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This Volume is for REFERENCE USE ONLY
2529(1 1
RADIO BROADCAST
VOLUME XIV
NOVEMBER, 1928, to APRIL, 1929
GARDEN CITY NEW YORK
DOUBLEDAY, DORAN & COMPANY, INC.
1929
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INDEX
(*Illustrated Articles. Editorials in Italics)
PAGE
* A AND B Power from the D. C. Lines
r\. (William B. Dall) 34
*A-Power Unit, The Improved Knapp. 43
Aircraft Radio 18, 234
Aircraft Radio, Progress in the Field of. 93 *A11 About the Dynamic Loud Speaker
(Joseph Morgan) 159
Allocation Plan, WGY's Attack on the. . . 163 Allocation Plan, WGY Protests New. ... 92 Allocation Repairs the Broadcast Struc- ture, New 16
Allocations Attempted, Regulation of. . . . 373 Allocations, Fitting Receivers to the New. 234 "A. C. Band-Pass Screen-Grid Receiver, An— The Master "Hi-Q 29" (William
E. Barton) 117
*A. C. Operated Tube Tester, A Simple
(The Laboratory Staff) 173
*A. C. Screen-Grid Browning-Drake Re- ceiver, The New (Glenn H. Browning) 115 *A. C. Tubes. The "Chronophase" for
(Bert E. Smith) 126
Amateur and Commercial Radio 374
*Amplifier and Power Supply for the
"Vivetone 29," An (R. F. Goodwin). 45 Amusement Industries, Radio May Yet
Become the Cornerstone of 91
*Apparatus, New 52
* Apparatus and Its Applications, New
127, 194
*Are Filters Needed in A. F. Amplifiers? (Keith Henney) 250
*Armchair Chats on Short- Wave Sub- jects (Robert S. Kruse) 189
*As the Broadcaster Sees It (Carl Dreher) 32, 102, 185
*Audio Oscillator, An Inexpensive . (Edward Stanko) 186
*Audio System of Dynamic Speaker Reproduction, A New (Frank C. Jones) 29
*Automatic Volume Control System. New (Charles Williamson) 299
Aviation, A New Radio Service to 297
*TD POWER from the D. C. Lines, A
JD and (William B. Dall)
'Band-Pass Filters, Some Experiments
with (Kendall Clough) 104
*Band-Pass Screen-Grid Receiver, An A. C.— The Master "Hi-Q 29" (Wil- liam E. Barton) 117
'Battery-Operated Receiver, An Eco- nomical (Howard E. Rhodes) 257
Book Reviews:
Advertising by Radio, by Orrin E. Dunlap, Jr. (Edgar H.
Felix) ... 388
B. B. C. Handbook, The 1929, by The British Broadcasting Corporation (Carl Dreher).. 252 Laboratory Treatise on B Bat- tery Eliminator Design and Construction, A (Howard E.
Rhodes) 125
Practical Radio, by James A. Moyer and John F. Wostrel
(Carl Dreher) 162
Practical Television, by E. T. Larner (Carl Dreln 354
34
PAGE
Radio, by Elmer E. Burns
(Carl Dreher) 252
Treatise on 25 Testing Units for Service Men, A (Howard
E.Rhodes) 116
*Broadcast Engineering (Carl Dreher)
246, 311, 402
Broadcasting, In the World of 297, 373
Broadcasting Increases, Commercial .... 18
Broadcasting Stations, Mexican 358
Broadcasting Stations, With the. .93, 164, 235 "Browning-Drake Receiver, A Loop- Operated (J. H. Gockel) 171
*Browning-Drake Receiver, The New A. C. Screen-Grid (Glenn H. Brown- ing) 115
*Building Receivers for Television (Zeh
Bouck and James Millen) 35
*Business Side of Radio Servicing, The (John S. Dunham) 236
CHARACTERISTICS of Power
V^ Rectifiers (Roger Wise) 393
"Chart for Making DX Measurements,
A (James B. Friauf) 188
*"Chronophase" for A. C. Tubes, The
(Bert E. Smith) 126
*" Chronophase" Screen-Grid Receiver,
The (Bert E. Smith) 49
Commercial Broadcasting Increases 18
Commerical Radio Telegraphy and Tele- phony 165
Commissioner Robinson Stands Firm . . 163 "Condenser Type Loud Speaker, The
(Joseph Morgan) 369
Congress Considers the Commission's
Record 372
"Crystals, Quartz (R. C. Hitchcock) ... 85 "Cuban Short- Wave Receiver, A (Frank
H. Jones) 313
"TAX Measurements, A Chart for
LJ Making (James B. Friauf) .... 188 Davis-Dill Publicity Barrage Begins, The 233
Decisions of the Courts 236
"Double-Detection Short-Wave Set, A
(Robert S. Kruse) 309
"Dynamic Loud Speaker, All About the
(Joseph Morgan) 159
"Dynamic Speaker Reproduction, A
New Audio System for (Frank C.
