Radio mirror (Jan-Oct 1923)

RADIO DIGEST ILLUSTRATED Multiple Phone Connector A Simple and Inexpensive Way of Making Connection Frequently one wishes to use two 01 more phonos on the receiving set. A simple and inexpensive way of making the connection is by means of the arrangement ShoWIl in the illustration. Two pieces ot sheet brass or copper measuring about % inch wide and o inches long are required. Also, you will need six or more spring connectors taken from old dry cells. If posts. The phone cord tips are then attached to the spring connectors. If phone condensers are not used or condenser is not equipped with binding posts, the brass strips may be mounted on a piece of bakelite or other panel material, or to the panel itself and connecting wires from the set should then be attached to the brass strips. ^O BRA55 OR COPPER SPRING CONNECTORS BRASS .STRIP SPRING CON ■ HECTORS 50LDE.R Et> TOGETHER. one wishes to use three headsets in multiple, three of the spring connectors are soldered to each of the pieces of brass. If the phone condenser is equipped with binding posts for wire connections, a % inch hole should be drilled through each of the brass pieces near the lower end, and they may then be attached to the phone condenser by using the regular binding t =£ BAKE LITE Oft HARDRUB8ER ■BRASS STRIP A simple arrangement for connecting phones in series is shown in the second sketch. Here the brass strips are supported on a piece of bakelite in any desired manner. Additional connectors soldered together in pairs are also required. The sketch shows the method of connecting two phones in series. — P. Starck, Sterling, 111. Efficient Single Tube Set Using the hook-up shown with a single wire aerial 80 feet long and 30 feet above the ground and an ordinary ground I have heard fifty different stations, the most distant ones being KLZ and KEAF at Denver, Colorado. I am using a 23 plate condenser and a vernier condenser in parallel with the primary of the vario coupler, but these are not absolutely necessary, i=m.|.H^. although they make tuning easier. It may appear that the variometer in the grid circuit is not necessary, but I find that without using it, the tube filament must be turned on more brightly to obtain the same results. By using it the life of the tube is lengthened and also the tuning is made easier. When condensers are not used the variometer is absolutely necessary for tuning. I also found that the plate voltage for the better operation of this set may be found by letting the tube oscillate and then rotate the tickler coil. If a click is heard in the phones, as the tickler is rotated, the voltage is too high. It should be lowered in small steps until the click is eliminated. This will be the best voltage to use. Lower voltage will bring in a weak signal and a high one will be difficult to tune. When the plate voltage is right the set will be easy to tune. In selecting a detector tube I find that the best one to use may be found by turning the filament rheostat about half way and inserting different tubes, in turn, in the socket. The one which gives the brightest light is invariably the best. I have obtained better results with this set than any of my friends using a onetube set, either homemade or otherwise. — John Brown, Toungstown, O. using both ends, or the instrument can be connected to one end and a regular ground connection can be used on the other. — A. A. Vawnut, Chicago, 111. How to Make "Silver" Dials Secure a sheet of stiff brass, cut it to the shape desired with whatever diameter is wished and clean it top and bottom with steel wool until it is bright. Having drilled the shaft and supporting screw holes for the knob, make a solution of sulphuric acid and rain water, using three parts of acid to one of water. Pour the acid into the water slowly, employing a porcelain bowl as container. Dip and wash the disc in this solution. Melt some tinfoil in a clean pan and when the foil has completely melted dip the brass disc in it, allowing it to remain for about fifteen seconds. Place it in a pan of water to cool. The finish is made by rubbing surfaces with a small piece of clean cloth until the "silver" shines up brightly. The marking may be done with a pen and good ink, or indentations may be stamped in the brass disc before silvering. This treatment may be applied to all the brass work on the set with a resulting neatness in appearance. It would be well to give each