Radio Digest (Apr 1925-Jan 1926)

June 6, 1925 RADIO DIGES T— Illustrated 21 Changing Regenerative Set to Reflex Add Radio and Audio Frequency to Old Set This set can be made by remodeling that old single circuit regenerative one tube set, which is causing a lot of trouble into a reflex with the addition of a Radio and audio transformer and one more tube, WORKSHOP KINKS EARN A DOLLAR— L THERE are many little kinks worked out at home that would aid your fellow Radio worker if only he knew about them. There are new hook-ups, new ways of making parts and various unique ways of operating sets that are discovered every day. Radio Digest is very much interested in obtaining such material. Send them in with full details, including stamped envelope, so rejected copy may be returned. The work must be entirely original, not copied. RADIO KINKS DEPARTMENT Radio Digest, 510 North Dearborn St., Chicago making a two tube reflex, non-radiating with little cost. You can use the same 7x12 panel, variocoupler with taps, seven to the aerial and seven to the ground, grid condenser and grid leak and the same variable condenser, 23 plate, across the rotor and the same jack. The only things to do are to add one audio and one radio frequency transformer with another socket and connect the wires up as shown in the hook-up and you will have a set that will work very good. — George L. Maurer, Williamsville, N. Y. Grid Leak Troubles Being a reader of Radio Digest and a Radio fan, I thought I would pass along a little remedy which is a cure for coughs, colds, influenza, whooping cough and the measles, which occur in the "fixed grid hak" when they take cold or get damp. My set began to give me trouble with little squeaks like those produced in loud speakers by touching the tips of fingers to the grid supports, increasing more intensely, or like mice fighting, increasing to the intensity of two torn cats on a back yard fence on a cold December night, which would naturally scare any Radio station out of the neighborhood and the set go dead. I first made a thorough Inspection of my set and finding nothing wrong as far as I could see, I diagnosed the case as "grid leak sea seakness." I knew that quinine, calomel or pills would do no good. My ]!:• rlir, friends did not Been"! to understand the ailment, but on referring to a catalogue it stated, that the grid leak was placed in a glass capsule to keep out dampness. There was a clue. Maybe my grid leak was damp. I held the grid high above a lamp for several minutes until warm and when I replaced it in my set, which had landerlng "torn eats" and disappointing my friends as listeners in. the station In simply grand. J. W. Moore. Some detectors require very critical filament adjustments for best results. asK "are they genuine Tkadiotrom?JL WD-li Radiotron TWO TUBE NON-RADIATING SET ©ttlV.'B ©90V "&0+A Switch for Aerial Combination When the new wave lengths went into effect I was bothered with tuning and to aid my reception I devised the switches as shown. The aerial used is 200 feet long, 100 feet to a length and an insulator was placed In the center of one length. I T 1 LEAD \T0 6TeOOND ONE UP. ST. «SV)\TCH Lf> IB Ti TO SET The leads were taken from each side of the insulator and one from the 100-foot length. This gives me the use of either 50, 100, 150 or 200 feet of aerial as desired.— Leo E. Collins, Los Angeles, Calif. Counterpoise Reduces Static Learning that KGO, Oakland, California, was going to broadcast until 11:30 p. m. (2:30 a. m. eastern time) I decided to try and receive them. The static was very bad but finally I succeeded in picking them up by using a very unique method of arranging the aerial system. I remembered an article about the transmitting aerial system of an amateur in Milan, Italy, In which It stated that the writer of the article used a counterpoise over his aerial. I use a three circuit regenerative receiver having a fixed coupler. A variable condenser does all the tuning and therefore broadcast stations always come In at the same place on the dial. I kept track of the dial markings of various stations so that 1 could know where various wave lengths should come in. On that particular night I could not even pick up (|,( carrier wave of K«:ii at tot WD-11 idiotron first on account of the heavy static, so I disconnected the aerial and ran a wire from the aerial binding post to a metal bed, using the detachable metal knob on the bed post as a binding post. This arrangement cut out almost all the static and