Jones) 29
"Dynamic Speakers, Measurements on
(Frank C. Jones) 316
* T? CONOMICAL Battery-Operated •L-' Receiver, An (Howard E.
Rhodes) 257
"Efficient Push-Pull A. F. System, An
(Kendall Clough) 241
"Examination for Radio Servicemen, An
(J. B. V. Meacham) 405
"Experimenter's Armchair, The (Robert
S. Kruse) 380
LTEDERAL Radio Commission, A
r Well-Balanced .. 372
"Fellows of the Institufcou^he (Carl
Dreherj *»*uj^uj 51
"Few Radio Questions yfrSWreH, A .... 166
PAGE
Fight for Short- Wave Allocations, The ... 92 "Figure in Radio Progress, A (Edgar H.
Felix) 227
"Filters Needed in A. F. Amplifier? Are
(Keith Henney) 250
Fitting Receivers to the New Allocations . . 234
Frequency Control, More Discussion on. 373
"f^RID-LEAK, Grid-Condenser De- VJ tection (Frederick EmmonsTer- 303
man)
"Grid-Leak Power Detection (Frederick Emmons Terman) 382
I-fERE and There 18
-f 1 High-Frequency Allocations 297
"High-Power Output Tube, A (K. S.
Weaver) 329
"High-Voltage Metallic Rectifiers for B-Power Units, New (J. George
Uzmann) 120
"Home Study Sheets, "Radio Broad- cast's":
Alternating Current, Pt. Ill 28 Calibrating a Radio Wave- meter 183
Effects of an Electric Current,
The 27
Experiments with a Wave- meter 254
Fundamental Radio Theory . . 397
Inductance Standards 398
Plotting Curves 307
Plotting Power Tube Charac- teristics 184
Resonance in Radio Circuits.
Pt. 1 107
Resonance in Radio Circuits,
Pt. II 108
Transmission Unit, The 253
"IMPORTANCE of Impedance Rela-
1 tions (C. T. Burke) 322
"Improved Knapp A-Power Unit, The. 43 *In the Radio Marketplace ....267, 331, 406
In the Visual Broadcasting Field 94
In the World of Broadcasting 298, 373
"Inexpensive Audio " Oscillator, An
(Edward Stanko) 186
"Isotone Screen-Grid "Super," The
(Dudley Walford) 174
*T7"NAPP A-Power Unit, The Im-
43
proved
*T ABORATORY Information Sheets, t-^ "Radio Broadcast's":
Advantages of Dual Push Pull 276
Alternating-Current Ratings. . 132
A. C. Tubes 206
Analysis of Filter Circuits, An 274
Audio Amplifiers 204
Audio Transformer, The 56
Balancing Radio Receivers ... 56
Band-Pass Circuits 206
Bucking Coils in Dynamic
Loud Speakers 112
Circuit for Short-Wave and
Broadcast Reception 60
Effect of Room Acoustics. . 346
634466
1 '2i
INDEX— Continued
PAGE
Electrifying Battery-Operated
Sets 346
Filter Circuit Characteristics. 274 Formulas for Power Output . . 352 Frequency Characteristics of Television Amplifier Devel- oped by. the Bell Telephone
Laboratories 134
Heater Connections for A. C.
