Christian Radio Project

Here is the first rough draft of the preface and first chapter of the book. Enjoy and God Bless!!

 

Preface


In these days it has been more and more evident that the return of our Lord is at hand, and that the time is running out.  There are only so many people that can be reached by pulpits, door-to-door witnesses, and missionaries.  The vast majority of people who have never heard the Gospel are people who have probably never darkened the door of a church, and  would probably just "pretend they aren't home" if and when the neighborhood preacher comes calling.  In foreign countries, many people have never heard the Gospel due to a repressive government regime that does not allow its people the freedom of worship, much less a Christian media, or a thriving church.  Many other countries do not have the freedom of speech or expression which we cherish so much as Americans, thus keeping the knowledge of the true and living God from many ears and hearts.  In such cases, it is extremely important that the voice of a few good Christians can reach the ears of as many unbeliever as possible.  This is where missionary radio comes into play.  In the past and even today, stations have broadcasted in secret or off shore, and sometimes in the very heart of hostile territory.  Such radio stations have been referred to by many as "pirate" or "clandestine" stations.  Men and women have risked or even lost their lives by spreading God's Word in this fashond, while others have been blessed enough to go on undetected and unmolested.  Running a Christian radio station can even be dangerous in countries where such radio stations are perfectly legal, due to mass religious extremism and intolerance of Christians in such countries.  In other countries such as the islands of the Caribbean, such radio stations are often allowed to operate freely and without a license.  It is not uncommon for a small and inexpensive radio station with a few watts of power to cover a whole island country.  You will be surprised to learn how inexpensive it is to set up a small radio station in a foreign country or even on your own city block.  In the United States, the FCC (Federal Communications Commission) allows "micro-power" broadcasting stations of a few milliwatts of power to operate within specified (and strict) guidelines that could cover up to a quarter mile if properly constructed.  Such stations would be great assets for churches, scouts, AWANAS, and Christian campgrounds.  Easy-to-build electronic kits that are readily available can be purchased at a low price and matched electronically to ho-made antennas for broadcasts over long distances.  Kits can also be modified or amplified to put out more power where regulations allow.  The FCC is also currently issuing LPFM (Low Power FM) licenses to such organizations in need of a bit more power.  We will go into more details on these in later chapters.  Higher power transmitters are also available for miles of coverage, and they do not cost that much more than the lower-powered transmitters available on today's market.  We will cover studio setups, antenna design, feedlines, obtaining programming, and more.  Reading this book will save you time and money in designing and setting up your station!

 

Chapter One

 

Types of Stations and Their Purposes:

There are various types of  radio station setups and transmission types that a radio station can use to reach its intended audience.  The type of transmitting and studio equipment that you will need to obtain will depend upon legality issues,  the purpose of the transmission, the location of the station, and the amount of range that is required to do the job.  Some governments such as the United States Government have established guidelines and at least some tolerance for unlicensed broadcasting while other countries do not tolerate it whatsoever.  Some Caribbean Island countries do not require any type of broadcasting license whatsoever.  The Canadian government actually has looser regulations on unlicensed broadcasting (as far as how much power you can use and how far your signal can therefore go) than the regulations imposed by the FCC in the United States. A Christian radio ministry can use most every type of radio broadcasting installations which include but are not limited to simple systems in church auditoriums that are used to assist the hard at hearing.  Then there are applications designed to reach an audience (although somewhat targeted) such as unlicensed "FCC Part 15" neighborhood or college stations here in the US. Then there are LPFM (Low Power FM) licensed stations which cover entire small cities and towns with a few watts of power and minimal equipment costs. Then there are the full-power AM, FM, or Shortwave stations which use many watts (many thousands of watts in fact) of power to cover anything from a large metro area to half the globe!  The bigger and more powerful the station, the higher the cost of setup and operation, not to mention licensing and equipment.  A local radio station here in the Kansas City area, Calvary 88.5 FM KLJC has an operating budget of over $300,000 a year (and growing), and they are considered a to be a very modestly funded Christian radio station covering the Kansas City area.  Even at that great a price, most of their personnel are volunteers!  This is why we mention in depth how to assemble and legally operate small unlicensed stations for peanuts as well as construct more powerful semi-professional and professional stations.  In the United States, if you think you are going to just obtain a 1,000 watt transmitter, a mixer, and a record collection and just start broadcasting, you are wrong!  Licensing alone on a "professional" radio station can cost many times the price of the station's equipment and facility, not to mention the operating expenses.  Operating an unlicensed or licensed low-power radio station can often save you and your organization a lot of red tape and several hundred thousand dollars when compared with operating a mega-power radio station!

Unlicensed Radio in the United States (Part 15 Radio Stations)

Unlike so many other countries, the United States allows its everyday citizens the right and privilege to possess and operate small low-power radio stations to cover their immediate community.  Typical ranges of these stations are generally anywhere from 50ft of coverage to 1/2 mile of coverage without a license.  The FCC has also recently developed a means by which an organization can obtain a license to construct a station using a bit more power in order to service a small to medium sized city or town.  This service is called the LPFM or Low Power FM service.  On this service, if approved, a station can be set up by an organization many times for $1,500 or less!  See full details on Part 15 of FCC (Federal Communications Commission) Rules and Regulations at www.fcc.gov  Information on LPFM (Low Power FM) stations is also available at this website.

Part 15 AM Stations

  On the AM broadcast band (550 Khz - 1700 Khz) you can operate a small radio station whose transmitter puts out no more than 100 miliwatts (1/10 of a watt) of power and uses no more than a 10' long transmitting antenna.  Depending upon the quality of transmitter you use, the location of the antenna, and how well you modulate the signal, typical range can be anywhere from 1/10 of a mile to 1/2 of a mile of solid coverage with weaker coverage of up to 1 mile.  These stations can often be set up for under $1000 and are great for use as ":talking billboards" for local churches, small town or neighborhood radio stations, college campus or Christian camp stations, or ministry to local shut-ins from your church location.  The advantages of "Part 15" AM operations are as follows:

* Part 15 AM Stations can legally cover much more area than Part 15 FM Stations.

