What Radio Readers Want to Know 



Increasing an Umbrella Aerial. 



C. A. P., Fresno, Cal., asks : 



Q. 1. Would it be advisable to add 2,000' 

 of wire to my umbrella aerial ? 



A. 1. If you add the wire so as to make 

 the length of the antenna greater it will be ad- 

 visable to add the amount of v>rire you men- 

 tion. It would be better if you could ar- 

 range so as to have this wire extend 300 or 

 400 feet out from the pole. This would give 

 you a longer fundamental wavelength, which 

 is necessary when receiving from stations 

 using verj' long wavelights for transmission. 



Q. 2. Can I hear Arlington with a silicon 

 detector? 



A. 2. It is possible that you could hear 

 NAA. Stations along the Atlantic coast with 

 aerials no larger than yours have heard the 

 high power stations of the Pacific coast. Very 

 recently we had occasion to note the recep- 

 tion of Berlin by an amateur station in Massa- 

 chusetts. The operator used an oscillating 

 audion in connection with a home-made re- 

 ceiving set. His aerial was about 150 feet 

 long and 50 feet high, although 300 feet above 

 sea level and in sight of the ocean. Very ex- 

 cellent work is being done by well informed 

 amateurs who are using oscillating audions. 



Q. 3. What is the best receiver for long 

 distances? 



A. 3. We would advise you to equip your 

 station with an oscillating audion. For in- 

 formation regarding audions, oscillating au- 

 dions, radio telegraphic transmitting and re- 

 ceiving apparatus write to the DeForest 

 Radio Telegraph & Telephone Co., 101 Park 

 Avenue, New York City. Be sure to mention 

 the fact that you desire the instruments for 

 amateur experimental work, as the price is very 

 much lower for this kind of work than when 

 sold for commercial operation. They will 

 supply you with bulletins covering the subject 

 on request. 



Q. 4. What station uses call 2GN? 



A. 4. We have no record of these letters 

 being assigned as yet. 



Radio Receiver Information. 



M. H., Wilmette, 111., a.sks : 



Q. 1. What is the natural wavelength of an 

 inverted L aerial of total length 85 ft., 5 

 wires on 9 ft. spreader, and 55 feet high ? 



A. 1. About 200 meters. 



Q. 2. What size wire is most efficient for a 

 loose coupler to receive 600 meter wave- 

 lengths? 



A. 2. It makes very little difference what 



size wire is used. In general the useful sizes 

 run from about No. 22 to No. 28 B. & S. 

 gauge. 



Q. 3. What would be the dimension and size 

 of wire necessary to make a loading coil from 

 10,000 meter wavelengths? 



A. 3. Wind No. 28 S. C. C. magnet wire on 

 a cylinder 5" in diameter and about 30" 

 long. 



Q. 4. Does the secondary circuit also need 

 loading? 



A. 4. Yes, or the two circuits would not be 

 tuned to the same wavelength. The second- 

 ary circuit is usually increased in period by 

 shunting the secondary of the tuner with a 

 variable condenser of large capacity. Load- 

 ing inductance is also used the same as for the 

 primary. 



Receiving Set For Amateurs. 



J. A. Strossman, Mt. Sterling, asks : 



Q. 1. I have a four-wire aerial 90 feet long, 

 50 feet high at one end and 30 feet high at the 

 other. Is this a fairly good aerial for ama- 

 teur use? 



A. 1. We should consider it quite satisfac- 

 tory. 



Q. 2. What is the natural wavelength of this 

 aerial ? 



A. 2. About 225 meters. 



Q. 3. How many miles should I receive with 

 this aerial, using a double slide tuner, galena 

 detector, and 1,000 ohm receivers? 



A. 3. Local conditions so affect the receiv- 

 ing range that it is even worse than guessing 

 to try to give any distance. For this reason 

 we do not publish receiving distances in this 

 column. 



Q. 4. What is the best all around detector 

 for amateur use? 



A. 4. Galena is usually considered the most 

 sensitive of the single minerals. Silicon will 

 keep its adjustment better but is not as sen- 

 sitive as galena. 



Radio Abbreviations. 



A. R. L., Pittsburgh, Pa., asks : 



Q. 1. Will you please feive me the meaning 

 of the following abbreviations used in sending 

 radio messages? CK, HR, SRNS. 



A. 1. CK is the abbreviation for check 

 used to state the number of words in the 

 message. HR stands for here and is used to 

 indicate that a station has a message there 

 for transmission. It is sometimes used to 

 acknowledge the reception of a message. We 

 can find no reference to your third abbrevia- 



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