1	A Gentle Intro to Radio Communications
2	Recipe Approach to Subject Big Concepts Regulations Frequencies Bands and channels How Radio Waves work Modulation Antennas Basic Electronics
3	Regulations Transmitting of radio waves is regulated by the FCC Set up in 1934 (coincident with bottom of the Great Depression) Controlled all radio spectrum among various user groups Commercial broadcasters Ham radio operators Government & Military Specialized services
4	Regulation Drift FCC has been decreasing regulation of ham radio for numerous reasons: Ham radio growth has slowed Shortwave listening is static AM broadcast audience share is declining In general COMPETITION IS UP
5	Manage Spectrum Mandated Balance the public need, interest and concern against limited spectrum while encouraging the state of the art. AM superseded by stereo FM explosion in the 1960’s Color TV over black and white Satellite services and cable over open air And the Internet provides nearly instant distribution of anything as do cell phones with built-in cameras
6	Why Mess with Ham Radio? National security: hams are a pool of very talented communications operators Examples: Military Affiliate Radio System (MARS) SKYWARN: Tornado spotters Pool of electronics techs for many uses. Ham radio is robust (relatively) compared to single-point-of-failure technologies Ham radio really is fun
7	What Ham Radio Can Do For family use: replace the kid’s cell phones. Wide area dependable keep-in-touch. Talk to the space shuttle and ISS Bounce signals off the moon (and meteor showers and more) Keep moving text, data, and even pictures when the internet goes down Provide emergency communications after earthquakes, floods, and tornadoes.
8	Licenses There are several grades of license Starting February 23^rd, no Morse Code Three main classes of license are Technician (the starter license) General (the most common license) Extra Class (the serious hobbyist)
9	Do you need a License? Only if you intend transmitting. No license needed for shortwave listening No license needed for listening to police and fire scanners. Some municipalities have rules which may conflict with the FCC’s rules about things like listening to police and fire radio systems while in a car. You probably are within your rights to challenge such rules, but do you really want to be a “test case?”
10	The Art of Listening Radio is largely about being an information sponge. Most people get into it slowly by starting off listening to far away radio stations at night. With a good radio at night, every channel on the AM band and almost everything on the FM band is occupied!
11	The Jump to Shortwave The “second step” for a lot of people is to either start chatting on a citizens band radio, or start listening to shortwave. Shortwave stations can generally be heard 24/7 but you need to know which bands work best and why. This is where we start the technical discussion.
12	This Won’t Hertz Radio waves as a high frequency alternating current – or AC. Each cycle is called a Hertz. It used to be a cycle but that was too simple. Middle C on a Piano is 440 Hz. A Kilohertz being 1,000 Hertz, Middle C is 0.44 Kilohertz. You can’t hear above 20 Kilohertz although bats and dogs can. “Longwave” radio begins around 30 Kilohertz
13	Now We’re in the Radio Spectrum “Medium Wave” is the AM broadcast band. That’s .5 to 3 Megahertz but the AM stations end at 1.7 Megahertz. “Shortwave” is from 3 to 30 Megahertz. “Very High Frequency” goes from 30 Megahertz to 300 Megahertz. “Ultra High Frequency” goes from 300 Megahertz to 3,000 Megahertz (up through channel 83 or so on TV) The we bump into Super High Frequency services like radars and such.
