Radio Broadcast (Nov. 1925-Apr 1926)

360 RADIO BROADCAST ADVERTISER Radian Panels in black and Mahoganite come cut in all standard sizes The double advantage of RADION SUCCESSFUL set manufacturers and experienced amateurs know that there are two important requirements for any set: 1. Efficient reception. 2. Good appearance. The selection of RADION goes far toward fulfilling both these requirements. RADION Panels possess superior insulating qualities not equaled in any other panel made. And RADION has such a beautiful surface finish that it noticeably enhances the appearance of any set. New No. 10 4-inch Radion Dial, built to conform to the fingers, helping you to get close tuning. This double advantage of RADION is due to the fact that it is the only insulation that was made to order for radio purposes exclusively . The high-resistant characteristics of RADION Panels mark all RADION low-loss parts — Sockets, Dials, Insulators, Tubing, etc. Adopted by leading manufacturers and sold universally by radio dealers. No. 2 Radion Socket for new UX tubes with collar adapter for old type tubes. No. 4 same as No. 2, without collar adapter for new UX tubes exclusively. Send for booklet , "Building four Own Set." Mailed for 10 cents Manufacturers: Our facilities and equipment for the manufacture of moulded parts are second to none. Write us for prices on quantities. AMERICAN HARD RUBBER COMPANY Dept. C-13 11 Mercer Street New York City Chicago Office: Conway Building Pacific Coast Agent: Goodyear Rubber Co. San Francisco Portland Rap ion 'The Supreme Insulation Made to order for radio purposes exclusively By HAROLD JOLLIFFE The time has come, the Walrus said, To talk of many things; Of shoes and ships and sealing-wax, Of cabbages and kings. — Carroll. THE fellow who came out with that clever remark about economy, certainly was a wise old bird; his head was in the right place, and he knew what he was talking about. We do not know who the originator of this bright little maxim was; he probably dates 'way back down the dim corridors of time to the obscure and misty past, when the ancient Phoenicians dauntlessly set forth in their little vessels to invade the shores of distant Britain with their varied trade. Quite likely it had its inception at a far earlier date than that; maybe it was around about the time when that little fellow, David, got peeved and knocked his enemy, the great and husky Goliath, for a home run, with a well-directed stone from his sling. But no matter when, where, or how. It is an axiom that applies now as ever; and it holds just as forcefully in radio as in anything else under the sun. You can't get away from it. Take vacuum tubes, for instance. As everyone knows, for the standard price of two and a half dollars you can walk into any radio dealers' and purchase a good tube; a tube of recognized quality; a tube which is the result of the constant efforts of many of the greatest scientists of the age, and years and years of tireless study and ceaseless experiment. Millions and millions of dollars have been expended to bring it up to its present high state of perfection, and it has embodied in its construction all those desirable and necessary qualities which make for an efficient, serviceable tube. It is rated at a certain voltage and current consumption, and is guaranteed to perform exactly as indicated by the manufacturer when his directions, regarding its use and care, have been followed carefully, and provided it is not abused. Therefore, such a tube may be expected to do all that is claimed for it. And yet, there are those who will waste one dollar — yes, one buck's the price! Can you beat it? — on a tube which, in the first place, is probably a "second" of a so-called independent manufacturer; a tube which, if rated as consuming .25 amps., will more than likely draw considerably in excess of that amount; a tube which may not even fit its socket, for that is exactly the case with some of the three-volt variety. You have to take a file and rub down what appears to be a small brass rivet projecting from one side of the base, before it can be inserted into a socket; others sit wobbly in their sockets because their bases have a diameter of one-sixteenth inch less than the internal diameter of the shell of the socket, which results in uncertain contact. The writer knows of a case where an elderly couple had a four-tube receiver, and the tubes, having become worn out through continued use, needed replacement. Despite warning, they bought four tubes of the above-mentioned type, and without a word of exaggeration, these tubes gave absolutely no satisfaction. They ate very heavily into the dry A batteries — the tubes were of the three-volt class — and produced a most annoying whining sound which could