Radio Digest (Oct 1923-July 1924)

February 9, 792 '., RADIO DIGEST — Illustrated OPERATING AND TROUBLE SHOOTING | For the Owner of a c Ohe {Royalty fTM g/'Jicdlo K E N N E Model V D Y THE new receiving unit Model V combines an unusual degree of selectivity and precision with Simplicity in tuning. But, even though .simplicity has been attained, the observation of certain precautions named below will usually improve the operation and add to the enjoyment to be had therefrom. also strengthened i the point of being objectionable, The simplest and most effective way to uce such Interference is to decrease both the length and the height of the antenna. This makes the set tune "sharper" although at the same time It reduces signal strength correspondingly, It is therefore wise to a middle course. Best all-around results usually obtained with an aerial consisting of a single bare copper wire, number 12 or 14, suspended at a height of 20 to 40 feet and from 100 to 200 feet long. Where greater signal strength is desired, lengthen or raise the aerial; where greater selectivity is desired, shorten or lower it, or use a wave trap. In the absence of an outdoor aerial, any one of the interior types may be employed. Ground A good ground system is desirable, the best practical method being to connect a ground wire number 12 or 14 gauge, Aerial Almost any type of aerial is suitable, although a properly constructed outside antenna is to be preferred. In general, it may be said that the strength of the received signal increases with the height and length of the antenna. While this is quite desirable, yet where static and other disturbing conditions are present, these disturbances are either bare or insulated, to a cold-water pipe. Connection should be made through a ground clamp firmly fastened to pipe and soldered to the ground wire. While a good aerial and ground system is recommended, it is interesting to know that this receiving unit operates quite well without a ground connection of any kind. It operates without an antenna, provided the ground wire is attached to the an TtMfanljiulJO No. 12 of a Series Featuring Experiences of "ALL-AMERICAN" Users can " transformers on both sides with first class results. The two r.f. transformers were identical. No Others Equal the "AllAmerican" By T. J. Gehlert, Benton Harbor, Mich. "I hooked up a tWO-Stage radio anywhere near brinding in the results nerertnr anf4 o Twn ctaort aitrfin* that the two 'AHAmerican' Radio Freaetector ana a two-stage audio quency Transformers produced. frequency set USing All-Ameri "I have never been able to get, with other transformers, the good results that I get when I use 'All-American/ " And over 500,000 other radio enthusiasts will readily agree with Mr. .f Gehlert ou this. That Hearing about * js why AU.Americans it being better to | » are the most popular have r.f. transform 3£?Ah,s^3 "• aQd most widely used ers that were made of all transformers. special for first, second and third stages, I obtained a SPecial °ffer set of these of another make but they didn't come All the better dealers tell the "ALL-AMERICAN" RAULAND MFG. CO., 208 N. Jefferson St., CHICAGO PIONEERS IN THE INDUSTRY All-American Kadio Frequency Transformer for wave lengths 150 to &00 meters. Price $4.75. The best — why pay more? All-American Power Amplification diagram-circular and Book of 22 Tested Hookups sent for 4c in stamps to cover mailing. More than 500,000 in use Standard on the better sets Audio and Radio Frequency: Power Amplifying (input and output^ Ael~. ._ AMPLIFYING TRANSFORMERS largest Selling Transformers in the World "("") PERATJNG and Trouble Shooting" is a Radio Digest feature whose purpose is to study the late models of various standard receiving sets and to show the newly initiated broadcast listener, who has purchased such a set, how he can operate it to get the best there is in it and how he can overcome minor difficulties which may be causing some trouble. On pages II, 12 and 13 this week the Kennedy V and the Garod RAF arc described. Radiophans with other kinds of sets will also find these articles worth reading, particularly the notes on trouble finding. tenna binding post. In other words, it will give quite fair results if the ground binding post is left disconnected and '■ the antenna or ground wire is connected to the antenna binding post. Interference While it has a high degree of selectivity, there are some instances where interference is so strong that it is practically impossible to eliminate it. In such cases, the following suggestions may be helpful: Where code signals are the source of interference it will generally be found that these signals are being transmitted on special government wave lengths (within the authorized broadcast waveband) or else it may be that the signals are being transmitted above certain authorized wave lengths that could not ordinarily interfere with broadcast reception. This is almost certain to be the case if a slight movement of the tuning dial, either to the right or left, will lose or tune out the offending signal. It is difficult to tune out a strong code signal, on any regularly authorized wave length, that is being transmitted at a distance of only two or three blocks from a receiver. Likewise, it is extremely difficult to tune out a powerful broadcasting station located within one or two miles of a receiver. In quite a few cases where interference is present to an unusually marked ble to e! a small wave trap i i the antenna and the antenna binding post on '• trap connectThe aerial is < A of this i ninal is connected to the aerial binding po the recei'. One striking fact about the use of a wave trap with the Kenned that the wave trap does not in any way affect the regular dial settings or tuning operations. Special Caution In a majority of cases where trouble is encountered fn the operation of th: ceiver it is of external origin and c;: traced either to the A batteries, B batteries, socket adapters or tubes. These will now be considered separatA Batteries Since faulty A batteries form one of the most frequent sources of failure to operate, the following suggestions are of particular importance: When dry cells are employed their life ranges from three to six weeks, depending on the number of tubes used and the amount of service to which the batteries are subjected each night. For this reason this type of A battery should be tested frequently. When it is found that (Continued on page 12) HILCO VARIOCOUPLER Type "E" Contains primary and Secondary winding of the HILCO Latiice Banked type, and is ideal for use in single, two and three circuits^ close adjustments in wave lengths of 20S to 600 meters; very selective, sharp tuning and variable thru wide range. Price $7,00. Specified as Standard Equipment in Erla Re f tex and other well-known receiving circuits. What a Difference the HILCO Variocoupler Makes! Put a HILCO variocoupler or variometer in your set and note the "difference! The dominant and exclusive features of HILCO inductance coils are — 1st, lattice bank type of winding, which suspends the wire in air with the successive turns crossing each other at right angles. {.This winding possesses much greater efficiency than honeycomb and dvolateral windings, and should not be confused voith them), 2nd, The unique design of mounting the winding, with minimum amount of insulating or energy-absorbing material employed. These .construction features make HILCO inductance coils very setective and sharp-tuning, enabling the most distant broadcasting stations to be brought in right thru nearby stations. HILCO Radio Products are now sold by most dealers and jobbers. If your dealer or jobber can't supply you, send his name with order and we will see you are supplied. DEALERS AND JOBBERS: Hilco Radio Products are profitable, satisfactory merchandise, with quick turnover. Write for literature and discount: Type A Variometer, very selective and sharp-tuning thru a range of from 200 to 600 meters. Price $6.00. HILCO TYPE Rl Inductance Coil for Relnartz circuit: will tune to wave lengths of 200 to 600 meters. Price $2.50. HILCO Krystlkoil - moat efficient for crystal sets; winding tapped for tuning from 280 to «M meters. Price $1.25. A. E. HILL MFG. CO., Atlanta, Ga, U. S. A.