Tubes 272
Hook-Up for Short-Wave and
Broadcast Receivers, A .... 60 Importance of Bass Notes .... 348 Importance of Correct Fila- ment Voltages 354
Mathematics of the Tuned
Circuit 348
Moving-Coil Loud Speakers . 58, 204 Neutralizing and C^u Bat- ing R. F. Circuits . . ." 412
Obtaining Grid Bias frqm B-
Power Units 414
Power in Broadcasting Har- monics 348
Power Output 58, 132. 206
Power Output Characteristics
of Vacuum Tubes 132
Resistance-Coupled Amplifiers
130, 132, 202
Shielding 204
Simple Two-Way Telephone
Set 414
Supplying Power Devices from
220 Volts A. C 130
Television 58, 60, 134
Test for a Faulty Push-Pull
Amplifier 352
Three Types of Graphs 272
Voltage Gain in Resistance- Coupled Amplifiers 274
Wavelength-Kilocycle Chart . . 276 Where A. C. Hum Originates. . 276 'Laboratory, "Strays" from the (Keith Henney):
Accuracy of the "Slide-Back"
Voltmeter 97
Accuracy of Variable Con- densers 240, 301
Approved Amateur Intermedi- ates 378
Cause of Winter Static 377
Correction, A 378
Dynamic Vs Magnetic Speak- ers 23
Empirical Rules and Formulas 170 Experiments With the Pentode 377 "Gyps" Are Still At It, The. . 24 How Long Will the Engineers'
Job Last? 240
How Much Output Power Is
Needed? 169
How to Stabilize Rice Ampli- fiers 24
How Useful Is a Tube? 240
Hum in the "Lab" Circuit
Receiver 97
Impedance of Standard Loud
Speakers 240
Importance of Reducing A. C.
Hum 301
Is a 112 Tube Needed in the
First Stage? 98
League of Nations to Broad- cast 301
Life of A. C. Radio Tubes .... 378 More Data on Underground
Aerials 98
New High Voltage Rectifier
Tube 240
New Precision in Quartz Plates 24 New Radio Tubes in England 301 New Radio Tubes Needed. ... 24 New Regulations of Radio
Commission 240
New Trends in Radio Design 300
Novel Dynamic Baffle 378
Obtaining C Bias for A. F.
Amplifiers 169
Output Vs Voltage Amplifica- tion . . 377
PAGE 1 ' Phantom ' ' Power Tubes .... 378
Portable Radio Sets 24
Power of Station Harmonics. . 239 Present Designs Do Not Con- sider Economy 23
Rated Voltages Should Be Ap- plied to Tubes 239
Receiving on 600 Meters with
Lab. Set 301
Regarding Power, Efficiency
and Energy 239
Regarding Series-Filament
Operation 23
Removing Noise in Shielded
Receher 301
Selectivity in the Browning- Drake Set 301
Seven New Radio Booklets. . . 24 Some Interesting Formulas . . . 169 Task of Editing Radio Copy,
The 170
Test for Screen-Grid R. F.
Tubes, A 240
Three New Pamphlets Availa- ble 239
Two New A. C. Tubes on the
Way 300
Underground Aerials 24
Vacuum Tubes as Fuses 377
What Is a Dynamic Speaker? 169
Letters from Readers 137, 354
""Loop-Operated Browning-Drake Re- ceiver. A (J. H. Gockel) 171
*Loud Speaker, The Condenser Type
(Joseph Morgan) 369
*Loud Speakers— A JDebate 109
*]\ /TANUFACTURED Receivers, 1VJ. "Radio Broadcast's" Service
Data Sheets on (See Set Data Sheets)
41, 121, 177, 265, 327, 304 Manufacturers' Booklets
56, 128, 199, 270, 334 *March of Radio, The (E. H. F.)
16, 91. 163, 233, 296, 372 Market, The Real Size of the Radio ... 379 *Marketplace, In the Radio. . . .267, 331, 406 *Measurements on Broadcast Receivers
(L. M. Hull) 230
*Measurements on Dynamic Speakers
(Frank C. Jones) 316
*Measuring a Receiver's Performance
(Kenneth W. Jaryis) 167
Mexican Broadcasting Stations 358
Milestone in Television, A 17
*Modulator for the 1929 Short-Wave
Transmitter, A (Robert S. Kruse) ... 38 *More Data on the Sargent-Rayment
(Howard Barclay; 197
More Discussion on Frequency Control. 373 *Multiple-Receiver Antenna System, A
(V. D. Landon) 291
ATEED for Defining Television Prac-
1\ tices 18
New Allocation Repairs the Broadcast
Structure 16
*New A. C. Screen-Grid, Browning- Drake Receiver, The (Glenn H. Browning) 115
*New Apparatus 52
*New Apparatus and Its Applications
127, 194
*New Audio System for Dynamic Speaker Reproduction, A (Frank C. Jones; 29
*New Automatic Volume Control Sys- tem (Charles Williamson) 299
*New High- Voltage Metallic Rectifiers for B-Power Units (J. George Uz- mann) 120
New Nation-wide Picture Transmission Service 18
New Radio Service to Aviation, A 297
*New Trends in Radio Designs for 1929- 30 (Keith Henney) 14
*New Uses for Power Amplifiers (Fred H. Canfield) 367
News of the Radio Industry 94, 236
Newspaper Has Radio Picture Transmitter 18
PAGE
* /^ORGANIZATION, An Unusual W (Robert S. Kruse) 302
*"Our Readers Suggest ..."
