Radio Digest (Apr 1925-Jan 1926)

RADIO DIGES T— Illustrated June 6, 1925 Questions and Answers Tot Use in Car (13757) TTTL. West Palm Beach, Fla. I have read, followed, measured all sorts of hook-ups, have written to all sorts of places, but can not find what I want. I am looking for a small compact powerful complete set or hook-up to be used with a loop or a real small outside antenna, to put inside a Ford coupe or with a small outside antenna on top of car, to be fastened stationary with or without loudspeaker. Tubes TJV199 or C2:1:1. The cabinet shall not be larger than 10 or 12 inches in length, width will say 5 to 7, depth about 6 to 7, loud speaker. I have seen all sorts of hook-ups but when ready to order one you always find out. something won't work. I want to keep it stationary in my car which will give me satisfactory results, but always find the way I want it fastened is always too long. Xow I come to you. Tell me where or what kind can I buy ready made or will build the set or hook-up. which will answer my demand. It cannot be longer than Sxl2 inches or I cannot use it, and would prefer S inches with loud speaker. A. — We have carefully read over your letter relative to your needs for a receiver. It looks to us as though you want the impossible as we do not know of any set operating on dry cell tubes that can be constructed in a cabinet of the dimensions you give on which one could be at all sure of loud speaker operation from a loop or small antenna on your car. Probably the nearest approach to what you wish would be the Acme four tube reflex, as the improved model is now equipped with their D coil which permits of use of an outside aerial. However, the average reflex is not particularly good on dry cell tubes since the 199 is not capable of carrying a great amount of energy, on the other hand, to use six or seven tubes of any type with proper spacing between the various parts requires a cabinet larger than the dimensions you give. In this case we are unable to help you as you want something that will not come out for another year. A year from now the super-regenerative circuit in two or three tube form will probably have been developed to a practical form in which case you can readily construct the receiver you want. At this time, however, there is no such set. Two Stage BF Hookup (13639) FFB, Kokomo, Ind. Please give me the hookup of a two stage amplifier which may be added to a regenerative set. A. — The hookup requested is shown on this page. The coils may be similar to those used in the tuned RF described by Mr. Walters recently. The last transformer marked T consists of a plate coil same as in the other transformers and another coil which may consist of about ten turns wound over the plate coil. It would be advisable to wind the coils in the low loss fashion. Log-g-ing Stations (11959) JWT, Humboldt, Tenn. Should stations on the same wave length dial the same even though they are different distances from the receiving set? A. — The distance between the broadcasting station and the receiving set does not make any difference in dialing. 300 meter stations will dial the same whether 50, 500 or 2000 miles away, if actually on their published waves. Men to build radio sets In spare time. Leon Lambert, 501-H Kaufman Bldg., Wichita, Kansas. ILLCITE SUPER RADIO RECEIVER. No Tubes, A or B Batteries. Operates Speaker. Clarity, Distance. Write Ellcite Radio Co., Box 193, Buffalo, New York. MAN WANTED in every district immediately. Remarkable value Men's, Women's, Children's Shoes and Hosiery direct — saving Wearer 40%. Experience unnecessary. Permanent, steadily increasing income. Write today. Tanners Shoe Mfg. Co., 6-431 C Street, Boston, Mass. 200,000 SATISFIED CUSTOMERS HEAR DISTANT STATIONS O M LAMBERT CRYSTAL SETS ^\J NEW COPYRIGHTED PLANS. »1 OO COMPLETE KIT AND PLANS, S 3 .OO LEON LAMBERT WICHITA, KANSAS Radio Tubes Exchanged d in your old tufip — any make — any condition—and we will send you a Brand New Guaranteed Tube, r>f aha lever type you require, for $1.75. All uhlp m 4 np by _ Insured Parrel «p | #0 • . O. 1). Send no money -<jrder today C.«.D. D-R-C RADIO CO. 327 S. LaSalle St. Chicago. e50TU1*N CONNECT IN SERIES WITH LEAD FROM lASTFILTERTO DETECTOR TUBE FILAMENT, .