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Super computers monitor and manipulate all electrical activity in the brains of subjects of Remote Neural Monitoring.   If you are subjected to Remote Neural Monitoring the hive mind team who monitor and surveill you on a twenty four hour per day basis will keep detailed records of everything you say and do as well as detailed records of everything you eat and of each time you visit the bathroom.  Because markers are being placed in the food supply via the packaging, they can also monitor your food as it travels through your alimentary canal.  They can monitor it being digested and assimilated and even eliminated.  Targeted individuals of Remote Neural Monitoring have absolutely no privacy because technology is locked onto their unique brain signature on a constant basis so that their behaviour can be detected and evaluated at all times.  If you wish to keep some privacy in your life you aught to eat food that has not been wrapped in packaging so as to avoid food markers.  Apples and carrots normally contain markers but bananas and potatoes may be safe to eat. Medication contains markers.    When microwave transmitters are banned we will return to absolute freedom on this earth.  The existence of satellites is an easily proveable hoax.

If you happen to use electronic devices such as smart phones or wireless modems you are being mind controlled and you are having your brain entrained.  There is no defence against mind control.  You are being mind controlled to believe the following   " We love you Daddy government,   We love you Mammy Church,  We have a childlike mindset, We love our servitude,  If anybody criticizes Daddy government or Mammy church we will gang up on them and psychologically torture them by the use of directed energy weapons and voice harassment technology until they die in ruin."

A moment ago, a technologically induced, microwave hearing voice which I heard coming from inside my head informed me of the following "You will only have privileges while you are generating money for me." The internal voice then went on to inform me that I am a slave.

Microwave hearing which is the science of projecting human voices inside the heads of extremely unwilling and non-consensual human beings is now widespread throughout Ireland and the wider world. It was used in the first Iraq war and it was then known as "Voice of God Weapons". It can only manifest inside the heads of human beings who are first sprayed with nano technology from chemtrail spraying of the skies over our heads. We inhale and ingest the nano technology which penetrates the blood brain barrier and we eventually become receivers and transmitters of sounds, visions and other sensations.

Since the advent of this technology some individuals have misinterpreted their experiences as supernatural and extra-terresterial. This is not the case. All supernatural and extra-terresterial experiences are simply advanced brain weapons combined with holograms and military psychological operations.

Privileges are the domain of slaves. My rights are my birth-rights. No legislation can ever change my rights. The law has nothing to do with my rights. My rights can not be added to or subtracted from by another human being ever. Some individuals falsely imply that they have man-made authority over other human beings. They are wrong. Our rights are actions we take that dont harm anyone. We all have the same rights by virtue of being human beings.

Microwave hearing and technological enslavement of human beings can only exist while microwave transmitters and 5G millimeter wave transmitters are in place throughout our countries. All technology being used to slowly and incrementally enslave the human race is ground based. The existence of satellites is a hoax. At least eighty percent of human beings are unknowingly working to enslave the human race. They are mostly lawyers, politicians, government administrators, telecom engineers, main-stream media, etc.

Please organize to have microwave transmitters and related paraphernalia dismantled urgently.

Initially, when a targeted individual first begins to be brain mapped, they can not be seen inside their own homes by the neuro weapons operatives who are doing the brain mapping. The targeted individual can only be heard by these neuro weapons operatives.
However, when the targeted individual is partially brain mapped they can then finally be seen by the neuro weapons operatives. Their clothing can not be seen. The targeted individual can only be seen in a totally nake...d state.
The outside contractors who wish to eventually invest money in order to use the neuro enslaved targeted individual for slave labour when said targeted individual is eventually fully neuro enslaved, is not always made aware of this fact by the main team of brain mapping staff.
The outside contractors look at the partially brain mapped targeted individual inside their own homes on their monitors and they speak to them via electronic brain link capability and they demand to know why said targeted individual is walking around naked inside their own home.
The outside contractors have complained to the main team of brain mappers that when they hone in on prisoners while in their prison cells they can see them fully clothed. They do not understand the anomoly of only being able to see partially brain mapped targeted individuals inside their own homes in a naked state.

This neuro enslavement of ordinarly good will human beings inside their own homes is being carried out wirelessly be means of directed energy weapons and voice harassment technology. We can stop it happening simply by demolishing all microwave transmitters and having them banned from our countries. We must also refuse to allow 5G millimeter wave technology to be erected throughout the world because it will mean worldwide enslavement of the whole human race if it is allowed to be installed.

The picture above was uploaded to his gmail account. The moment I saw his picture, I instantly remembered corresponding with him. At that time he was in West Africa and I was very glad to have someone from that region of the world participating in our organization. He was requesting to be added to our Buddy List to which I replied, 'sure.' Then a month later for unexplained reasons, he wanted to deactivate his account. http://govsponsoredstalking.info/?p=2463

Hi All! I am new comer to this site.I am a female from Canada (Toronto) Like most of you here - I am a victim of gangstalking and electronic harassment. It took me a while to realize what was going on since I found it hard to believe such thing was going on. I even thought I was going unstable. After searching on the net, I came to know the whole world is experiencing some sort of electronic harassment/organized stalking. The gangstalking part I am still trying to understand as to how they do it. Wherever I go, shopping mall, bank, to the grocery - they seem to know exactly where to find me to harass me. Even yesterday, I was standing in line, they cut me off, tripped me making it look as it was an accident. One night, I woke up all of a sudden as if something was chocking me. I have been made to feel sweat at night, then I would be cold. I would wake in the middle of the night with high anxiety but there was nothing for me to fear. My mother is also experiencing the harassment. She has been going through increased heart rate and heart pain. Took her to ER and everything was fine. She has extreme eye pain with blurred vision, she feels dizzy and there things have never happened before this onset. As I am new to this gangstalking and electronic harassment, I am reaching out to anyone who can help me out with how to block/shield against these electronic devices - I am also experiencing mind control which seems like they can read my mind. Any help from anyone, i would really appreciate. Thanks all for reading my post. Stay Blessed all!

Source: http://govsponsoredstalking.info/?p=2355

Due to the nature of the crimes inflicting him, he has been forced out of his home and into the streets. But that has not discourage him from exposing these Targeted Individual crimes against humanity.

He is in need financial assistance so he can use the money to eat, shower and live some level of existence.

Your financial contributions should be sent to Paypal to the email address: targetedindividualawareness@gmail.com

Thank you for your support and have a nice day.

Video: Where To Invade Next? Targeted Individual Awareness

Video 2: I Need Your Help. Please Help Me.

I am seeking your financial support to purchase land. The land will consist of 5 to more acres. We will use it as a safe haven for individuals who are being targeted with electronic harassment and organized gang stalking.

Electronic harassment is a form of torture that involves the use of micro-wave weapons. These weapons are experimental and there use is highly classified. However, they have been known to cause cancer and disabled a person inability to live a normal life. We have been in contact with the government about this problem, but it has been difficult to get them to stop.

Organized Gang Stalking are individuals who have been contracted by the United States government to carry out these illegal experiments. Their role is basically to assist and enforce instructions that is given to them, which includes gathering and reporting data to their superiors.

The land will house a garden and a place for the Targeted Individual to congregate without worrying about some of the harassment that we endure on a daily basis. In the later months, we will use the land to encourage economic independency by encouraging entrepreneurship, which is key to rebuilding our lives.

For instance, we plan to sell some of the produce that we grow to the public. And the other idea is raise awareness by making clothes that highlight our position.

If you believe in Human Rights and want to give us a chance to be whole again, will you consider a kind financial contribution today?

Any amount will be welcome ($1, $5, $25, $50, $100, $250, $500, $1,000) or more. Thank you for your cooperation and we hope we hear from you soon.

