AM Broadcast Band: Facts, Figures and Trivia

Full book — Parts, Chapters, and Sections

Front Matter
Part I — The Signal: How AM Works
Chapter 1 — The Physics of AM
  1. How an AM Station Gets Its Signal Into the Air
  2. Groundwave, Skywave & the M3 Map — Why the Dial Changes at Night
  3. Ground Loss vs. Frequency — Why Lower on the Dial Goes Farther
Chapter 2 — The Tower & Antenna
  1. How the Tower IS the Antenna
  2. AM Band First Vertical Radiator: WABC 1931
  3. The Development of Vertical & Directional AM Antennas
  4. Inside the Tuning House — Base Insulators, ATUs & the Austin Transformer
  5. Feeding the Tower — Series, Shunt, Skirt, Top-Loaded & Sectionalized
  6. The Capacity Hat — Making a Tower Taller Without Adding Steel
  7. Ground Radial Systems
  8. Wire Antennas — The Original AM Antenna
  9. Antenna Oddities & Unusual Designs
  10. Borrowed & Disguised Radiators — Flagpoles, Smokestacks, and the Church That Was an Antenna
  11. Why So Many AM Towers Skip the Paint — The 200-Foot Rule
  12. Marking the Towers — Paint or White Strobes
  13. Blaw-Knox Diamond Towers
Chapter 3 — Directional Arrays & Switching
  1. Directional Arrays — How They Work
  2. Unequal-Height Arrays — Steering the Skywave with Tower Height
  3. The Three Phasor Club — DA-3 Stations
  4. Throwing the Switch Today — How the Pattern Changes Now
  5. Throwing the Switch at Sunset and Sunrise — When the Pattern Changed by Hand
  6. The Antenna Monitor — How a Directional Station Proves Its Pattern
  7. Reject Networks — How One Tower Carries Two Frequencies at Once
  8. Diplexing — Two (or Three) Stations, One Tower
  9. Isocouplers & Detuning — Sharing (and Not Disturbing) a Hot Tower
  10. The Accidental Array Element — Cell Towers, Bent Patterns & Detuning
Chapter 4 — Modulation & Transmitters
  1. How AM Is Actually Modulated — From Plate Transformers to Pure Code
  2. The Loudness Wars — How AM Learned to Shout
  3. The Spinning Plate Supply — Motor-Generator Sets
  4. Who Built the Transmitters — A Roster of AM Transmitter Makers
  5. The Transmitters That Pay for Themselves — Cutting the AM Power Bill
  6. High-Efficiency Modulation — Doherty, Ampliphase & the Power Bill
  7. The Plasma Speaker
Chapter 5 — Lightning, RF & Safety
  1. Ball Gaps & Static Drains — How the Tower Survives Lightning
  2. Why Every AM Transmitter Site Has a "Jesus Stick"
  3. AM Transmitter Building Grounding — Why There's So Much Copper
  4. Don't Touch the Tower — RF Exposure, MPE Limits & the Fence
Part II — The Stations
Chapter 6 — The Station Classes: A, B, C & D
  1. AM Station Classes — From Roman Numerals to Letters
  2. AM Antenna Mode Codes — ND1, ND2, DA-1, DA-2, and More
  3. 50,000 Watt Non-Directional AM Radio Stations (Class A)
  4. 50 KW Class A Directional Stations
  5. Class A Stations NOT at 50 KW
  6. Class B — 50,000 Watts Daytime, but Throttle Down at Night
  7. The Near-50 Club — Class B Directionals at 25 kW and Up
  8. The Deepest Cut — 50,000 Watts by Day, a Nightlight After Dark
  9. The Unchanging Pattern — Class B Stations That Never Switch
  10. Featherweight Class B — Regional Licenses, Local-Class Power
  11. The 400 Club — Class C Graveyard Overachievers
  12. 50,000 Watt Class D Stations
  13. Flea Power Champions — The Lowest Nighttime Power
  14. Noncommercial Educational AM Stations
