Radio.

Transcription

1 Radio Merit Badge Workbook This workbook can help you but you still need to read the merit badge pamphlet. The work space provided for each requirement should be used by the Scout to make notes for discussing the item with his counselor, not for providing the full and complete answers. Each Scout must do each requirement. No one may add or subtract from the official requirements found in Boy Scout Requirements (Pub SKU 34765). The requirements were last issued or revised in 2009 This workbook was updated in January Scout s Name: Unit: Counselor s Name: Counselor s Phone No.: Explain what radio is. Please submit errors, omissions, comments or suggestions about this workbook to: Workbooks@USScouts.Org Comments or suggestions for changes to the requirements for the merit badge should be sent to: Merit.Badge@Scouting.Org Radio is a way to electronically communicate without wires. Radio sends information from one location to another using electromagnetic waves. The information could be morse code, your voice, music, or data. Electromagnetic waves are created when we get an electrical circuit to vibrate electrons back and forth thousands or millions a time per second. a. The differences between broadcast radio and hobby radio Broadcasting is a one way transmission to many receivers at the same time such as a local music station or television station. Hobby radio is the use of radio by ordinary people such as ham radio operators to communicate with each other or to control models. b. The differences between broadcasting and two-way communications. Broadcasting is a one way transmission to many receivers at the same time such as a local music station or television station. Two way communications are a back and forth conversation between two stations. Both stations then take turns transmitting and receiving. Two way radio is used by police, fire, ambulances, planes, trains, ships, astronauts, and folks like you every day! Copyright U.S. Scouting Service Project, Inc. - All Rights Reserved

2 c. Radio call signs and how they are used in broadcast radio and amateur radio. A call sign is a special name for a radio station that is used to identify the station from all others in its radio transmissions. In the US, all radio stations that must have a license must also have a call sign. Broadcast station call signs are usually 3 or 4 letter names, such as WABC or WGN. Ham radio call signs have different formats that include a number that tells the region of the country in which the station was licensed. Ham call signs look like these: K2BSA, WØSTU, W1AW, KF5CLZ, KB4SA, K0B. d.the phonetic alphabet and how it is used to communicate clearly. A phonetic alphabet uses special words to identify a call sign letter. Radio communications are sometimes noisy and unclear. Many letters of the alphabet sound similar, such as C, D, E, G, P, T, and Z. To help receiving stations understand a call sign in noisy conditions, a phonetic alphabet may be used by transmitting operators. So, the call sign K2BSA would be transmitted as Kilo, Two, Bravo, Sierra, Alpha. Letter Pronunciation Letter Pronunciation Number Pronunciation A Alfa (AL fah) N November (no VEM ber) 0 ZEE row B Bravo (BRAH VOH) O Oscar (OSS cah) 1 WUN C Charlie (CHAR lee) P Papa (pah PAH) 2 TOO D Delta (DELL tah) Q Quebec (keh BECK) 3 TREE E Echo (ECK oh) R Romeo (ROW me oh) 4 FOW er F Foxtrot (FOKS trot) S Sierra (see AIR rah) 5 FIFE G Golf (GOLF) T Tango (TANG go) 6 SIX H Hotel (hoh TELL) U Uniform (YOU nee form) 7 SEVEN I India (IN dee ah) V Victor (VIK tah) 8 AIT J Juliet (JEW lee ETT) W Whiskey (WISS key) 9 NINE er Radio - Merit Badge Workbook Page. 2 of 27

3 K Kilo (KEY loh) X X Ray (ECKS RAY) L Lima (LEE mah) Y Yankee (YANG key) M Mike (MIKE) Z Zulu (ZOO loo 2. Do the following: a. Sketch a diagram showing how radio waves travel locally and around the world. Radio - Merit Badge Workbook Page. 3 of 27

