The Radio World

Hawke's Bay Tribune, Volume XIX, Issue 220, 4 September 1929, Page 7

The Radio World

NhW YORK SFEAKS TO BYRD HOW A SPECIAL ANTENNA MAKES ACTUAL CON\ EKSATION POSSIBLE. The Antarctic Continent until recently contained probably the deepest solitudes m this world. With the advent of short-wave wireless telephony and the arrival of the Byrd expedition at Little America much of this isolation has disappeared. The following article gives a short descrip-. tiou of the station-antenna at WGY, Shhenactady, New York, which is nowused for putting the transmissions on the air for Commander Byrd and his companions. When Shackleton returned to Lyttelton on March 25, 1909, from his “Farthest South,” nothing had been, heard ot him for a year. The same conditions pertained with Scott on his 1902-1904 expedition.. For a stretch of 12 months he was lost to the whole world, until he returned to Lyttelton in the autumn of 1904. On the second expedition, which ended in his tragic death on March 29, 1912, his fate was not known until the Discovery arrived in Lyttelton Harbour in February, 1913, with the blue ensign flying at half-mast from her “peak.” Compare this with what the world knows of the doings of the members of the Byrd expedition, and with the way that they are informed of the news of the world. They know all about the airplane St. Louis Robin and how long it stayed up in the air, they know all about the round-the-world cruise of the Graf Zeppe lin, and they know all about the well being of their families and friends

Y T ou can picture to yourself a group of men huddled around a stove each Sunday in a wind-proof hut. The gales whistle cutside and it is dark. The men are at the radio receiver, and it has been sending dots and dashes ever since their arrival. Suddenly a voice comes from the set. and Commander Byrd and his men are hearing word-of-mouth greetings from their mothers and friends in America. The expedition had had short-wave Mnrse eve" since it arrived at the Ice Barrier, hut not until just before the winter did it have radio telephony. HOW IT IS ALL DONE. The whole thing hinges on an antenna—at the sending end—an aerial that increases ten-fold the directional power of station W-2XAF, the shortwave station of WGY, maxing a 26kilowatt station the equivalent of a 200-kilowatt station in effectiveness in one direction. This antenna at Schenectady faces the south, and it is used for one programme only, and then but once every other week. . The engineers call it the “Byrd” antenna, because when this particular “radiator” is in use the messages are directed to Commander Byrd an his men at Little America. The “Byrd” antenna is the contribution of Dr. F. F. W. Alexanderson to the happinness of the expeditions’ personnel as it winters through the long Antarctic night. In erecting this special aerial the General Electric Company’s engineers are bringing to the Byrd broadcasts the latest devices known to the art m promoting reliability of reception The “Byrd” antenna is of the horizontal type, and it is similar to the one constructed for programnib transmission to Germany, and facsimile experimental work with the Pacific Copst. It it one of a dozen or more antennae that sway above the 54-acre transmitting laboratory at Schenectady. These antennae hang from steel masts from 150 to 20 feet high, from plain wooden masts, and from masts with crossbars, not unlike scaffolds in appearance.

Usually the station W-2XAF uses a vertical aerial about 50ft in length, but the new antenna is actually 12 antennae in one, consisting of two sections of a draughtboard, each section made up of three squares. One section is known as a reflector. Only the horizontal wires of the system function as antenbae, the vertical wires being for support, or power transmission to radiating wires. YEARS OF RESEARCH WORK. The horizontal antenna wns developed after years of research along lines suggested hy Dr. Alexanderson of the General Electric Company. The effectiveness and carrying powci of horizontally polarised radiations weir discovered by Dr Alexanderson in 1924.

When transmitting with horizontally polarised waves, the so-called ground wave is quickly absorbed, leaving only the high-angle radiation, which in its carrying power appears superior to the vertically polarised wave. With the horizontally point ised system, it is possible to shoot most of the energy into the air, and with the antenna now in use to direct the greatei part of this energy in any desired direction, instead of dissipating it in every direction over a comparatively small area. The use of horizontally-placed nn tenna in facsimile work has assisted immeasurably in assuring transmission to the Pacific Coast. Both German and English radio observers have reported a great increase in signal strength and short-wave broadcast signals when the horizontal antenna system is used. '

All future Byrd programmes of station WGY will be broadcast on the special antenna, and while it is unlikely that even this system will penetrate the heavy static of severe snowstorms, there is assurance that the explorers will get a much better signal strength than was previously possible.

