Phrack Philes: Radio Hacking - The Basics of Radio

I managed to fall into the peculiar website of phrack.org while googling "AM radio basics", and came across an article which I've read before, but then got curious about the website it's hosted on.. I wasn't quite sure what kind of website it was..

,. +@';;+: #@;;;;;;;@. @@';;;;;;;;;@@ `+@@+;;;;;;;;;;;;+@; +@#;;;;;;;;;;;;;;;;;;;@@ :@+;;;;;;;;;;;;;;;;;;;;;;;@ '@;;;;;;;;;;;;;;;;;;;;;;;;;;++ `@;;;;;;;;;;;;;;;;;;;;;;;;;;;;;@ ##;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; @';;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;# ;#;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;' `;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;@ ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;. ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;+ #;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;# ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;'` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;# +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;@ .@@@@@` @;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;# @@@+;+@@@ ';;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;'` ;@;;;;;;;;#@ @;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;@#;;;;;;@ #+;;;;;;;;;;;@` ;@;;;;;;+;;;;;;;;;;;;;;;;;;;;;;;;;':';;;;;;: @;;;;;;;;;;;;;;@ @@;;;;':;;;;;;;;;;;;;;;;;;;;;;;;;:::';;;;; #;;;;;;;;;;;;;;;;@ #;;;;;#::;;;;;;;;;'#@@@#+';;;#;;+::':;;;;;# #;;;;;;;;;;;;;;;;;;@ .;;;;;#:::;;;;;;;;;;;;;;;+@@@@'@#::;;;'+;;;@:` ;;;;;;;;;;;;#@@@@#;;;# +;;;#:::::#@@@@@###@@@@@#';;;:::::,...#@;;+;;@` .;;;;;;;;;;@@: `+@';` ,;;;::+::::+............:++::::::'....#;;@;;;;@ `#;;;;;;;;#@ ## :#::'@@:::::+..........;#:::::::@.....#;;';;;;@ @;;;;;;;;@` `#@# @:::#..,::::::;@#,.....@:'::::::@:@@@+,@;;;@;;;+ `@;;;;;;;;# `@#...,# ;+,....@::::::::;......:':::::@@+ .;;;;@@;;+ .@;;;;;;;'. '@.......:@'@'....'::::::::+;@....#:'#::++ ,. #;;;@;#;@'@; ;@;;;;;;;' :@..........'+,.....':::::::;'@.....':;#+@` @ :@;;@;';;;;;+@@;;;;;;;;; @............:......+:::::::.:#.....:;@..@' ;, ::@@#;;@;;;;;;;;;;;;;;;, ,@@@@# #'............@.:##+;,':::::;+:'......:...'@ :::;;##@#;;;;;;;;;;;;;@ @@;;;;;#@' @.............,#;@ :@@::::#+:,...........@ @:::@;;@.;'';;;;;;;;;;@ @;;;;;;;;;;+# @..............;@@ :`#+::#::............@@. ;::::#, @;;@;;;;;;;;@ @+;;;;;;;;;;;;;;: @................@ ;# +;:'::............#,@@#++:::::;@: @;;#@;;;;+@@@@+;;;;;;;;;;;'@+` @................@ #@ ;@:::,...........@....#:+::+@@@@@@,#;;;#@@@#;;;;;;;;;;;;;+@+ @................@ +;+;@............#'..':'+:::@.....@##;;;;;;;;;;;;;;;;;'@@, @................# +,...............;..,:,.::::#......@##;;;;;;;@@@@@''#@@` #................:: ,:.................,...@:::::#......@+@;;;;;@#``````@. `,..............#:+ #..............;.....,::::::::+@...,,.@#;;;@`#``````, #.............+::'` `@..............#.....@:;::::::;,....@ +@@+'``+`````.. ,.............:::'.. @@@@..................'::;::::@,......: .@````+`````,` #...........#:@::...:;:.@:.#...........@@;...++#::::::+;......; `@`````'`````;` '..........;,::::@;'...+................:..'.;:::::::::::....@ @```````;`````+ @,........'.+::::'.....'................+....#::::+;::#......@ @````````;.````# @..........,:::::+.....#..............+.;....::::::;.........+ ',``.``````:.````@ @..........@:#:::#.....;..+'.........'.@.....:::+++#,........` @````@``````,,````@ @..........@@+::::@.....:@:##+@@@#+';........'::';;+........: `+```;;@``````,:````@ @..........