Indianapolis Times, Volume 36, Number 248, Indianapolis, Marion County, 26 February 1925 — Page 24

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GRID LEAKS ARE BIGGEST LITTLE THINGS IN RADIO Similar to Carburetor of Automobile —Controls Energy, Par A great many years utter Un Intraftnrflnii of the thro* element racwni tube to the radio art. the tioe of an extremely high restotuee In Mta with the grid of the tPbe weft mostly a matter of hit or tniaa. i Wireless operators, who at heart are all expeilmporters, found that a pee ell flee or a atnear of ink connecting the giM lead to the grid element, mad* ft very considerable difference sensitivity of their receiving V,, tthK vent nail y manufacturers of equipment Incorporated a erode fcgh reamtaace to Moomptht this result. Since the advent of radio for the it Will! iuimu iit of entertainmeent to millions, the grid leak has come Into more and more respect and It is now onaiiiKlnrwl verily “the biggest little thing fat radio." Changes in tube aonr'truction, as regards the various voltages used for their operation, different, types of filaments, a multlplWUy of circuits, all mean a different value of grid leak for most efficient operation. Bow It Works When the specifications call far a "one meg*’ or “two meg” grid leak, they moon that one million or two mfßion ohms of resistance are required to enable the accumulated tthargu of the incoming signal to grid on the in grid to be free the sneoeeding electric chaige. A simple analogy may be mad* of the carburetor of an automobile. The motor is the detector tube of the receiver, the carburetor the grid leak. If the carburetor la fed too mnch gasoline, the motor is choked and, as a result, stops, and by the same token If the grid leak allows too much of a charge to remain on the grid of the tube It chokes, or, as we sap. paralyses. If the carburetor is fed too little gasoline, decreased power results in the motor and our analogy to the grid leak is of too low a value de-

■Why Pay M ore? What comes from the horn la the real test of any Radio. Atwater-Kent RADIO is chosen by those who know, not merely because they are treasonably priced—but because Bka reputation for quality and gtormance that is unsurpassed. iffiDURTUBE sets |K $65 to SBS FIVE-TUBE SETS SBS to SIOO SIX-TUBE SETS $lO5 BEAUTIFUL PERIOD MODELS t $2lO to $350 ■TERMS IF DESIRED Wttov* prims do not include 'tabes and hattentee. Ike CARLIN ►MUSIC CO. 143 E. WASH. ST. Phone MA ht M 8

ARMY AND NAVY ON THE AIR

a-tmhMamssaiiETiai nnoci) - \ O-AMYtAMO 3TATWH j — ( THE MAP SHOWS HOW CLOSET. T NAVAL RADIO STATIONS DO T THE COAST LINKS OP THE UNITED STATES AND ITS FOBS ESSICNB. 7HE ftRMT STATION S. COVERING THE INLAND AND COAST, ARE SHOW N BY CROSS ED CIRCLES THE BLACK OR CLEB ARE NAVAL RADIO STATIONS, AND THE TRIANGLES ARK COMPASS STATIONS.

creased sensitivity results in the receiver. Valve for Detector Tube The grid leak may be considered as a valve controlling the amount of electrical energy that the detector tube can efficiently take otre of without overload.

Short Cuts # • • Things to Know in Building and Operating a Receiver,

SHE hook-up enthumaot should try out the directional ware trap. It consists of a loop inserted to the antenna lead and timed to series with a variable condenser of about .002 mfd. capacity. If 48 feet of No. 14 wire lq wound on the loop Corn. • • • Fhone tip connectors can be made with No. 1* or SO bare copper wire, if it la coded and shaped around a match stick. When flushed a tip is Inserted to each end f the ooii, the other two tips going to the Jack. • • • An extra headband can be made with XVi feet of No. IS wire and a pair of pliers. If om uses the band on the phones as a model Single headband will be useful when you want to “split" phonos with a guest. • * • Eyelets taken from a pair of od shoes can be used for bearings sh rotor shafts on home-made coils. • • • Make a two-wire antenna support by crossing sticks in the shape of an “X" over the comb of the house and holding them in place with screws. C English “Howler" Located London. —The wireless “howler" which so seriously interfered with reception from the United States during the recent wireless week has been disclosed. It is the old wireless station at Northoki, Middlesex, constructed fifteen years ago, and described by up-to-date enthusiasts as being hopelessly Inefficient, and wheezes, as it sends out its Morse messages, are rah. '-* wireless reception all over the country." To Ettndnato Howls The frame of an audio-frequency transformer may be grounded to rid the set of howls caused by magnetic feed-back or tatercapactty acton. These eddy currents "xe shortcircuited to the ground. Great Britain’s patent office has th been swamped with new Inventions In radio, lent ,ar the number of applications was IN, an Increase of SOB over lffi.