Please click this link to donate: https://www.gofundme.com/self-efficiency

My nextstore neighbors downstairs have been using cybernetics on me to cause me health problems through a microchip in my brain. I also believe they use sonic ear on me because I have had popping in my ears on and off and it sounds like rice krispys popping, my ears are also very sensitive to sound also I feel pressure in my ears. They have also used electronic weapons on me made up of guns ETC. I know this because I bought a gps tracking device and caught signals coming into my apartment from their apartment and I have also felt high amounts of electricity going through my body making me feel anxious at times. I think they caused the frontal antrophy in my brain because I did not have that in 2008 before the microchip was put in my brain. I also think that these people have caused damage to my lungs from cutting the oxygen to my lungs on and off. I believe they have caused the skip in my heart beat when they caused my heartbeat to go up well over a 100 beats per minute the reason why I know this is, I had no heart problems I had a normal angiogram in the past. They have also caused me stomach problems because I have thrown up a lot in the past. I believe that these people have murdered people before in the past through electronic weapons that he and she has used on people in the past and this people are very experienced in what they do. And that the murders was covered up because it look like the person died from a normal health problem.  I also have proof that the doctors at Renown hospital lied to me about my mri photos of the brain because they told me that my mri of my brain was normal with no foreign object. I later paid a doctor online who reviewed my 2012 mri of the brain from Renown Medical center and he told me it look like frontal antrophy of the brain. My sons wife a radiology tech was visiting my apt I showed her my 2012 mri photo of my brain and she told me it look like there was a foreign object in the left side of my skull at the time. But I later reviewed the mri photos of my brain for 2012 and found a photo that look like the microchip was in the leftside of my brain. I have evidence that there is a microchip in my brain because I bought a radiofrequency wave bug detector and took it outside and the light was all lit up on it I took a video of me standing by it when it was all lit up. I also had bought another radiofrequency wave detector CC308 in the past and I took it to a park by valley RD in Reno,Nv and when I got there I turned on the rf detector the all the lights was fully lit up when I would move away from the detector some of the light would go off when I would move close to it the all the lights would fully go on. I know that my neighbors was paid off by my ex-boyfriend Charles M who implanted this microchip in me in 2009 and that his mother Lillian B probably helps him pay these people to kill me through this microchip and electronic weapons made up of guns etc. One reason why he pays these people to kill me is because I broke up with him and I will not go back to him. The other reason why he pays these people to kill me is because he doesn't want anyone to know that he implanted the microchip in my body when he drugged me in 2009 and did it without my consent. I haven't been able to get this surgically removed from a doctor because the doctor covers up the microchip in my body by saying there is nothing there. I think that these doctors,mri,ex-ray depts are getting paid to lie about the microchip in my body because my mri of my brain for 2012 clearly shows a microchip in my brain and I have had my sons wife a radiology tech verify this. I have evidence from a rf detector I also have evidence from a gps tracking device. I still can't get any help from the Reno police dept even after filing a police report against these people who do this to me. I have even wrote the City mayor and President of the United States and have not received a response back. I know these people will murder me and hopefully if I die someone will read this letter and know who did this to me.

 This book contains few months length typing up of the V2K conversation. They seemed to be engaged in the endless radio talking over threats, persuasions, and criminal investigations. 25 dollars. Over 11,000 words and 300 pages. It has the extra section "100 questions to the Direct Voice Hearing Speakers" and their replies.

Hello everyone,

I am a 19 year old german voice-to-skull victim since may this year. I figured out that the mind control started about a 1.5 years ago.

At that time a feeling in my nose started which felt like something is pressing from the inside plus it was running all the time. I thought it was some kind of nose disorder but after getting information I now think it is an effect caused by the infection of the V2 nerve http://en.wikipedia.org/wiki/Maxillary_nerve.

I got my information over the months from various sources (http://www.free-targeted-individuals.com/, multiple blogs and homepages, videos and pdf documents) and I also found out that they are able to do this since at least 2001 (http://epic.org/privacy/airtravel/foia/foia1.html).

My guess would be that it is some kind of nanotech infection but I still think about wether they do this with single persons or entire populations. And there is also the big question wether we talk about use or abuse of this technology. The book by electric angel offered a lot of information, especially when it comes to the V2k, which electric angel tells us does not mean "voice to skull" but is an acronym for the parasitic infection of the V2-nerve with k which is a technical short for coupling coefficient http://en.wikipedia.org/wiki/Inductance.

You have to spread that information about the V2k acronym, it is very accurate and important!

Now there are limits for guessing what the technology might be but I specialized on analyzing the crap they talk all the day and I can tell you it is nothing but Hypnosis! They use a technique called "classical conditioning" http://en.wikipedia.org/wiki/Classical_conditioning , it is very important for you to look that up and study it!

They use this -> http://en.wikipedia.org/wiki/Stimulus%E2%80%93response_model

Maybe they also use NLP - Neurolinguistic Programming http://en.wikipedia.org/wiki/Neuro-linguistic_programming where we come to my next guess that we are all confronted with coldblooded/pedophile/sociopathic/cocaine-snuffing satanists.

Well, NLP is just some specialized form of hypnosis and there we got its (german) mascot called Vakog:

Now let's compare it with this picture of Baphomet:

Satan is also referred to as "the one-eyed".

Now don't get me wrong I'm not a strict christian, but it is very much likely that these people are devil worshippers.

So I wanted to ask you all some questions about your experiences with this particular problem of being mind raped day after day:

1. Did it start all of sudden? Was it that you woke up and there they were discussing like it was the most regular thing on earth? Voices that you never heard before?

2. Do they use words or simple phrases often and always with the same accent? Words and phrases that you didn't use to say?

3. Do you see flashing lights when you close your eyes, hear a steady frequence noise, hear clicks in your head or notice radical changes in mind activity or elselike?

4. Did you notice difficulties in visual imagination, loss of eyesight, blury vision, loss of focus?

5. Do they keep on radically talking their hypnosis bullshit no matter what you think?

6. Did you notice memory loss or especially short-term memory loss?

7. Did you find countermeasures/methods/tactics/devices/body movements which help?

I will continue this post and tell you some experience how to use psychological warfare to beat them at their own perverted game. Never forget that you still have your imagination which is more powerful than bullshit talks, you can use to harass them with their own strategy.

Good luck and keep it up everyone!