NEW TUNING DEVICE A SLIDE-RULE. Side-rule tuning, an innovation tn radio reviving sets, together with several • Iher important departures in radio design, is utilised for the first time in a new American set. The new simplified tuning device resemblvj a slide rule, and as a tiny

NEWS FOR LISTENERS,

knob moves across the precision scale, calibrated in kilocycles, accurate tuning is obtained. The tuning knob of this super-automatic selector operates over full-visioned illuminated scale, with space provided at the top of the kilocycle figures for marking the exact positions of the stations. A vernier adjustment is obtained by turning rtie knob instead of running it across the scale. There are only two additional controls— the volume adjuster and the radio snap switch designed to put the sot “on" or “off.” The tonal quality can be altered • ■ in- ■ -accordance with the owner’s preference or the acoustics of the room. This is regulated at the factory for what is considered to be the best reproduction over the entire musical scale, how-ever, by means of a simple adjustment the high notes can be reduced and the bass notes increased, or vice versa. MYSTERY OF FADING Signal fading ,that peculiar phenomenon which causes radio signals to rise and fall in intensity, at times with remarkable regularity, but mostly with an uncertain and irregular periodicity, seems to be not of meteorological origin. Without doubt, fading eventually will be found to be related directly to changing conditions in the conductivity of the total atmosphere, especially the outer ionized portion of the stratosphere, variations in the height or level of the Heaviside Layer, or, perhaps, to some extent in counter earth-currents which may affect the uniformity of the transmitted earth wave to some slight degree However, it is likely that a certain amount of fading is due to atmospheric conditions This is an assumption only, although years of meteorological and radio correlations seem to indicate that such niav be the case- It appears that this form of fading results from large movements of ionizezd atmosphere drifting past transmitting or receiving stations, mostly the former. It is quite likely that the conductivity of the mass of ionized air is of sufficient importance to affect the transmission of the electromagnetic waves being broadcast out from the antenna of the transmitting station directly below. The action is that of an absorbing and deflecting blanket spread over the transmitter, which effectively prevents ail of the power of the emitted wave from passing on and up toward the Heaviside Layer. Thus, the variations in the transmitted wave are similar to power variations : and the result is that the received signal will vary in intensity. This form of fading is slight compared to that, produced through other natural phenomena, Much has been said about the effect of weather on the intensity of radio signals. It seems to be true that this occurs; but the correlation is' ge'iieTa'lly associated with temperature more than with air pressure, ekr-ept‘ that pressure and temperature always are directly related. In other words, reception is best, and reaches over greater distances, during clear, cold weather, and is not so satisfactory, relatively, in warm and stormy weather. Regardless of tho 'time of'' yehr, temperature is higher during cloudy and stormy periods and lower when the weather is" clear arid' the air pressure higher Clearing weather is associated with a fall in temperature, and is decidedly more favourable to the best radio reception and freedom from static. SELECTIVITY. There are several points which must be considered when discussing the subject of selectivity (states an exchange). Considering an oscillatory circuit, in which we assume that the resistance remains comparatively constant over its complete tuning band, it would probably be better to use a large inductance and small tuning condenser; since this type of circuit gives a higher radio-fre-quency voltage than one employing a small tuning coil and large condenser. This fact can be proved both mathematically and by laboratory tests with various types of coils. However, in most oscillatory circuits, the resistance does not remain constant, but varies considerably at r ifforent points of the band. The resistance of the coil is usually much higher than the resistance of the condenser j and the resistance of the condenser remains almost constant except at the low end of the capacity scale From this standpoint, it would be better to employ an oscil lately circuit with a small coil and large tuning condenser; since a circuit is much sharper when the resistance is low than when it is high. In general practice, however, there is a nominal value in which both the resistance and voltage are considered. In this way, by balancing the values of resistance and voltage in the circuit, a value will be found in which neither the voltage nor lesistance is at the best point, but the complete oscillatory circuit supplies best results. Of coursp, this involves a different condenser value for each type of coil considered; and for this reason, no particular condenser can ho recommended to give the best selectivity. PROGRAMMES FOR TO-NIGHT IYA, Auckland—s p.m.: Children's session, conducted by Uncle Tom. 6; Dinner session. 7: News session, market reports. 7.40: Talk, Madame M. Milne, “Health Foods and Diet.” 8: Presentation of orchestral concert bv Leys Institute Orchestra, “Old Faithful,” Holgman; contralto solo. Miss K. Christ, “Morning,” Speaks; instrumental. Orchestra, (a) “Air,’ Matheson, (b) “Invitation to the Dance,” Weber, (c) “Minuet.” Beethoven; recitals, with musical accompaniment, Mr. A. Mc.Skimming, (a) “Good-bye, God Bless You,” ield, (b) selected; instrumental, Oichestra, selection from ‘‘The Gondoliers,” Sullivan; humour, Mr, D. Flood, mirthful moments; tenor solos, Mr. K. Kenoaly, (a) “Tho Secret,” Scott, (b) “Pale (Continued on foot of next column)