@.+:;;@##..,,,...@@,.........,@#@.@::+;;#........' @``.`'.,@``````.;````@ #..........;.;'..#@;;. ,......'@++@'.. :..#:#;;@.......+ @```.:..;@``````.'````@ #............;;...@;#.@ #..:;'#'''''@@' ;.@;@';;#.......+ '.```@.#.;.@``````.+```.@ #............@....@;+#,.......#+''''''@@ ',+';;;;+......' @````...'...@``````.#```.@ @.................@#,...........+''''''@ #,..@;;;:......@ `:```+#..+.:.,@```````#```:@ ..................'+..............+''''' +....:;;@.......@. @````;.:....@``@.``````@```;@ +...............';;,....,'+'.......;#++@,......';@........'@+```:...#:..:``.#```````@```+# +..............';++...@,....':...............;;++.........@````#:....#;``@..@```````@```# ,,............#,.@+@@@,......+,............#;;@..........@```...##...;``.,..'.``````#,`@ #..................@.........@.........+#;;##.........,.```@...#..:``@..#..#.````'``:# ;.................@..........;@'...'@#;#';@..........@````,@.+.:.'``..:.'..,.```,``@ +.................@..........'.@@#';'#,..@:..........:```+``@,..,``@:.:..@..+``'``;; +.................@.......;@'.#+@@@.......'#........+````+```@..'``,.++...#@```,``@ +..................:....;....,.............:@.......#```:.````#:``@....++.,.``'``;. #..................,@##...#.';..............;+.....:````@.'````'``,.@..:,,@```.``@ #..........................:.................+.....@````,..#`````@.,.+.:.'```'``' ;............................................@......```@....:.````#'..';.;```.``# :...........................................@....#````'.:.#..+````:+.,.@```'``+ +@@#.................,+@@@@@@@#':,..........#....;```+...#....#`````@...`.`.``; #@''++,............,@@@;;;;;;;;;;;'+,.........+..:````@#..#'...:,,````@#+@@@``# ,#''''+#+.........#@@@@@@;;;;;;;;;;;;+.........#..#```,..;.,..;;...#`+@,:;..'@`` @;''#''++@+....;@#@'';;'@;;;;;;;;;;;;@..........@.````@...''...#..'.+@.@;....,@ @;;+'''###@@@@@##@;;;;;;@;;;;;;;;;;;;:...........@```.;;..:.#.;.;.,.+...@.......++. @;;;''#+''#'''''#;;;;;;;@;;;;;;;;;;;;.............+``@..@:...::..#;.@....#,........,@ #;;;;;;;#+#'''#;;;;;;;;;+;;;;;;;;;;;;..............,`@...#...'.+...#@.....#,........@ ';;;;;;;;;;;;;;;;;;;;;;';;;;;;;;;;;;;+.............@'.#....;.,..@...',.....+:.......@ :;;;;;;;;;;;;;;;;;;;;;;;@;;;;;;;;;;;;;@.............@@..:#...@....;:.,@......##......@ +;;;;;;;;;;;;;;;;;;;;;;;@@#;;;;;;;;;;@,............@:#....+..,'.+.:`@;#.............+ ;;;;;;;;;;;;;;;;;;;;;;;;@@@@@#;;;;;@'..:.........,+`@.:.#..#+..,:+``@..;...........# #;;;;;;;;;;;;;;;;;;;;;;;;''#@@@@@#';;#...........#``.+...#...:..'.,``@..#..........@ +;;;;;;;;;;;;;;;;;;;;;;;;'+;;;;;;;;;;;'..........:```@'..#.'.+..+.#```@...,........:@ #';;;;;;;;;;;;;;;;;;;;;;';;@;;;;;;;;;;;;:........;#```@.'.....'..:#.``::...#........@ `#;;;;;;;;;;;;;;;;;;;;;;;+;;@;;;;;;#;;;;;'@+:.....@.``'...'+..#.#'.@```:`............@ @;;;;;;;;;;;;;;;;;;;;;;;;+;;'#;;;;@;;;;;;;;''@#...@```@...:.'....,:.``+``....+......+. @;';;;;;';;;;;;;;;;;;;;;;+;;;@;;'@;;;;;;;;;;;+@#;@'``,';.:...##.#.@```.``'..........@ @';;;;;;;;;;;;;;;;;;;;;;;+;;;##@@@'';;;;;;;;;;@:.#```@...#.....;.,.``#```@.........:. +;;;;;;#;;;;;;;;;;;;;;;;;';;;;@#;;';;;;;;;;;;;#@ +```@..,.;.#..#.#``````@@:........@ #;;;;;;+;;;;;;;;;;;;;;;;;;';;;;@';;;;;;;;;;;;;;;@ ```#::.+...#...;`.`#``.@@@.......,` @;;;;;;'';;;;;;;;;;;;;;;;;;;;;;;;@;;;;;;;;;;;;;;;@#```@..#...#.;#.#``.```@@:`;......@ @;;;;;;;@;;;;;;;;;;;;;;;;;;;;';;;;@+;;;;;;;;;;;;;;;:``;;..#.'...,.@.