* Equipment is available inexpensively and transmitters can be purchased completely assembled or you can build them from a kit.

* AM stations provide superior coverage to technologically-challenged areas such as third world countries where FM is not yet as widely used.

* In areas where FM is more popular than AM (most major cities), it is easier to find a suitable frequency of operation on the AM Band.

Of course, with any good thing there are a few disadvantages as well.  They include the following:

* Short range AM stations may sound good during the day but are extremely limited at night time by signals from far-off AM stations which fade in and out, thus drowning out your low power signal.  Atmospheric changes happen after dusk which allow other signals from distant commercial stations to "walk all over" your signal.  If you are an unlicensed part 15 station, you must accept any interference that you get from other stations, even if it causes your station's signal or frequency of operation to be "undesirable".

* Unless you have some very expensive AM broadcasting equipment, the audio quality of your signal will be somewhat less than that of an FM signal.

* AM signals tend to fade and are somewhat directional.  Signals can be picked up better in one direction than another.  AM signals may be blocked by bridges or large concrete and metal framed structures as well.  In crowded city conditions, large buildings can block or even absorb your signal, which may keep your signal from radiating more than a few hundred feet.

* An effective AM broadcast antenna and ground system is quite a bit more difficult to assemble and tune than an FM broadcast antenna.  AM antennas are somewhat larger than FM antennas and AM antennas require ground radials for maximum effectiveness.  Ground radials are wires attached to the "ground" connection of the transmitter.  They are a series of many wires that are several tens of feet long and extend in a circular pattern from the antenna in all directions.  When broadcasting on the AM band with just 100mw of power, your signal won't go far at all without them!  AM antennas require more "acherage" than FM antennas which can efficiently radiate a signal the maximum allowable distance from a table top setup.  FM antennas do not require extensive grounding systems as do AM for proper performance. 

*In the more technically advanced countries such as the US, European Countries, and Japan, most of the population listens to FM and rarely tunes to the AM dial.  Just because your signal is able to be heard does not mean that it will be heard.  If you want an audience on AM, you may have to do some "advertising" before you reach any real audience.  It is quite possible that at least for a while you may be the only listener that your station has.  This may not be a bad thing at first as you try to work all the "bugs" out of it!

AM Transmitters:

There are many "Part 15" AM transmitters available on today's market that are either pre-fabricated or sold in kit form.  There are several pros and cons of purchasing either, but for simplicity and ease of use, I suggest that you purchase a pre-built transmitter for starters.  About the best pre-assembled AM Transmitter on the market today is the Hamilton Range Master. 

 This transmitter is probably the most coveted transmitter in the field of "Part 15" AM broadcasting.  While it only puts out 100mw of power (the same as the rest of them), the signal can be modulated up to 130% which can be heard for a much farther range than the other transmitters and kits which only modulate their signal at 100% or less.  Many users have gotten up to 3 miles range with the Hamilton Rangemaster, as opposed to 1/4 to 1/2 miles with other transmitters.  The only downside to the Hamilton Range Master is its price tag of $1,000 which pretty much puts it out of budget for the average joe basement hobbiest, but attainable for most churches.  Hamilton has even been known to give discounts to churches and non-profit organizations, but there is no guarantee of that!  A more commonly available pre-assembled transmitter is the "Talking House" Transmitter which was originally developed as a real-estate selling tool.  With a decent antenna and grounding system, ranges of 300ft to 3,000ft are easily achievable.  These transmitters are digitally tuned and can either play a pre-recorded message (similar to an answering machine for real estate purposes) or be fed from a live source such as a mic and mixer board.  Although these are not quite as good range-wise as the Hamilton Range Master, they are a little more cost effective.  New, they cost about $400 to $600, but I have seen them sell on Ebay for less than $50.  Definitely worth every penny!  Other transmitters on the market such as the British-made "Gizmo" PLL-tuned AM Transmitter ($100) and the "Metzo" PLL-tuned professional AM Transmitter ($300) can be used with similar if not identical results.  This about does it for pre-built AM transmitters that I would recommend.

AM Transmitter Kits:

Although it is easier to start up a radio station using a pre-built transmitter, it can also be quite a bit more costly to do so.  There are some kits out there today which would definitely compete with or beat any pre-built AM transmitter.  Building a transmitter from a kit requires good soldering skill and a steady hand, as well as familiarity with electronics schematics and a working knowledge of basic electronic test devices such as a multi-meter and the resistor color code.  If you or someone you know has these skills, than building a transmitter from a kit will be just the thing for you.  If you are not electronics-smart, you will need to either purchase a pre-built transmitter or find a friend that is a licensed HAM operator and/or knows a thing or two about electronics assembly.  It is not rocket science, but it does require practice, practice, and more practice before you are "good".  To get started in electronics, perhaps you should first purchase an electronics kit from your local hobby store such as a 500-in-One Electronics project lab.  Assemble each of the projects in the lab, and then try your hand at soldering a small and simple AM Transmitter kit such as the Chaney AM Broadcaster Kit which is available for just $8 plus S&H from www.chaneyelectronics.com .  If it works alright and you don't destroy the thing in the process, then you are probably ready to tackle a more advanced kit (or not).  The SSTRAN AM transmitter kit is said to put out almost as good of a signal  (if not better) as the Hamilton Range Master transmitter mentioned previously. 

 The kit costs only $100 and is quite easy to assemble in comparison to other AM transmitter kits such as the North Country Radio AM-88 Kit or the Ramsey AM-25 kit www.ramseyelectronics.com.  Other kits and kit manufacturers make kits that are appealing not only because of their high quality but because of their ease of construction as well as low part count and low cost.  The best of these kits is the Vectonics VEC-1290k AM Transmitter Kit available from www.vectronics.com for just $29.95 plus s&h. 