Hear a Madden Built Radio la Yoar Ttorae PIfQM WEb. NM TOM E. MADDKN * BOH.

THE INDIANAPOLIS TIMES

COURT MAY DECIDE HAZELTINfS RIGHT A, H, Grebe and Company Is Subject of Suit, Bv VUk Service NSW YORK. Feb. 26.—A hereto ta w e uarevealed page In the history of tlh-> neutrodyne circuit may be laid opyr to the public In the course of a suit brought by the maaeltine Corporation and the Independent Radio Manufacturer*, Ino. against A. H. Grebe A Cos. This page, according to the de£*kOdanla, may reveal that the neutrodyne patent held by Prof. Lotts Hazel tine of Stevens Institute of Technology had beene dedicated by him as public property and therefore raises the question whether he could revert the patent to his personal benefit. “Hawltlne was employed by thet Navy Eepartment during the war," the Grebe company explains, “to design a radio receiver for Oo*erament use, and while in the service of the Government developed a circuit arrangement for which United States patent No. L 450.080 was later granted." Subject of Stilt It Is this patent that the ITazeltine interests declare In their suit is being Infringed upon by the Grebe company in its synchrophaac receiver. “Having developed this circuit in the employ of the Government," the explanation goes on, “Haseltine evidently considered that it belonged to the people of the United States, as he applied for a patent under what is known as the dedication act. Tiiis provides that the patent shall become the property and be open to the use of the public. Who Owns It? “Having thus dedicated his Invention to the people of the United States, ITazeltine reconsidered his gift and took steps to recover It, by canceling from his patent tion papers the dedication clause. The patent office permitted this change of front, but the pubfic was In ownership from July 14, 1919, to Jan. 31, 1933. “It is a serious question, which must be deckled by the courts, whether Haseltine was acting within his legai rights in withdrawing his dedication." Back of this suit, however, A. H. Grebe sees an attempt of the Hsxelttoe interests to boost their stock. “I view this suit as a political ges-

Increase WASH IN'JTON. Vhb. ft— Imports of radio equipment In South Africa were more than six times greater during 1934 than the previous year, according to reports reaching the Department of Commeroe. It Is > sttmafnil that the 1994 Imports were 153U.390, compared to tmjn tor 1933.

tare Intended to create renewed Interest in the declining stock issue of the Haseltine corporation and its licensees," he says U.BOOjOOd Station A superpower station, costing about $4,000,000. is to be built In the Philtpptoee. Eight eteel towers will support the transmitting aerial.

FADA RADIO SETS Vo# will find our Radio Department a convenient and economic*,' pJbce to bay Radio Seta and Accessories. Come in and see these famous FADA Receiving Sets. Expert service, low prices. FADA NEUTRO-JUNIOR This-lube outfit, with a simple 2-dial control, ha Conservative range &00 miles, frequently over p / ro-UU 1,000 miles , f *,/•= With Tubes, Batteries and Loud Speaker, Complete f 120.00

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SPECIAL Bell-Tone Loud Speaker, $6,75.

INDIANAPOLIS RADIO SCHOOL Learn Radio as a Profession or Hobby NIGHT SCHOOL COURSE Monday, Wednesday and Friday Nights 7:00 to 9:30^ Taught in a Manner That Any One Can Understand This Come Starts Monday Evening March 9th at 7:00 P. M. Have your name enrolled now ao thet you can start at that time. The coat of this night come of instruction b reaaonable enough to be within the reach of an j pocketbook. For Further Particulars, Schedule of Study, Eta. Call or Write P. O. DEEDS Registrar 248 W. Maple Road Boulevard Phone, Washington 1343

HOUSE HOSTILE TO RADIO FUND Appropriation Need • Not Seen by Members, WABHINTGON, Feb. 26.—1a spite of necessity for ar additional appropriation for the radio service iws the approval It has received by President Coolidge and the Budge* Bureau, there seems te be some doubt as to whether it wtß be adopted by the House. Chairman Martin B. Madden of the House Appropriation Committee Is not entirely convinced of the necessity for the additional appropriation which is needed to increase the field force of Inspectors. Madden and one or two of the committee members are Inclined to oppose the appropriation. An executive arsaWm of the committee win be he*d wtthto a short time at which the fate of the appropriation will be decided. Russia to IjoefevOe Here’s the champion distance getter. John Relhl of Louisville. Ky„ reports having heard music from a station In Petrograd, Russia, during the recent international tests. Reihl’s aet is a flve-tutie neutrodyne. Phone Cl rcle 3530 I FIX ’EM RADIO-DOC Radio and Electrical Serrice 711 N. Alabama StAerial Specialist