Sollers Point Technical High School

April 26, 2010

David M. SchultheisDirector, RF Power System

Products

The History of Communications

NORTHROP GRUMMAN PRIVATE / PROPRIETARY LEVEL I

What are some of the oldest communication systems?

2April 21, 2023

Oldest known European cave painting are 32,000 years old

Fire and Smoke Signals

3April 21, 2023

The smoke signal is one of the oldest forms of communication in recorded history

Communication by Drum

4April 21, 2023

West African talking drum

• The talking drums of Africa can imitate the inflections and pitch variations of a spoken language and are used for communicating over great distances

• Throughout Sri Lankan history drums have been used for communication between the state and the community, and Sri Lankan drums have a history stretching back over 2500 years

• It works just about like the Morse code, except that the Morse code uses letters as units, and the drum communication uses words.

Communication by Semaphore

5April 21, 2023

Popular in the late 18th - early 19th century and are still in use today

Carrier Pigeons enable long distance communication

6April 21, 2023

• Historically carried messages only one way, to their home

• Pigeons have been trained to fly back and forth up to twice a day - 160 km round trip

• One of the carrier pigeons most important roles in communication history is in getting messages back to military planners during WWI

Pony Express delivers mail between the East and West Coasts

7April 21, 2023

Pony Express ran from April 3, 1860 until October 1861

Installation of the East-West Telegraph Line – October, 1861 marks the end of the Pony Express

“What hath God Wrought”Friday, May 24, 1844 at 8:45AM

Ran 24/7 through summer and winter• 183 Riders – change every 75 to 100 miles• 400 Thoroughbreds – change every 10 to 15 miles• $100/month

International Morse Code

April 21, 20238

•Morse code is a type of character encoding that transmits telegraphic information using rhythm

•Uses a standardized sequence of short and long elements to represent the letters, numerals, punctuation and special characters of a given message

•Commonly known as "dots" and "dashes" or "dits" and "dahs

A AW

Voice Communications

9April 21, 2023

Telephone – Invented by Alexander Graham Bell on March 10, 1876

No form of communication revolutionized the daily lives of ordinary people more than the telephone

• Michael Faraday (1791-1867) proved that vibrations of metal could be converted to electrical impulses. This was the technological basis of the telephone

• 1861 Johann Philip Reis in Germany built a simple apparatus that changed sound to electricity and back again to sound

• According to the famous story, the first fully intelligible telephone call occurred on March 6, 1876, when Bell, in one room, called to his assistant in another room. "Come here, Watson, I want to see you.“

The Birth of the Wireless Age

April 21, 202310

1860 British scientist James Clerk Maxwell – mathematically predicted the existence of electromagnetic waves that would travel at the speed of light

1880 German physicist, Heinrich Hertz demonstrated this radiation (radio)

1894 British scientist, Oliver Lodge sent Morse Code over a distance of ½ mile

1896 Italian scientist, Gugliemo Marconi improved upon Hertz’s apparatus in additionally improved other devices to extend the range of the wireless system

Many scientists from different countries contributed to the development of wireless communications

Radio Communications is born!

11April 21, 2023

Wireline Timeline

Early AM Radio ReceiverFM Signal Generation

AM Signal Generation

Digital Radio is less susceptible to Interference

April 21, 202312

How does Digital Radio work?• Transmitter sends program signals broken into

fragments and coded in numbers• Transmitter sends each fragment many times to

increase the chances of it getting through• Fragments put together by the Receiver to make an

uninterrupted program signal• Very wide band - single digital signal can carry six

stereo music programs or 20 speech programs. 1500 times wider than those used in analog radio!

And then there was Bluetooth!

Radio made all this possible…

Positive Effects of Wireless Technology

• Convenience– Portable devices can transfer of data with no physical connection

• Wireless networks can also be easier and cheaper to install– Important in places where running wires would be prohibited or impossible – Allows internet access in places where it would not have been possible

• Cell phones, laptops and PDAs allow for increased mobility and flexibility– Allows cell phone users to talk with contacts while traveling or performing

other everyday tasks such as walking the dog  – PDA’s and other portable devices can receive and transmit data wirelessly,

allowing people to work even when they are out of the office 

• Cell phones and other portable communication devices allow contact with emergency services without a landline or power outlet 

• Wireless communications offer a great sense of safety and security

13April 21, 2023

Negative Effects of Wireless Technology

• Primary drawbacks of wireless technology are Privacy, Security and Health related issues

• Privacy Risk: Enhanced 911 services which allow emergency response personnel to view a callers exact location when a call is made to 911

• Security Risks: The main issues arise due to the fundamental functionality of a wireless network; broadcasting a signal out over an area. Any computer within this area with the correct equipment can not only connect to an unsecured network, but can also capture data that is being sent.  

• Health Related Risks: – Scientific studies show that high levels of radio frequency energy can warm spots

of the body and lead to tissue damage.  Evidence does not show that any health problems are associated with using wireless phones.

– Even if cell phones do not directly cause physical problems, they can still be hazardous if not used responsibly.  A major cause of injury associated with wireless phones is distracted drivers.

– Radio Interference – the radio frequency energy emissions can interact with electronic devices such as pacemakers, defibrillators and hearing aids.

14April 21, 2023

Optical Communications

15April 21, 2023

Fiber Optic Transmission Free Space Laser Communication

• The first laser communication link between Lawrence Livermore and the top of the 915-meter-high Mount Diablo, 28 kilometers away, transmitted data at 10 Gbps, a rate comparable to 6,400 conventional T1 data lines, 1600 channels of television, or 160,000 simultaneous phone calls.