``'``:@+ @.....: ;#;;;;;;@;;;;;;;;;;;;;;;;;;;;;@;;;;;@;;;;;;;;;;;;;;'@``@......@..'.'``:```:`: `@...+ @;;;;;'@;;;;;;;;;;;;;;;;;;;;;;@;;;;;+@;;;;;;;;;;;;;;+`.#,:#.....#.#``.:``'`; @+.@ @;;;;'@;;;;;;;;;;;;;;;;;;;;;;;+;;;;;;@';;;;;;;;;;;;;;`@...#..@..:,;``+```.`. @# @;;;@+;;;;;;;;;;;;;;;;;;;;;;;;;+;;;;;'@;;;;;;;;;;;;;;'@..'..'..+.@```.``#`' @@#+;;;;;;;;;;;;;;;;;;;;;;;;;;;@;;;;;;@';;;;;;;;;;;;;@,;.:..#'...:``#`````` @';;;;;;;;;;;;;;;;;;;;;;;;;;;;'+;;;;;@@;;;;;;;;;;;;;@..;:....##@``````#`+ `@;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;#;;;;;#@;;;;;;;;;;;;;@#.;.##...:,`.#``.``` @;;;;;';;;;;;;;;;;;;;;;;;;;;;;;;;;@;;;;@@;;;;;;;;;;;;;@.#...@.#.@``.```'`+ +;;;;;;#';;;;;;;;;;;'@@##@@';;;;;;;;@;;+@;;;;;;;;;;;;;;@.+#.#.@.'.``'``:`` @;;;;;@'+;;;;;;;'##''''''''@;;;;;;;;'#+@+;;;;;;;;;;;;;;@...+..++@``:```:`# +'@;;''''@;;;+@'''''''''''''#;;;;;;;;#@+;;;;;;;;;;;;;;;@@..+',..@#`:``'`` +'@@+''''''''''''''''''''''+;;;;;;;;;@';;;;;;;;;;;;;;;@.#...+.,..@```.`# @''''''''''+'` `.;#@@#'''';;;;;;;;;;@;;;;;;;;;;;;;;;@..#.;.,;...``#`` .@''''''''+ `@#''';;;;;;;;##;;;;;;;;;;;;;;',#..+:.+,.@`````# @#'''''''@ ``` `@''@;;;;;;;;@';;;;;;;;;;;;;;@``#..;....```#`` @@'''+@; ,:+@@` @'''#@';;;;#@;;;;;;;;;;;;;;;@```#..,..#``.``# `@@@;;` +# `@''''''+#;;@';;;;;;;;;;;;;;;@@```+...:```'`. ++;;;# #@'''''''''@@;;;;;;;;;;;;;;;#, @```',.'``:``+ .@;;;;;;@ @+'''''+@@;;;;;;;;;;;;;;;;@ @```'+```:`# +#;;;;;;;;;#@@@@@@@@' ';#''+@@#;;;;;;;;;;;;;;;;;@ @```;``'`;@ @+;;;;;;;;;;;;;;;;;;;;;'@@, ';;@@@@';;;;;;;;;;;;;;;;;;@ @`````.:`:# #;;;;;;;;;;;;;;;;;;;;;;;;;;#@+ #+;;@@@;;;;;;;;;;;;;;;;;;;@. @.``#``'`' +;;;;;;;;;;;;;;;#;;;;;;;;;;;;;#@#;;;@+@;;;;;;;;;;;;;;;;;;@; @.```@ +# ,;+#@#@# #;;;;;;;;;;;;;;';;;;;;;;;;;;;;;;;;;;+''@;;;;;;;;;;;;;;;;@@ @@::. # ,'@'. @ @;;';;;;;;;;;;;;';;;;;;;;;;;;;;;;;;;;;#''+@;;;;;;;;;;;;#@` ` # ,#'. @ @;;;#;;;;;;;;;;@;;;;;;;;;;;;;;;;;;;;;;#'''''#@#';;;;;@@ :#: :' +;;;;;#;;;;;;;;';;;;;;;;;;;;;;;;;;;;;'+''''''''''''+, ;+`` +: ;;;;;;+#;;;;;;';;;;;;;;;;;;;;;;;;;;@@''''''''''''@ `+ : '' @;;;;;;;#@;;;;#;;;;;;;;;;;;;;;;;+@@;@@+''''''''#: # ` ;#. `;;;;;;;;;#@@;;;;;;;;;;;;;;+@@@#';;;#@@@@+''#@+ @ @ `;@: ,;;;;;;;;;;;@@@@@@@@@@@@@#';;;;;;;;;@;#@@#; .; ,::,` +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;'@ ., ';;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;## @ ,'@', '; @;;;;;;;;;;;;;;;;;;;;;;;;;;;;;@+ ;` `:'@+:. @ #+;;;;;;;;;;;;;;;;;;;;;;;;;+@: :'+##+':,` #` ;@+;;;;;;;;;;;;;;;;;;;#@@. `## '@@#';;;;;;;;'+@@@#` ;.. :#@@@@@@@#: ;.;  The basics of Radio 0 - Introduction 0.1 - Technical Terms 1 - Radio Basics 1.1 - Radio Waves 1.2 - Carrier 1.3 - (RF) Frequency Bands 1.4 - Wavelength 1.5 - Transmission 1.6 - Receiving 2 - AM Radio 2.1 - What is AM Radio? 2.2 - Modulation 2.3 - Demodulation 2.4 - Circuits 2.4.1 - Receivers 2.4.2 - Transmitters 3 - FM Radio 3.1 - What is FM radio? 3.2 - Modulation 3.3 - Demodulation 3.4 - Circuits 4 - Misc 4.1 - Pirate Radio 4.2 - Wireless Telephone Tapping 4.3 - Jamming 5 - Conclusion 6 - Bibliography

