Radio mirror (Jan-Oct 1923)

RADIO DIGEST June 9, 1923 ZENITH 1R DETECTOR AND 2M AMPLIFIER HOW TO OPERATE UNITS CLEARLY EXPLAINED Apparatus Comprises Regenerative FeedBack Detector and Two-Stage Amplifier— Selective and Sensitive See Photo Diagram on Facing Page The standard receiving set illustrated on page seven is a Zenith 1-R Receiver and 2-M Amplifier, manufactured by the Chicago Radio Laboratory, Chicago. It comprises a three-circuit regenerative feed-back tuner and detector combined with two stages of audio frequency amplification. Some of its features are: Total elimination of body capacity by proper concentration of electro-static and electro-magnetic fields without the use of metal shields or screens; reduction of high frequency resistance to a minimum and consequent increase in signal strength and efficiency; unusual selectivity and distance range achieved by radical departures from customary methods of construction. Battery Connections to Set In the photo diagram the first photo shows the front view of the set and its controls. The lower view illustrates the panels with the mounted apparatus as moved from the cabinet. When inserted in the cabinet the binding posts project from the back through holes in the base. The antenna and battery connections are made to these posts. The detector plate battery and likewise the amplifier plate and biasing batteries are incorporated in the interior of the cabinet. These then do not have to be added to the external connections but are shown for clearness and simplicity. The photo diagram illustrates the method of making the connections between the I-R receiver and the 2-M amplifier. It is particularly important that the positive pole on the storage battery be connected as shown on the diagram. The positive pole is usually marked "Pos," "P" or "x" and is frequently painted red. The negative is marked "Neg," "N" or " — " and is frequently painted black. This applies to the B batteries also, where the positive lead is red and the negative lead is black. Loud Speaker TJse Whenever a loud speaker is used in connection with the 2-M amplifier, extra B battery should be connected to posts No. 5 and No. 6. This extra B battery should be not less than 67% volts, and preferably should be 90 volts. It may consist of three or four 22% volt B batteries connected in series (i.e., positive of one to the negative of the next, and so on), or may be two of the 45 volt or one of the 90 volt B batteries on the market, whichever is best available. Positive should connect to No. 5 and negative to No. 6. When using a loud speaker in connection with the 2-M amplifier, never connect it to posts No. 5 and No. 6 in series with the extra B battery, as is sometimes done with other types of amplifiers. Always connect the loud speaker terminals to a telephone plug and insert this plug in whichever step of the amplifier is required for the strength desired. Instructions for Operation When the installation has been completed insert the three vacuum tubes in their respective sockets inside the instruments. It is better to begin operating the instruments by using the head phones rather than by attempting to use the loud speaker at first. Never use the loud speaker for tuning, but tune using head phones only, switching to loud speaker when tuning is completed and station is heard clearly in phones. The detector rheostat should be set be HERE'S YOUR CHANCE TO LEARN MONGOLIAN SHEFFIELD, ENG. — A Radio experiment of great interest is to be made here soon. General Ferrie, Director-General of Radio Services to the French Government, has agreed to broadcast to three Sheffield schools, each fitted with sets, a fable and a poem in French. The experiment, it is believed, will lead to students in all countries getting a first-hand grasp of foreign languages by listening in to the teaching in native schools. tween points 8 and 9 and the amplifier rheostats a little further advanced. If either UV-201A or C-301A tubes are used all rheostats are set between 0 and 1. Place the head telephone plug in jack No. 2 in the amplifier, turn the battery switch to the "on" position, and with the pointer of secondary tuner knob on graduation 2 turn the pointer of the tickler knob very gradually to the right. It is better when adjusting these two pointers to use the small knobs for making these adjustments. As the pointer is gradually moved to the right you will notice a faint "scratchy hiss" in the telephone and you will note