  15. Daytime-Only Directional — The Stations That Drop the Array at Night
Chapter 7 — Power & the 50 kW Club
  1. 50 KW Stations — Records & Firsts
  2. The Superpower Era — WLW at 500,000 Watts
  3. The Bones of the Nation's Station — What's Left of WLW's 500,000 Watts
  4. 50 KW Honorable Mentions — Complex Arrays
  5. The Blowtorch Capital — Which Metro Packs the Most 50,000-Watt Stations
  6. Higher Power at Night Than Day — The Top Ten
  7. The 1-Watt Club — Lowest Nighttime Power
  8. Lowest Daytime Power in America
  9. 50 KW by Day, High Power After Dark
Chapter 8 — Sites, Towers & Survival
  1. Rooftop & Sharing Arrangements
  2. Rooftop AM Towers
  3. Stations With Separate Day & Night Transmitter Sites
  4. Tower Sites Lost to Development
  5. Mountaintop AM Stations
  6. The Last Big Bets on AM — CBS Radio, the Move That Never Happened
  7. Towers Near Water
  8. The Shortest Tower in America — WVOA 1540
  9. How AM Towers Die — Ice, Wind, Aircraft, and Thieves
  10. The Standby Tower — How a Serious AM Station Never Goes Silent
  11. When the Ground Took the Steel — Loma Prieta and the AM Towers, 1989
  12. The Case of the Stolen Tower — WJLX 1240
Chapter 9 — Around the Bay & the Regions
  1. Alaska Class A Stations
  2. AM Broadcasting in Hawaii
  3. AM Station Classes by US Territory
  4. AM Radio in the US Territories
  5. AM Powerhouses of Puerto Rico
  6. The Multilingual Dial — Silicon Valley/San Francisco Bay Area AM Band
  7. KSFO 560 — "The World's Greatest Radio Station"
  8. Musical Chairs on the Bay Area Dial — The End of KGO and 560
  9. Motor City Steel — Why Detroit Lights Up the Most AM Towers After Dark
Chapter 10 — Beyond the U.S. Dial: Mexico, Canada, Cuba & the Border Blasters
  1. Border Blasters — The Outlaw Megawatts Across the Rio Grande
  2. AM Powerhouses of Mexico — More Than 50,000 Watts, Past and Present
  3. Canadian Clear-Channel and Powerhouse Stations
  4. Cuba, the Bahamas, and the Signal War — The Caribbean Clear Channels
  5. The Other Clear Channels — Treaty Clears of Canada, Mexico, Cuba & the Bahamas
  6. Radio Martí — The 100,000-Watt Station Aimed at Cuba
  7. AM from the Islands — Broadcasting Across the Caribbean
Part III — The History
Chapter 11 — History & the Golden Age
  1. The Four Companies That Built American Broadcasting
  2. General Electric's Radio Laboratories — WGY, KOA, KGO
  3. The Radio Corporation of America — WJZ & WJY
  4. Westinghouse — The First Broadcaster, and the First Chain
  5. AT&T and Western Electric — The Commercial, and the Exit
  6. Christmas Eve, 1906 — Fessenden and the First AM Broadcast
  7. KQW / KCBS 740 — The Station That Started It All
  8. Three-Letter Callsigns — the Pioneer Stations
  9. The First President on the Air — Warren G. Harding
  10. The AM Networks — Red, Blue, CBS, and the Birth of the Big Four
  11. The Breakdown of 1926–27 — The Year the Dial Went Lawless
  12. The Night the Dial Changed — Radio's "Moving Day," 1941
  13. The Golden Age & Decline of AM Radio
  14. The First-Station Wars — Who Really Got There First
Chapter 12 — The News America Heard First
  1. The Lone Eagle Lands — Radio Finds Its National Audience
  2. The Trial of the Century — Smuggling the Verdict Out by Radio
  3. The King Who Gave It Up — An Abdication Heard Live in America
