Radio broadcast .. (1922-30)

THE TUBE BUSINESS NEW DEFOREST TUBES A NEW D.C. screen-grid tube has been announced by De Forest. This tube uses an oxide-coated filament which is much heavier than the usual thoriated "mitter. It operates at one third the temperature, has plenty of emission to last over 1000 hours, and is free from microphonic noises. DeForest has also placed on the market a new 210-type tube with an oxide-coated filament and a very large plate with ap- propriate supports and insulation to guard against breakdown when used as a high-frequency oscillator. It is capable of dissipating 25 watts on the plate. WORLD'S LARGEST TUBE LINE SONATRON MANUFACTURES 44 distinct types of tubes, thereby backing up its well-known slogan of having the world's largest radio tube line. MUSIC FOR EMPLOYEES TWENTY TWO loud speakers have been installed in the assembly and manufactur- ing departments of CeCo's new million- dollar plant. One hour each morning and each afternoon the employees are per- mitted to listen to music transmitted over this network of loud speakers. It has been determined that this innovation decreases fatigue, increases production, and de- creases shrinkage. FINANCIAL NOTES THE BALANCE SHEET of the Hy-Vac Radio Tube Corporation, as of June 30th, after giving effect to the sale of 38,000 shares of stock showed net tangible assets of $283,640.03. Current assets amounted to $246,910.31 including cash in the amount of $201,309.69 as compared with current liabilities of $12,384.02 or a cur- rent ratio of over 19 to 1. An issue of 400,000 shares of the newly formed National Union Radio Corpo- ration at about $40 per share starts the company off with an initial capitalization of $16,000,000. In the seven months ending July 31, CeCo sales were off 3.7 per cent, from a year ago. The Noma Electric Company with the Pilot Radio and Tube Company has pur- chased the plant of Everett Mills in Law- rence, Mass. The entire production will be concentrated there within a year. This plant has floor space to the extent of 1,500,000 square feet. A MANUFACTURING FORMULA A COMMON DENOMINATOR which any tube manufacturer can use to determine the number of tubes per day he can turn out is the amount of floor space in square feet per tube per day required. It has been determined that about two square feet is necessary and that a figure of from two to three square feet per tube per day Harry C. Holmes means a well-ventilated factory with ample space for operators so that they can work efficiently. Thus a factory with 20,- 000 square feet of floor space can turn out a maximum of about 10,000 tubes a day, and somewhere between this number and Tube Sales and the Serviceman BY HARRY C. HOLMES General Sales Manager, Deforest Radio Company THE SERVICEMAN is one of the most valu- able outlets we have in the vacuum tube indus- try. He is not only a ser- viceman, but a good-will emissary and anexcellent salesman as well, since he generally speaks from experience. The serviceman cares but little about the deco- rative scheme of the tube carton or the superlative claims of the maker. He is interested in just one thing: a good vacuum tube. A serviceman with faulty tubes is as badly off as a mariner without a compass, since he has nothing to go by. The serviceman is fully familiar with this point, and as a result he generally Incomes "sold"' on some particular line or lines of tubes. Once convinced himself, he l>ecome the best type of salesman. The capable serviceman inspires confi- dence in the radio set owner. He is the doctor who cures the ailing set, and in nine chances out of ten the replacement tubes he prescribes are the tubes the owner will continue to buy in the future. Serviceman salesmanship, I believe, is the greatest antidote we have to-day for "bargain" tubes and merchandising bally- hoo. You can't fool the serviceman in quality. He knows. And by his recommend- ations the radio public is getting to know and to appreciate quality vacuum tubes. 6000 tubes a day indicates a combination of economical use of floor space and good working conditions for the operators. QUICK HEATING TUBES MARVIN CLAIMS the world's record in the construction of a quick-heating tube. It is the MY-227, is guaranteed to heat in five seconds flat, and compares favorably with all other tubes of this type with re- spect to life, freedom from hum, etc. GOOD TUBE BULLETINS CHIEF ENGINEER D. F. SCHMITT, of E. T. Cunningham, Inc., and his staff en- gineers must be congratulated on the excel- lence of their engineering bulletins. We have the bulletins on the cx-345 and the c-324 tubes and they contain not only the usual material about dimensions, proper voltages, etc. butalso a complete setof char- acteristic curves, methods of using the tubes properly, and a bibliography of articlas dealing with the particular tube in ques- tion. Such material is invaluable for engin- eers in the tube or receiver business. TRIAD'S TUBE BOXES WE HAVE already commented on the triangular shaped tube boxes of Triad. Tests conducted over a period of some weeks have disclosed the fact that there was but 2 per cent, damage to boxes of this type compared to 18 per cent, with the usual four-sided carton. OPERATING COST OF A. C. SETS ACCORDING TO George Lewis of Arcturus all this talk that it is costing more to oper- ate the modern a.c. sets than the old-style battery sets is unwarranted. If anyone, according to Mr. Lewis, will take the trou- ble to compare the number of revolutions that the wheel in his electric light meter makes when his radio is turned with the number when a 75-watt lamp is lighted, he will find out the number of watts the set takes. It amounts to less, in dollars and cents, than is required to charge a storage battery and buy new B batteries regularly—such as we all had to do a year or so ago. BULLETIN ON THE S. G. TUBE THE ATWATER KENT radio dealer bul- letin No. 3, July 17, 1929, has an interest- ing and instructive illustration of the man- ner in which a screen-grid tube prevents unwanted oscillation and squealing. If the receiver of a telephone is put near the mouthpiece of the transmitter, the tele- phone line will oscillate or howl. If the mouth piece is screened with a sheet of metal or other material the howl ceases. Thus it is with the screen-grid tube, says the Atwater Kent bulletin. The screen- grid between the grid (input or mouth- piece of tube) and the plate (the output or receiver of the tube) prevents oscillation. At the same time the amplification due the tube can be increased some five to ten times over that obtainable with three- element tubes. The explanation is a simple graphic picture of the screen-grid tube and might be used by tube manufacturers who want to help their dealers sell the new tubes, by informing them properly about how they work. Atwater Kent suggests that dealers put the bulletin, which is appropriately illustrated, in their show window. NEW TUBE MANUFACTURER THE DILCO RADIO TUBE CORPORATION, Harrison, N. J., is a new addition to the list of those in the tube business. The ad- vertising agency is Charles Dallas Reach of Newark. 30 • • NOVEMBER 1929