47, 114, 192, 260, 324
*Phonograph-Radio Amplifiers (How- ard E. Rhodes) 88
Picture Transmission Service. l\eiv Na- tion-wide 18
Picture Transmitter, Neuispjpzr Has Radio 18
*Power Amplifiers, New Uses for (Fred H. Canfield) 367
*Power Rectifiers, Characteristics of (Roger Wise) 393
*Power Supply for the "Vivetone 29," An Amplifier and (R. F. Goodwin) . . 45
*Practical Radio Service Records (John S. Dunham) 392
*Problems in Synchronizing Television Receiving Discs (Boyd Phelps> 123
*Production Testing with Oscillators (Richard F. Shea) 387
Program Possibilities May Open New Radio Market, A Study of 296
Progress in Short and Long Wave Radio 235
Progress in the Field of Aircraft Radio . . 93
*Push-Pull A. F. System, An Efficient (Kendall Clough) 241
VARTZ Crystals (R. C. Hitch-
cock) 85
*Questions Answered, A Few Radio. . . . 166
J~>ACE for Television Publicity, The 17
-A. Radio Abroad 94
*" Radio Broadcast's" Home Study Sheets (Keith Henney) (See Home)
27, 107, 183. 253, 307, 397 ""Radio Broadcast's" Laboratory In- formation Sheets (Howard E. Rhodes) (See Laboratory)
56, 130, 202, 272, 346, 412 ""Radio Broadcast's" Service Data Sheets on Manufactured Receivers
(See Sets) 41, 121, 177, 265
*" Radio Broadcast's" Set Data Sheets
(See Sets) 327,403
*Radio Design for 1929-30. New Trends
in (Keith Henney) 14
Radio in Foreign Countries 19
Radio Industry, News of the 94
Radio Manufacturers, With the 165
Radio May Become the Cornerstone of the
Amusement Industries 91
Radio Picture Transmitter, Newspaper
Has .... 18
*Radio Service Records, Practical (John
S. Dunham) 375
Radio Service to Aviation, A New 297
*Radio Servicing, The Business Side of
(John S. Dunham) 236
Real Size of the Radio Market. The ... 379 *Real Versus Apparent Selectivity
(Kenneth W. Jarvis) 399
Reasons for the 300-Mile Chain Regu- lation 92
Regenerative Decision, The 164
Regulation of Allocations Attempted .... 373 *Removing Nonsense from Short-Wave
Transmission (Robert S. Kruse) Ill
*Routine of Testing Receivers, The (John S. Dunham) 375
•OARGENT-RAYMENT, More Data O on the (Howard Barclay) 197
Schedule of the Best Short- Wave Programs 298
Schedule of Broadcast Television Trans- missions 234
*Screen-Grid Browning-Drake, The New A. C. (Glenn H. Browning) 115
*Screen-Grid Receiver, An A. C. Band- Pass— The Master "Hi-Q 29" (Wil- liam E. Barton) 117
*Screen-Grid Receiver, The "Chron- ophase" (Bert E. Smith) 49
*Selectivity, Real Versus Apparent (Kenneth W. Jarvis) 399
*Service Data Sheets on Manufactured Receivers, "Radio Broadcast's" (See Set Data Sheets) 41, 121, 177, 265
INDEX— Continued
PAGE
*Service Man Should Study, What the
(John S. Dunham) . . . . , 294
*Serviceman's Comer. The
101, 181, 255, 319, 389 *Servicing Home-Made Radio Receivers
(B. B. Alcom 179
'Servicing. The Business Side of Radio
(John S. Dunham i 236
Set Data Sheets. " Radio Broadcast's": A. C.-66 Dayton Receiver.
The 121
Bosch Model 28 Receiver, The 404 Bremer-Tully 8-20 Receiver,
The 177
Browning-Drake Receiver.