Moon,” Logan; instrumental, orchestra, (a) “Keltic Lament,” Foulds, (b) ‘Humoreskke,” Dvorak ; valse de concert, Orchestra, “Weaner Madln.” Ziehrer; male choir, Don Cossacks, “Song of the Volga Boatmen,” record; instrumental, Orchestra, (a) selection of Scottish melodies, arranged Myddleton, (b) ‘'S’a.'s and’stripes, 1 ' march contrako -clos, Miss K. Christy, (a) “Heine e Heine,” Princess Te llangi Pai, (b) “Irish Folk Song,” Foote; humour, Mr. D. Flood, more merry moments; ’cello solo, Pablo Casals, “Traumerei,” Schumann, record; tenor solo, Mr. K. Kenealy, “Bird Songs at Eventide,” Coates; selection. Band of H.M- Gernadier Guards. “Regimental March Medley,” record. 2YA, Wellington—Silent day. 3YA, CHRISTCHURCH.—S p.m.: Children's session, conducted by Uncle;Frank and Mother Hubbard. 6: Dinner session. 7 : News session. 7.30: Addington stock market reports. 8: Selection, Studio Orchestra, “The Girl of the Golden West,” Puccini; madrigal, followed by soprano solo, Salon Quartet and Miss C. Aslin, (a) “From Oberon to Fairyland,,” 'Stevens, (b) “Waltz Song,” German, ’cello solo, Pablo Casals, “Melody in F,” Rubinstein, record; lecture-recital, Mr W. Hutchens, “Old English Folk Songs,” arranged Hutchens; instrumental, the Studio Orchestra, (a) “Miniature March,” Tschaikowsky, th) “Meditation,” Glazounof. (c) “Grasshoppers’ Dance,” Bucalossi: baritone solo, followed by soprano and contralto duet, Salonell Duo, “Sainted Mother,” Wallace; recital, Mr J. F. Montague, one-act play, “The Devil’s Rock,” Betty Kerr; contralto solo, Miss D. Mitchell, “Ah, So Tu Dormi,’’ Vaccai; tenor and baritone duet, “Salvator Duo, “Flow Gently, Deva,” Barnby; 'cello solo, Lauri Kennedy, “Hungarian Rhapsody,” Popper, record; orchestral, the Studio Orchestra, ballot music, “Faust,” Gounod; baritone solo,, Mr J. G. Young, “Toreadors’ Song,’’ Bizet; humour, Mr J. F. Montague will entertain with a humorous item; violin, flute and harp, Neapolitan Thio, “Simple Aveu,” Thomas, record ; tenor solo, followed hy vocal quartet, Mr H. Blakely and Salon Quartet, (a) “Jean,” Meade, (b) “How Sweet the Calm,” Blackburn.

4,YA, DUNEDIN.—6 p.m. : Children’s session, conducted by Aunt Anita. 7: News session. 8: Relay of 3YA, Christchurch, Studio concert, contributed by the Salon Quartet, Mr J. F. Montague, the Studio Orchestra anil Mi W. Hutchens, lecture-recital on old English folk song-; dance programme.