Try exsplaining to the lads down the pub on a footy weekend how a remote control works and theyd laugh at me ,i remember when i was just one of the lads going out every oppotunity drinking lots and having fun.I never used to have to think about what i was going to say conversation just flowed.Seven years ago i was unwillingly entangled in the world i now know as v2k(voicetoskull)"welcome to the worlds most evilest radio station"i heard from an unknown source.At the beginning when it first started i was taking alot of drugs which didnt make matters any better,but then i only thought i could hear things ,theres a massive diffrence to thinking you are and actualy hearing it .Me and my partner were taking amphetamines as part of our sex life and all was well and good until i started hearing whisperings around my girlfriends presence i could never make out what they were saying but i remember thinking i could hear sex everywhere,i even started following my girlfriend to the toilet because when she wasnt in eye shot the whispers became louder,looking back at that time in my life i realy believe i was under the influence of drug induced phycosis,a genuine mental illness but netherless my health detereated fast,i was becoming more and more paranoid to the point of wondering if there was any hidden devices checking phone calls and text messages and aiming all my anger at my girlfriend.Everybody has there own ways of having private moments but under the influence of drugs all your senses are heightend your hearing been one of them.I eventualy come to the conclusion that it was my neighbours listning to us having sex and as far as i was concerned my girlfriend was in on it,this is common side affect of both drug induced phycosis and v2k ,(what im trying to say is that in order to hear v2k you already need to be in an unfit mental state as the two are so much alike.)To cut a long story short i ended up pouring petrol all over my neighbours car only giving second thoughts to lighting it at the last minute,if id have lighted it my doctors said i would have been sectioned for maybe up to two years.Anyway we ended up moving homes to a bungalow down the street and all was well for the first two weeks until one night while i was alone there was this loud hissing sound,i was under the influence of drugs i must admit but this was diffrent,it got so loud i started to feel sick,it was a feeling of clhostrophobia and i imediatly started to worry and thats when it happened."remember zoe sheard thats my girlfriend",the words floated around me as if i could catch them,i immediatly ran out of the house to my mothers who wasnt happy at getting woken up in the early hours but that hiss was still there.Now i understand you must think im a raving lunatic because i always seem to be on drugs but honestly with the situation i am in it was an outlet,a release if you will as things seemed to make sense ,i could hear more clearly without me second guessing what i was hearing.Things from a v2k point of weiw progressed rapidly as when i was trying to sleep there was a mist of mixed voices swirling around me,bits of conversations slipping through my mind.My perpitrators were in total control of what i was hearing until one day they slipped up,i was sat on the couch watching tv when i saw a cobweb stringing its way across my tv to the window shimmering in the sun ,as soon as i saw it i heard"oohhh hes looking at a cobweb"from then on i knew sight triggers sentences.When you realise its sight that triggers there sentences you can do all sorts of things with it,you can control what you hear and soon begin to realise that your hearing your own imagination(as well as the broadcasters)in a diffrent dialect,mannerisms everything.I remember hearing what they called the worlds worst rape,i heard and felt everything,when she screamed i jumped as it sent a shock to my head!the perpritrators was shoving his hand and wrist up through her ass and was saying hes going to snap her ribs from the inside while threatning another woman saying she was next.I was that scared i imagined another person in another room,maybe this was a way of comforting myself but once it had died down i could hear a man crying outside but on looking there was no one there,obviously neither one was there ,i realised i was all alone.I phoned my girlfriend and told her what id heard but she was having none of it,as i tried to get her to come visit me i was tortured by what i now know was me threatning myself through there broadcast.What i mean is when they broadcast you are given thought projection but the voice you here is unrecognisble to you,this voice you hear has second person gramma which you asscociate with as it is so foreign to you.It was another day and another argument with my girlfriend over the phone,i shouted at her you fuckinn slag and put the phone down when i heard"he called her a what?,im sergant slaughter and you are talking to one of my women".The prerecorded spotlight audio alpha tone conversions(alphabetical recordings of vowels) distribute through the infrared transmitter which converts the sound into light by the emitters (a device used to exude any signal, beacon, light, odor, liquid, fragrance, ionizing particles or any other type of signal.)The light carries the modulation which is  the process of varying one or more properties of a high-frequency periodicwaveform, called the carrier signal, with a modulating signal which typically contains information to be transmitted that are spotlight audio conversions(alphabetical vowel recordings) through subcarriers which are a seperate analouge or digital signal carried on main radio transmissions

Radio is the transmission of signals through free space by electromagnetic waves with frequenciessignificantly below visible light, in the radio frequency range, from about 3 kHz to 300 GHz.^[1] These waves are called radio waves. Electromagnetic radiation travels by means of oscillating electromagnetic fieldsthat pass through the air and the vacuum of space.

Information, such as sound, is carried by systematically changing (modulating) some property of the radiated waves, such as their amplitude, frequency, phase, or pulse width. When radio waves strike an electrical conductor, the oscillating fields induce an alternating current in the conductor. The information in the waves can be extracted and transformed back into its original form.

The spotlight conversions is amplitude(am)air modulated which is the magnitude of change in the oscillating variable with each oscillation within an oscillating system. For example, sound waves in air are oscillations in atmospheric pressure and their amplitudes are proportional to the change in pressure during one oscillation. If a variable undergoes regular oscillations, and a graph of the system is drawn with the oscillating variable as the vertical axis and time as the horizontal axis, the amplitude is visually represented by the vertical distance between the extrema of the curve and the equilibrium value that is broadcast on 95khz or 250khz frequencys.You subconciously register vowels through your paranoid state as they are now non-linear ,a controled emission of air controled by your eye sight, there is a connection between your mind and the surface area of what you see(if you aim the spotlight speaker at a wall the sound you convert appears to be coming from the wall if you aim it at the door the sound appears to come from the door) but you asscociate them with subconcious colour as blinking amplifys a reminder of the constonants you just saw accociated with BLACK,the surface area your mind connects to while your eyes are open registers all subconcious BLACK light surrounded by the infra ultra alpha tone A as said before this is a memory of a letter(A) chosen as an option other than EIOU(that are still registerd by sight but only as memory when eyes open))to form the letter BLACK while blinking the letter A has created a sound wave reflected back to the mind off the sight surface area amplifing the constonants around it  which replace all non-linear memory EIOU while blinking converting a memory and above it  reason being is that flash thought memory replacements register all the vowels surrounding BLACK  but only A while your eyes are open which triggers constinonts from the light at the point of what you see.B L enters your mind from the point of what you see which replaces the choice of A E I O U as a raised sound and a trigger for a subconcious action which will register directly in your brain.B L becomes non-linear air,but this should never be as it should be a natural projection of sound ,as you scroll your eyes the memory of B L is replaced by A E I O U only this time the vowels are amplified above B L collecting additional constinonts through way of sight eventualy triggering yourself with the letter B L A C K over and over again depending on the surrounding air waves which fluctuate up and down creating a paranoid viscious circle of pure mental torture .When you blink you are constontly reminded of the letter B L A C K and bring with it the surrounding vowels as you asscociated these with other possible word combinations.When you reopen your eyes these possible word combinations start to trigger other subconcious colour alpha tones until all subconcious light creates a subconcious frequency created by exchanging 21 letters of the alphabet with light emissions .The remaining vowels are used to trigger the v2k broadcasters vocal as the more constinonts you hear think and remember the more there vocal raises above them .As you create memorys of your surroundings these can be used for controled triggering using either a live broadcast or triggering for synthetic telepathy.

I tried QuietComfort, the acoustic noise cancelling headphone, recentry and found it reduces the certain noises. I don't want to buy one as I have been having problem with the Hum type noise and the direct voice hearings for years. But it's possible that some people might be interested trying the QuietComfort headphone to feel free from the V2K and other audio related EH.

I might buy one, but I don't really know that would be beneficial for myself. I got some stuffs damaged and I don't want a new tool with me now as it might be broken as well.. Does anyone want it and become the second reviewer of the product???

                                         FREEDOM FIGHTERS FOR AMERICA
                                     "FIGHTING FOR FREEDOM AND LIBERTY"     http://www.freedomfightersforamerica.com 

10-3-1012
Chris Zucker,Pres.FREEDOM FIGHTERS FOR AMERICA
Is interviewed by Nick Spinner of Electronic Harassment/ organized stalking  on Talk shoe
channel # 97862

Chris speaks on targeting issues that people under the govt-mob assasination program
are experiencing , and the subject of the new world order in the targeting system

.http://recordings.talkshoe.com/TC-97862/TS-673423.mp3

1:15mins  

V2k broadcasters use spotlight audio technology,the processor converts audible sound(including speech)into millions of ultratones which reflect back to the origonal source enabling directional sound.They use sonar software by cakewalk to broadcast additional tones by way of vowels recorded and repeated vocaly through the spotlight speaker then additionaly through there broadcast which can be c.b radio or internet radio.The additional tones recieve on all known recievers dispercing  them everywhere through loudspeakers(Tv radios mobile phones air)and travel on the very air we breath.The vowel ultratones go undetected as they flood the air within our homes going unoticed by the majority of the population,only to be percieved by the already ill.You and me both know you are paranoid about something otherwise you wouldnt be reading this.V2k starts when you are at the point of paranoia,reason being is when you become paranoid you concentrate on silence to find the solution as to why you feel the way you do.V2k IS concentrated air,a slight rise in sound which only  the ill percieve.Remember vowels are a letter between breaths which happen inbetween the sounds you make while speaking ,when you register v2k you will have thought you have heard voices or indeed has either way your thoughts are projecting to the point of sight.Because you have become so paranoid you have given yourself symptons of mental illness as you further more concentrate on silence which inturn percieves the vowel ultratones ,because this is a subconcious rise in sound it exchanges information with your eyesight movement.So let me illitarate,paranoia becomes a mental illness as you concentrate on the air around you,the vowel ultratones surrounding you are percieved by your subconcious mind causing a connection between your breath and your sight,a vowel has now become a magnet to all you see alphabeticaly,let me remind you we spell at an astronomical speed giving us awarness of self being learning from our subconcious register to colours which helps us form  the words we speak and hear.If you have ever thought you are hearing voices and are reading this chances are you are a v2k target although some of you dont know it yet,when you look around you collect constinonts which trigger your sight(vowels)e.g your breath amplifys your connection to what you see which in turn has constinonts within them,a constinont is the shape your mouth makes when forming sound,as you are not making any sound this becomes the broadcasters trigger.A constinont is now a subconcious search for greater sound which only registers another vowel which is of lesser sound giving the feeling of no escape and a forced way of thinking as the process repeats itself even while sleeping.So now you are caught in a loop that forces you to think which because your paranoid will turn into a search for hidden devices conspiracy theories and all other matters of illness.So let me give you a quick recap,your paranoia becomes a constant search for silence which combines with the vowel ultratones which amplifys the letters you see by way of sight.The volume of air you see will be that in your mind only to pick up constinonts which are a natural movement of creating sound.You think 5 vowels while searching and recieve constinonts by way of colour these exchange with vowels creating sound out of colour.Your left to give yourself a mental illness by exchanging letters of the alphabet into colours then back into the alphabet, the letters B L are rememberd through five vowels triggering them into voices which you cant escape ,these voices could either be yourself or a v2k broadcasters either way theres still no escape.

