The Birmingham age-herald., 1922-06-18


 frequency ampiification. When this was attached to the loop aerial no one in the room could hear the music from Newark, although 1t could be heard faintly in the head telephones.
 Receiver Eliminates Sparks
 One of the astounding character istics which make the new receiver the ideal broadcast apparatus Is its ability completely to eliminate park signals It wipes them out abso- lutely.
 Tn explaining this. Armstrong pointed out that the incoming spark sets up free oscillations in a regen- erative circuit, which continue until the next spark comes along, and the greater part of the energy is In these free vibrations.
 The program which had been set aside for Wednesday at WIZ consist ed of literary night" wherein au- thors read selected chapters from their works. Realizing that this would not give a complete all-round demonstration of the remarkable possibilities of his new apparatus. Armstrong asked for an amplifica- tion of the program. Miss Eva Leoni, a well-known soprano who had sung to the radio audience two days pre- viously, volunteered again and so facilitated the reproduction of well-rounded program.
 In the new system these free vtbra- tions are completely wiped out be- cause every twenty -thousandth of second the resistance of the circuit becomes positive and thus chops the free vibrations out before they have rharca n ha bntIf
 The significance of this lies in the fact that with the new receiver In general use the amateur wireless operators can flood the ether with spark signals to his hearts content every night, without Interfering with his neighbor, who is trying to listen to a broadcast entertainment. This Is very important. because 1t eltmi- mates the possibility of the battle which was impending between the general public and the general body of amateurs.
 The future possibilities of the new system are .imitless. One of the most important of them is bound up in the ability of the apparatus to operate economically and efficiently upon short waves. It will be possible In the near future to utilize the receiver with the system now being developed of short wave wireless telephony. using reflected wave which will give the utmost degree of secrecy attainable.
 Armstrong Very Modest
 Although Armstrong has steadfastly refused to talk about any of the re- markable inventions. he did say to me yesterday during a conversation that he had succeeded in getting down to 5o-meter wave lengths with the new system. and that this experiment had confirmed the fact that the apparatus amplified four times greater on the short waves.
 On waves of this length, using re- Electors shooting a beam of waves in one direction. wireless telephone con- versation has already been accom- plished by Franklin in Europe over s distance of 200 miles with the older types of receivers. With Armstrong; s latest receiver this distance could be greatly increased with the same amount of transmitting power.
 Despite the fact that Armstrong. who >is naturally modest. Is reticent about the value of his Inventions. his friends have no hesitation about pointing out their value. In this con- nection Louis c. Paceni, a membe of the institute and one of his CO., workers, in discussing 1t with me, said:
 When we take into consideration the fact that the super-regeneratIve system is 100000 times more sensi- tive than the regenerative circuit, it is we'll to point out that the regenera- tive circuit itself Is several hundred thousand times better than the ordi- nary circuit.
 Extreme AmpIification Obtained
 ITO make this point clear to the layman. it. should be pointed out that with the regeneratiye circuit using a detector and two-stage amplifier. with careful adjustment with the zero beat, so that you can get signai which you can barely hear In the telephone, if you switch over to a super-regener- ative circuit using practically the same equipment with the same num- Der of vacuum tubes the same signals can be heard in loud speaker over the entire room. This gives an idea of the extreme amplification. Another important point is the fact that with a multi-stage radio frequency amp1ifier 1t is very hard to change wave-lengths. but by using the super-regenerative method the wave length range can be very easily changed Such 8 change does not require more than two adjustments. one in the secondary circuit and the other on the feed-back or rcgenera- ton.
 With fixed inductances a wave length range from 15o to 500 meters can be covered without difficulty or changing the inouctances or capac- ities. In other words. you get a wave length ratio of four to one, say, start ing at 100 meters you would get 400 meters. and starting at 25 you would get 100 meters. Of course, if the inductances are made adjustable the difference in the. wave-length range can be greatly increased.
 Opens Up n New Field
 Tt seems that Armstrong. in addi- ton to giving the radio world an in- vention which. Is capable of reception on short wave-lengths in . tremen- dously efficient manner heretofore unknown. has opened up new field. using extreme frequencies and ampli- flying them without difficulty. Practically speaking. using the Armstrong super-regenerative circuit 1t Is possible to use only two vacuum tubes and a small loop about one meter in diameter and hear any of the broadcasting stations like WIZ with telephones lying on the table at distance of 40 to 50 miles from the station. With the addition of another vacuum tube as an ampli- fer 1t is possible with the same equipment to hear the same station at the same distance over an entire room by means of loud speaker. ir- respective of whether or not the loop | is in a steel building.
 'Tts possibilities on short waves are also very important. With three tubes ! it does the work of the super -heters J. dyne receiver which used nine vacuum tubes. but it goes lower In the wave length scale than the super hetero- dyne. It's importance can be further emphasized when it Is pointed out that at the present time there are no