part a heavy coat of lacquer or good varnish to prevent tarnishing. — R. U. Batty, Chicago, 111. MYERS TUBES Dealers: Write for Discounts Hudson-Ross, 123 W. Madison, Chicago Antenna Protects House The antenna will not attract lightning any more than a lightning rod, telephone wire, gutter pipe or tin roof. The antenna, if installed properly, is much less likely to be struck than any other object in the neighborhood. During a thunderstorm the antenna should be grounded, as when it is connected direct to the earth it serves as a medium which permits the static to pass from the air to the ground, as does the lightning rod. There is no risk with a Radio antenna properly installed. Indoor Aerial Erection ■When erecting an indoor aerial, hang up aboxit 100 feet of wire, making the loop as large as possible, with the fewest number of turns. String the wires through the hall and around a room, or they can be given several turns around the ceiling in one room. Connections can be made by cRactio &/ie S^mxtacerSaprewB THE two sizes of Magnavox meet every requirement — from home gathering to large public audience. To hookup is simple — no extras or adjustments are required. R-3 Magnavox > Radio with 14-inch horn (V illustrated) For homes, offices, amateur stations, etc. . $45.00 R-2 Magnavox Radio with 18-inch horn For store demonstration, large audiences, dance halls, etc. . . $85.00 At good dealers everywhere The Magnavox Co, Oakland, Cal. New York Office : 370 Seventh Ave. R-A-D-I-O BUY HERE FOR LESS Radio Supplies purchased here are sold under a positive guarantee of satisfaction. We carry the largest new stock of first quality merchandise. Complete Parts for Reinartz Circuit Includes 1 7x18 Formica Panel, 1 Bakelite Socket, 1 Howard Vernier Rheostat, 23 Plate Condenser, 11 Plate Condenser, 3 Switch Levers, 2 Dozen Switch Points, 1 Reinartz Wound Coil, 1 Variable Grid Leak, 8 Binding Posts, 25 Feet Tinned Wire, 1 Base for Coil, 1 Mounting Base Board, and 1 Diagram to Construct This Set. Complete , $11.45 ORIGINAL TYPE "C" BALDWIN UNITS $4.95 COMPLETE PARTS FOR REG. RECEIVING SETS This includes 2 Variometers, 1 Coupler, 3 Dials, 1 Rheostat, 1 Cunningham Detector Tube, 1 Bakelite Socket, 1 Mahogany Cabinet, 7x1$ Formica Panel, 6 Binding Posts, 1 Switch Lever, 12 Switch Points, 2 Stops and 1 Diagram to construct this set. Set is djl 7 QC capable of receiving 1,000 miles if installed with outdoor aerial *?*■ ' »vO VARIABLE CONDENSERS $4.30 Value, 43 PLATE, now. $1.75 $3.10 Value, 5 PLATE, now . $1.25 $3.70 Value, 23 PLATE, now. $1.45 $2.70 Value, 3 PLATE, now. $1.15 $3.30 Value, 11 PLATE, now $1.35 U.S. A. Signal Corps Av!^4°-wType Western Electric Phones, $7.95 Each Phone Cap is covered with large soft rubber ear cushions, and an aviation leather helmet goes with each set! These are the only phones to pass the Government specifications for sensitiveness and loudness, the requirements called for in aircraft reception. COMPLETE PARTS FOR FLEWELLING CIRCUIT Includes 6x14 Formica Panel, 23 Plate Condenser, 3 Micon .006 Condensers, 1 Freshman Variable Grid Leak, 1 Remler Leak, 2 Coil Mount, 2 Honeycomb Coils, 2 Coil Plugs, 1 Socket, 1 Howard Vernier Rheostat, g Binding Posts and 1 Diagram 41 O /IC to Wire and Construct This Set. Complete «pl^,43 MAGNAVOX, Loud Speaker, Type R3 $34.95 VARIOMETERS GENUINE MAHOGANY, $5 VALUE, NOW $1.95 VARIOCOUPLERS, $4.50 Value, Now $1.75 HONEYCOMB COILS 1,500 Turns $1.50 1,250 Turns 1.50 1,000 Turns 1.25 750 Turns $1.00 250 Turns 75c 150 Turns 60c 100 Turns 50c 75 Turns 40c 50 Turns 40c 35 and 25 Turns 40c $8.50 Guaranteed 3,000 Ohm HEAD PHONES $3.65 RHEOSTATS 45c Sponge Rubber EAR CAPS, Pair 50c DIALS, 2, 3 and 3^ in 25c THORDARSON AMPLIFYING TRANSFORMERS $4.50 VALUE, NOW $2.95 GREWOL DETECTORS $1.65 Signal Corps Super Sensitive Microphone Transmitters, $2.45 Solid Copper Aerial Wire. 100 ft Spaghetti Tubing, yard , Cord Tip Plugs Lightning Arresters 35c 10c 60c 95c 2-Slide Tuning Coils, at 3-Coil Honeycomb Mountings, i^bs $4.20 Phone Caps, for mostly OC» all phones AUt. Signal Corps Hot Wire «e Att Ammeters, at q>0.*±0 $1.95 Anti-Capacity <C1 CA Switches jpi.OVf $2.65 45c 95c Lightning Switches Hydrometers, now at Freshman Variable Grid Leaks FORMICA PANEL J" thick, Square Inch. He BLACK OR BROWN WE GUARANTEE ALL MERCHANDISE PURCHASED OF US Mail orders receive immediate attention BUY HERE FOR LESS CHICAGO SALVAGE STOCK STORE 509 South State Street, Chicago, 111.