|=---------------------=[ The basics of Radio ]=-------------------------=| |=-----------------------------------------------------------------------=| |=------------------=[ shaun2k2 <shaun at rsc dot cx>  ]=----------------=|  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  --[ 0 - Introduction      Ever since our discovery of radio, in around 1902, we have proceeded to utilise it for many different purposes -- from sending others short messages, to transmitting large and critical data sequences to other computer systems.  As time has gone on, as useful a technology as radio is, it is barely noticed anymore.  When most people think of 'radio', they picture a small black device sitting in their car, which they will use to listen to their local radio stations during car journeys.  On the other hand, very few people realise the true usefullness of radio, often forgetting that their cellphones, televisions, satellite TV and alarm systems all too use radio to complete their task on a very regular medium -- radio is not just that boring old thing gathering dust in the corner.      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.  Some electronics knowledge is useful in radio, though not totally necessary.  Most circuits presented here are quite rough, and can be greatly improved upon in many ways.    ----[ 0.1 - Technical Terms  Below is a description of technical terms used throughout the article:   RF          -- Any frequency within the radio spectrum, which can be                used by to transmit and receive radio signals.  Modulation  -- A technique used to package data into a radio signal                which is of use to the destination radio receiver.  AM          -- Amplitude Modulation.  This involves shifting the amplitude                of a radio signal's carrier very slightly in sympathy with                a modulating signal.  FM          -- Frequency Modulation.  FM modulation involves shifting the                frequency of a radio wave's carrier very slightly in                sympathy with a modulating signal.  Receiver    -- Any device which is capable of receiving radio signals                sent by a radio transmitter.  Transmitter -- A device which can transmit radio waves into the                surrounding environment.  Aerial      -- A medium to large piece of wire which is used by either a                radio transmitter or receiver to propagate or detect an                incoming radio signal.  In a radio receiver or transmitter,                an aerial acts as one plate of a capacitor, whilst the other                plate is taken place by the Earth.  Antenna     -- See aerial.  Wireless    -- Refers to any technology which communicates data without the                need for a wired connection.  Most wireless devices, such as                cell phones, televisions, and others use radio, but several                do use technologies such as infrared, which is not covered                here.  Radio wave   -- A radio wave is an 'electromagnetic' wave, most commonly                 containing data to be received by a remote radio receiver.  Oscillator   -- Refers to an electronic circuit which 'oscillates', or                 'vibrates', to complete a certain task.  Oscillators are                 used in radio to transmit radio waves at a given                 frequency -- the rate at which the oscillator oscillates is                 the RF (see RF) at which the wave is transmitted.  Common                 oscillator circuits, also used in this paper, are LC                 oscillator circuits, and crystal-controlled oscillators.  Crystal-controlled oscillator   -- An oscillator circuit whos oscillation frequency is                 controlled by a 'crystal'. See oscillator.  LCoscillator -- An oscillator consisting of a capacitor and an inductor,                 whos frequency of oscillation is controlled directly by the                 capacitor, which is usually variable.  See oscillator.  Capacitor    -- Device which stores current as an electrical field.  Broadcast    -- A term used to describe transmitting radio waves into the                 atmosphere.  Wavelength   -- The physical distance between two waves on the same                 frequency, transmitted successively.  Bands        -- Frequency Bands are a range of frequencies used                 interchangeably or commonly for the same type of technology.                 For example, televisions often use the VHF band.  Frequency    -- Number of cycles per seconds. Frequency can be used to                 describe how often an oscillator oscillates.  Sidebands    -- When modulation of a carrier is applied, two extra                 bands are generated, both slightly higher and lower                  than the carrier frequency, equating from the 'sum and                  difference' of the carrier and audio                 frequency.  These two bands appear at either end of                 the RF carrier, hence the term 'sidebands'.     --[ 1 - Radio Basics  ----[ 1.1 -  Radio Waves      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.   ----[ 1.2 - Carrier      An 'RF carrier' can be thought of as the part of the radio wave which can be modulated to 'carry' a data signal. An analogy to help with understanding this is to think of turning on a flashlight and pointing it towards a wall.  The light which is seen on the wall is the 'carrier'.      Before and without modulation, the carrier of a radio wave contains no data, and just contains peaks of an RF voltage.                            peak voltage                         ||\\    ///\    //\\                        || \\  //  \\  //  \\                        ||  \\\/    \\\/    \\                               RF carrier       Because sending radio waves with a carrier containing no data would be almost useless, a carrier is 'modulated' to contain data. There are various modulation schemes in wide use, but the two most common schemes are AM (Amplitude Modulation) and FM (Frequency Modulation). These are discussed later.   ----[ 1.3 - (RF) Frequency Bands      As we can gather from listening to a variety of radio stations, different forms of technology use an entirely different 'band' of radio frequencies on which to send and receive their radio signals.      The entire range in which radio signals are transmitted extends from around 30KHz, up to about 30GHz.  This whole range of available RFs (Radio Frequencies) is known as the 'radio spectrum'.  The radio spectrum's range of frequencies, and their concurrent uses are shown in the below table.  +-------------------+----------------------------+---------------------+ | Frequency         | Uses                       | Name                | +-------------------+----------------------------+---------------------+ | 30KHz-300KHz      |   Long-wave radio, useful  | Low Frequency (L.F) | |                   |   for long distance        |                     | |                   |   communications           |                     | +-------------------+----------------------------+---------------------+ | 300KHz-3MHz       |   Medium wave, local radio | Medium Freq (M.F)   | |                   |   distant radio stations   |                     | +-------------------+----------------------------+---------------------+ | 3MHz-30MHz        |   Short wave radio         |  High (H.F)         | |                   |   Communications           |                     | |                   |   Amateur radio            |                     | +-------------------+----------------------------+---------------------+ | 30MHz-300MHz      |   FM Radio                 |  Very High (V.H.F)  | |                   |   Police radio             |                     | |                   |   Meteorology Comms        |                     | +-------------------+----------------------------+---------------------+ | 300MHz-3GHz       |   Air Traffic Control      |  Ultra High (U.H.F) | |                   |   TV                       |                     | +-------------------+----------------------------+---------------------+ | 3GHz-30GHz        |   Radar Comms              |  Microwaves (S.H.F) | |                   |   Satellites               |                     | |                   |   Telecommunications (TV & |                     | |                   |   telephone)               |                     | +-------------------+----------------------------+---------------------+       Since certain frequency bands are used to accomodate important communications, such as the VHF band, it became illegal to transmit radio waves at certain frequencies without a license. It was made so because transmission of radio signals at important frequencies could interrupt critical communication, such as communication between police officers with their radio transmitter devices.      All frequencies within the radio spectrum are invisible to humans. Light frequencies which are visible to humans, i.e frequencies which are present in the light spectrum, operate at *much* lower frequencies.   ----[ 1.4 - Wavelength      Wavelength is the physical distance between a peak in one radio wave, to the peak in another radio wave transmitted successively -- on the same RF.  As a general analogy, the wavelength can be thought of as the distance that the peak in a given wave will have travelled in the space of time for one cycle. This can be calculated using the below simple formula.  |\ = V / F  * |\ = lamda   V  = Velocity   F  = Frequency      Using this formula, the wavelength for an example scenario can be calculated, when the RF is 27MHz.  The speed of light is 300 million meters/second, which is therefore the velocity of the electromagnetic wave.  |\ = 300,000,000 / 27,000,000  = 11.11r      Looking at the above calculation, what can be gained? It seems that the wavelength for waves transmitted in the example scenario is 11.11 (recurring) meters, so from this, it can be gathered that a peak in a particular radio wave will have travelled 11.11r meters in the time it took for one oscillation of the transmitting oscillator. But how can we know how long this oscillation period takes? We can calculate this using the formula '1 / f'.  1 / 27,000,000 = 0.0000000370r      This means that within the miniscule time frame of 0.0000000370 (recurring) seconds, the peak within the radio wave should have travelled approximately 11.11 (recurring) meters.      