that as the first pointer is changed to a different position this "hiss" in the telephones is also secured at a different position on the tickler pointer. If this pointer is turned too far to the right you may hear a loud, unpleasant "howl" in the head telephones. This "howl" is an indication that pointer is turned too far to the right. With one hand on the left small knob and the other on the center small knob, keeping tickler pointer at all times far enough to the right so that the hiss continues, revolve secondary tuner pointer over the portion of the scale between 1 and 5. A series of clear flute-like whistles will be heard, 'provided broadcasting stations are in operation within your range. It will be noticed that when you locate one of these whistles, that as you move the secondary pointer the whistle is first of very high pitch, and as the movement of the pointer is continued the pitch becomes lower, and finally the sound is lost entirely; and as the movement of the pointer is still continued the whistle is again heard low in pitch, and on further movement increases higher and higher until lost again. The center of this whistle, or the silent point, is the exact setting for the station transmitting. Once such a whistle is located and a silent point found, gradually turn tickler pointer to the left. This requires again an adjustment of the first pointer to keep at the silent point. Then tickler is turned slightly further to the left, and secondary again adjusted. This operation is continued until the hissing sound in the telephone stops, and the station should then be heard clearly. The operator should learn to adjust these two simultaneously and not first move one and then the other. It will be found, usually, that on one or two points on lower switch the operator will be unable to secure the hissing sound by turning tickler pointer. These "dead" points should thereafter be avoided. They are, usually, depending on the antenna used, points 3 and 4, 4 and 5, or 5 and4 6. Should there be more than two of these "dead" points, it is good evidence that there are exceptional losses in the antenna, and a better antenna should be provided. DON'T PASS THIS-BUYtT I /fg» a n m-m WorldRadio Batteries SAVEYOU 50% WRITTEN 2YRCUAR WRITTEN 2 YEAKI GUARANTEE Every World User Is a Booster Because you deal direct with a manufacturer who is responsible for the performance and quality of the Battery. Summer Static Overcome 'Good-bye Aerial' World-Radio-Battenes 6 Volts— 40 Amps., 6 Volts— 80 Amps., $8.50 $12.50 6 Volts— 60 Amps., 6 Volts— 100 Amps., $10.00 $14.50 6 Volts $ 1 6.00 120 Amps. Full Rating Guaranteed MAIL YOUR ORDER TODAY. WE SHIP EXPRESS C. 0. D., SUBJECT TO INSPECTION, OR WILL ALLOW 5% FOR CASH WITH ORDER. ALL ORDERS SHIPPED SAME DAY AS RECEIVED. WORLD BATTERY COMPANY, 60 E. Roosevelt Rd., Dept. L, Chicago, 111. ANTENELLA No aerial or antenna needed All outside wiring, aerial, lightning arresters, switches and other inconveniences so inductive to static are eliminated. Merely plug Antenella in any light socket and you can enjoy all Radio pleasures in any room in your home, apartment or hotel. No current consumed. New Improved ANTENELLA NOW $1.25 \J JN 1-1 I formerly $2.00 At your dealer's — otherwise send purchase price and you will be supplied postpaid. (1ms. Freshman (o. Inc. \Kartiol Condenser V&cducts 106 SEVENTH AVENUE, ' NEW YORK After the 'dead" points have "been located, set the lower switch on the contact just below the dead points and adjust pointers secondary and tickler until you hear clearly and loudly a fairly distant station, selecting your time for this when a local or nearby station is not transmitting. Supposing the "dead" points in this case are 5 and 6, set lower switch on point 4 and adjust till you hear the station clearly. If point 3 is better than point 4, try point 2. After you secure the best point on lower switch, try movement of upper switch until you find the best point on it for that particular station. It is possible that when you desire to hear a particular station and have adjusted both as above indicated, there will be some undesired interference which prevents you hearing the station clearly. In such a case, still assuming that points 5 and 6 are found to be dead, try point 7, again adjusting secondary and tickler until the station is heard, then 8 and 9 on both, and lastly the various points on upper switch, until you have found the best point above the "dead" points. This procedure