 One of these would even make an ideal first kit for someone learning to solder.  This kit stands up nicely to pre-built transmitters such as the "Gizmo" or the "Talking House Transmitter" as far as range and clarity of the signal.  It just goes to show you that a more complex transmitter does not necessarily mean a higher quality transmitter!  Remember when building this and other AM transmitter kits to set the frequency of operation as high up in the band as possible, as mathematically an AM transmitter can broadcast up to 10 times as far at 1700khz than it can at 550khz due to antenna and signal efficiency ratios!  Many have claimed to have heard their Vectronics VEC-1290K Transmitter at a distance of 1/4 mile! 

Part 15 AM Antennas

On a commercial AM Station, the broadcast antenna is usually at least 1/4 wave length.  At 1000 khz, this would be approximately 225 ft long! In order to be compliant with part 15 of FCC Rules and Regulations for unlicensed broadcasting in the United States, the antenna element (A in below figure) can be no longer than 10' in length, thus assuring that the signal will not propagate very far.  The FCC makes this requirement because it is their intention that an unlicensed station's signal die out quickly outside its area of coverage to prevent possible interferant to licensed radio stations. Part 15 AM Antennas are generally connected directly to the output of the transmitter to avoid signal loss from running coax cable from the transmitter to the antenna.  In order to get much range at all, the transmitter must be properly matched to its antenna. Matched means that the antenna is configured to radiate the maximum amount of signal possible in conjunction with its transmitter.  A field strength meter is the best way to measure the efficiency of your antenna.  The higher the reading on your meter, the better your antenna is radiating its signal.  Antennas are generally constructed of  1/2" to 1" diameter copper tubing or aluminum antenna mast.  Sometimes antennas are matched to their transmitters through a simple capacitive coupling from a trimmer near the antenna output of the transmitter as is the case with the Vectronics VEC-1290k AM Transmitter kit mentioned earlier.  For maximum efficiency, a "loading coil" (B in below figure) is often assembled at the base of the antenna in order to effectively "lengthen the antenna electrically".  A typical loading coil is wound on a 6" piece of 2" diameter PVC pipe and consists of about 200 turns of #28 magnet wire.  "Taps" are wound on the coil about every 10 turns or so.  The transmitter is then hooked to the bottom-most "tap" via an alligator clip and the top most "tap" is hooked to a 9' 6" mast of copper tubing.  The transmitter is then turned on and the clip from the transmitter is moved up one "tap" at a time until the highest field strength is displayed on the field strength meter.  Once the highest possible strength is shown on the meter, the antenna is matched and the clips are replaced with wires that are soldered permanently in place.  

A tophat (D in above picture) can be placed on top of the radiating antenna mast to help propagate more of the signal skyward than groundward.  A top hat can be a circular piece of metal of any reasonable diameter, or some short "radials" of wire protruding from the very tip of the antenna in an even plane type configuration.  Remember, the height (not width) of the tophat does count as part of the 10' allowed for the full height of the antenna!  Here is one other set of illustrations below that may help a little more as far as the construction of your antenna's loading coil and configuration.  Then there are the ground radials (C in the above picture) which are wires jetting out in a circular pattern that are buried underground directly under your antenna.  They are joined at the center, and the center is wired directly to the ground terminal of your transmitter.  Yes, this is why they call it a "ground terminal"!!  Any old type of wire can be used for making your ground radials.  Electric fence wire is cheaply obtainable and works very well.

Please realize that these are only the specifications for Part 15 Low Power AM (LPAM) stations and should not be confused with the antennas that are used with full-power AM stations which will be addressed in later chapters!  Full powered AM stations use much longer antennas and usually quite a few feet of coax cable as a feedline!  You may wish to mount your Part 15 antenna on top of a large metal mast or rooftop as shown in the below picture.

 

The advantage to this type of setup is that the mast is connected to the ground and does not count as lead-in wire since it IS the transmitter's ground.  Also, this type of setup will allow your part 15 AM transmitter to broadcast from a good altitude with the largest antenna permissible.  This type of antenna system is commonly referred to as a "whip-and-mast" system.

 

Part 15 FM Radio Stations

Although Part 15 AM stations can legally have more range than Part 15 FM stations, a part 15 FM station may still be powerful enough for use as a small neighborhood, campground, church, or college radio station.  The FM spectrum offers both superior sound quality and a better medium for attracting more listeners than its AM counterpart, especially in densely populated city blocks and apartment complexes.  Although FM signals are strictly line-of-sight in nature, they can cut through concrete and steel barriers a lot better than AM signals can.  Also, FM signals are not directional like AM signals are.  A Part 15 FM station can be set up and operated from an average size desktop space and without all the fancy ground radials and loading coils.  The antennas are much simpler to construct and match to your transmitter.  Average transmission range of most Part 15 stations when operating under legal means will be just over 300ft of coverage for FM Stereo, and maybe 500ft for FM Mono signals. In the best of cases, a car radio may barely even copy your signal at a distance of 1/4 mile. It will be up to you wether you want (or need) your station to transmit in stereo or mono.  Both are allowed under part 15 FCC guidelines, and the guidelines do not differ at all between FM Stereo and FM Mono stations.  Transmitters can be ordered fully assembled or can be built from a kit.  There is really not that much difference between a kit-built transmitter and a pre-assembled transmitter as far as range and quality is concerned with a Part 15 FM station, however, using a pre-assembled transmitter is easier than building one of course!   Maximum legal transmitter power on the FM bands is a little harder to calculate than on the AM bands, unless you have access to a field strength meter.  This is because FM signals are governed in legal field strength levels rather than actual transmitter output power and antenna length, although the combination of these two things have everything to do with how much field strength is emitted.  On the FM broadcast band (88mhz - 108mhz), your field strength is limited to 250 microvolts per meter, measured with a field strength meter positioned 3 meters from your antenna.  If you are unsure of how much power your fm station is putting out, YOU MUST have someone measure this for you and you must decrease your transmitter power down to legal levels. 