Wavelength might seem quite a useless thing to calculate on its own, but it comes in very useful when it comes to calculating suitable aerial lengths for both radio transmitters and radio receivers. As a rule of thumb, an ideal length for a radio aerial is around 1/2 of the signals wavelength. This can be calculated very easily.  11.11 / 2 = 5.555 (roughly)      From this calculation, we can gain the knowledge that a near ideal radio transmitter/receiver aerial can be constructed to be of around 5.5 meters. Exact precision is not generally critical to the overall operation of the radio transmitter/receiver. For example, where portability of equipment is more of a concern than great efficiency, 1/4, 1/8 or even 1/16 of the wavelength in meters is often used for the length of the radio aerial.  11.11 / 4 = 2.7775 11.11 / 8 = 1.38875 11.11 / 16 = 0.694375      From this little experiment we can see that we can turn a length which is considerably out of question due to portability desires, into a length which is much more suitable, yet efficiency is not affected too much.      This technique is very commonly employed to calculate sensible lengths for radio aerials.  However, other techniques are also employed, especially in the case of satillite TV.  Notice how TV satillite dishes house tiny holes in the body of the dish? These holes are specially sized to ensure that radio waves with wavelengths less than that associated with the desired RFs (3GHz-30GHz) do not create an electrical current in the aerial wire, as suitable radio waves do. Holes based upon the same principle can also be found when looking inside a microwave oven.  ----[ 1.5 - Transmission      Perhaps one of the most difficult concepts to grasp in radio is how radio waves are actually broadcast into the environment. As touched upon previously, radio waves are transmitted using oscillators in electronic circuits, and the rate at which the oscillator oscillates is the frequency at which the radio waves are transmitted.      As an example, we will focus on using an LC tuned oscillator circuit in the radio transmitter circuit.  LC oscillators are made up of an inductor (L), and a capacitor (C).  If we consider how a capacitor stores current, we can come up with the conclusion that it is stored as an electric field between two plates -- these two plates make up the capacitor. During one oscillation (also known as a 'cycle') of the LC tuned circuit, all available current is stored first in the capacitor as an electric field, and then as a magnetic field associated with the LC circuit's inductor.  After a *very* short time period (1/f), the magnetic field is turned back into an electrical current, and begins to recharge the capacitor again.  Because the inductor's magnetic field is beginning to change back into electrical charge, the inductor turns another electrical field into a magnetic field in order to counter-act the change. This continuous cycle of quick changes keeps the current in the LC circuit flowing in the same direction, driven by the current stored in the inductor. When the inductor's charge eventually becomes zero, the capacitor becomes charged again, but with the opposite polarity. After each oscillation (cycle), energy loss has occured, but not all of the energy loss can be accounted for as energy lost as heat from the inductor's coil. Thus, we can gather that some energy has been 'leaked' from between the capacitor's plates, as electromagnetic energy -- radio waves.      If we consider this, we can conclude that the further apart the plates in the capacitor are, the more energy is broadcast ('leaked') as radio waves.  This must mean that if we have a capacitor with plates spaced 1 meter apart, more energy will be broadcast as radio waves than if the capacitor had plates spaced a very small distant apart. By thinking even deeper, we can conclude that to maximise 'leakage' of radio energy, a capacitor is needed in the LC tuned oscillator circuit with plates spaced at quite a distance apart.  It just so happens that for this task, to maximise broadcast of radio waves, the world's largest plate can be used to take the place of one plate of the capacitor -- the Earth!  The other capacitor plate needs just be a suitably lengthed piece of wire, which is an equally common sight -- this piece of wire is known as an 'aerial'!      In real-world radio transmitters, oscillator circuits are used to make a small current 'oscillate' in an aerial wire.  Because of the constant change of energy form in the oscillator circuit, the current oscillating in the length of the wire becomes electromagnetic and is radiated as radio energy.      Back to the length of the aerial in relation to wavelength; this is where the length calculated earlier comes in handy. From the knowledge gained here, we can assume an adapted LC oscillator circuit as below.                  Capacitor           Inductor               ________________             |                )             |                )            ---               )____________  Aerial            ---               )             |                )             |________________)       As a concept, using the adapted LC tuned oscillator circuit above, the transmission of radio waves can be thought of like this; radio waves are generated due to the propagation of an electric current in an aerial wire. It is, as we have learnt, the 'leakage' of electromagnetic energy from between the two plates of the capacitor which causes broadcasting of radio waves.       As oscillations occur in our LC tuned circuit, all available energy is stored in the capacitor, followed by energy (electrical current) not leaked as electromagnetic waves being fed into the inductor.  This whole process measures one oscillation, and once one oscillation is over, the whole process repeats itself again, and each time energy is being lost as radio waves from the acting 'capacitor' (aerial and Earth). Therefore, it is the rate at which the LC circuit is oscillating (the 'frequency') at that determines the frequency at which the radio waves are broadcast at -- thus determining the RF of the radio signals.  ----[ 1.6 - Receiving      The concept of receiving radio signals is based upon almost the opposite of the concepts of transmitting radio waves. In similarity to radio transmitters, radio receivers also use an aerial, but for a totally different purpose; for detecting the radio signals in the environment. As described previously, radio waves are a form of energy, propagated as electromagnetic waves through the air. Thus, when radio signals transmitted by nearby radio transmitters pass the aerial of the receiver, a *tiny* RF alternating current is generated in the aerial wire.  When a signal becomes present in the aerial wire, 'wanted' radio frequencies are 'selected' from the assortment of RF currents in the aerial, using a 'tuned circuit'.      As an example, we'll focus on the LC tuned circuit as in the previous  section, due to the simplicity of this circuit. RF current of the 'wanted' frequency can be selected from amongst the other RFs by use of an LC tuned circuit, which is set to resonate at the frequency of the 'wanted' radio frequency.  This selection is done because the LC tuned circuit has low impedance at any frequencies other than the 'wanted' frequency. Frequencies other than the 'wanted' frequency are prevented from passing through the circuit because they are 'shorted out' due to low impedance of the LC circuit at any other frequency than the resonant frequency (the frequency of the 'wanted' signals).      Following the selection of correct radio frequencies from the other RF signals, the radio receiver will usually amplify the signal, ready for demodulating.  The technique which is adapted by the receiver for demodulating the radio signal into the modulating signal is totally dependant on the type of modulation being used in the received radio wave.  In the case of an AM radio receiver, a selected signal will be 'rectified' and thus demodulated, using a low-drop germanium diode. This process basically turns the alternating RF current back into a direct DC current, which represents the power strength of the AM signal.  Next, the RF component is generally removed by using a capacitor. The output product of this process is a recovered modulating signal which can be fed to a pair of high impedance headphones.  The diagram below represents how the selected RF current is rectified by the diode.                                                          ||\\  //\\ ----------------------|>|--------------- ||\\ //\\   || \\||  \\                                         || \\||  \\   \/\/\/\/\/\/  AM Modulated Carrier  diode                     Modulating signal                                               (RF carrier present)       After being rectified by the diode, the AM radio signal is still not suitable to be fed to an audio output, as the RF carrier is still present. The RF carrier can be removed by using a single capacitor.                                      | | ||\\  //\\  ------------------------| |---------------------  /\  /\ || \\||  \\                         | |                      /  \/  \  Modulating signal                  capacitor          Modulating signal                                                     (RF carrier removed)       The output of the capacitor is a recovered modulating audio waveform which is suitable for passing to an audio output device, such as a set of headphones with a high impedance.      This technique is likely to be the simplest way to create an AM radio receiver, commonly known as the 'crystal set', used by the mass in the 1920s.  Other receivers are more often used to produce a higher quality of audio output, such as TRFs (Tuned Radio Receivers) and Superhetrodyne receivers.      The whole system model of a radio receiver at its most basic level can be thought of as the below diagram.            Modulated Radio Signal (electric current generated in aerial wire by radio wave)                   |                  \|/             Signal amplified                   |                  \|/            Signal demodulated                   |                  \|/           Modulating signal       Although the techniques and components needed to achieve each step of the diagram are different, most receivers stick to this sort of system.  