Indianapolis Times, Volume 37, Number 122, Indianapolis, Marion County, 21 September 1925 — Page 29

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MICROPHONE TO HELP FARMERS LOCATE INSECTS Detects Sound of Beetle Boring Heart of Pine Tree. Farmers may take a radio microphone to their com cribs and determine whether insects are eating their stored grain. Lumbermen may carry a microphone into the forests and ascertain whether insects are boring into the heart of the timber. As fantastic as it may seem, this new application of the principles of radio has received the official recognition of such a distinguished scientist as Dr. L. O. Howard, chief of the bureau of entomology of the United States Department of Agriculture.

Radio Principles Upon this strange use of the radio waves, lie comments: “Mention may be made of Prof. C. K. Brain’s discovery in South Africa of the adaptation of certain radio principles to insect investigation, in which he shows that, by the use ofthe microphone, the presence of insects may be determined. Not only the wood boring insects, boring in wood, but of insects stored in grains.” Thousands of farmers and lumbermen are equipped with radio receivers, but you would hardly expect them to be equipped with microphones. The latter are employed for the sending rather than the receiving - of electric energy and their use is confined largely to broadcasting stations. Therefore, in view of the limited use of microphones, some manager of a broadcasting station may be approached by a farmer or lumberman for the use of his microphone. Mr. Studio, manager, do not hastily have the applicant examined for lunacy, for in the light of this recent discovery, his request is sensible. Great I<os Millions of dollars worth of grain and timber are exacted annually by an army of insects. As might bo expected, they do not work with a blast of trumpets, but subtly and silently they bore into the bin of stored grain or stately pine tree. The sensitive microphone capable of picking up the slightest sound, is enabled to detect the presence of the beetle boring into the heart of a pine tree or an insect taking the kernel out of a grain of wheat. TIPS MAKE CONNECTORS Plume Apparatus Will ,Sbve Time In I Porting Wires. * Phone tips and phone-tip jacks will make a battery connector that will save many minutes of sorting the wires. Use the jacks in place of binding posts on the terminal board and fasten the tops on another terminal board of the same size in such a way the tips will insert nicely in the jacks. The tips are soldered to the battery heads.

JUST 20 YEARS AGO— Harry A. Bremer built his first wireless apparatus. He has since both contributed to the development of radio and learned from il You profit by ttlat knowledge sSQ/f wben y t>u bu - v P arts or sets. B-T Condenser Efficiency is not equalled. The 17 plate .ftiOßli mi fn t*e .* ~ . , straight i.ine Fre- Ibe i>.. I. Late-time Bearing — a most linqueney (covers 200- , , 550 with b-t Toro- portnnr tcature — is not even approached, “if ,c ll*°nV tTer 0ri £ inal “Lifetime” design, beautiful Seuu u Back." workmanship, superior results. The B-T “Euphonic” is the greatest improvement in mechanical construction of audio transformers in $ years. “Euphonic” means‘‘Pleasing -\nH| to the Ear.” All distortion due to v • crossed leads is eliminated by new 'IBM | E i mounting methods. BETTOR TUNING, Bth EDITION (oversize) is the best dime's worth iu radio. Pull of what you need to ktow whether you're a set owner, or about to buy—a set builder or just a fan. Send 10c today for copy. INDIANAPOLIS DISTRIBUTORS Van Camp Hardware A Iron Cos., Kruse Connell Cos., BREMER-TULLY Mfg. Cos. 532 S. Canal 8L Chicago, 111.

Experimnet With Wavelengths NRA Service Writer | IARTFORD, Conn., Sept. LI 21.—Station WTIC at I * Hartford, and WEEI at Boston, have been permitted by the Department of Commerce to exchange their wavelengths in an unusual experiment. It is an attempt to learn whether local conditions have any appreciable effect on one wavelength, as opposed to another. This is sought particularly in its re gion to topography of the territory and surrounding structures. WTIC now is broadcasting on WEEI's wavelength of 476 meters, while WEEI goes out on 348.6 meters, which is WTIC's regular wavelength.

GREATEST YEAR IS SEEN AHEAD Local Dealer Says Demand Felt Earlier. The radio demand is being felt earlier this year than ever before, according to Frank W. Wood, local radio dealer. “Radio business is opening up months ahead of any other year, and these activities point to, the greatest year in radio history. The tendency is toward the better class of merchandise, and the wide variety of radio programs which the fans have to select from with the better tube sets attracts them. Last year the radio interest did not awaken until after the first of the year, while this year every section of the country is taking up radio earlier than before.” Wood believes that, that part of the public which heretofore paid little attention to radio is beginning to become interested, principally because of the high character of entertainment which is being offered by the broadcasting stations. KEEP FILAMENT NORMAL lllieaslat Should Not-be Turned up— Would Release filer.lrons. Do not burn the thoriated filament tubes at too great a brilliancy; do not turn up the filament rheostat above normal. This will forCe too much current throUfcT *he filament and release the electrons so fast that the filament will become “run out" or free electrons in a short time. The filament will turn all right, cut there will be little or no signals. RADIO ENTHUSIAST George K. Arthur divides his time before motion picture cameras and radio receiving sets, when possible combining both business and pleasure. While on location in northern California, his automobile was equipped with a portable superheterodyne set. On one trip he received messages while going forty miles an hour.