 Anything over 250 microvolts per meter could land you a big fine or prison time if someone complains that your signal is interfering with their reception!  The FCC has placed this regulation on purpose to make sure that all unlicensed FM stations drown out after a few hundred feet, being barely detectable after a few blocks.  In the state of Florida, it is now a felony to operate a radio station without a license other than as specified in Part 15 or FCC rules and regulations.  Violation of this law could mean a jail term of up to five years, so if you are bent on operating your station illegally, don't do it in Florida!  Some kits on the market are designed not to exceed FCC power limits when constructed according to the instruction books.  These kits are the Ramsey FM-10c, FM-25, and the Velleman FM Transmitter kits mentioned in the kit reviews section of our website.  Also please keep in mind that if your kit does exceed FCC power limits, it is YOU who would get in trouble, NOT the kit company!

 

Part 15 FM Transmitters

Like part 15 AM Transmitters, part 15 FM Transmitters can either be built from a kit or purchased in assembled form.  Pre-manufactured FM transmitters suitable for use as a Part 15 FM Transmitters include any FCC Part-15 accepted transmitters and stereo modulators such as Belkin Tunecast or Ipod transmitters available at your local Wal-Mart or Best Buy.   Belking TuneCasts are available at www.belkin.com and can put out up to 50' of strong signal when unmodified.  Imagine what one will do if hooked to a proper antenna!

 These transmitters are often inferior to those which can be built from a kit, and often require the attachment of an external antenna to obtain any real range at all.  Many people have cracked these open and hooked either a 1/4 wave (see antenna length formula and table below) wire or telescoping antenna to the antenna output of these transmitters.  Results depend as much on the transmitters as the kind of antenna you hook to the transmitter.  On the Belking Tunecast, the antenna is intertwined with the wires inside the audio cable.  Simply hook this wire to some type of larger external antenna and range should improve.  I recommend a 25" piece of wire (about 1/4 wavelength for the FM band).  Some of these transmitters operate on only1.5 to 3 volts of electricity (one or two AA batteries).  To boost the range, try hooking such transmitters up to a 9 to 12 volt regulated power supply.  This will most likely increase the range substantially if it doesn't burn the thing up.  I tried this when modifying a kid's toy wireless FM microphone and the results were astounding.  By hooking a 1/4 wave antenna up where the stubby little wire antenna was, I was able to change the range from about 10ft to about 30ft.  Then I replaced the 2 AA batteries with a 9 volt regulated power supply and the results were even more astounding.  By increasing the power at this level, the range jumped from about 30ft to about 250ft!  These modifications will require a decent level of electronics skill and background and should not be attempted by a newbie.  If you are a newbie, you would be better off assembling an FM-10c or FM-25 FM Transmitter Kit from www.ramseyelectronics.com and leaving it at that!  

 The FM-10c will cost about $50.00 to assemble, and the FM-25 will cost about $150.00 to assemble.  The step-by-step instructions are very easy to follow, even if you have never built a kit before in your life.  You may be able to find one of these pre-assembled on Ebay, but you will end up paying substantially more for the assembled transmitters than the unassembled kits!  Kits such as the FM-10c may be difficult to get exactly on frequency, and the frequency may occasionally drift, making it difficult for digital receivers to lock onto the signal for long periods of time.  This is why I would recommend a PLL-Synthesized transmitter such as the FM-25 if you plan on reaching an extended audience. 

 The FM-25 stays right on frequency all the time, and is strappable for higher power output where regulations allow. If you aren't using much of an antenna, you may even be able to use the high power setting here in the United States!  The FM-10c is a decent transmitter, but the FM-25 is full of options that the FM-10c could never dream of fulfilling!   If these two models from Ramsey Electronics aren't enough for you, Ramsey also offers a professional FM exciter transmitter with a digital frequency readout called the FM-100 (as if an FM-25 isn't enough). 

The FM-100 even offers on-board mixing circuits which enable you to adjust audio input and microphone levels without the use or need of an external mixer board (although I would still recommend that you use one).  The only downside to the FM-100 is its $300 price tag!  For LPFM license holders, Ramsey also offers a 1-watt version of this kit which is enough power to cover a whole town!  Another item of interest which would be a more-than-substantial transmitter for use in the part 15 FM service would be an "FM Stereo Generator" if you can find one at a swapmeet or on Ebay for a decent price.  These make the coolest part 15 FM transmitters because they have both wired and composite audio inputs for ease of hookup to your stereo mixer.  They also have an adjustable RF output stage allowing you to vary the power.  When hooked to even a simple dipole antenna such as a pair of TV rabbit ears, one of these can broadcast several hundred feet.  One guy I was talking to on Ebay was telling me that he hooked his FM Stereo Generator up to a professional FM broadcast antenna and he could hear the thing a mile away. 

Pictured above is an old Heathkit FM Stereo Generator.  I have one of these that was made by a different manufacturer and I know first hand that these things work quite well.  At the press of a button, you can select the stereo separation for your region.  At the turn of a knob, you can adjust the modulation from your sound source.  On mine, there is a meter which tells you what percentage of modulation your signal is at to avoid overmodulation.  The output can generally be adjusted between a few microwatts and a few milliwatts, similar to the above mentioned kits.  In all, the range and performance is about the same as that of the kits listed above, but with so many other "whistles and bells".   I got mine on Ebay for $50 and it is worth every penny.  Hook one of these up to a decent linear amplifier and you will have one heck of a nice LPFM transmitter.  More on those later!

Part 15 FM Antennas

When referring to antennas, you often hear people referring to a "quarter wave dipole" or a "half wave groundplane".  Your antenna needs to be a special length for the frequency you are using in order to properly radiate your signal.  The wavelength of your antenna in inches (for a quarter wave antenna) can be calculated by using the following formula:

                                                                         234/freq=length of rod in feet

This means that for an operating frequency of 88.1mhz, the following equation would apply:

234 / 88.1 = 2.65 ft

2.65ft * 12inches = 31.8"

This means that the most basic antenna for an FM Transmitter that is transmitting on 88.1mhz would be a wire or rod measuring 31.8" in length.