The 266
Croslev Model 704-B Receiver,
The" 328
Crosley Model 705 Receiver,
The 328
Day-Fan 8-AC Power Set, The 403 Fada 50. 70, 71, 72 A. C. Elec- tric Radio Receivers, The . . 122 Federal Type D (60 Cycle) Re- ceiver 327
Freed-Eisemann Model NR-80 42 Freshman Model "G" Re- ceivers 41
Freshman Model Q Receiver. 178 Freshman Model 2N-12 Re- ceiver, The 403
King Model H. Receiver, The 404 Majestic Model 70-B Receiver,
The 328
Philco Electric Receiver. The. 265 Short-Wave Allocations, The Fight for . . 92
Short- Wave List 358
*Short-\Vave Receiver, A Two-Tube T. R. F. (William Bostwick and W. T.
Thomas) 20
Short-Wave Stations 141
'Short-Wave Subjects, Armchair Chats
(Robert S. Krusei 188
'Short-Wave Superheterodyne, A
(Robert S. Kruse) 262
Short-Wave Transmission. Removing
Nonsense from i Robert S. Kruse) . . . Ill 'Short-Wave Transmitter, A Modulator
for the 1929 < Robert S. Kruse) 38
'Simple A. C. Operated Tube Tester, A
(The Laboratory Staff) 173
'"Skyscraper" Screen-Grid Receiver,
The (Clifford Dentoni 95
'Some Experiments with Band-Pass
Filters (Kendall Clough) 104
'Sound Motion Pictures (Carl Dreher)
32, 102, 182, 244, 314, 385 '"Strays" from the Laboratory (See
Laboratory) 23, 97, 169, 239, 300, 377
Study of Program Possibilities May
Open New Radio Markets, A 296
'Synchronizing Television Receiving Discs, Problems in (Boyd Phelps) ... 123
T*ABLE of Wavelength Allocations . . 323
J. Television. A Milestone in 17
'Television Abroad? What Prospects of
(Lawrence W. Corbett) 11
'Television, Building Receivers for (Zeh
Bouck and James Millen) 35
Television Practices, Need for Defining . . 18
Television Publicity, The Race for 17
'Television Receiving Discs, Problems
in Synchronizing (Boyd Phelps) 123
PAGE
Telecision Transmissions 17
Television Transmissions, Schedule of
Broadcast 234
*Television. Unscrambling (Boyd
Phelps) 157
Test Set for the Radio Service Man. A
(B. B. Alcom i 99
'Testing Receivers, The Routine of
(John S. Dunham) 375
'Thermionic Milliammeter, A (G. F.
Lampkin) 325
300-Mile Chain Regulation, Reasons for
the 92
'Transmitting Amateur Television
(Boyd Phelps) 247
'Trouble Shooting in the Power Unit
(B. B. Alcorn) 264
'Tube-Tester, A Simple A. C. Operated
(The Laboratory Staff) 173
'Two-Tube T. R. F. Short-Wave Re- ceiver, A (William Bostwick and W.
T. Thomas) 20
*T TNSCRAMBLING Television (Boyd
U Phelps) 157
'Unusual Organization, An (Robert S. Kruse) 309
T/rISUAL Broadcasting Field, In the. 94 r ""Vivetone 29," An Amplifier and
Power Supply for the (R. F. Goodwin) 45 'Volume Control System, New Auto- matic (Charles Williamson) 299
'Volume Control Systems 259
JI/G Y'S Attack on the Allocation Plan 163
rr WGY Protests New Allocation Plan 92
WRNY Television Transmissions 17
Wavelength Allocations, Table of 323
Well-Balanced Federal Radio Commis- sion, A 372
'What is a Good Tube? 335
What is Public Interest? 17
'What Prospects of Television Abroad?
(Lawrence W. Corbett) 11
'What the Serviceman Should Study
(John S. Dunham) 294
'When the Set Stops Working (B. B.
Alcorn) 25
With the Broadcasting Stations. . .93, 164, 235
With the Radio Manufacturers 165
AUTHORS Alcorn, B. B 25, 99. 179, 264
Barclay, Howard. . 197
Barton, William E 117
Bostwick, William 20
Bouck, Zeh 35
Browning, Glenn H.. . 115
Burke, C. T 322
Canfield, Fred H. . . 367
Clough, Kendall 104, 241
Corbett, Lawrence W 11
PAGE Felix, Edgar H.