14	Bands and Channels A “band” is a range of frequencies. Like the “shortwave bands” Meter Band Frequency Range Remarks 120 m 2,300 - 2,495 kHz tropic band 90 m 3,200 - 3,400 kHz tropic band 75 m 3,900 - 4,000 kHz shared with the amateur radio 75/80 meter band 60 m 4,750 - 5,060 kHz tropic band 49 m 5,900 - 6,200 kHz 40 m 7,100 - 7,300 kHz shared with the amateur radio 40 meter band 41 m 7,300 - 7,350 kHz 31 m 9,400 - 9,900 kHz 25 m 11,600 - 12,100 kHz 22 m 13,570 - 13,870 kHz 19 m 15,100 - 15,800 kHz 16 m 17,480 - 17,900 kHz 15 m 18,900 - 19,020 kHz 13 m 21,450 - 21,850 kHz 11 m 25,600 - 26,100 kHz
15	A channel is a single frequency The channel is always the carrier frequency, or the implied carrier frequency is using a suppressed carrier which we’ll explain in a minute. Police and fire has “channels” and these are within the UHF and VHF “public service” bands
16	Propagation LF Low Frequency 30 - 300 kHz - Guided between the earth and the ionosphere - Ground Waves MF Medium Frequency 300 - 3000 kHz - Ground waves - E layer ionospheric refraction at night, when D layer absorption disappears HF High Frequency (Short Wave) 3 - 30 MHz - E layer ionospheric refraction - F layer ionospheric refraction VHF Very High Frequency 30 - 300 MHz - Line-of-sight
17	Listening Rules High frequencies (above 10 Mhz) work well in daytime. Lower frequencies work well at night. Line of sight is the same day or night. “Gray line” propagation is interesting because that’s when “band conditions change” (twilight zone propagation) MUF is “Maximum Useable Frequency”
18	Modulation Types CW – Continuous Wave AM - Amplitude Modulation Center carrier wave (on 1 MHz for example) A 1 KHz audio tone will produce an upper and a lower “sideband”. These “beat” against the carrier and you hear the tone. FM - Frequency Modulation A center carrier “deviates” around a center frequency (such as 100 MHz) The width of the carrier deviation determines the volume and how fast is goes back and forth determines the frequency.
19	Single Sideband AM radio rolls off above about 5 KHz, and is pretty well gone at 10 KHz due to channel spacing. A 10 KHz tone produces a sideband 10 KHz above the carrier center frequency and then another one below the carrier. These are “upper” and Lower Sidebands In Single sideband (SSB), the highs are limited to about 3.5 kilohertz, the low roll off under 300 Hz, the carrier is done away with, and one sideband is suppressed. As a result, a ham radio SSB transmitter putting out 1.2 kilowatts has about the same “talk power” as a 5 kilowatt (5,000 watt) AM radio station
20	Antennas The one rule to remember is that a half wavelength antenna is 468 divided by frequency in Megaherz. The most common antenna is a “dipole” with a quarter wavelength on either side of a center feed point.
21	Sample Dipole At 3.8 MHz, each side of a dipole is about 61.5’ long
22	AM, FM, and VHF Antennas A quarter wave at 600 on AM is about 390 feet. A quarter wave at 1500 on AM is about 156 feet. At 100 MHz it’s about 28” At 144 MHz, which is the 2 Meter ham band, a line of sight band, you’re looking at about 19 ½ inches.
23	Exotic Antennas Loops can be any size – Art Bell has one of the largest, and you can see pictures at http://www.smeter.net/w6obb/antenna-farm.php Man good manufacturers such as Hy-Gain antennas http://www.hy-gain.com/manuals.php
24	Basic Electronic Components Resistors (heater element) Capacitor (stores energy) Transformer (steps AC up or Down) Chips and tubes Allow a very small voltage to control a big voltage Small voltage controlling big voltage is how all amplifiers work.
25	Basic Electronics Ohm’s Law E= I * R where E = Voltage, I= Current in Amps, and R = Resistance in Ohms
26	Basic Electronics The Power Law P= I * E where P = Power in Watts, I = current in Amps, and E = Voltage
27	Equipment Might want to start with a $100 class shortwave radio. http://www.radiolabs.com/products/radio/shortwave.php?PHPSESSID=a375ecd74e0644b11ba3f09d7ab6d16d I personally like the Kaito 1102 (which I have) and the Kaito 1103. Why? Under $100, good shortwave listening, portable, rechargable, and can get Morse Code and SSB with a little paitience.
28	First real Ham Rig Icom 718 is a good starter unit. Get it with the UT-106 digital signal processor installed for under $600. Sample site: http://www.twowayradioonline.com/IC718.asp
29	Where Does the Hobby Take You? Broadcast engineering Cell Phone engineer Shipboard electronics officer Electronics tech of all stripes Ham radio contests Ham radio satellites (www.amsat.org) The International Morse Code Preservation Society (www.fists.org)
30	The Big National Organization American Radio Relay League www.arrl.org Lots of licensing, books, studies, lists of ham fests and so forth.