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ADIO AMATEUR. NEWS
REG. U.S. PAT.OFF.
-The 100% Wireless Magazine"
GRAND OPERA BY WIRELESS
See Page 100
15 Cent's SEPTEMBER
1919 OVER 100
IL LUSTRATIONS Edited by
In This s s.0 e:
REVIEWING RADIO HISTORY By Dr. Lee de Forest
FUNDAMENTAL OPERATION OF VACUUM TUBES By David S. Brown
GRAND OPERA BY WIRELESS By H. Gernsback
GUARDING THE ETHER DURING THE WAR By P. H. Boucheron
vt It MN U'BLISHED BY EXPERIMENTER PUBLISHING qtr., ., N. Y. C. www.americanradiohistory.comwww.americanradiohistory.com
"ASK ANYONE WHO HAS USED IT"
WENT THROUGH CHATEAU -THIERRY, ARGONNE AND MEUSE OFFENSIVES A soldier who used a Brandes Headset all through the war brought it to us for slight repairs afterward. He knows that a Brandes is the best that can possibly be made. You ought to hear him talk. (Name on request.)
"Suprrinr" Set- 20(X) nhms. $L Score l00% efficiency in actual use
Sharp, Unblurred, Readable Signals assured by BRANDES MATCHED TONE" -
Exactly matching the tone of both receivers in each set and thus eliminating all confusion due to unmatched harmonics.
lirandes Wireless Headset sent to you on trial for 10 days. Test it,- compare it with others, -for sensitiveness, clearness, distance. Prove for yourself the fine quality, the "matched tone." The two diaphrams, toned exactly alike, strengthen the signals and prevent blurring. Used by many U. S. Government experts, and experts abroad; by colleges and technical schools; and by professionals and amateurs everywhere If dissatisfied, your money back without a question.
SEND 4o FOR CATALOGUE "G..
C. BRANDES, Inc., Room 823 32 Union Square, New York, U. S. A. WIRELESS RECEIVER SPECIALISTS
AMAZING AUDION DETECTOR
VALUES- $9.5 -0 $11.75 $18.85 $22. (22
Remarkably efficient and handsome audion control panels within the price limit of EVERY AMATEUR, BUILT AND DESIGNED FOR THE AUDION, AS ONLY THE MAKERS OF THE AUDION CAN BUILD IT. IN THE PAST, INSTRUMENTS OF THIS CALIBRE HAVE NEVER
BEEN OFFERED AT TWICE THESE PRICES. GENERAL SPECIFICATIONS, ALL MODELS: Beautifully engraved and grained genuine bakelite panels; 4 prong heavy nickeled tube receptacles; smooth running, positive acting, adjustable rheostats; impregnated efficient mica stopping condensers;
adjustable or fixed grid leaks with polished nickel covers; bakelite covered binding posts with new slotted positive
:I connecting feature: positive segmentally connected nickel plated switches; 40 volt B battery of two 20 volt type units cast en block with operating life of 6 to 12 months - a remarkable advance in B batteries; handsome quartered oak cabinets, round corners. standard de Forest "Early English" finish; perfect workmanship and expensive design throughout. Type P -400 Audion Panel -Consists of tube receptacle, grid leak and condenser, rheostat and binding post for connection to tuner, A and B batteries on bakelite panel 71/2" x 71/2" without cabinet and B batteries $9.50 Type P -401 Audion Panel -Same as above with cabine,
$11.75 Type P -402 Audion Panel- Larger panel with 40 volt B battery in cabinet $18.85 Type P -500 Audion -Ultraudion Panel -Type P402, Panel
P500- $22.00 with two switches for audion -ultraudion connection and
either 20 or 40 volt B battery in cabinet $22.00 TYPE P401- $11.75 NOTE: All de Forest audion apparatus is sold without the tubes. Audion detector oscillator or amplifier tubes, $7.00 each additional.
Catalog sent on receipt of I Oc in stamps to cover postage.
DE FOREST RADIO TEL. & TEL. CO., 1397 Sedgwick Avenue, New York City
September, 19 19 RADIO AMATEUR NEWS 97
AMPLIFY YOUR RADIO SIGNALS O NE of the greatest drawbacks since the invention of wireless telegraphy is the receiving of weak signals at the receiving station. Many devices were proposed to improve this condition, but without suc- cess, on account of the mechanical difficulties encoun- tered in these ampli- fying devices.