16, 91, 163, 227. 233, 296, 372, 388 Friauf, James B 188
Dall, William B 34
Denton, Clifford 95
Dreher, Carl. .32, 51, 102, 162, 182, 185, 244,
246, 252, 311, 314. 354, 385, 402
Dunham, John S 236, 294. 375, 392
Gockel, J. H
Goodwin, R. F. . .
171 45
Henney, Keith
14. 23, 97, 169. 239. 250, 300, 377
Hitchcock, R. C 85
Hull, L. M 230
Jarvis, Kenneth . . . . 167, 399
Jones, Frank C 29, 316
Jones, Frank H ... 313
Kruse, Robert S.
38, 111, 189, 262, 302, 309, 380
Laboratory Staff, The 173
Lampkin, G. F 325
Landon, V. D 291
Meacham, J. B. V 405
Millen. James 35
Morgan, Joseph 159, 369
Phelps, Boyd 123, 157, 250
Rhodes. Howard E 88. 116, 125, 257, 412
Shea, Richard F... 387
Smith, Bert E 49, 126
Stanko, Edward 186
Terman, Frederick Emmons. . . .303, 382 Thomas W. T. . . 20
Uzmann, J. George
120
Walford, Dudley 174
Weaver, K. S 329
Williamson, Charles 299
Wise, Roger 393
PORTRAITS
('Portraits in "The March of Radio")
'Aird, John
'Bowman, Charles A. .
'Cady, Walter G. 'Christiansen, Kay Clark, Clarence R.
'Frigon, Augustin . . . .
296
296
235 164 402
296
'Gilmour, Hugh 93
Goldsmith. Alfred N. 51, 228
'Horton, J. W..
163
Kemp, G. S 156
Kyle, Colin 369
"Linden, Adolph F 372
'Manson, Donald 296
Raycroft, Louis B. F. 366
Copyright, 1929, by DOUBLEDAY, DORAN & COMPANY, INC.
RADIO BROADCAST ADVERTISER
Hammarlund Hi-Q 29
Authorized Official Distributors
Silver-Marshall Kit Headquarters
National Short Wave Aero Products
WE are ready to ship all parts specified in this publication, as well as those parts called for in other leading radio papers. Tie up with a house that is amply financed to carry a complete and varied stock of merchandise. Royal-Eastern has been in business since 1897' — 31 years — and we are known to have the fastest snipping facilities in New York. Send for our new 1919 trade catalog. There is a copy for you. It is chock full of all the latest radio and television developments, as well as kindred electrical lines. We feature only nationally advertised merchandise. All kits are in stock — Send your order today — Prompt shipment is assured. We know you will like our service!
SEND for 100 page CATALOG
"We Pay The Freight."
ROYAL-EASTERN ELECTRICAL SUPPLY COMPANY
16 West 22nd St. New York City
ROBERT s. KRUSE
Consultant and Technical Writer
103 Meadowbrook Road, West Hartford, Conn. Telephone Hartford
ArelfourTubes Jus Limping Along /
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[$1. 10, with mount- " ing (in U. S. A.) at all dealers.
Give them NewLite
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Write Dept. R. B. 11
SELF-ADJUSTING''/^^/
30 FRANKLIN ST., NEW YORK
Out-Selling All Other Kits!
Sargent-Rayment Screen Grid Seven
Designed by the
Inventors of the
Infradyne
Manufactured by Silver-Marshall, Inc.
A Station for Every Dial Degree
That is the average performance of the Sargent-Rayment Seven over the entire dial. Under average conditions 100 stations per night can be heard with it.
The Sargent-Rayment Seven has an amplifier composed of four screen-grid tubes. There is no regeneration. No "grid suppressors" or other counteracting devices are used to stop oscillation, the oscillation is fundamentally eliminated in the circuit design thus allowing every bit of tube amplification to be retained for useful work. Under these conditions are we unreasonable when we claim that this receiver has more power, more sensitivity and more selectivity than any- thing else ever offered for sale? Watch the DX records go to smash this winter!
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If you send this by AIR MAIL we will answer same way.