^M-I'ItItW CW Oscillator for Use on Tour Filter Super (13504) .TWA, Los Angeles, Calif. Asks for a hookup of a separate heterodyne to be added to the four filter superhet to enable the reception of CW signals. A. — The hookup appears on this page. The six turn coil may be left connected permanently in the set. When it is desired to receive CW it is only necessary to turn the tube on. Harkness Reflex (13756) CWA, Sacramento, Calif. I built up the two tube reflex set as described in the April 12 and April 19, 1924 copies of the Digest. Now here on the Pacific coast, they tell me I cannot buy a two element tube, also that it is obsolete. So I used a crystal detector. I get distance and local stations but with no volume to speak of. Also I find that the set is very sharp tuning, and seems to oscillate a little, that is, you tune to the whistle. Now I also find that when I get both dials in resonance at any given point the set is quiet, but when I turn one dial off an awful howl comes out of the speaker. I am in hopes that some one has had the same trouble and can give me some help. I am enclosing a stamped addressed envelope for a reply so I can get the set to working before I get the Digest. I have not missed a copy of the Digest for over two years but lost a few and had to write for the one that had this hook-up in. The article was written by Mr. H. J. Marx. A. — We are unaDle to advise you on the difficulties you are having with your two tube reflex since it would be very difficult even if we were on the ground and able to experiment with it to locate the undesirable reactions you get. The constants given for the various parts by Mr. Marx were correct when the two element diode tube is used but these parts might not balance each other and prove suitable if a crystal detector is used. The reflexes are very tricky and the results secured are not consistent which is one reason for their being used less and less in favor of tuned R.F. Since the price of tubes has dropped that is no longer any serious I'LL SHOW YOU HOW I ' There are thousands more bigpay fascia * I ing radio positions open than there arem__ I to fid them. I know what and where these real positions are — ard 1 can Qualify you, in a few weeks epare time, to fill one of these positions ao you can earn ' I $3 ,000 to $ 1 0,000 a Year— Learn . I have successfully trained thousands of men .o at Home Electricity, Wireless and Radio for 16 years. I*** MMmu* I can make you a full-fledged radio expert qulckty: s titled, big I f man. Yoa will learn how to install and maintain transmit | z and receiving apparatus, professional and aroat I eea. You will know Radio thoroughlyand will gel ._ . ger money because of your better, broader training. I nic Ca» f>fA| Send name and address for f p^aeirreei.. full out|irje of my cour8e and bow to get the big A. R. E. Twin SuperdOlt I 'Y>'%fl Experimental Set absolutely FREE. Writ* ma ' .'avNWK mrsonatryl Irwin J. Mende's I AMERICAN RADIO ENGINEERS 1 646 N. Michigan Ave., Dept. gg^ Chicago | If FN JOY winter reception all summer! The 1 Static Eliminator -the newett and most || startling thing in Radiocut* out practically ^ all static without loss of volume! H And in addition it will help increase seieo || % tivity, tune out local lUtions, sharpen lignab, rtmovj || || noiiet, leuen interference and prevent re-radiation ! || Use it with any receiving set simply hook \ |§ up to your aerial lead-in -and enjoy perfect reception unmarred ^ ll.fat/Qjf, Sathfaction guaranteed. Money refunded at once, if returned within S dayi. I" economic reason for refiexing and the best advice we can give at this time is to discard the set in question and experiment with other types of circuits. Static Reducer (1375S) EDP, Louisiana, Mo. I am in favor of getting twice the stations on the air at once. There is one serious thing with Radio. That is receiving when there is a storm near your receiver. I am experimenting in that line. Has any one success in that line? A. — TVe have your letter of the 16th and wish to advise that the matter of a storm near ones receiver comes under the head of static. So far no one has had much success with static eliminators although within the past two or three months announcement has been made of the more or less successful experiments of Mr. McCaa. In the near future we will present a static "reducer" which will at least guarantee the strength of the static being less than the strength of the program. Shielding' tritradyne (13741) RRE, Macon, Ga. I have a model L2 Ultradyne, which is very satisfactory in volume and sharp tuning, with the exception of our one local station, WMAZ, Mercer university. I have a great deal of trouble up to 325 meters in tuning this station out. WMAZ is a 100-watt station, broadcasts on 265 meters, and is located at a distance of about one mile from the set. I have experienced no difficulty in separating any other stations with this set, and on the same aerial and ground with my old model Ultradyne had no difficulty in tuning out WMAZ. Anything that you might be able to suggest as to cause and remedy for this trouble will be very much appreciated. I enclose stamped envelope for reply. A. — We have your letter relative to your Ultradyne receiver. It occurs to us that since the Ultradyne contains several PATENT ATTORNEYS PATENTS. Booklet free. Highest references. Best results. WATSON E. COLEMAN, Patent Lawyer, 644 G Street, Washington, D. C. DURHAM Grid Leaks Used by Eagle,Howard,Thomp* son, Zenith and others. Fit all sets. Sold on guarantee. Metallized Fixed Leaks CQv 18 sizes; under '/4 meg., "^ 75c; over V* meg., 50c. Class