Other types of receivers and their circuits are discussed more indeph in the section they are related to.   --[ 2 - AM Radio  ----[ 2.1 - What is AM Radio?      AM Radio refers to any form of technology which makes use of Amplitude Modulation to modulate the 'carrier' with information. To package a radio wave with often complex signals, the carrier of a radio wave is shifted in power very slightly in sympathy with a modulating audio or data signal. Next to morse code, AM is one of the simplest forms of modulation, and with this, comes its disadvantages.  ----[ 2.2 - Modulation       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'.       The simplicity of AM modulation can be demonstrated with a simple diagram like the one below.   ||\\    ///\    //\\ || \\  //  \\  //  \\  --->  \  /\  /  --->     \\    \\ ||  \\\/    \\\/    \\        \/  \/            \\ ///\\                                                 \\// \\                                                       RF Carrier            Modulating signal        AM signal        As you can hopefully make out from the diagrams, whenever the modulating signal (the signal which we are modulating) increases in voltage, the amplitude (power) of the RF carrier is increased in sympathy with the modulating signal.  When the voltage of the modulating signal declines in voltage, the opposite of above happens.  After AM modulating the carrier, the signal has usually twice the 'bandwidth' of the original modulating signal.   ----[ 2.3 - Demodulation      When an AM designed radio receives a radio wave, as previously noted, a small RF alternating current is generated in the aerial wire.  Because of the AM modulation of the carrier applied by the sending transmitter, the voltages in the carrier are larger and smaller than each other, but in equal and opposite amounts.  As a result, to recover the modulating signal, either the positive or the negative part of the modulated signal must be removed. In the simplest AM radio receivers, the modulated signal can be 'rectified' by making use of a single germanium low-drop diode.     \\/\/\/\/\  \\  /// //    ---------------------|>|----------------- \\  ///  //   \\// \\/                                                \\// \\//                                                     AM radio signal                  diode         Modulating signal        Here, part of the carrier has been removed, resulting in recovery, or 'rectification' of the modulating signal.      Because the carrier frequency (the RF of the radio wave) is usually significantly greater than the modulating frequency, the RF carrier can be removed from the resultant modulating signal, using a simple capacitor.   \\        //                   |  |  \\  ///  //    ----------------|  |----------------  \  /\  /  \\// \\//                     |  |                   \/  \/   Modulating signal           capacitor             Modulating signal (with RF carrier)                                (without RF carrier)       By exposing the rectified signal to a capacitor, the audio signal (or otherwise data signal) is smoothed, producing a higher quality of audible output.  At this point, the modulating signal is more or less recovered.      Although this technique of AM demodulation can be made to work to a satisfactory level, the vast majority of commercial radio receivers now adopt a design known as 'superhet', which I will explain briefly here.      Superhet receivers are based upon the principle of 'mixing' two signals to produce an intermediate frequency. The diagram illustrates a superhet receivers operation.   Carrier in ---> Tuned circuit  ---> Mixer ---> IF amplifier ---> Detector                (selects correct RF)    |                           |                                       |                           |                                        |                           |                                Local oscillator               Audio Amp                                                                   |                                                                   |                                                                 +--+                                                                 |  |                                                                 +--+                                                                 \__/                                                            As we can see, superhet demodulation is significantly more complex than 'rectification'.  Superhet receiver systems, like the above system diagram, works basically as follows.  First, an RF alternating current becomes present in the circuit, because of the electromagnetic activity around the aerial.  Signals of the correct radio frequency are selected via a tuned circuit, and inputted into one input pin of the 'mixer'.  In the meantime, the other input of the mixer is occupied by the 'local oscillator', which is designed to be oscillating at a frequency just lower than the inputted radio frequency. The output of the mixer is known as the 'Intermediate Frequency' (IF), which is the difference between the local oscillator frequency, and the frequency of the received AM radio signal. Next, the 'IF' is amplified, and passed to an 'envelope detector'. The output of the envelope detector is the modulating audio signal (an AF -- Audio Frequency), which is in turn amplified, and outputted to the user via a loudspeaker or other audio output device.      Since the local oscillator is almost always set to oscillate at a frequency of approximately 465KHz *below* the frequency of the carrier input, the output of the mixer will always be a 'carrier' of 465KHz -- which still carries the modulated information.  After the signal is amplified by the IF amplifier(s) (there can be more than one IF amplifier), the signal is now demodulated by the detector -- which is often just a single diode.  As mentioned above, the modulating signal recovered by the system can be fed to an amplifier, followed by an audio output device.      As well as producing a higher quality of audio signal, superhet receivers also eliminate the need to be able to tune multiple tuned circuits in a TRF (Tuned Radio Receiver).  TRF designs become awkward when it comes to tuning them into different radio frequencies because of the many tuned circuits needed -- superhets overcome this problem as they always 'know' what the collector load will be -- a 465KHz signal. Superhet designs can also be adapted to work with FM radio signals, assuming the 'detector' is changed to a suitable detector for FM signals (i.e phase detector).   ----[ 2.4 - Circuits      Since radio technology is a frequently discussed topic across the Internet, many radio circuit design implementations are readily available, ranging from very simple circuits, to quite complex ones. Here I present some radio related circuits which most people with a bit of electronics knowledge and the right components can build.   ------[ 2.4.1 - Receivers      Discussed above was the historic 'crystal set' radio receiver, which allows anyone with a long enough aerial wire and a few components to listen to AM radio bands.  Below is the basic crystal set radio receiver circuit, which is very easy to construct.       Aerial Wire             D1 *         |            Q1         |               ____|>|__________________         |_____________|/             |          |         |             |\             |          |  _______|_____          |            |          | (             |         |            |          | ( L1         --- C1 *   |        C2 ---         0  high impedance (            ---        |           ---         0  headphones (             |         |            |          | (_____________|         |            |          |         |               |            |          |         |_______________^____________|__________|         |               | (not joined)         |_______________|         |        GND  - C1 should be a variable capacitor to allow the station to tune into   other frequency bands.  - D1 should be a low-drop germanium diode -- non-germanium diodes   won't work.       From previous discussion, we can figure out that the above 'crystal set' AM radio receiver works as follows; incoming radio waves generate a tiny alternating current in the aerial wire, from which 'wanted' radio frequencies are selected, by the tuned LC circuit. Selected current passes through a diode, which 'rectifies' the signals, thus demodulating them. Before the diode, there is a simple transistor, which amplifies the 'wanted' frequency. The only reason for this is to make the quality of sound slightly better. Any remaining RF components are removed using a single capacitor -- this consequently has the effect of smoothing out the signal. The product audio signal is passed to a set of headphones -- these *must* be high-impedance, or nothing audible sounds on the headphones.      As was noted earlier, this type of receiver was used frequently in the 1920s, and gave even newbie electronic enthusiasts of that time the opportunity to build something that would be considered very useful at that time.  To make decent use of the 'crystal set' circuit, around 60-70 turns of wire around a rod of ferrious metal would create a good aerial.      Designs like above are never used in commercial radio receivers anymore. Excluding superhet receivers, TRFs are occasionally used to produce low quality radio receivers. Below is a simple TRF receiver schematic.                    