However, this was recently solved by the introduction of an ex- ceedingly sensitive mi- crophone transmitter, which is known to de- tect sound waves with great accuracy and magnify them through an intermediate tele- phone circuit.
By the employment of the new DETECTAGRAPH- TRANS- MITTER, the amateur can amplify the radio signals to such an intensity that he can hear the signals about his station with- out the need of the telephone head set.
By the addition of a loud talking tele- phone he is able to hear the messages many feet away from the instrument. He is also able to demonstrate the operation of his wireless apparatus to his friends.
The super- sensitive DETECTAGRAPH-
TRANSMITTER herewith shown is two and three - eighths inches in diameter, five -eighths of an inch thick and weighs less than three ounces. It is the most sensi- tive sound detecting device ever brought before the public.
Practical Instruments for Commercial and Scientific Purposes.
Our Special No. 25 Loud Talking Receiver Price, $4.00 Complete
Our Super -Sensitive Detectagraph Trans- mitter. Price, $7.00
Our Jup erSens / /ive /,Niccophone Troesmi / /er
The manner in which the amplifying process is attained is by attaching with tape the DETECTA- GRAPH - TRANS- MITTER to the reg- ular wireless receiver as indicated in the diagram.
Other Uses Not only is this in-
strument applicable for amplifying radio signals, but it can be used with equal satisfaction for magnifying other sounds. Phonograph music can be transmitted from one place to another by means of this in- strument, and those who are af- flicted with deafness will find enormous benefit by using this transmitter.
It is the greatest device for build- ing your own loud talking tele- phone, detectagraph and other de-
v i c e s. Can be used for any pur- Prl... $10.00 Coerlets p o s e where a sen s i- tive de- tecting instru- ment is required.
Loud to /hing telephone
i i Our Sensitive woo Ohm Radio Telephone Recover
Medal "B" Hors, with Loud Talkies Reo.lver, Cord Plugs
and Desk Stand
Model "C" Horn, with Loud Talking Wall Receiver. Price,
FOR THE EXPERIMENTER FOR DETECTIVES FOR THE DEAF
DETECTAGRAPH This detecting instrument of marvelous sen- sitivity can be used for detecting secret con- versations. Outfit consists of Sensitive Transmitter, 25 -ft. Black Cord, Receiver, Headband, Case and Battery. Complete DETECTAGRAPH JUNIOR DEAF -PHONE The outfit consists of a Super- Sensitive Transmitter, with a cord connector; Super - Sensitive Ear Piece with small black cord; Black Single Headband; Black Case and two small Batteries. Transmitter 24 inches in diameter, 3á of an inch thick. C 00 and weighs less than three J.- ounces. Complete
Detectagraph Rheostat. especially mode for am- plifying circuits.
Super Sensitive No. 40 Receivers to be used In connection with Detect- agraph Transmitters.
$10.°° .6_ .... Boissonnault Co., 25 Church ' St., N. Y. C.
de As per your ad in Radio Amateur News.
please send me free cir. Order direct from ad. Or unit. for culars and full particulars free descriptive circular. For your 4, Imes. aeout your Detectagraph De convenience use the coupon.
BOISSONNAULT COMPANY 25 CHURCH STREET NEW YORK CITY
Makers of Super -Sensitive Microphone Devices
' STATE You hrn rfit by mentioning the "Radio Amateur N etas" wJ, ro writing to advertisers.
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RADIO AMATEUR NEWS September, I 9 I 9
"Government Radio Control Once More." By H. Gernsback 101
"Reviewing American Radio History" By Lee De Forest, Ph.D., D.S.C. 102
"Guarding the Ether During the War" By P. H. Boticheron 104
"Static Eliminator of Considerable Merit" By Edgar Terrain Johnstone 105
"Grand Opera by Wireless" By H. Gernsback 106
"Government Radio Control" 108 "5 -Kw. Navy Transmitter"
By W. H. Priess 110 Coast Artillery Radio School 109 "The Pickard Double -Deck Receiver"
By Walter J. Henry 112
"A. B. C. of Wireless Reception" By H. K. Dunn 113
"Fundamental Operation of Vacuum Tubes"
By David S. Brown 114
"The Latest Design in Antenna Switches" By E. T. Jones 116
"Construction of An Audion 'B' Storage Battery"
By Herbert Webb 117 "Some Real Ideas"
By Zip 118
"Moulded Condensers for the Amateur" By L. A. Bartholomew 119
"A Radio Experimenter's Re