Now for some more options:

89.1 mhz = 31.5"

90.1 mhz = 31"

91.1 mhz = 30.8"

93.1 mhz = 30"

95.1 mhz = 29.5"

97.1 mhz = 28.9"

100.1 mhz = 28"

103.1 mhz = 27.25"

106.1 mhz = 26.5"

107.1 mhz = 26.2"

107.9 mhz = 26"

These antenna lengths are just the "rod" lengths of the main radiating element and the ground element.  While one element or ariel soldered directly to the transmitter's antenna output will radiate a signal at that frequency, there are more efficient ways of transmitting a signal..  The next most basic form of antenna is a "dipole" antenna.  On a dipole antenna, the elements are stacked vertically.  One element is attached via a piece of coax cable to the antenna output, and the other end is attached to the ground element.  Both elements are 1/4 wave length for greatest efficiency as shown in figure below.  The coax cable is standard CB-type 50 ohm coax which is sold at Radio Shack.  The "di" in "dipole" refers to the number 2, or "2 pole" antenna.  Even the simple introduction of a ground element will improve antenna's overall efficiency as well as overall transmitter range.

 

I built one of these out of a pair of TV rabbit ears and it works perfectly for local neighborhood broadcasts.  Just extend the ariels to the correct lengths and either solder them in place or put electrical tape on them to keep them from changing length.  Make sure that the antenna element is facing straight up and the ground element is facing straight down.  Yes, it would probably help if you mounted the rabbit ears on a long vertical pole.  Make sure that neither element of the antenna touches any nearby object, especially not a metal object as this will majorly mis-match your antenna.  Also, try to keep the coax cable run as short as possible to avoid signal loss.  50 ohm coax cable can be a killer at a power level of 10mw.  It is a good idea to mount your antenna outdoors if possible, and in as high up a location as possible.  The second floor works much better than the first floor for maximum range! 

Another easy-to-build antenna which I will suggest is the "ground plane" antenna.  This antenna uses one 1/4 wave ariel as a radiating element, and uses four (4) 1/4 wave aerials to form a "ground plane" from which the radiated signal is reflected for greater efficiency.  Aluminum or copper welding rods can make good aerials when cut to their appropriate wavelengths.  To build this antenna, you will need five (5) 1/4 wavelength pieces of stiff wire as well as a SO-239 RF connector (available from radio shack for a few bucks).  You will need to go ahead and solder one of the 1/4 wave length elements to the "center pin" of the SO-239 as shown below.  There are also 4 holes, one on each corner of the connector.  In these holes, go ahead and solder the remaining 4 aerials as shown below and bend them  in a 45 degree angle from the center element as shown below.  Now hook a short length of CB -type coax from your transmitter and terminate it using a PL-259 connector so it can be hooked to your antenna.  The same rules apply regarding the best location for your antenna.  While this functions in much the same way as the above antenna, it does yield a considerable amount more range and the cost is still next to nothing. 

 

 

 

The very nature of Part 15 FM Stations suggests a severely limited coverage area at a minuscule power level.  The area which they can efficiently cover is limited both by power and efficiency of the antenna.  Both of these factors contribute to the field strength of the signal, which is limited to 250 microvolts per meter as mandated by the FCC.  Although installing a professional quality FM antenna on your Part 15 station may slightly improve the quality of your signal, it will not do much at all for the effective range of your signal.  This is because, by design, there is only so much that 250 microvolts per meter field strength can possibly do!  This is why it is best to stick with simple homeade antennas instead of wasting money on expensive professional antennas which legally can transmit no farther.  LPFM or licensed low-power FM stations, however, would really benefit from the use of a professional antenna because their legality is delineated strictly in the amount of transmitter power they can use, not the field strength which they can produce!  Keep in mind when operating an LPFM station that the FCC is unfailingly strict in enforcing its policies including the legal power limit.  Even with the most sensitive of FM radio receivers, a legal part 15 FM station will barely be readable at 1/4 mile.  If your station can be heard more than 1/4 mile away, you can bet that you are exceeding the legal FCC power limits of 250 microvolts per meter at 3 meters.  Also keep in mind that many FM transmitters and FM transmitter kits already exceed FCC power limits without the attatchment of an external antenna.

 

LPFM (Low Power FM) Licensed Stations

In response to the growing need for small community radio stations, especially in remote areas where there are few FM stations, the FCC has created the LPFM or Low Power FM radio service.  This service allows some local community and religious groups to obtain a license to operate a small FM station of either 10 or 100 watts for service to their immediate community.  In FCC terms, this is how LPFM Stations are defined:

"These stations are authorized for noncommercial educational broadcasting only (no commercial operation) and operate with an effective radiated power (ERP) of 100 watts (0.1 kilowatts) or less, with maximum facilities of 100 watts ERP at 30 meters (100 feet) antenna height above average terrain (HAAT). The approximate service range of a 100 watt LPFM station is 5.6 kilometers (3.5 miles radius). LPFM stations are not protected from interference that may be received from other classes of FM stations. A construction permit is required before a LPFM station can be constructed or operated.

LPFM stations are available to noncommercial educational entities and public safety and transportation organizations, but are not available to individuals or for commercial operations. Current broadcast licensees with interests in other media (broadcast or newspapers) are not eligible to obtain LPFM stations." --Excerpt as stated on www.FCC.gov

Because these stations are not allowed to be run by any commercial organizations, this kind of license works quite well for would-be Christian station operators to organize and form a radio station.  The main drawback to this type of licensing is that thousands of applications are received by the FCC while only a small fraction of them are actually approved for construction of a station.  This is in part because most or all of the available frequencies on the FM band are often already in use in most major metropolitan areas, and many bedroom communities are not far enough away from major metro areas to avoid interference.  Also, the FCC is pretty touchy about allowing one of these stations to even move into a frequency adjacent to that of a commercial station due to their theory that it may cause interference. 