4 Explain how the broadcast radio stations, WWV and WWVH can be used to help determine what you will hear when you listen to a shortwave radio? Stations WWV and WWVH are US government radio stations that broadcast precise time and frequency information 24 hours per day, 7 days per week, on several HF (and lower) frequencies. WWV is located in Fort Collins, Colorado. WWVH is located in Hawaii. These stations broadcast time signals on 2.5, 5.0, 10.0, 15.0, and 20.0 MHz, so radio operators can tune into these HF frequencies to see how well those frequencies are being reflected by the ionosphere. If the signals from WWV and WWVH are strong, the ionosphere is likely reflecting well and shortwave signals may be easily heard from those locations b. Explain the difference between a DX and a local station. A DX station is a station at a far distance, usually in another country from your own. Local stations are close by, and certainly inside the US. The term DX is a Morse Code shortcut for the word distance. Hamradio operators are commonly interested in making contact with DX stations, outside of the US. Discuss what the Federal Communication Commission (FCC) does and how it is different from the International Telecommunication Union. FCC: The FCC is the Federal Communications Commission. It regulates and issues radio licenses in the United States. International Telecommunication Union: The ITU is the International Telecommunications Union and the agency of the United Nations that establishes international standards for radio. Radio - Merit Badge Workbook Page. 4 of 27

5 3. Do the following: a. Draw a chart of the electromagnetic spectrum covering 100 kilohertz (khz) to 1000 megahertz (MHz). b. Label the MF, HF, VHF, UHF, and microwave portions of the spectrum on your diagram. c. Locate on your chart at least eight radio services such as AM and FM commercial broadcast, citizens band (CB), television, amateur radio (at least four amateur radio bands), and public service (police and fire). Radio - Merit Badge Workbook Page. 5 of 27

6 AM Broadcast Short wave FM Broadcast TV Ham 40m Ham 2m Ham 70cm Marine Ham 10m A I R P ol ic e 100kHz 1MHz 10MHz 100MHz 1000Mz 100kHz 1MHz 10MHz 100MHz 1000MHz Radio - Merit Badge Workbook Page. 6 of 27

7 4. Explain how radio waves carry information. Radio waves are created when an oscillator circuit gets electrons to vibrate thousands or millions of times per second. An amplifier in the transmitter makes these Radio Frequencies (RF) more powerful. If the circuit is turned on or off in a pattern using a telegraph key, information may be sent using Morse Code.You can also talk into a microphone and have a circuit then modulate the radio waves to have them carry your voice signal. In both cases, these radio waves are then fed to an antenna which lets them travel through space. An antenna somewhere else catches the radio waves and feeds them to a receiver where they are demodulated into Audio Frequencies (AF) and played through headphones or a speaker. Include in your explanation: transceiver, transmitter, receiver, amplifier, and antenna. Transceiver: A transceiver is a radio that has both a transmitter and receiver in the same case. Transmitter: A transmitter converts voice into radio frequencies, makes the signal stronger, and sends the radio frequency signal to the antenna to be sent through the air Receiver: A receiver gets the RF signal from the antenna, modulates it into frequencies the human ear can understand and sends the modulated signal to the speakers/headphones Amplifier: An amplifier in the transmitter makes these Radio Frequencies (RF) more powerful Antenna: an antenna which lets radio waves (RF) travel through space 5. Do the following: a. Explain the differences between a block diagram and a schematic diagram. Radio - Merit Badge Workbook Page. 7 of 27

8 Block diagram: A block diagram shows the different sections of a transmitter or receiver Schematic diagram: A Schematic diagram shows circuit components of the device and how these components are connected b. Draw a block diagram for a radio station that includes a transceiver, amplifier, microphone, antenna, and feed line. c. Explain the differences between an open circuit, a closed circuit, and a short circuit. Open circuit: A switch is open and the current cannot flow thru the circuit Closed circuit: The circuit is complete and the current flows thru the entire circuit Short circuit: A short circuit is where the electrons take a short cut and don't flow where they should. d. Draw eight schematic symbols. Radio - Merit Badge Workbook Page. 8 of 27

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