the single sideband revolution

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THE SINGLE SIDEBAND REVOLUTION By Forest Cummings, W5LQU (ex W0WKW) 1 S S B

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S S B. THE SINGLE SIDEBAND REVOLUTION. By Forest Cummings, W5LQU (ex W0WKW). A LITTLE HISTORY. - PowerPoint PPT Presentation

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Page 1: THE  SINGLE  SIDEBAND  REVOLUTION

THE SINGLE SIDEBAND REVOLUTION

By Forest Cummings, W5LQU (ex W0WKW)

1

S S B

Page 2: THE  SINGLE  SIDEBAND  REVOLUTION

A LITTLE HISTORY2

Think back to the early 1950s. No transistors, internet, computers or transceivers. AM was the voice mode of ham radio along with many heterodynes, selective fading, and 6 KHz bandwidth. CollinsAmateur radio equipment then was the 32V-3, 75A-3, and the KW-1

SSB had no carrier, required only 3 KHz bandwidth, and providedabout 9 to 12 dB increase in talk power for a given power amplifier

But, SSB required stable frequencies and very good filters. Collins had both; the PTO and Mechanical Filters

But, Collins realized that single sideband was coming. There were some commercial users, and when I joined Collins in 1953, there was already a SSB Study in progress. A special group was investigating the Techniques and Requirements for SSB

Page 3: THE  SINGLE  SIDEBAND  REVOLUTION

SSB REQUIREMENTS3

Stability of the VFO and Selectivity (PTO and Mechanical Filters)

System Linearity of mixers and amplifiers

Balanced Modulators and Product Detectors

Linear Power Amplifiers and intermodulation distortion

Collins studied SSB and reported on Techniques and Requirements needed for SSB then used Ham Radio for SSB development : the KWS-1 and 75A-4. Key Factors for SSB were:

Page 4: THE  SINGLE  SIDEBAND  REVOLUTION

THE REPORT ON SINGLE SIDEBAND

4

Page 5: THE  SINGLE  SIDEBAND  REVOLUTION

SSB AND COMPETITION5

The Military (SAC) needed reliable long range communication for their operation in the polar regions (Cold War). Their interest in SSB precipitated several competitive modes to be proposed. Warren and I spent many hours on the road and at various meetings promoting the Collins SSB suppressed carrier approach

Double Sideband Suppressed Carrier

Collins Single Sideband Suppressed Carrier

Clip and restore SSB to utilize AM Transmitters

Single Sideband Reduced or Pilot Carrier

Central Electronics had marketed a 10 watt SSB exciter (10A) and the sideband slicer using a phasing method of generating the SSB signal. They called the sidebands 1 and 2. And Hams were using SSB very successfully.

Page 6: THE  SINGLE  SIDEBAND  REVOLUTION

“QUA” (I HAVE NEWS OF……)6

“QUA” (I HAVE NEWS OF…...) HAM HISTORY: Over the years, the military and the electronics industry have often drawn on the ingenuity of radio amateurs to improve designs or solve problems. Hams provided the keystone for the development of modern military communication equipment, for example. In the 1950s, the Air Force needed to convert its long-range communication from Morse code to voice, and jet bombers had no room for skilled radio operators. At the time, hams already were experimenting with and discovering the advantages of single sideband (SSB) voice equipment. With SSB, hams were greatly extending the distances they could transmit.

Air Force Generals Curtis LeMay and Francis ―Butch Griswold, both radio amateurs, hatched an experiment that used ham radio equipment at the Strategic Air Command headquarters. Using an SSB station in an aircraft flying around the world, LeMay and Griswold were able to stay in touch with Offutt Air Force Base in Nebraska from around the globe. The easy modification of this ham radio equipment to meet military requirements saved the government millions of dollars in research costs.

Brief exerpt from: The ARRL Handbook for Radio Communications, 2011

Page 7: THE  SINGLE  SIDEBAND  REVOLUTION

THE SSB EXPERIMENT7

Use “Ham Radio” (KWS-1 and 75A-4) to test it out

Fly them in a SAC aircraft over the polar and Pacific Ocean regions and also have them at the SAC base in Omaha

Test communications with Offutt Air Force Base (SAC)in Omaha and “Hams” all over the world

Page 8: THE  SINGLE  SIDEBAND  REVOLUTION

THIS IS THE PLANE8

A C-97 Aircraft with Collins 618S 100watt AM Transmitters(A B-29 from WW2 converted for passenger service)

Page 9: THE  SINGLE  SIDEBAND  REVOLUTION

KWS-1 AMATEUR TRANSMITTER9

The KWS-1 in March 1956

Page 10: THE  SINGLE  SIDEBAND  REVOLUTION

THE KWS-1 TRANSMITTER10

KWS-1 RF Unit Po = 600 watts(same size as the 75A-4)

HV & LV Power Suppliesand Blower (2000v @ 500mA)

Contains 26 vacuum tubes

Page 11: THE  SINGLE  SIDEBAND  REVOLUTION

HERE’S HOW WE DID IT11

The QSL Card

Willie, Butch & Art

Page 12: THE  SINGLE  SIDEBAND  REVOLUTION

THE FLIGHT PLAN12

Page 13: THE  SINGLE  SIDEBAND  REVOLUTION

THE “HAM” INSTALLATION13

A KWS-1 and 2 75A-4s

Page 14: THE  SINGLE  SIDEBAND  REVOLUTION

THE OPERATING POSITION14

Page 15: THE  SINGLE  SIDEBAND  REVOLUTION

THE ANTENNA COUPLER15

A manually tunedHigh Power (180L)Antenna Coupler

Page 16: THE  SINGLE  SIDEBAND  REVOLUTION

THE FINAL ADJUSTMENTS16

Do you recognize this guytweaking up the 75A-4?

Page 17: THE  SINGLE  SIDEBAND  REVOLUTION

IN FLIGHT OPERATION17

Arthur Collins

Butch Griswold

Melville GrosvenorNat Geographic

Page 18: THE  SINGLE  SIDEBAND  REVOLUTION

THE FLIGHT RESULTS18

1. March 25 – April 3, 1956 71 hours flight time - over 1000 contacts Omaha - Alaska – Tokyo – Okinawa - Guam – San Francisco - Omaha

2. June 29 - July 7, 1956 42 hours flight time - over 1200 contactsOmaha - Andrews – Goose Bay – Thule – Alaska – California – Omaha made contact with National Geophysical Year group at the South Pole

The flight was a great success and proved beyond a doubt that SSB was a superior mode of long range communication, especially in the in the polar latitudes

Page 19: THE  SINGLE  SIDEBAND  REVOLUTION

COLLINS SSB EQUIPMENT19

Military: ARC-58, 1 KW aircraft transceiver, 10KW PA, 45KW PA(Modified KWS-1s and 75A-4s to military frequencies) and large Billboard Antennas. This was the “Birdcall” project. Collins had astation at Cedar Rapids called “Liberty”

Ham Rigs: KWS-1,75A-4,KWM-1,KWM-2,32S-1,75S-1,30L-1,30S-1,KWM 380

Commercial / Military: 618T-1,2,3 400 watt PEP SSB Transceiver wasVery successful and Collins produced over 80,000 of these units over many years

As a result of the SSB experiments, Collins developed many SSB units for the Military, Hams, and Commercial users

Page 20: THE  SINGLE  SIDEBAND  REVOLUTION

EPILOGUE20

It was a really fun and interesting time to be involved in the SSB Revolution !