The FCC has established that the FM broadcast band is divided into "channels" which represent all possible station frequencies.  These channels are evenly spaced apart.  This was done so that the maximum possible number of FM stations will fit on the FM broadcast band.  According to FCC terms and conditions for LPAM and commercial FM Broadcasting, the following are frequencies on which an FM station may broadcast (in megahertz). 88.1mhz - 107.9mhz in .1mhz  (or 100khz) steps.  For example, 88.1, 88.3, 88.5, 88.7, and 88.9mhz would be the available "channels" on the 88mhz portion of the band.  The same holds true for all frequencies 88.1mhz-107.9mhz.  Most commercial stations are separated by at least 100khz or one "channel" to avoid interference from one station to another.  For example, if one radio station was operating on 92.3mhz, then 92.1mhz and 92.5mhz would both be empty on either side of 92.3mhz to prevent interference to surrounding stations.  In regards to LPFM licensing, the FCC has somewhat of a "double standard" which requires LPFM stations to be at least 2 adjacent channels away from commercial stations, for example, if a commercial station was broadcasting on 88.1mhz, then 88.3 and 88.5mhz would both have to be empty, and the LPFM station would be assigned to 88.7.  Channels 88.9 and 90.1 would also have to be free of commercial stations in order for the LPFM station to operate on 88.7.  This is one way the FCC "gets out of" issuing LPFM licenses.  Chances are that if your organization wishes to obtain an LPFM station license, you won't be able to!  Unfortunately, that is just the cold hard fact of the matter.  For more information on LPFM licensing, visit www.fcc.gov or write your local FCC field office. Although Part 15 FM stations are not subject to such rules, care should still be taken to assure that the adjacent channel on each side of your frequency is empty.  This will only keep you from causing interference in the long run.  Hopefully, in reading this, you will be able to see the the advantages that even part 15 operation has over LPFM.  The FCC still has not developed a LPAM or Low Power AM service despite numerous requests from would-be station operators.  Evidently the FCC believes that the terms of Part 15 AM operation are generous enough.  Again, many of us including myself would disagree with this assessment.  LPFM transmitters are available from many different resources including Ramsey Electronics at www.ramseyelectronics.com as well as other manufacturers such as www.vhf-transmitter.com .  LPFM transmitters can cost anywhere from $100 to $10,000.  At times you will see them go on Ebay for $200 to $1000.  This is actually not too rare an occurence.  Ramsey makes FM broadcast antennas which can handle up to 200 watts of power, perfect for your LPFM station.  Comet also makes similar antennas in similar price ranges.

One example of such a transmitter is the Ramsey PX-50 50-watt LPFM transmitter shown above.  You too can own one of these beauties for just $2000.00.   This actually is not too bad a price for a professional quality and full-duty LPFM Broadcast transmitter.  It would be wise to obtain your LPFM license before ordering yours however.  This would be way too cool a transmitter to wind up as a doorstop!  Below is an example of a smaller and more modestly priced LPFM transmitter from www.vhf-transmitter.com.  Although it doesn't have near the features or power of the above transmitter, it may be better suited to missionary groups on a budget.  You can own one of these for $260.00.  Now that is affordable!

This transmitter puts out 15 watts, which is well in the range of a common LPFM transmitter which can legally range from 10 to 100 watts of power.  While it may not have as many features as the above Ramsey transmitter, how many features does one really need to run a small community Christian station.  The Lord does require His servants to be a good steward of their funds.  That is one of the main reasons that I am writing this now. 

LPFM Antennas

As far as LPFM antennas are concerned, you would probably be well advised to purchase one that is commercially made.  They are not only easier to install, but more efficient and can make your 10 to 100 watts of power go a good deal farther than a cheap home made wire antenna.  Below is an example of such an antenna from Ramsey at www.ramseyelectronics.com .  This is the Ramsey FMA200 Professional FM Antenna, costing only $129.99.

She is a true thing of beauty.  This antenna 5/8 wave antenna will efficiently radiate up to 200 watts of power.  Not only would this be the ultimate antenna for your LPFM station here in the US, but also for higher power stations in foreign countries.  Even a Part 15 FM transmitter might cut it for a small village station if you hook it up to one of these.  I know for a fact that the FM-25 would put out quite a signal when assembled in high power mode and hooked to one of these with a short piece of coax cable! 

One similarity of LPFM and Commercial FM licensing is that they both require an application fee to the FCC.  The LPFM fee is generally less than the commercial license fee, and for churches and non-profit organizations, the FCC has been know at times to waive the application fee.  For current fees schedule you will need to visit the FCC website at www.fcc.gov.  If your application is improved, the FCC will then issue you a Station Construction Permit.  Issues of antenna height and location, as well as station transmitter power and coverage radius will be covered in full.  The FCC may also require you to obtain permission before installing a new antenna system or a new transmitter, since either may increase or decrease your range and change the acceptability of your station or coverage area.

Commercial AM Stations

Although obtaining a commercial radio station in the United States will probably cost your organization somewhere in excess of one million dollars, it may not cost that much to set one up in foreign countries.  The FCC application fee alone can cost hundreds of thousands of dollars.  An AM broadcast station will also require the use of a huge vertical antenna or tower in order to radiate its signal.  Commercial AM stations can range in power from 500 watts all the way up to 50,000 watts.  The transmitters are generally the size of a large industrial refrigerator and are kept in a climate controlled room.  The transmitters are generally vacuum tube powered, and often times the replacement of just one of these tubes can range in the thousands of dollars.  Below is a picture of a common triode broadcast transmitter tube.  Even the most basic of AM broadcast transmitters may contain several of these!

  An AM radio tower generally has 160 ground radials jutting out from the base of the tower in even patterns.  The ground radials are 1/4 wavelength long, or 44 meters in length for a station operating at 1700KHZ.  The main tower is generally 5/8 wavelength tall which is 110 meters in height!  It would take more than 5 kilometers of wire to build a ground system consisting of 120 radials, not to mention an open field at least 88 meters wide.  This is a huge difference from the Part 15 AM station specs mentioned earlier! 

   

Needless to say, a commercial AM station requires not only a great deal of funds to construct, but a great deal of land to construct it on.  An AM station uses the entire tower as the radiating element for its antenna!  Below is pictured a typical commercial AM transmitter.  Not something that you would keep in your church basement!