THE INDIANAPOLIS TIMES

SUPER-POWER NOT CURE FOR TAPING’ Bureau of Standards Announces Static Is Not Overcome by Increasing Number of Kilowatts.

Rtl Timet BOccvll WASHINGTON, Sept. 21.—Three important conclusions have been reached by the Bugifau of Standards as the result of an analysis of higher or super-power broadcasting during this summer. In the order of their importance they are: Super-power will not prevent fading. Super-power will not cause excessive interference or blanketing of smaller stations. While materially increasing the service range of a station, _supvrpower will not overcome static on "reception at great distances. Power Increased Throughout the summer a number of stations have increased their power to 5 kilowatts as a result of the recommendations of the last radio conference. WGY used 50 kilowatts on three evenings for test purposes. After measurement of the signals, the following report is made by the Bureau of Standards: "H’he past summer has witnessed a ten-fold increase of power used in many of the broadcasting stations, as well as experiments on still higher powers, running up to 50 kilowatts. Measurements on the actual signals delivered by these stations have been made by the Bureau of Standards. Department of Commerce and cooperating laborities. These measurements culminated in special observations on the alternating 50 and 2(4 kilowatt transmission of WGY, Aug. 22, 24 and 25. Some surprising conclusions can be announced. “The results are remarkable for some things that did not happen, as well as for some that did. First and foremost, high power has not resulted in signals of overwhelming intensity. Even the 60-Kilowatt trewnmissions reached many listeners with an intensity which was not noticeably greater than that of many other

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stations on moderate power. Excessive interference or blanketing of lower power stations is another element of the popular picture of “super-power which has failed to materialize. Thq.se results, from the viewpoint of scientific investigation, are regarded as important verification of the calculations of radio engineers, who have consistently maintained that the apprehensions of stilling effects of higher power were wholly unfounded. Signal Fluctuation “The most startling conclusions are in reference to fading, or signal fluctuation. At all distances greater than about 50 miles from a station, actual tests show that the received wave intensity is continually fluctuating. the variation from maximum to minimum being us great as 100 to 1. The ear is notoriously insensitive to intensity changes, otherwise the reception of distinct broadcast programs would be quite unacceptable. Increasing the power was found to effect no improvement in the degree of fluctuation. It can therefore be definitely stated that high power is not the solution of the fading problem. “For still another reason, the distance over which a broadcast station gives highly satisfactory, dependable service is quite limited. This is the omnipresent back-ground of static and all sorts of electrical disturbance, which requires that the radio wave have more than a certain minimum intensity in order to assure reception free from interference. Have Certain Area There is an area around every broadcast station whithin which such perfect reception is assured and beyond which it Is not possible to rely on night-time reception free from disturbance. Daytime reception is in general not possible at all beyond

this area. Thsi zone of really dependable radio service around each broadcasting station is surprisingly small, but its area is approximately proportional to the station’s power. This is found to be the prime reason which makes high power even desirable from one standpoint of improved public reception. “More specific conclusions cannot yet l>e stated by the Department of Commerce on the special fifty-kilo-watt tests of Aug. 22 to 25. Further experimentation with high l>ower can be expected. Particular attention is being given to fading in further studios by the Bureau of Standards and co-operating labor attories. More data on. the effects of atmospheric conditions which give rise to fading are seen as the only hope of extending satisfactory radio reception to great distances.” WIRE COIL IS ANTENNA HELP Higher Wave Lengths May Be Picked Up. Two simple principles applied to the average receiving set will enable the operator to keep in tune with all waves from 200 to 600 meters. If a coil of wire is placed in series with the antenna, it fias virtually the same effect as increasing the wave of the antenna, thereby making it possible to pick up higher wave lengths. The largor the coil, the greater will be the increase in wavelength. If a variable condenser is placed in series with the antenna or ground wire, the wavelength range of the set Is reduced. The smaller the capacity of the condenser, the greater will be the cut in wavelength. To place a coil in series with the antenna, connect the lead-in wire to one end of the coil and run a wire from the other terminal of the coil to the antenna binding post on the set. A series condenser is connected the'same way.