guests with a compeling reason to stay in their rooms in the evening. The Robert Morris was equipped in March, 1925, and the unusual feature of the arrangement is that the widest possible programme choice is offered to the listener. A plug with three jacks is provided in every recom, and the three jacks provide the "programme at the moment being transmitted over the Blue or Red Networks. of the National Broadeasting Company or the Columbia chain. The radio control room is located on the top floor of the hotel, and the equipment, in the mn2in office on the first floor, is operated by remote control. Constant voluine level throughout the hotel is maintained by using compensating and repeating coils, By grouping the jacks in the yarious rooms in parallel series it is possible to maintain reception in every room in the hotel even though trouble develop in the outlet in one or more rooms.

MERICAN files report that a Mrs. 4 i. C. Green, of 418 East Manhoning Street, Punxsutawney, Pa., while | at home alone listening to the broadcasting of WGY Schenectady was startled by the appearance of a drunken intruder who had foreed her front door, Suddenly A. O. A*oggeshall, an announcer of WGY, calmly requested the invader to "Please stand by.’ The sound of a man's voice was too much for the unwelcome visitor, and he turned and hurriedly left the house and Mrs. Green was left free to continue her enjoyment of the programme. AN American radio editor says:- ~* We understand from an unimpeachable authority that the engineers 1 of a certain radio manufacturing company built into stock receiver models a few years ago, audio amplifiers so good that nearly all vf them came hack. Criticism arose from the fact that these receivers seemed more noisy than sets of other manufacturers; more static came in, and "whistles" were more eyident. It was a simple matter at the factory to put filters in the amplifier system, cutting down on the two ends of the’ frequency spectrum. Then the receiyers stayed sold. It is a fact that many hundreds of these receivers have been sold to Bell Laboratories engineers and their friends. As soon as. they are received out comes the solGering iron, off comes the filters, and out of the loudspeaker come the low and high frequencies that are so essential to good quality.

N extraordinary new type of eleetrie bulb without wires, deyeloped by Dr. Phillips Thomas, research engineer of the Westinghouse Electrie and Manufacturing Company, glows when held within range of a powerful, electromagnet, and continues to glow for ten minutes after the power is shut off! Though you could turn it off, undress, and jump into bed by its light, it has no such immediate utilitarian purpose. It was developed by Dr. Thomas in the course of experiments he is conducting on the transmission of power by radio. THOUGH bedridden for many years and suffering from arthritis, an old lady living not far from Sydney has taken a new lease of life since she came into touch with radio. Until recently she felt that she was out of contact with the world, but now that a radio set has been installed in her rcom, she feels that she is better informed of the happenings of the outside world than when she was able to move about. Everything is now heard over the air, and such a wide range of music and entertainment news and speech is brought to her that she finds a, wider field open in her declining years than she had experienced for the past twenty. Now the guests of a New York City hotel have radio programmes on tap through the touch of an electrie switch. The entire hotel has just been wired for radio, and two central receiving sets are on the thirty-first floor. Nearly all the 1600 rooms have loudspeakers. * MANX of the New Zealand listeners enjoy listening to 2GB, Sydney, when static is not too rowdy, a report from Australia, states: Station 2GB, which is every day increasing in popularity, has made a move forward in the right direction by moving into its new studio this week. The new studio is almost three times as large as the previous one in use, and not only will 2GB be able to present such items ns orchestral and bands, but it will mean that their transmission will he better on account of the larger space.