Radio age (Jan-Dec 1924)

18 RADIO AGE for May, 1924 The Magazine of the Hour W FIGURE 5 The diagram above shows the Ultra-audion receiver as it should be connected when loose antenna coupling is employed. {Continued from page 16) Honeycomb The honeycomb coils are very good mediums for carrying out these ideas, and can be arranged in the manner shown in Figure 3, illustration 3. A circuit diagram for their connections is given under Figure 6. The receiver described in the March, 1924, issue (How to Make a Low Loss Tuner) is basically the same, the difference lying in the manner in which the coil is wound. At any rate, the honeycombs should have the following values: A, 20 turns; B, 50 turns, and T, 55 turns or less. The tickler of the receiver in the March issue (The Low Loss Tuner) FIGURE 6 A wiring diagram for the honeycomb coils shown in Figure 3, Illustration 3. can, by the way, consist of as high as 35 turns, with a gain in efficiency. Figure 3, illustration 4, shows what is meant by close coupling, and is used in neutrodyne, super-heterodyne and other circuits as a coupler. In this case, coil A should not have more than 8 turns for the greatest possible effectiveness. More turns will broaden the tuning and defeat the purpose of this type of coupler. If tnore turns are desired for the primary or A coil, the windings should be separated as shown under illustration 6, which provides a space of variab'e distance between A and coil B. The Wizard $10 receiver uses this type of coupling. (The Wizard was described in the April, 1924, issue.) This covers about all methods of coupling as far as sets go with the exception of Figure 3, illustration 5, which shows how the loose coupling idea may be carried out with flat coils. Two circular discs are cut out of bakelite or heavy cardboard or wood, and 15 toothpicks (the number of toothpicks is not important except from a mechanical standpoint) are clamped between these two discs, which are held together by a brass screw. The coupling coil is wound or rather woven on these toothpick supports, and is placed in inductive relation to the main coil of the set as shown. The connections should be made as shown in the circuit of Figure 5. Just a hurried trial of one of these systems will probably greatly surprise the average reader as to their effectiveness. These suggestions are valuable in cases where a tuning system for a receiver is accessary with but a few materials at hand. The unit shown under Figure 3, illustrations 4 and 6, are especially handy, as they can be used as wave traps couplers (fixed) and can be used on loop aerial receivers instead of the loop. The writer will be glad to offer suggestions to interested readers. Requiescat I^HE following letter, is sent to us from Mrs. Ada Richardson who says it came from "our boys in Indianapolis" and she wanted RADIO AGE readers to know about it: Dear Home: Thought I would write you and tell you about a very sad event which befell us yesterday. To wit: A great calamity has fallen upon our home, our transformer mourns, and cannot be comforted. It was only yesterday our tube smiled up to us with sweet and confiding reassurance. But long before dawn it passed into that great beyond from which no tube ever returns. We shed a tear for our vanished playmate, and showered curses upon the terrible "B" battery, whose powerful current no self-respecting filament can long withstand. A strange calm is visited upon our radio. The strains of beautiful music which once poured softly forth from its inmost recesses have died away completely. Even the variometer has become strangely grim and silent. Our grief is more than we can endure; we are breaking under the strain. It was vengeance, horrible vengeance, but the "B" battery has been paid in full. No longer can it hold a grudge against us for dropping it downstairs. We pray it shall have no mercy, and may it have to atone to the fullest extent for its destructible sin before it can find peace and everlasting happiness. I thank you! Well, it was tough luck and a tube only costs five dollars, so be careful! I have found out that "B" battery doesn't work worth a cent in the filament. RALPH. "ALAS, POOR Y0R1CK, I KNEW HIM WELL*