RADIO BROADCAST
NOVEMBER, 1928
WILLIS KINGSLEY WING, Editor
KEITH HENNEY EDGAR H. FELIX
Director of the Laboratory Contributing Editor
Vol.4X. No. i
Cover Design - - - From a Design by Haney Hoptyns Dunn Frontispiece
Pictures Transmitted in One Minute at Radio World's Fair What Prospects of Television Abroad? - Lawrence W. Corbett New Trends in Radio Design for 1929-30 - - - Keith Henney The March of Radio - An Editorial Interpretation
New Wavelength Allocation Plan Need for Defining Television Practice
Newspaper Has Radio Picture Transmitter Commercial Broadcasting Increases Here and There Aircraft Radio Radio in Foreign Countries
A Two-Tube T.R.F. Short- Wave Receiver
William BostwicJ{ and W. T. Thomas "Strays" From the Laboratorv
Dynamic vs. Magnetic Speakers Regarding Series- Filament Operation Present Designs Do Not Consider Economy
What is Public Interest? The Race for Television Publicity WRNY Television Broadcast* A Milestone in Television New Nationwide Picture Service
How to Stabilize Rice Amplifiers New Radio Tubes Needed
Keith Henney
The "Gyps" Are Still at It New Precision in Quartz Plates Seven New Radio Booklets Portable Radio Sets Underground Aerials
B. B. Akorn
When the Set Stops Working
"Radio Broadcast's" Home Study Sheets - -
No. 9. The Effect of an Electric Current No. 10. Alternating Current — Part HI
A New Audio System for Dynamic Speaker Reproduction
Franl( C. Jones As the Broadcaster Sees It Carl Dreher
Sound Motion Pictures — Part II Commercial Publications
A and B Power from the D.C. Lines -William B. Doll
Building Receivers for Television Zeh Bouci( and James Millen A Modulator for the 1929 Short- Wave Transmitter
Robert S. Kru.se "Radio Broadcast's" Service Data Sheet on Manufactured Re-
ceivers
No. ii. Freshman Model "G" Receivers
No. 11. Freed Eisemann Model NR-8o
The Improved Knapp A-Power Unit
An Amplifier and Power Supply for the "Vivetone 29"
R. F. Goodwin "Our Readers Suggest —
Short-Wave Plug-in Coils Improving Capacity Feed-Back Circuits
Receiving Without an Aerial Tuning-m With a Distant Loud Speaker
Polarity Indicators Home-made I. F. Transformers
Reducing Hum in the Detector Prolonging the Life of the 171 A
Reducing Hum in A.C. Sets Special Soldering Irons for Difficult Jobs
The "Chronophase" Screen-Grid Receiver - Bert E. Smith
The Fellows of the Institute - Carl Dreher
New Apparatus - - - Useful Information on New Products Manufacturers' Booklets "Radio Broadcast's" Laboratory Information Sheets - -
No. ijj. Balancing Radio Receivers No. 158. Hook-up for Short-Wave and
No. 134. The Audio Transformer Broadcast Receivers
No. 135. Television No. ajo. Circuit for Short-wave and Broad
No. 336. Moving-Coil Loud Speaker* cast Reception
No. »j7. Power Output No. 340. Television
The contents of this magazine is indexed in The Readers' Guide to Periodical Literature, which is on file at all public libraries.
IO II 14
16
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AMONG OTHER THINGS. . .
A FUNDAMENTAL part of the policy of this magazine is the careful scrutiny of everything appearing in its pages, from the smallest advertisement to the most intricate of technical articles. We have always felt that our first duty to the reader was to protect him from misleading statements and in- accuracies of whatever sort. This rr.agaiine is not, however, the expression of one man's opinion, ncr even of the group respon- sible for editing and publishing it. We have frequently given space to articles on technical subjects in which the authors came to conclusions at variance with our own opinions. Almost in- variably after the appearance of the magazine we would be del- uged with letters and telephone calls demanding to know why we "said" this or that. The editorial expressions of this maga- zine, whether general or technical are always definitely identi- fied. Articles from other sources are also indentified, and for the opinions expressed, the author is alone responsible. We wel- come the opportunity of printing controversial articles.
'"PO JUDGE from reports which reach us, the motion-picture JL industry is in nearly as complete a turmoil as that in which radio found itself some years ago. The cause of the trouble is, of course, the application of synchronized and non-synchronized sound accompaniment to the "feature picture." This develop- ment is bringing into play practically all of the experience that broadcasters have so laboriously accumulated in the past few years, and is drawing into the movie field many broadcasters and other engineers who have developed apparatus and its uses for this work. In this connection, the pages of Carl Dreher's department, "As the Broadcaster Sees It," are well worth watching, for Mr. Dreher is including much first-hand and practical information on sound motion picture work. Much of this work is being done by expert radio service men.