They have no "about" page, in which to determine some form of overview of basically what the site is about, nor state any objective or definition. So I went way back to their originating Volume One, Issue One, released on November 17, 1985 to find out.. "Welcome to the Phrack Inc. Philes. Basically, we are a group of phile writers who have combined our philes and are distributing them in a group..." Interesting.. But what's a phile? They didn't say, so I looked it up.. Combining form suffix: -phile denoting fondness for a specified thing. A combining form meaning “lover of,” “enthusiast for” that specified by the initial element: Anglophile; bibliophile; demophile. It originates from the Greek word "philos", meaning "loving" Ok.. that's pretty cool. My part15ophile today is really no more than a link to a particular "phile" about RADIO found lingering amongst Phracks vast midst of other topics scattered on the ocean of their website,.. Released:   July 17, 2004 Entitled:     Radio Hacking Subtitled:   The Basics of Radio By:            shaun2k2 This article is divided up into four parts. The first part describes the basic theory of radio, and examples to illustrate some of the common day uses of it. In parts two and three, AM and FM radio details are outlined showing various different circuits to illustrate how these principles can be applied to real-life, functioning circuits. Section four is a misc. section, presenting some miscellaneous interesting points.   There's a few excerpts below. Read full article here:   phrack.org/issues/62/11.html

Excerpts:

Radio waves, otherwise referred to as 'radio signals', are simply electromagnetic waves.  Radio waves are transmitted by devices called 'radio transmitters' or 'transmitters' for short.  Despite our wide and many uses for radio waves as a whole, we actually known very little about 'radio'.
We do know, however, that radio waves are a form of energy, which act exactly like they have been  propagated as any other type of wave we know of. For example, an audio wave.
Radio waves are made up of three things; an electric field, a direction, and a magnetic field.
Despite our underlying ignorance of radio and its properties, we can predict and use its properties to our  advantage to undergo a wide variety of different tasks -- and will probably do so for a long time to come...
                                   ~~~
AM Radio refers to any form of technology which makes use of Amplitude Modulation to modulate the 'carrier' with information... ..AM is one of the simplest forms of modulation, and with this, comes its disadvantages...
                                   ~~~
AM Modulation involves nothing more than shifting the power of a radio wave's carrier by tiny amounts, in sympathy with a modulating signal...
Amplitude, as you probably already knew, is just another word for 'power'...
..After AM modulating the carrier, the signal has usually twice the 'bandwidth' of the original modulating signal.
                                   ~~~
Pirate Radio stations are simply just radio stations ran by individuals who are not licensed amateur radio enthusiasts...
..Some 'pirate radio' stations keep within the FCC terms, by transmitting at low-power.
These types of stations are often referred to as 'free radio', or 'micropower stations'.
..The US allows transmission of radio signals at *microscopic* power, making the limitations almost useless for unlicensed radio enthusiasts, thus causing them to resort to pirate radio.
                                   ~~~
To avoid being busted, it is probably a good idea to stay within the legal power limits.  Otherwise, a Direction Finding device used by the authorities could easily track down the exact location of the transmitter. 
                                   ~~~
Read full article  here:  http://phrack.org/issues/62/11.html