often gives equally good receiving conditions and does away with the interference. In case it is desired to tune out a nearby broadcasting station and receive distant stations, quite satisfactory results are usually obtained by either setting lower switch on point 1 or 2, and varying upper switch till the best point is found where the distant station comes in clearly and the local station is not heard. Sometimes the local station can be eliminated by using the lower switch on points 9 and 10. This especially applies when the local station is operating on 360 meters, and the distant station is operating on 400 meters. For Radiophone reception, the small knob and pointer at the bottom to the right should be left on point 2, although under certain conditions the longer or 400 meter broadcasting stations will be received quite clearly when this switch is set on point 3, but with corresponding change in position of the secondary pointer, which will then be found to be somewhere nearer the lower end of the scale. . It will be noted from the instructions given that for ordinary conditions all but two of the adjustments provided are left fixed, once found. After these have been found the operator confines his efforts to the secondary and regeneration controls, using the small knobs to manipulate them. Meters, measuring the time during which persons are listening in on a radio concert, is the suggestion coming from South America. Actual use was made of such an arrangement recently in Belgrano, a suburb of Buenos Aires. RITTER LOOP AERIAL $1 All parts supplied; can be assembled in 10 minutes. We guarantee that _ the Ritter Loop will eliminate lightning troubles. Reduces static, interference and noises from your neighbors' regenerative sets. Come and see the Ritter Loop Assembled. By mail 10c extra. RITTER RADIO CORP. 232 Canal St., near Centre New York WITH TWO GOOD CONDENSERS AND A B-T VERNIER TUNER you can hook up the latest circuits with absolute vernier control and greatly superior results. Detailed diagrams furnished. 180-758 meters. Price $5.00 BREMER-TULLY MFG. CO. 532 S. Canal St Chicago ^./f.G/fEBE&CO. Me. ViatfTOm HILL, HEW YORK. IS ivSVe* idle!) Doctor Mu, exalted sage of radio, will make an announcement of utmost importance to the readers of this paper within a few days. BARGAINS THAT SATISFY VARIOMETERS Raysol (Kiln-dried parts) $2.00 VARIOCOUPLEKS Eastern Green Silk Wound 1.60 Queens (ISO degree) 2.30 Moradio (Cotton covered) 1.50 Moradio (Enameled) 1-50 Eastern Long Wave (150-3200 meters) 5.50 Cockaday Coils 2.35 CONDENSERS Regal, 43 Plates, .001 Mid. Cap 2.25 Regal, 11 Plates, .00025 Mid. Cap 1.65 American Bell, 43 Plates with Vernier 3.95 American Bell, 23 Plates with Vernier 3.65 Arrow, 23 Plates with Vernier 3.50 Phone By-pass, A. J. M 35 RHEOSTATS Regal (High quality, 8 ohm) .70 Klosner Vernier 55 Paragon SO Roberts 6 Ohm Standard 60 Bradleystats •••• I-30 Resistances SOCKETS Moulded 35 Rameco 35 Turney (All Metal) 25 TRANSFORMERS (Radio Frequency) Tricoil (of Subway Reception Fame) 1.35 Radio Laboratory RT-1 2.50 Murad T-ll 2.20 Baldwin 1-55 DIALS Kesco 3% -inch Moulded 30 Kesco 3-inch Moulded 25 Kesco 2-inch Moulded .25 American Hard Rubber, 3-inch 50 American Hard Rubber, 4-ineh $0.55 Eleetrose, 4-inch Fada Knob 55 Emeloid 3-inch Unbreakable 30 Emeloid 2-inch Unbreakable -. 20 Vernier Dial Adjustment 20 HEAD TELEPHONES Royal Phones 3.75 Telephone Connectors, Regal, for 3 Pair Phones .90 Phonograph Attachment "T" Shape l.OO Radiophone Adapter (Rubber Moulded) 1.35 TUBES Meyers High-Mu (Last Lot) 4.35 BATTERIES ("B" Only) Volton 22V2 V., Small Size \ .90 Volton 22% V. Medium Size 1.14 Volton 22y2 V. Large Size 1.55 Volton 45 V., Medium Size 1.98 Volton 45 V. Large Size.' 2.50 MISCELLANEOUS Single Circuit Jacks 25 Double Closed Circuit Jacks 35 Telephone Plugs 65 Bus Bar Wire, per foot 015 Spaghetti (any color), per length 07 Single Coil Mounting 35 Double Coil Mounting 2.00 Triple Coil Mounting 2.50 All Atwater-Kent, Radio Corporation of America, Fada, DeForest. Dubilier, General Radio and Brach merchandise — Special prices on inquiry. We also carry in stock at all times all parts for Flewelling, Reinartz, Reflex, Cockaday, HazeltineNeutrodyne, Mawhinney and Armstrong Super-Regenerative Circuits. All merchandise guaranteed by both the manufacturer and ourselves. Will be shipped upon receipt of purchase price, including postage. Radio & Mechanical Trading Corporation 23 WARREN STREET, NEW YORK CITY