Radio mirror (Jan-Oct 1923)

April 28, 1923 RADIO DICK ST Practical, Easily Made Single Tube Reflex Set Part II— Wiring the Set By H. J. Marx AFTER, the apparatus has been mounted on the panel there are still three . parts to be taken into consideration. The tube socket, the audio frequency transformer and the Radio frequency, or reflex transformer. Figure 1 shows a baseboard measuring six Inches by seven inches and 5/18 inches in thickness. Naturally the size of this baseboard is dependent on the cabinet size, for this reason no provision was made for it in the panel laryout. ■7 u*vwr or GAS* BOAKJi Figure 1 In the illustration a suggested arrangement of these three units is given. The secondary terminals of the Radio frequency or reflex transformer should be facing the primary terminals of the audio frequency transformer in order to keep the leads as short as possible. The crystal detector is connected in series between the grid terminal of the Radio frequency transformer and the plate terminal of the audio frequency transformer. The by-pass condenser should be connected across the primary terminals of the audio transformer. Inductance Tap Switches The inductance switches used are of the type with the contact points on a mounting plate in the rear of the panel. Since each switch has 15 contact points and there are only 6 each rough and fine tap connections only the alternate contact points were used and the last 4 points were left open. The odd points on the dial of the switch, 1, 3, 5, 7, 9 and 11, are connected while the remaining points are open. If desired, however, the first and second, third and fourth, etc., can be connected together and thus eliminate the open points which may confuse a person In turning. The leads from the taps on the variocoupler are usually long enough to make connections without a lengthening piece. The contact points on the switch are slotted so that it is a simple matter to 6lip in the leads. Soldering the Wires A little soldering paste is placed on each point and when the soldering iron is applied the flux will flow into the slot and around the wire. Then when the solder is applied it will fill up to the slot and lock the wires in position with good electrical contact. Antenna and Ground Connections Looking at the rear of the panel the antenna binding post is in the upper right hand corner. Following the circuit, the lead runs from this point to the terminal of the rotating plates of the variable condenser, then to the one secondary terminal of the variocoupler. From here it goes to the lever terminal of the inductance switch, and over to the grid W. T. 501 Peanut Tubes, 4 V. Vi Amp. with Adapter $Z75 (Use storage battery or 3 dry cells in series) R. V. T. 5-6 V. Detectors 2.75 R. V. T. 5-6 V. Amplifiers 3.35 (Sent on receipt of price. No C. 0. D. orders accepted) 1 Tube Regenerative Receiving Set with Detector Tube and 3000 Ohm Headset. VERY SPECIAL VALUE 29.75 LUX MANUFACTURING CO. 1043 North Wells Street CHICAGO. ILLINOIS the audio frequency trans terminal former. The lead from the ground binding post connects only to the lever terminal of the other inductance switch. Battery Posts Connections The binding post in the lower right hand corner (rear view) is the A-f terminal and the lead runs direct to this post on the tube socket. The two posts in the center are for the connections to the negative sides of both A and B batteries. These two posts are connected together by one lead which then runs to the rheostat, then to the one side of the .002 mfd phone and battery by-pass condenser, in addition this lead connects to F — terminal on the secondary of the audio frequency transformer. The lower left binding post is the B+ terminal and is linked to the phone post above it, in addition the lead connects to one terminal of the open circuit jack. The other terminal of this jack is linked to the top left binding post, the other side of the by-pass condenser and the B+ side of the Radio frequency or reflex transformer. Tube Socket Connections The positive filament lead has been added, the negative filament terminal of the socket connects to the rheostat. The grid terminal connects to the secondary of the variocoupler and the fixed plate terminal of the variable condenser. The plate binding post on the socket connects to P terminal of the Radio frequency or reflex transformer. In reflex this compact arrangement of apparatus is an important feature as it avoids unneoessarily long leads. Because of the double duty imposed on the tubes naturally inductive interference will be unduly noticeable and should be avoided. Voltage of A Battery The A battery voltage should be 6 since peanut tubes are not recommended for reflex circuits. The B battery voltage at about 90 will give best results although with different tubes it may have to be changed. The construction of a suitable cabinet is left to the discretion of the builder. THE END In winding your loose coupler, both coils are wound in the same direction. Cunningham Detector Tube Cunningham Amplifier Tubes I Pr. 2000 Ohm Frost Phones included with each genuine COLIN B. KENNEDY Type 281 Short Wave Regenerative Receiver and Typo 521 Two Stage Amplifier, Latest Type. Standard Price $145.00 ($10 with order and balance on receipt of goods.) We can save you money on Crosley Sets. Write for Prices Satisfaction Guaranteed IMPERIAL PUB. SUPPLY CO. Cedar Rapids Iowa »Here sy our opportunity. Radioneeds * you. Win success in this fascinating field. Trained men in demand at highest salaries. Learn at home, in your spare time. Be a Radio Expert I will train you, quickly and easily, to design, construct, install, operate, repair, maintain, and. eell a!) forma of Radio apparatus. My newmetheda are the most sneeessf ul in existence. Learn to earn. $1,800 to $10,000 a Year P D E7 CT Wonderful, home-construction . tnbe ■ Imfc b receiving set, of latest design. Writef or"Rad io Facts" free. Engineer Mohanpfc, American Electrical Association Dept. 24-4 4513 Ravcnswood Ave., Chicago THE ARTHUR PUDLIN VARIABLE HIGH RESISTANCE Leak Has made the ROSENBLUM Circuit possible Hear 3,000 miles on 1 tube Blue prints FREE on receipt of 2 cent stamp Variable high resistance leaks, price 75c with .00025 condenser, $1.00 ARTMICA Condenser, all capacities, 25c Our PRODUCTS endorsed and used universally by E. T. Flewelling, Wtn. Rosenblum and other noted Radio inventors ARTHUR PUDLIN ENGINEERING CO. 329 East 29th Street New York City, N. Y. SUPER Radio Frequency Transformers Get your Receiving Set in readiness to overcome the difficulties experienced in warm weather, by equipping with Super Radio Frequency Transformers and the Super Loop Aerial. Greater Audibility Comparative tests with the Super Radio Frequency Transformers and other makes show three to ten times the audibility. Use With Any Amplifying Tubes These transformers are adapted for use with any standard amplifying tubes and give wonderful results with the new Cunningham or Radiotron tubes. Gives Remarkable Range In the Mississippi valley, with loop aerial only, using two stages of Super Radio Frequency, Fairbanks, Alaska, Honolulu, Porto Rico, and Mexico City have been heard with clarity and volume, and Amateurs from coast to coast are picked up with ease. SPECIFICATIONS: Fits any standard vacuum tube socket, or can be used without socket. Wave length band 180 to 650 meters without necessity of radio frequency condenser. Furnished in two stages, No. 1 and No. 2. Complete instructions and circuit diagrams with which these transformers may be used, are furnished with each transformer. Radio Frequency Transformer No. 1 .r. $4.50 Radio Frequency Transformer No. 2 M«. ..... 5.00 Super Loop Aerial 9.00 Sent prepaid to any part of U. S. on receipt of purchase price Super Antenna Company, Quincy, Illinois, U. S. A.