Aerial             |              C5*   C6   +9V            |        ________________________________________            |        |     |    |       )                    |            |        |    ---  ---      )  LC2              |-|            |        |    ---  ---      )                 __| |            |        |     |____|_______)                 | |_|            |        |        |                           |  |   C8           ---  C1   |        |            D1     C7      |  |___| |____0           ---      _|_     Q1_____________|>|________| |_|_|/   | |    0   LC1      |    R1 | |      /                  |     | |   |\ Q2   _________|__     |_|  __|/                   |            |  High impedance   |           )     |  |  |\_____              |            |  headphones   |           )     |  |        |              |            |   |           )     |  |        |              |            |  ---  C2 *    )___| |__|_       |              |            |  ---          )   | |    |      |              |            |   |           )   C3     |      |              |            |   |___________)          |      |    C4        |            |                          |      |_____         |            |                          |      |    |     R4  |-|      R6 |-|                     R2  |-| R3 |-|  ---        | |         | |                         | |    | |  ---        |_|         |_|                         |_|    |_|   |          |           |                      ____|______|____|_________ |___________|                                        0V   - C2 should be a variable capacitor - C5 and C6 should be variable capacitors - Resistors of sensible values should suffice - Capacitors of sensible values should suffice        As in the 'crystal set' receiver, when a radio signal is 'picked up' by the aerial, the proper frequency is selected using the LC tuned circuit.  The signal is passed to a transistor amplifier.  However, this time, the transistor amplifier has a 'tuned collector load', because of the tuned LC circuit (LC2) at the collector leg of the transistor.  Next, the signal is rectified, stored in a few capacitors until enough current has collected, and is eventually fed to the user with the high impedance headphones.  The use of the tuned collector load at the transistor causes for the receiver to be more precise, amplifying only the signals which are at the frequency of LC2's resonant frequency.  As expected, this causes for a higher quality of audio signal to be fed into the users headphones, making this a much better radio receiver.       A few things can be done to improve the above receiver, such as adding yet more tuned amplifiers, and perhaps adding a few more resistors and capacitors for safety and efficiency purposes.    ------[ 2.4.2 - Transmitters      All that we really need to do when designing a simple radio transmitter is keep in mind that we require an oscillator -- either tuned or crystal controlled -- and a series of amplifier circuits which boost our signal. After these stages, all that is left is to make the signals oscillate in the aerial wire.  Below is a simple radio transmitter schematic.                                                                                                                         Aerial                                                                       |                                                                      |   ___________________________________________________________________|  |                        |                 |       |         |      |  |                        |                 |       |         |      |  |                     L1 )                 |       |         |   L3 |  |                        )          R3    |-|   C3 |         |__    ) |-|  R1   Crystal         )                | |     ---        |  |   ) | |_________|_____________)                |_|     ---        |  | C5) |_|        |||            |                 |       |         | ---  )  |                        |_______| |_______|_AM ___|_______|/  ---  |  |                       /        | |         Modulator     |\___|___|  |__________| |________|/         C2                      Q2    |    |  |          | |        |\   Q1                          (PNP)   |    )  |          C1           |                                     ---   )  |                      |-|                                 C4 ---   )  M                      | |  R4                                 | L2 )  |                      |_|                                     |    |  |                       |                                      |    |  |                       |                                      |    |  |_______________________|______________________________________|____|   - TR2 is a PNP transistor - M is a microphone      This circuit works by oscillating at the frequency controlled by the crystal (27MHz would be legal in the UK), amplifying the signal with tuned collector loads at the transistor (TR1), and then by radiating the signal off as radio waves by oscillating the signal in the aerial wire. Amplitude modulation is added to the signal by varying the gain of the transistor driver, by connecting it to the output of a microphone. The above circuit is quite inefficient, and is likely to produce low quality signals, but it can be used as a starting point to building a simple AM radio transmitter. It's probably illegal to operate the above circuit on frequencies requiring a license, so some countries *require* the circuit to be crystal controlled on a 'model radio' RF.  One improvement to be made on the schematic is to amplify the output of the microphone before feeding it to the transistor driver.      Possible devices which could apply the AM modulation are audio amplifiers, or even op-amps.  An audio amp following the oscillator would produce a higher quality, stronger signal, but would also provide power gain (i.e amplitude gain), in sympathy with the audio signal produced by the microphone.  This gain of amplitude due to the audio amp has essentially applied Amplitude Modulation of the carrier signal, because the power of the signal has been altered according to the inputted audio signal (at the microphone).  An ordinary op-amp could be used in a similar way, but by substituting the non-inverting input pin with a suitable power supply.  Essentially, this would cause for an outputted gain from the op-amp, according to the audio signal, because the two inputs to the op-amp are compared, as such.    --[ 3 - FM Radio  ----[ 3.1 - What is FM radio?      FM radio just means any form of technology which makes use of radio with FM modulated signals. To modulate a radio wave's carrier with information, FM transmitters shift the frequency of the carrier very slightly, to be in sympathy with a modulating signal.   ----[ 3.2 - Modulation      FM modulation consists of little more than shifting a radio wave's carrier frequency very slightly in sympathy with a modulating signal's frequency.  Modulation of an example audio signal is shown in the figures below.   ||\\    ///\    //\\ || \\  //  \\  //  \\  --->  \  /\  /  --->       ||\\  /\\  // ||  \\\/    \\\/    \\        \/  \/              ||\\ //\\ //                                                   ||\\// \\//                                                       RF Carrier            Modulating signal        FM signal      The diagrams show that when the frequency of the modulating signal increases, so does the given carrier frequency, and the opposite when the modulating signal's frequency decreases. This is shown in the FM signal diagram by the bands being spaced widely apart when the modulating signal frequency is increasing, and more closely together when the modulating signal's frequency is decreasing.   ----[ 3.3 - Demodulation      When an FM modulated carrier signal is detected by the receiver's aerial wire, in order to recover the modulating signal, the FM modulation must be reversed.      Most modern FM radio receivers use a circuit called the 'phase-locked loop', which is able to recover FM modulated radio signals by use of a VCO (Voltage Controlled Oscillator), and a 'phase detector'. Below is the system diagram of a PLL suitable for use in FM radio receivers.       FM signal in -------------> Phase  ---------------                                 Detector             |                                   |                  |                                   |                  |                                   |                  |                                   |                  |                                  VCO                 |                                    |__________________|                                                      |                                                      |                                                      |                                                      |                                                      |                                             Modulating signal                                                    out       The above PLL is able to recover the modulating signal by having one input to a phase detector as the modulated carrier, and the other input as a VCO oscillating at the frequency of the RF carrier. The phase detector 'compares' the two frequencies, and outputs a low-power voltage relative to the difference between the two 'phases', or frequencies. In essence, the outputted voltage will be relative to the frequency by which the carrier's frequency was shifted during modulation by the transmitter.  Therefore, the output of the PLL, known as the 'phase error', is the recovered modulating signal. In addition to being outputted from the small system, the voltage is also given to the VCO as 'feedback', which it uses to 'track' the modulation.  Acting upon the feedback received, the frequency of oscillation is altered accordingly, and the process is repeated as necessary.      In the past, less efficient and reliable circuits were used to demodulate FM radio signals, such as the 'ratio detector'. Although the 'ratio detector' is less sophisticated than PLL methods, a functioning ratio detector circuit is actually a little more complex than PLLs.      It should be noted that superhet receivers, touched upon a little earlier, can also be used as FM radio receivers, but their 'detectors' are different to that of an AM superhet -- for example, a PLL circuit or ratio detector discussed here could be used in conjunction with a superhet receiver to make an FM radio. This is the method which is actually adopted by most commercial radio receiver manufacturers.  ----[ 3.4 - Circuits   ------[ 3.4.1 - Transmitters      The same general principles apply to FM radio transmitters as they do to AM radio transmitters, except that information must be modulated in a different way.  In AM radio transmitters, the carrier frequency is more or less always constant.  However, in FM transmitters, the whole principle is to alter the carrier frequency in small amounts. This means that a tuned oscillator circuit is not appropriate, because we need to alter the frequency accordingly, not transmit at one static frequency.  