Built like a tank, this commercial AM broadcast transmitter puts out 50,000 watts and takes up 51 square feet of floor space.  Transmitters like this can cost tens or even hundreds of thousands of dollars.  Sometimes a lucky individual might find something like this on Ebay for $5,000 to $20,000.  The rest of us would pay dearly for one of these!  At the bare minimum, if you want to compromise on costs you may be able to use converted HAM radio gear and a 1000 watt linear amplifier as a makeshift transmitter.  These are less reliable and provide less range than a professional AM transmitter.  A converted 160-meter transmitter would most likely cost you a few hundred dollars, and the linear you would need can either be home-built or obtained for maybe a few hundred to a thousand dollars at a hamfest (an amateur radio swap meet which occurs a few times annually in most major cities).  You might not need a linear amplifier if all you are going to do is cover a single city area, since most 160-meter transmitters put out between 50 and 100 watts. Pictured below is just such a transmitter, a Heathkit DX-100.  A local area amateur radio operator may be able to help you in the location and modification of one of these.

 You can also save money by using a radio tower as short as 1/4 wave, but this will cost you dearly as far as antenna efficiency and effective range.  Beside the cost of the transmitter, the building, the land, and the tower, one must also consider construction of a decent studio.  At the bare minimum, you will want a decent DJ mixer, a microphone, a few top quality CD players and tape decks, and a computer for studio automation.  Most studio equipment can be obtained at your local Radio Shack store and is not too different from the audio equipment you use in your church auditorium except for the fact that you are feeding sound into a massive transmitter and tower instead of loudspeakers  One advantage of a commercial AM station is that there are many vacant AM frequencies available in most areas, verses FM where you may be on a rather lengthy waiting list to obtain an open frequency and construction permit.  You may be asking me "why did you immediately jump to commercial AM stations".  The answer to this question is actually quite simple.  The fact is that there is currently no LPAM or Low Power AM service in existance because it has not yet been established by the FCC.  The only type of AM station that you can currently operate non-commercially is a part 15 AM station!

 

Commercial FM Stations

Commercial FM stations, like commercial AM stations are extremely expensive to apply for, let alone construct and operate.  Even low-budget commercial FM stations cost about $600,000 per year just to operate.  Commercial FM stations are basically any FM station that operates at above 100 watts of power.  Some FM stations operate at 10,000 watts of power or more!  Commercial FM transmitters are generally smaller in size than commercial AM transmitters, and the commercial FM towers and antennas do not require as much land as their AM counterparts because ground radials are rarely used at the base of an FM tower.  Below is a picture of a standard FM broadcast radio tower.

This is actually an example of one of the larger FM broadcasting antennas.  It is referred to as a "cogwheel" FM broadcast antenna.  These are engineered specifically for the exact wavelenght of the signal and are designed to distribute the signal as evenly as possible in all directions.  It is somewhat comparable to an isotropic radiator (a fictional antenna which radiates signals perfectly in all directions).  While transmitters often cost up in the thousands to tens of thousands of dollars, an antenna like this can cost more than the transmitter itself!  FM antennas are mere extensions of the tower from which they broadcast whereas AM antennas usually consist of the entire tower.  Ok, ok, ok, we will show a more "economically priced" FM broadcast antenna as well! 

 

This BroadCom professional broadcast antenna can handle up to 1600 watts of power (enough to cover an entire major city area plus some) and costs only about $400 for all of us financially strapped  folks.  LPFM transmitters are a maximum of 100 watts.  Anything above 100 watts is considered a commercial grade transmitter. Below is a low-end example of a standard commercial FM broadcast transmitter.

 

Although small compared to some FM transmitters, you get the picture.  Most of the ones in service today are mounted on a metal rack which is roughly the size of an average kitchen refrigerator.  This one is a Turgicom 250 Watt FM Stereo Transmitter.  I have seen a few 5kw broadcast transmitters which were maybe 4 to 5 times the size of this one.  You too can be the proud owner of one of these for a starting price of $3,000.  They only go UP from there.  Imagine the electric bill at 5kw!!

Foreign, Makeshift, Clandestine, and Pirate Stations

While some foreign countries, namely South American countries have much more lax communications laws than here in the US, there are some countries such as Great Britain which do not allow any type of unlicensed broadcasting whatsoever. In China, if you were caught broadcasting without a license, they would probably just shoot you on the spot and then bill your family for the bullet. Many foreign countries do not give their citizens any freedom of worship whatsoever, let alone freedom of religious expression on the airwaves. Other North American countries such as Canada have even more lax radio regulations than here in the United States. In no way do we support or condone any illegal broadcasting activity here in the United States or Canada. We do, however, prayerfully support those brave souls who risk their lives every day in hostile places around the globe who presume upon themselves to outlaw religious freedom and expression. These countries treat the word of Jesus Christ our Lord with hostility and contempt, and any missionary brave enough to broadcast to or within these countries is a hero of the faith. There are many martyrs who have lost their lives doing exactly that. As with Paul and Silas in the New Testament, we see that often times serving the Lord and preaching His Word does require us to commit acts of civil disobedience. Here we will cover not only the technical aspects of foreign, legal, and covert operation, but we will also cover techniques one may use to avoid the authorities in hostile territory. Such acts of civil disobedience are not for use in the United States and Canada, since these countries provide their citizens with freedom to worship as well as licensed broadcasting and some limited forms of unlicensed broadcasting which are perfectly legal. If you violate the laws of any government, you do so at your own risk. We will cover ways in which you can minimize this risk if need be. First, we will begin with the technical stuff as always:

Higher Power, Sub-Standard, and Makeshift Transmitters

Perhaps one of the most notorious and widely used FM Stereo transmitter for this application is the Ramsey FM-25 PLL Synthesized transmitter which is mentioned above. Here in the United States, we assemble this transmitter in "low power mode", however, it can also be assembled in "high power mode" which boosts the output power from 8mw up to 25mw. At this power level and with a professional antenna, such a transmitter can cover an entire small village or town. Also, a simple outboard amplifier has been designed to be used with the FM-10 and FM-25 transmitters to boost their power level from 8mw up to 70mw. Below is the schematic for those interested in constructing this device. US and Canada users MAY NOT use this amplifier for any reason!