ANEW ZEALAND radio distributor writes us he is in- terested in communicating with American radio manu- facturers who wish New Zealand distribution for kits or com- plete sets, either a.c. or d.c. operated. Manufacturers who are interested may communicate with the editor.
"pOR those to whom the news has not yet traveled, we J- repeat the announcement made in this column last month : the bound volume of RADIO BROADCAST Laboratory Information Sheets Nos. 1-190 is now available at $i. Order from your newsdealer or directly from the Circulation Department of Doubleday, Doran.
'"HO JUDGE from the comments in many letters, the Home JL Study Sheets are increasing in popularity. It may have escaped the attention of many who are following these Sheets that we are quite willing to examine the answers to the problems in each Study Sheet. These answers will be promptly examined and returned with our comments.
THE December issue will contain an interesting article on band-pass filters, an interesting and practical article on television, more good data for the service man and professional set builder, instructions on how to grind quartz crystals, a number- of important constructional articles — and our regular departments.
— WILLIS KINGSLEY WING.
DOUBLEDAT, DORA7\[ ^ COMPACT, IXC., Garden Qity9
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Pictures Transmitted in One Minute at Radio World's Fair
This radio-photo receiver was demonstrated by the Westinghouse Electric and Manufacturing Company for the first time in the New Madison Square Garden, New York, during the week of the radio show. The apparatus is capable of converting electrical impulses into a complete photograph in less than one minute. Because of the difficulty in securing a wavelength assignment Lie demonstration was carried on with the use of wires. However, the engineers state that the equipment functions equally well by radio within the limits of fading and static. The chief advantage of this new apparatus is that it reduces the time required for the transmission of a photograph from five minutes to one minute. The size of the repro- duced photograph is five by eight inches
10
DEVICE PUTS MOVIES ON THE AIR This apparatus is the heart of the television motion picture transmitter developed by West- inghouse. It is used at KDKA for the broadcasting of radio motion- picture programs
By LAWRENCE W. CORBETT
IN DISCUSSING the progress of television the technical press of the United States and Great Britain appears to take turn in de- ploring the lack of initiative of its own countrymen and in praising that of its rivals across the Atlantic. Yet, if we take the opinion of no less an authority than Sir Oliver Lodge, we must admit that the eading exponents of the art in both countries are equally up against a stone wail and that the limitation of the apparatus they are using at
present will not permit further improvement.
But Sir Oliver Lodge, and other equally famous scientists whose opinions incline in his direction, are by no means pessimistic of the ultimate success of television. His criticism applies only to that apparatus now commonly used by many of those who claim recog- nition in the art. Mechanical con- trivances, Sir Oliver believes, are limited by certain physical restric- tions which it will be inordinately impossible to surmount. To use his own words:
Cathode rays or moving elec- trons are the only things likely to be sufficiently docile and con- trollable to be used as the agents for television. No material things are likely to be able to move quickly enough, but electrons re- spond so instantaneously that, if devices can be invented for utiliz- ing them, the theoretical difficul- ties with the required rapidity of motion would begin to disappear both from the sender and the re- ceiver, especially as photoelectric response is almost infinitely rapid.
A. Campbell Swinton, whose early apparatus was described in an article on television which appeared in RADIO BROADCAST for July, 1928, by R. P. Clarkson, appears to have realized the limita- tions that mechanical equipment would impose upon television, as
The British Situation
BY NORMAN EDWARDS Managing Editor, Popular Wirekss and Modern Wireless
FOR months past the question of television has been agitating the minds of the British public, and day by day the Press in all parts of Great Britain has been persisting in dinning into the public ear that "television is here."
The Baird International Television Development Co., backed by British capital, invested for the development of television in England, now definitely has promised a television service by the end of the current year, despite the fact that the British Broadcasting Corporation, uhich has a monopoly on broad- casting in England, has refused to cooperate with Baird and bis associates be- cause, in the opinion of the Chief Engineer of the B. B. C., and his advisers, the Baird system is not developed sufficiently to warrant it being utilised as a public service: and the Chief Engineer and bis associates in the British Post Office having investigated the Baird system believe it to be in a state of experi- mental infancy and unfitted for offering a means of service to the public.
Furthermore, the Wireless Telegraphy Act, which governs the use of radio in England, legally has been interpreted to cover television, and as the British Post Office refused to licence the Baird system as a public utility service, the question now arises in the public mind as to what Baird