The method used to overcome this problem is discussed a little later. A simple FM transmitter schematic diagram is presented below.                                                                       Aerial                                                                        |                                                                        |                                                                        |    ____________________________________________________________________|   |                               |                 |    |      |      |   |                               |                 |    |      |      )   |                               )                |-|  --- C3  |      )   |  R1                      L1   )             R3 | |  ---     |_ C4  )  |-|                              )                |_|   |      | |    )  | |                              )                 |    |      | ---  |  |_|               |   Crystal    |         C2      |    |      | ---  | L2   |_______________|||_____________|___________| |___|____|____|/   |   |   |                              /            | |             |\___|___|    |____________| |_____________|/                                      |   |            | |             |\  Q1                         Q2       |   |                              |                                     |   |            C1                |                                     |   M                             |-|                                    |   |                             | | R2                                 |   |                             |_|                                    |   |                              |                                     |   |______________________________|_____________________________________|       When audio signals are produced by the microphone, current carrying audio frequencies are amlified, and are used to modulate the radio wave.  Since the microphone does this all for us, there is no need to use modulation modules, ICs, or other technology.  In situations where an elecret microphone is not available to do the modulation for us, a varactor diode can be used to vary the capacitance in an oscillator circuit, depending on the amplitude of a modulating signal.  This varies the oscillation frequency of the oscillator circuit, thus producing FM modulation.    --[ 4 - Misc  ----[ 4.1 - Pirate Radio      Pirate Radio stations are simply just radio stations ran by individuals who are not licensed amateur radio enthusiasts.  Although radio is actually a natural resource, it has been illegal for a significant amount of time in some countries to transmit radio waves on certain frequencies.  Although transmitting radio signals on certain frequencies (around 27MHz) is legal in places like the UK, strict FCC regulations kick in, almost limiting the threshold to useless.  Because of this limitation, radio enthusiasts all around the globe see fit to set up pirate radio stations, which they use for their enjoyment, playing their favourite music tracks to the 'public', and for a breeding ground for aspiring DJs.  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 legality of pirate radio stations is questionable, but varies from country to country.  In some European Countries, you can be arrested for just owning an unregistered transmitter.  In Ireland, prosecution rarely takes place if registered radio stations are not affected, but it is still illegal.  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.      Contrary to popular belief, setting up a pirate radio station is not necessarily a difficult task.  At the minimum, someone wanting to setup a pirate radio station would need the following pieces of equipment:  - Stereos, CD Players, Microphones, etc. - Audio Amp - Audio Mixer - Transmitter - Aerial      Stations using only the above equipment can sometimes sound quite crude, and might interfere with other legal radio stations.  To avoid this, a 'compressor' can be used, which also limits the noise created by sudden loud noises in the background.      Although any of the example transmitters in this article probably wouldn't be sufficient enough to transmit music audio signals over the air, but they could be used as a starting point to building your own, more efficient kit.  Additionally, FM and AM radio kits can be purchased, which anyone with a soldering iron can build.      The length and height of the antenna depends entirely on how far the radio signals need to be transmitted.  By reading the previous sections, some information on getting a correctly sized aerial can be gained.  For example, a quick and dirty aerial for an AM pirate radio station could be around 15-20 feet tall.      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.    ----[ 4.2 -  Wireless Telephone Tapping      'Beige boxing' has long been the easiest and most exploited way to tap telephones, interrupt on neighbours conversations, and use enemies phone lines to make long distance calls to your friend in Australia. However, since beige boxing requires the phreak to lurk around like a ninja, a safer method can be used, which doesn't require you to be physically close to the target phone line.      As expected, audio signals on a target phone line can be transmitted as  radio signals at an arbitrary frequency, and be received by any phreak with  an FM radio receiver.  Although this concept is not new, it serves as an  interesting and useful project for radio newbies to try out.  Below is a  simple FM phone bug transmitter circuit.                    __________________________________________________________                   |                    |                                    |                   |                    |                                    | IN (green) ___.___|_______            |-|                                   |               |   |       |           | |                                   |               |  /\  LED  |           |_|                                   |               |  ---     | |           |___| |      op-amp                  |                |   |   C1 | |           |   | |---|\                         |               |   |       |__________|/      ____| >------- Aerial          | IN (red) _____|___|                  |\ _____|___|/                         |               |   |                    |     |   |                          |                 |   |                    |     |   |                          | OUT (green) __|   |                    (     |   |                          |                  /\                    (     |  /\  varactor                |                  ---                   (     |  ---                         |                   |                    (     |   |                          | OUT (red) ________|____________________|_____|___|__________________________|   - inductor should be about 8 turns of wire - aerial should be about 5 inch long       By interchanging the varator with a crystal, or by using a variable capacitor, the frequency band on which the bug transmits line activity could be changed accordingly.  The varactor making up part of the oscillator circuit is intended to alter the frequency of oscillation, depending on the audio signal inputted from the green wire of the telephone line.  The varactor diode can be thought of as an electrically variable capacitor, which in this case alters its capacitance in sympathy with the audio frequency on the telephone line -- causing for change of oscillation frequency, and thus frequency modulation.       The following op-amp provides additional strength to the signal, in an attempt to avoid a weak, unreliable signal.  For user-friendly purposes, the LED connecting to the red wire of the line pair should illuminate when a signal is present on the line.      The above circuit can be modified to be made more efficient, and a longer aerial is an obvious way of lengthening the range of transmission.  If a phreak was to contruct and use a device like this, all they would need is an FM radio to tune into the correct frequency.  There are much better designs than the minimalistic one above -- if a practical FM telephone bug is required, many plans are available.   ----[ 4.3 - Jamming      Technically, all it takes to carry out 'radio jamming' is to transmit noise at a desired frequency.  For example, if a person in the UK were to transmit RF noise at 30MHz+, police radio communications could possibly disrupted.  Although the principles are mostly the same, there are several different types of jamming.  - modulated jamming   This consists of mixing different types of modulation, and   transmitting the results at a desired radio frequency.  This is   designed to make receiving legimate radio signals hard or next to   impossible.  - CW (continuous wave)   CW jamming only involves transmitting a consistant carrier frequency   once tuned into a RF frequency/band you want to jam.  This again makes   receiving desired radio signals particuarly hard.  - Broadband   Broadband jammers spread Gaussian noise across a whole band of audio   frequencies, blocking legimate audio signals from easy receival.       A basic radio transmitter is easily modifiable, by adding a noise generator, to successfully jam arbitrary frequency bands.  Many other types of radio jammers exist, and their details are readily available on the World Wide Web.   --[ 5 - Conclusion      Radio is an extremely useful technology, which is at least as old as the atom.  But we are only just beginning to exploit its full usefullness in even new and up and coming technology, and probably will do for the next few hundred years.      As we've discovered, contrary to popular belief, employing the use of radio in electronic circuits isn't at all as complicated as one would think.  Because of this, the use of radio and be both used and exploitfully abused -- only a few basic principles need to be understood to make use of this wonderful technology.  Although the surface has only been scratched, and way forward is open.

We are interested in bringing North Carolina TI's together. If you are from this state and want to network, please contact me at: GSS 980-285-7950 and, or, David Mentz at: 910-264-9445. Thank you for your cooperation.