Not the best design in the world, but it does get the job done. It has been suggested on other web sites that changing the type of transistor on this amplifier may result in an output of over 100mw. This is mostly here say, since I haven't seen any real life examples of this. It is best just to stick with the above design, especially if you are a newcomer to radio broadcasting. If 70mw of power isn't enough and you need at least a few miles of coverage, than you would probably be better off using the Radio Communications Laboratory's RC2547T FM PLL Transmitter. This transmitter puts out a PLL Synthesized FM mono or stereo (external encoder needed) of up to 1 watt depending upon power supply and antenna used.

Get yours today from Radio Communications Laboratory Electronics Infoline at the following web address: http://www.electronicsinfoline.com/rcl/product_info.php/products_id/8  One of these will set you back about $45, and the shipping (from India) will cost you about $25.  Not bad at all considering the price of some of the kits on today's market that dont even hold a candle to this work of genius.  One of the coolest things about this transmitter is that the final RF power stage can be switched on and off, allowing you to use this transmitter in "low power mode" as a Part 15 Transmitter, or as a higher powered transmitter where regulations allow.  Just don't give into the temptation to switch on that extra power here in the United States, whatever you do.  Transmitters like these can be used with simple antennas such as a pair of TV rabbit ears adjusted to the appropriate 1/4 wavelength, or can be used with antennas intended for LPFM to achieve more range as well as signal quality.  For the price, you simply cannot go wrong!  In my opinion, any radio guru should have somethng like this lying around, or even better, in use. 

 

Stations In Hostile Territory

For operations in hostile territory, smaller transmitters like the RC2547T come in really handy because with some work and common sense, a missionary can fit an entire small radio station inside of a briefcase for mobile operaton as well as quick hide-away.  In a large briefcase, you can fit a small audio mixer, your transmitter, a rechargable battery pack and wall charger, and a collapsable fm dipole antenna.  Any pre-recorded programming can be fed into your mixer via a small handheld tape recorder, laptop computer, ipod, or palm pilot.  You will need to have a few other persons keep watch of the area in order to warn you if the authorities are approaching.  You should familiarize yourself with the direction finding capabilities of the radio authorities in the country which you are operating.  Before you broadcast, you should be well aware of their response time, the location of their home office, and the consequences should you get caught.  It helps if you choose a high-up location where you will be able to see anyone who approaches your "studio". 

 

 

 In Great Britan, clandestine radio operators often utilize abandoned tower blocks on the top of tall highrise buildings from which they make their broadcasts.  Just a watt or two of power from the top of a 10 story building can really carry a long way and reach quite a large listening audience.  Other clandestine operators have operated from cars or vans, either moving or stationery.  An old magnet mount CB radio antenna can be easily converted into a 1/4 or 1/2 wave groundplane antenna.  Simply remove any and all base loading coils and attatch a mast of appropriate length where the coils were.  A hot melt glue gun can be used to seal any cracks in the mast assembly against adverse weather conditions.  Some people have even reported better range with a magnetic mobile antenna than a fixed dipole antenna.  Many clandestine station operators have been known to leave their transmitter along with a pre-recorded program in a secluded area, and then go back for it later.  Electronic timers can be used to switch the transmitter on and off before and after the broadcast.  This way, if the authorities do arrive, all they will be able to do is capture the transmitter and recorder, leaving the oprerator still at large.  These are just a few suggestions which you may wish to consider.  Now for a few ground rules:

1. Stations that only operate a few hours a day run less of a risk of being caught than stations which operate 24 hours.

2. You should use as little power as possible to accomplish your objective.  It is a lot easier to get caught running a 100 watt station than it is to be caught with a 10 watt or 1 watt station.

3. Whenever possible, you should at least try to obey the local laws regarding unlicensed broadcasting.  Sometimes breaking the laws cannot be helped depending upon what country you are in.

4. Use a good bandpass filter between your transmitter and antenna.  This will prevent possible interference with other communications, which can only help keep you out of trouble.

5. Refrain from badmouthing any government officials, politicians or government policies.  This can only get you in more trouble when and if you get caught.  This is Christian Radio, so I don't think I need to warn you not to use profanity on the air.  Racial or ethnicaly incorrect comments are also a no-no.

6. Check your frequency of operation thuroghly prior to transmitting to make sure that there are no other signals with which you may be inadvertantly interfearing.  Check this frequency periodically and at different times during day and evening hours.  If you are using the AM broadcast band, this is especially important.  Most of the people who end up getting caught by the authorities have ended up getting caught because they interfered with something somewhere.  Also check the odd and even harmonics of your frequency up to the third harmonic with a police scanner.  If you can hear your signal at these harmonic frequencies, then it is time to invest in or build a good bandpass filter!

7. Never interfere with another station on purpose.

8. Know the office hours of your local communicaions enforcement authorities and try operating "after hours".  You will probably get caught faster if you broadcast your show at 12 noon every day than if you broadcast it at 3 am every day.

9. Make sure you do not mention your location on air for any reason.  Also make sure your "studio" is out of earshot of any telephones.  Authorities have apprehended many clandestine stations by calling telephones in or near the suspected vicinity of radio stations to see if they can hear the phone ringing over the radio.  You would be suprised at how many stations have been shut down by this very tactic.

10.  If possible, change locations frequently.  Have about 5 or 6 different locations staked out from which you intend to broadcast.  Locations should be as far away from the public through fair as possible.  Locations include mountain tops, woods, roofs of buildings, cars or vans, boats, or ships at sea.  Also vacant buildings, watertowers, and geographically secluded areas (hard to get to) make good broadcasting sites.  With these it often helps to get creative.  You may also try changing frequencies from time to time.

 

NOTE: This is BY NO MEANS a representation of the completed book!

There is much much more than this in the finished version which will be available for order

on September 1, 2007.  What you have just read is merely a rough notebook sketch of the first chapter!

There are 2 other chapters in the First Edition Release as well as transmitter kit reviews.

We will also be freely distributing many freeware and shareware DJ and studio mixing

software demos for your enjoyment and experimentation.

All of this and more will be avaiable on CD for a donation of just $10

to cover distribution and shipping, as well as help fund further research in the

engineering realm as far as transmitter design and further editions are concerned!!!