Radio broadcast .. (1922-30)

48 RADIO BROADCAST NOVEMBER, 1925 RADIO INVESTIGATION IS AS FASCINATING AS THAT IN OTHER FIELDS physical optics, drags Galileo and his telescope into the argument, and ends — 1 am sorry to say — by a rather harsh criticism of his opponent. If radio broadcasting were carried on between two perfectly definite power levels, radio receiving sets could be designed to function satisfactorily in the hands of the radio public between those limits. This does not exclude the super-sensitive sets for scientific and industrial use any more than the fact that the human being has eyes excludes the use of the telescope or microscope in similar fields. I do not know how much experience Mr. Dreher has had with the difficulties of properly adjusting telescopes and microscopes, but, from my own experience, I am thankful that my eyes function satisfactorily for most purposes without the aid of these complicated instruments which require so much skill for their satisfactory use, and at the same time are very expensive. Similarly, I am for a broadcasting system which will operate between fixed power levels so chosen that a relatively simple and inexpensive receiving set will function between these levels satisfactorily for general use, and will not require a great amount of technical skill on the part of the listener to operate it. While Mr. Dreher is unwilling to grant a high order of technical intelligence to the listener, he advocates putting in his hands the type of instrument which requires a maximum of technical intelligence to operate. This simply proves that he misunderstands the radio public, and does not know that the present trend in the manufacture of receiving sets and tubes is in the direction of making the complete receiver as near fool-proof as possible. Nature has been very kind in not placing the sun in the direct line of vision at the time when the light rays from the sun are most intense and by placing the sun behind the earth at night in order that the earth's inhabitants may enjoy the moon or star-lit heavens without any interference from the sun's rays. If Mr. Dreher can devise some scheme whereby he can shut down his super-power stations altogether, or remove them so far in space, time, or wavelength from the other broadcasting stations so that they will interfere as little — with the programs now being broadcast — as the sun interferes with our enjoyment of the heavens at night, I do not believe that any one will object, and he can enjoy his super-power stations to his heart's content. My opponent accuses me of not being courageous enough to enter the radio field against him. It was not lack of courage, but lack of a mean disposition, and, even now, after a second challenge, 1 would rather not do it. However, let us look into this little computation of his. He is a very clever and interesting writer and uses a lot of words to prove simply this: If you have 500 watts and increase it to 50,000 watts, everything else remaining constant (presumably, including the science of mathematics) you have one hundred times as much power on the antenna, and therefore one hundred times as much power at all other locations. Now, if he had had as much experience as I have had during the last fifteen years trying to transmit energy at different power levels to the points where you want it to go, instead of into copper roofs, water-pipes, steel buildings, etc., he would never have penned that article and misled his readers into believing that they were going to receive one hundred times the volume from WGY'S 5o,ooo-watt transmitter, on its first test, that they receive from our 5OO-watt transmitter. This is no argument against super-power, but against the deplorably misleading statements one reads in the radio press. Station WHAZ stood by on August 24, 1925, to allow WCY to complete their transmission tests, and our staff was as disappointed as the WGY staff with the results. It was my good fortune to be listening in at one of our test stations and the increase in power level at that location was almost nothing. The set I was operating is one we are at present using for field strength measurements. It makes one of the best receiving sets (I did not make it) I have ever had. On several occasions 1 have loaned this set to B. C. L.'s and they have been invariably dissatisfied with it, the reason being that it requires as fine and delicate adjustment as a high-grade microscope and when not properly handled will absolutely ruin the best program beyond recognition. Mr. Dreher's other contention regarding the advantages of one or two steps of amplification at the transmitter rather than at the receivers reads as easily as the one just discussed and is as misleading. Here again he assumes ideal conditions which do not exist. The simple fundamental error made in his assumption is that a receiving set receives energy only at the frequency for which it is tuned. He intimates that I have never listened to DX. Well, I have, and 1 have not only amplified DX signals to loud speaker value but have sent them out through our experimental station 2 XAP with sufficient power and clearness to be heard in California without appreciable distortion. These rebroadcasting experiments were carried out in connection with other experiments, the primary purpose of which was to determine the facts regarding the sensitivity and selectivity of the most widely used receiving sets already owned by the B. C. L.'s. Station 2 XAP was used as an interfering station with different amounts of power in the antenna and at different frequencies (wavelengths). The receiving sets were located at various points at different distances from 2 XAP. These experiments proved conclusively that increasing the power level of the interfering station, which is usually a local station, by as much as one or two step? of amplification prevented us from receiving stations which could be received at the lower power levels of 2 XAP with good enough quality for rebroadcasting purposes. It could not be expected that conclusions drawn from radio engineering experiments carried out through two cold winters would agree with opinions formed in a steam-heated New York City office. You must decide for yourselves which are of greater value. Space will not permit me to tell you the little I know about transatlantic radio telephony and telegraphy and how international broadcasting will be accomplished. I will content myself with the statement that our station has already been rebroadcast on the other side of the Atlantic, and I am not really as ignorant on the subject as Mr. Dreher would have you believe. I cannot agree with my opponent in his final conclusion to the effect that talk on this subject is of no value. If he really has a set that can be interfered with by a cat rubbing his back against the fence and cannot pick up a joo-watt station only one hundred and fifty miles away, we have learned something from his side of the argument, granting my points sum up to zero. The Memoirs of a Radio Engineer VI IN 1910 I graduated from the elementary school, and a little later my family moved to another house, where I started what may not have been an innovation, but it was certainly an early use of an expedient now very common — the resort to an indoor antenna where it is not feasible to erect one outdoors. The landlord objected to my trespassing on the roof of his three-story treasure, on the ground that I would wear through the sheet iron and cause the roof to leak, that I might fall off, that an antenna would be unsightly, that it would attract the unchained lightnings, etc., etc. So I strung two wires about fifty feet through our apartment and, as the neighborhood was one of frame structures, obtained satisfactory results, as the times went. I had a crystal detector, consisting of a piece of silicon, ground flat and smooth on one surface — God knows why, but the current superstition was that silicon should be used in that way — and imbedded in solder, with a blunt brass point pressing down on it. This was attached to the antenna and a gas pipe ground, and a 75-ohm receiver, swiped from some telephone desk set, connected in parallel with it. Once in a while this combination picked up signals very faintly. They were probably those of near-by amateurs. After a while I got together a tuner — a cardboard mailing tube about