not be eliminated and which was not due to any fault of the receiver, which was pulled apart and re-wired in an attempt to locate the trouble. In the end, they had either to buy four good tubes or let the receiver sit on the table and collect dust. Being devout fans they purchased the tubes, and presto! — the set worked like a charm. It therefore cost them sixteen dollars to replace the tubes instead of twelve. But they were attracted by the low price. False economy! They might just as well have thrown the cheap tubes into the ash can. What is the good of buying such tubes and taking a chance as to whether they will be any good? Admittedly, you will strike some good ones now and again, but at the most, they arc good for but a fraction of the service you would get from ihe better class. ■jr Tested and approved bv R \mo Broadcast -tV The writer, with the help of a certain dealer, tested several of these tubes with a device which registers the current in the plate circuit when the filament is heated to a certain temperature. If a recognized make of 201 -a tube was inserted in the socket, and the customary five volts applied to the filament, the milliammeter indicated a current of anywhere between 1.1 to 1.4 milliamps. But if one of the dollar variety were tried, it was seldom indeed that a reading of more than one milliamp. was obtained; many went as low as .75 milliamps., but only once in a while would the meter indicate a good tube. Then again many of them will not oscillate. The writer has three such tubes of the 201-A type which were loaned him for testing purposes. One will oscillate very strongly if a pressure of no less than 5.5 volts is applied to the filament. The remaining two will not oscillate at all, which, of course, renders them useless as detectors in a regenerative circuit. And do they play havoc with the A battery! I'll tell the world! AND transformers! CONSIDER audio frequency transformers. These, next to vacuum tubes, are probably the most delicate of all radio receiving apparatus. They must be designed and constructed with the greatest thought and care, for it is upon the design and construction of the audio amplifier that the quality of the received music depends. Oh, yes; the loud speaker does have a lot to do with it, but the audio amplifier first. Now, if there is anyone who believes it possible to produce a good transformer, one that will really do the work, for $1.50, let him take the floor and show us how! It simply can't be done, after the middlemen have taken their profits. Yet, a rather doubtful looking affair can now be purchased at that price at certain cut rate stores — one dollar for the winding and fifty cents for the core, is the way they advertise them. A socket for twenty-five cents, and not such a bad-looking affair at that. Cheap? Sure it is, until you apply the soldering iron and melt half of it. Nothing but "mud"! Radio fans! If you wish to build a good receiver, one that will reward you with the greatest possible clarity and distance for a given number of tubes, one that will be easy to work with during construction, one that you can pull apart without damaging the apparatus when you wish to switch over to another circuit — then purchase, steal, or otherwise acquire good, dependable apparatus. There's a reason! Take the case of John Brown, for instance. The radio bug bit Johnny good and hard; so having a nice little work bench and all the necessary tools down the cellar, he decided to " roll his own." Being a sensible sort of a fellow, he went out and bought the best he could afford, and since he didn't know much about it, he took someone along with him to show him what was what, and why. Johnny now has a fine outfit if there ever was one, a real low loss set, and he is justly proud of it. He gets splendid results; night after night the old stations come pounding in with a roar; and Johnny sits back in the old easy chair with a contented look on his face, and enjoys real radio satisfaction. His neighbor, just a few doors down, is always tinkering around, fixing this and changing that and wondering why in heck his set won't work as well as Johnny's. The answer is simple. Although he could afford it. he wouldn't spend the necessary cash to buy the good parts that characterized Johnny's purchase. Disregarding the reliable dealer down at the corner, he went to the other store where "a real low loss" variable condenser sells for a dollar and a quarter, and bought a lot of cheap stuff that Johnny and his experienced friend passed up with a grin of derision. He now has more sense, and is thinking of junking the entirety of his original purchase and starting in all over again with good apparatus. johnny Brown doesn't have to do that, so he is just that much money to the good.