  4. Oh, the Humanity — The Disaster Radio Didn't Carry Live
  5. 124 Seconds That Stopped the Country — Louis vs. Schmeling, 1938
  6. The Crisis That Made Radio News Grow Up — Munich, 1938
  7. The Morning the World Went to War — September 1939
  8. A Date Which Will Live in Infamy — How America Heard About Pearl Harbor
  9. Flash — The President Is Dead — April 1945
  10. Two Endings — V-E Day and V-J Day, 1945
  11. It Is an Atomic Bomb — Radio Opens the Atomic Age, August 1945
Chapter 13 — Emergency & Wartime
  1. Radio Silence, December 1941 — When the AM Band Became a Weapon
  2. CONELRAD — The Dial That Was Supposed to Save Your Life
  3. The Emergency Broadcast System — and the Day It Cried Wolf
  4. The Emergency Alert System — the Beeps Got Smarter
  5. Primary Entry Point Stations — The AM Backbone of the EAS
  6. The Night the EBS Failed — Loma Prieta, 1989
  7. AFRS on the Broadcast Band — Taking AM to War
  8. AFKN and AM Radio in Korea — The Frontline Network
  9. AFVN and AM Radio in Vietnam — The GI's Companion
  10. The Blue Eagles — Project Jenny and the Flying AM Stations of Vietnam
Part IV — The Listener & the Business
Chapter 14 — The Listener's Side: Receivers & DXing
  1. The Crystal Set — The Radio That Ran on Nothing
  2. Armstrong — The Man Who Built AM's Receivers
  3. The All American Five — The Radio Design That Put AM in Every Home
  4. The Regency TR-1 — The Shirt-Pocket Radio That Started It All
  5. The One-Tube Wonder — How a Single Tube Pulled In the World
  6. The One-Transistor Wonder — The Tube Set's Solid-State Successor
  7. Some Assembly Required — The AM Radio You Built Yourself
  8. Every Bedroom Had One — The Rise of the AM Clock Radio
  9. The Rich Man's Radio — When a Receiver Cost More Than a Car
  10. The Armstrong Portable AM Radio
  11. The Dashboard War — Carmakers Drop AM, Washington Pushes Back
  12. The AM Car Radio — From $120 Luxury to Standard Equipment
  13. AM Goes Digital — HD Radio and the All-Digital Bet
  14. Chasing the Skip — The Clear-Channel DXing Hobby
  15. When the Clear Channels Stopped Being Clear — How Night DX Changed in 1980
  16. The Tunable Loop — The AM Listener's Secret Weapon
  17. Pirates on the Dial — America and the Offshore Broadcasters
Chapter 15 — Rules, Operations & Economics
  1. Dockets That Shaped the AM Band — One Century of Paper Reshaping the Air
  2. NRSC-1 and the 10 kHz Ceiling — Why AM Sounds the Way It Does
  3. The Expanded Band — How 88 Stations Got the Top of the Dial
  4. The Expanded Band Today — 1610 to 1700 kHz
  5. Construction Permits to Nowhere — The Great Paper Boom of the 1980s and '90s
  6. The Fine Print — Frequency & Power Tolerances
  7. AM Stereo — The Standards War That Sank It
  8. Pre-Sunrise & Post-Sunset Authority — The Daytimer's Twilight Hours
  9. The Daytime-Only Era
  10. The Operator on Duty — When Every AM Transmitter Was Staffed Around the Clock
  11. Why Stations Used to Sign Off at Midnight — And Why They Don't Anymore
  12. The First Phone — The License That Ran the Transmitter
  13. The Night the Studio Emptied — How AM Radio Learned to Run Itself
  14. The Shrinking Transmitter — Why AM Sites Now Double as Backup Studios
  15. The Economics of Cutting Night Power
  16. What's an AM Station Worth? — The Rise, Peak, and Fall of Station Values