interference and increased the selectivity, but it considerably lessened the volume. I then connected the main aerial to the ground binding post and the volume was greatly increased while selectivity was still maintained. I then tried to receive KGO. I heard a faint carrier wave, then after very careful adjustment I heard the dance orchestra which the announcer later said came to the station from San Francisco. I believe that this idea of using a grounded counterpoise placed over the aerial will be of great interest to many listeners who desire to eliminate static and interference and get volume and long distance reception. — Donald Chapman, London, Ont. Inspect Aerial System The aerial system should be periodically inspected to see that the wires are taut. Any excess slack should be pulled in. Guy wires holding up he mast should be adJusted so that the pull from each direction is equalized. The mast should be carefully examined to see that It is perpendicular, and any excessive lean should be corrected by means of additional guy wires. Four pieces cut from two rubber sponges will eliminate microphonic noises in sets if the pieces are put under the corners of the Radio cabinet. Use of rubber under the loud speaker will make for quieter reception also. SENS IN YOUR Paralyzed Tubes to be Restored to Health in Our Laboratory QO Qf of your worn-out tubes can *sO /O he put in first class condition. We can REACTIVATE UV-201A. C B01 \, 1 \ 199, C-209 anil any nth it thorlated Blameni such as Atlas, Masnatron. Iv IVn t. (.r . Wo cannot reacurate t'V-uon, C-800, WD-11 or WD12 lubes, nor can wc reactivate hurneil out tubos. It Costs Yon Only $1.00 If we ran restore your tube ho thai it operate it ractorlU [f we ;iie Dot successful, our rharce l» only 25c Why bar the prlre for new tuben when we ran make yours as Hood as new fur only |1.00s MAIL IN YOUR TUBES TO US FOR PROMPT RETURN. Parcel Post. C. 0. D. A. O'CONNOR & COMPANY 9706 Euclid Ave. Cleveland, Ohio KORACH TUNED LOOP Tuninff Feature Directional Can Be Logged Collapsible ' IIOHOIOIIOIOIOMIIKOIIOIOIIIOOIIIOIOItOIOOlO' Miniiiiinmi liunnitirtiiiii t Miimrpjniiiiiiniwinin ■rio. Loop COCK IDA1 i Bi tl'\ la brine In 0,1 BO Vbi r • PI . Plymouth, en. Madrid, U l\ \ '. POftO FtlCO all'l ntlirr <>c n ,\p. err-YC'l ami recommended for tbe POCKADAI i r< iiurt • il I before wllb I i ■ «oo.| faith i|epo«H wllb your C. o l> Btitsfactlon fueranteed KORACH RADIO CO. Dept. 9, 309 So. LaSnlle St. Chicago, 111. Full Particulars an Rrqurit Dealers and Jabbers: Write at ante for attractive pro»osltlen. Repairing Broken Socket If you have a broken socket of the formed composition type do not throw it away. Sometimes sockets of this type can be efficiently repaired. Where a notch NF_W SLOT CUT HERE t is broken out cut a new one on the opposite side with a hacksaw then remark this posts as shown in the illustration. — John O. Foulk, Anadia, Kansas. Circuit Connections All circuit connections should be soldered. Terminal connections should be tight and free from corrosion. A wornout socket or switch, producing dim and flickering lights, should be replaced by material of ample capacity and rugged construction. If a cartridge fuse is used avoid a poor contact by keeping clips and ferrules free from corrosion. Wire for Spider Web Coils Do not use enameled wire on spider web coils for these coils impose a comparatively high mechanical stain on the insulation which often scrapes the en ri on touching portions of adjacent turns. This shorted turn will render the rect h practically inoperative. Double silk-covered wire is recommended for spider-web windings. Label the Leads Mistakes in making connections, w itch often result in the burning out of tubes, is a failing common to Radio begl] A good plan, anil one that will prove a reminder in making connections, is to have the leads from the A batteries and B batteries tagged with little tags marked with the voltage and polarity of each lead. Boosting Current The parallel connection of cells is us. .1 when a greater amount of electricity is available from one cell is desired. The positive terminals of all the cells art nected together and the negative terminal's are also connected. The voltage remains the same but the current capacity is increased. KESTER Rosin Core /MS0LDER Surc^is Safe and Simple APPROVED BY RADIO ENGINEERS a Oenulni CHICAGO SOLDER COMPANY 42.10 Wrlelitwwxl Ale . ChlOagO.U 1 A Ortftndioridfio'U/oTld'iLarff/it Manvjai luTfTi o/Scl/ Pluxing Solder Tour Dealer Tan Sun