Radio Digest (Oct 1923-July 1924)

February 9, 192 \ RADIO DIGEST — Illustrated WSm WAVE TRAPS NOW ON THE MARKET Manufacturers Meet Demand for Interference Eliminators with Two New Models Tests Made on Two Types Malone-Lemmon Control-O-Meter and Metro Wave Selector Explained for Benefit of Fans IN AN effort to locate and test various standard wave traps, selectors or whatever name they might be known by, it was found that there were not as many on the market as might be anticipated. Undoubtedly in various cities there are numerous traps available at dealers which are only produced for local trade. The idea, however, was to describe a few that have a more national distribution. Evidently the demand has been great because manufacturers were not in a position to deliver instruments for testing purposes. Two were available, but details of other instruments will follow later. The first one shown in the illustration is the "Control-O-Meter," a Malone-Lemmon product. The instrument is well made, having a sloping panel with two binding posts and one control dial. A card accompanies each instrument on which is given the calibration for eliminating specific wave lengths. On the one tested this is given as follows: Undesired Wave Length Dial Setting 300 meters 22 350 meters 29 400 meters 38 450 meters 49 500 meters 65 The instructions on this card should be of interest. 1. Set the instrument in a convenient location alongside the receiving set. Avoid having the connecting wires too long. 2. Disconnect the antenna lead wire from the set and attach it to one binding post of the meter. Now connect the other post on the meter to the antenna binding post on the receiving set. 3. Each instrument is tested and calibrated before shipment, results being noted on the "Factory Record." Malone-Lemmon "Control-O-Meter." Setting of Instrument The method of setting the instrument is as follows: Assume that WJZ (455 meters) is interfering with a concert from WEAF (492 meters). To eliminate WJZ, refer to calibration table on back of the instruction card and note that the wave length of 455 meters lies between 450 and 500. In column "Dial Setting" under "Factory Record" are the figures corresponding to 450. Slowly rotate dial between the figures coresponding to 450 and 500 until the point is noted at which interference diminishes. By advancing or retarding the dial a few degrees from this position a point will be found at which WJZ is completely eliminated. 4. It will be found that when the interfering station is once eliminated by a careful setting of the instruments, a further readjustment of the main receiver will not again bring back the interference. 5. The adjustment of the Control-OMeter to completely eliminate interference is quite sharp, loud signals disappearing' within a few degrees on the dial. In exceptional cases, supersensitive receiving sets located alongside of a powerful broadcasting station may require an additional instrument inserted in the ground lead. The Wave Selector Another instrument, shown in the second illustration, is the "Wave Selector" manufactured by the Metro Electrical Metro "Wave-Selector." Company,! This instrument is enclosed in a very neat compact case with a hinged cover. Instructions are . pasted in this cover and are as follows: 1. Binding post marked "Aerial" should be connected directly to the aerial. 2. Binding post marked "Set" should be connected to receiving set where the aerial usually connects. 3. Before adjusting main receiving set, the dial on the selector should be set approximately at 90. 4. The main receiving set is now adjusted in the usual manner in order to bring in the desired station to the greatest signal strength, regardless of interference. 5. To eliminate the interfering station, the dial on the instrument should now be slowly turned either to the right or left until the undesired station is at its minimum strength. 6. If the undesired station is still present, it wil be necessary to again adjust the main receiving set, with a final very slight adjustment of the selector. 7. Remember that every adjustment of the selector affects the tuning of the main receiving set and every adjustment of the latter affects the tuning of the sel< It Is only by the careful adjusts re-adjustments of both in combin;. that the two circuits can be absolutely balanced and th<; undesired station entirely eliminated. AH, WOE! ANOTHER ONE'S WED, GIRLS Pheminine Phans Lose Second Idol at WGR, Buffalo BUFFALO, N. T.— Alas and al Here is more bad news for pheminine phans. After L. B. Weller got ma: and ceased forthwith to be chief nouncer for WGR, the no less dulce' cents of Edward Stanko began to be h< ard from Maine to California as chief spc man at the Buffalo station. Some of those same pheminine pi who used to send Mr. Weller mash n are beginning to get keyed up ovei Stanko's voice and now along comes news that he too is married. The ceremony took place in Buff ah cently before City Judge Harry B. Lai.ison. Miss Fay Pepley of Hooversville, Pa„ was the bride. Bryan's Talk— "Is Bible True?"— Is Sent by WMC MEMPHIS, TENN. — What were deemed forceful arguments against modernism in the church were presented here recently by AVilliam Jennings Bryan by means of Station WMC, Memphis Commercial Appeal. The "Commoner's" address, delivered to a large audience in a church, was relayed to the newspaper's Radio plant, whence it was put on the air. The title af Bryan's lecture was "Is the Bible True?" The applause which his points evoked indicated that most of those who heard him still believed in the spiritual verities. Radio is described by a native of Africa as a powerful machine that can speak without mouth and hear without ears. 'iill i!i:i! Uninterrupted radio enjoyment for you is Federal's manufacturing policy EVERY radio set and each of the 130 parts manufactured by the Federal Telephone and Telegraph Company carries a guarantee of absolute freedom from mechanical and electrical defects. This guarantee is made possible through the efforts and skill of 25 years' research by experts in the radio field. When in the market for a radio set or parts it will pay you to investigate the unsurpassed services being rendered to millions of radio enthusiasts by Federal products. Progressive dealers everywhere carry the Federal line and will be glad to tell you what the name Federal signifies on radio sets and parts. Standard KADI O Products jfefceral ^elepfjcme anb Celegrapfj Company BUFFALO, N. Y. Boston New York Philadelphia San Francisco Bridgeburg, Canada Chicago Pittsburgh London, England ilii;;ii!!!iii!i