  17. Highest-Billing AM Stations Today — Where News Still Pays
  18. Radio Disney — The Kids' Network That Colonized the AM Dial
  19. ABC Radio — The Heritage Giants Disney Sold High
  20. Where the Legends Went — Religious and Multicultural Buyers and the AM Aftermarket
  21. AM Music Giants of the Past
  22. Family Radio — The Dynasties and the Mom-and-Pops
  23. Famous Names Who Owned AM Stations
  24. The Emptying Band — Fewer Voices on the Dial: AM's Deletion Era
Chapter 16 — Culture, Scandal & Programming
  1. Payola — Paying for the Hit
  2. Drugola — Payola's Watergate-Era Sequel
  3. The Goat-Gland Doctor — Brinkley and KFKB
  4. Know the Naked Truth — Norman Baker and KTNT
  5. "Fighting Bob" Shuler and the Silencing of KGEF
  6. The Radio Priest — Father Charles Coughlin
  7. The War of the Worlds Panic — Who Really Started It
  8. The Cover-Up Cost the License — RKO General
  9. The Broadcaster Cannot Be an Advocate — Mayflower & the Fairness Doctrine
  10. The Year a Million Songs Vanished — The 1941 ASCAP Boycott
  11. The Man Who Stopped the Music — Petrillo's Recording Bans
  12. Mae West in the Garden of Eden — The Sketch That Got Her Banned
  13. KSCO 1080 — 30 Years of Cheating
  14. The Fear You Can Hear — CBS Radio Mystery Theater
  15. All News, All the Time — AM Radio's 24/7/365 News Era
  16. The Top Five — Radio's Most-Broadcast Shows Were All Soap Operas
  17. The Top Five — Radio's Police Dramas
  18. The Top Five — Radio's Game Shows
  19. The Top Five — Radio's Comedies
  20. The Top Five — Radio's Detectives
  21. The Top Five — Radio's Theater of the Air
  22. The NBC Chimes — Three Notes That Owned the Airwaves
  23. Bee-Doop! — The Mutualert Tones That Ran a Thousand Stations
  24. AM at the Movies — The Stations of the Silver Screen
  25. AM on Television — The Sitcom Stations
  26. Cathedrals of the Carrier Wave — When AM Built Monuments
  27. Stations on Wheels — and Wings: Radio's Mobile Fleet
  28. The Grand Studios — Orchestras, Audiences, and the Hotel Ballroom
  29. Eyes in the Sky — When AM Stations Took to the Air
  30. Call Sign Oddities
Back Matter
Appendix A — Maps & Interactive Tools
  1. 50,000-Watt Non-Directional Stations Map
  2. 50 KW Class A Directional Stations Map
  3. Alaska Class A Stations Map
  4. Hawaii AM Stations Map
  5. Border Blasters Map
  6. Multilingual Dial of Silicon Valley Map
  7. Tower Height & Signal Strength
  8. Directional Array Explorer
  9. Phasor Array Explorer
  10. Flat-Top Antenna Length Explorer
  11. Top-Loading & Capacity Hat Calculator
  12. Detuning & Re-Radiation Explorer
  13. Groundwave Explorer
  14. Day/Night Skywave Explorer
  15. ATU T-Network Designer
  16. Station Class Dial
Appendix B — Reference
  1. The AM Broadcast Band — 530 to 1700 kHz
  2. Carrier Current AM — Building Wiring as Antenna
  3. The Other Voices on the Dial — Travelers' Information Stations
  4. Police Calls on the Living-Room Dial
  5. Why Do AM Stations Have FM Translators?
  6. The AM Stations With the Most FM Translators
  7. Reading the Coverage Map — Field-Strength Contours Explained
  8. When AM and FM Were One Station — The Simulcast Pendulum
  9. When AM Stations Lead with Their FM Frequency
  10. Directional by Choice
  11. Other Interesting AM Stations
  12. Other Notable Stations
  13. Trivia In Detail