Sealed Variable Leaks 3 sizes fit all sets; 75c each for 1 10, 5 and *TCC 10 megs I ^ cAt dealers or postpaid DURHAM & COMPANY, Inc. 1936 Market Street • Philadelphia, Pa. OUT AT LAST! /»,/-» r\r* "The Hawley" — A comL * I lit plete everlasting acid Jkf H 1 nickel-iron type storage U/aW««/t/ "B" battery. Special ' offer — 4-22% volts (90 volts), $10.00; 112% volts, $12.50; 135 volts, $14.75; 157% volts, $16. SO. Equipped so that a special detector or amplifying voltage is easily had. Chemical included and shipped separate. Nofhing to put together or buy extra. Elements are not a stamped on sice! affair and do nol rust — the connector is 99^ pure nickel. Yes! — they're firmly fastened and DON'T DROP OFF. New heavy shock-proof glass cells — and they're closed on the top. The only battery having same of this type. For those wishing to build their own — get the famous "Hawley" knock-down kits — more parts, all ready nickel connected elements, the special cells with special closed-in top and the worth-while patentpending features. New summer time prices — priced lower than any other set on the market with all the above extra features. All voltages. The onlv type or battery sold on a 2-year guarantee with a further guarantee of entire refund in 30 days without anv lfs, amis, or huts. Sample cell 35c prepaid; 35-page radio catalogue 10c. Order direct or write for my literature, guarantee and testimonials. Same day Shipments. Will ship C. O. T). if desired — simply pay expressman. Wholesale and retail. Address B. D. Smith, 31 Washington Ave., Danbury, Conn. inductances which cover the broadcast range it is probable that these coils are picking up WMAZ themselves in addition to the energy backed up by the antenna. Under these conditions it will be necessary to line the inside of the cabinet and the back of the panel with shielding material such as thin sheet aluminum and copper and ground this shielding. If the difficulty still exists to some extent a wave trap which can be permanently set for WMAZ should be used in the antenna circuit. AVe are quite sure that these suggestions will eliminate the station for you. Counterpoise vs. Ground (13 744) MEC, Montezuma, Ga. I have purchased a Zenitli Model VIII. I would like to know the advantages of an aerial composed of four wires in the form of a hammock stretched about 10 ft. above another just like it and the lower used as a ground. There is an engineer here wanting to construct some and if they are superior to the 1 strand aerial and regular ground I want one. A. — The type of aerial which you mention and which consists of four wires stretched 10 ft. above four others is not unusual and the lower antenna is known as a counterpoise. This is sometimes found an advantage where electrical machinery in the neighborhood causes undesirable interference. Where there is power line hum the antenna should consist of an aerial and counterpoise constructed after the plans of the Kane antenna advertised in Radio Digest. If one is not bothered with either of these forms of interference, there is absolutely no advantage of either system over the single straight wire 60 feet long with a 20 ft. lead-in used with a good, carefully made ground connection. Short Wave Reception (13751) EU, Succasunna, ' N. J. I have on hand a 46 plate vernier condenser. Can you give me a hook-up using this and a coil that would cover a wave length of from 20 to 250 meters, also plans for winding the coil or coupler. A. — It would be difficult to give you a circuit utilizing this very large capacity to cover the broadcast range and it is impossible to give you data for using this condenser in a hook-up covering any range between 20 and 250 meters. We are returning your 10 cents in stamps and wish to advise that we make no charge for our question service. The only condenser that can be used in circuits covering the range you mention would be .000125 and three sizes of coils would be necessary to enable you to do so. MOTORS $2.98, Good, Practical, twentieth horsepower, 115-volt alternating-direct current. ORDER NOW. PAY POSTMAN. Perry Trading Company, Dept. A6, 815 Lake, Racine, Wis. Get this great new MAP of THE AIR A MARVELOUS new way to chart your radio exploits — a beautiful Air Map. printed in three colors, with every station clearly marked and Time zones outlined! Size 28x34 inches. There's no limit to the useful and amusing ways you can use Collier's new Radio Map of the U. S. and Canada. With its help — You can find out INSTANTLY how far any station is If you use a directional aerial, you can point the loop exactly toward the station you want to get. The map also outlines the radio districts, and gives an alphabetical list of all stations and their operators. Thousands have already been sold. Get yours today! At your news-stand or radio dealer's, only twenty-five cents — or just mail a quarter to us. P. F. 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