HOW TO START UP A FM RADIO STATION AND
HOW TO START UP AN LPFM RADIO STATION IN THE UNITED STATES
WITH INFO ON HOW TO FILE AN FCC LPFM APPLICATION
Five Things You need to Know about LPFM Radio Stations
LPFM
Radio Stations can be started with fairly basic and low cost
equipment. There are however five things you must have to begin your
broadcast.
1.
FCC Certified
FM
Broadcast Transmitter.
2.
Antenna (Don’t cheap out here)
3.
Low Loss, High Quality Coaxial Cable
4.
Tower (leased or owned)
5.
Emergency Alert System
These
are the basic items you need to start a radio station. But what will
you broadcast? You still need some sort of studio.. Now the spending
starts.. But don’t worry, we have put together several packages to
fit just about any budget.
The LPFM Store has helped start up a number of FM radio stations in the United States and abroad as well as helping start up many LPFM radio stations in the U.S. We provide radio consultancy services for hundreds of customers. Our services include advising on radio installations, from licensing to full power and low power radio stations.
There are several ways to start up an FM radio station or LPFM radio station in the United States. The lowest cost licensed method is a low power FM license. The second method is a full power FM License or Non Commercial Educational License (NCE.) In this article we look at information geared towards LPFM radio. Much of the information is appicable to full power fm radio stations as well.
INFORMATION
FOR THE FIRST TIME BROADCASTER
Some
things you’ll need for the studio would include a good audio mixing
console, one or more microphones, CD players, automation computer and
software, production computer with audio editing software, maybe a
cassette deck, studio monitor amplifier, speakers and of course
headphones.
What’s
a Watt about
Every
LPFM station has a maximum ERP (Effective Radiated Power) of 100
watts based upon 30 meters above average terrain. The “ERP” is
determined by the type of antenna, height, type of cable and power
output of the transmitter – this might be between 10 watts and 250
watts.
Is
the Antenna Really Important?
Yes
– Yes and Yes! The antenna is your final link in your RF system.
This couples the energy developed by the transmitter and delivered by
your coax to the “air”. The more efficiently the antenna can
couple the energy to the ether – the better your station will
sound. Of course too much efficiency can get you into trouble by
exceeding the maximum “ERP”, so be careful when deciding on your
antenna. You can’t get too much efficiency, but adjustments of the
transmitter’s output power would need to be adjusted.
The
Basic Dipole
Otherwise
known as a vertically polarized antenna with roughly a 1:1 ratio,
which means one watt in equals one watt out. If your station is
operating in an area where you need to "reach out" to the
horizon, this antenna may make sense. It is an excellent car
reception transmitting antenna, but can be susceptible to a
phenomenon known as “picket fencing” More on that later
Circular
Polarized Antennas (CP)
These
use both the vertical and the horizontal. In a true “CP” single
antenna of this design requires about twice the Power compared to a
dipole. This is due to the gain ratio being less than one half. This
antenna does not reach the horizon as well, but does concentrate its
power on building penetration and close in stronger field strength.
You can recover the horizon by adding more than one antenna. This
also increases the overall gain of the system allowing you to operate
with a smaller transmitter.
Full
Wave Spaced Antenna
Adding
multiple antennas spaced properly will increase your gain. A two pay
system in a “CP” design would require about half the TPO or
Transmitter Power Output of a single bay “CP”. And as previously
mention it will send the signal toward the horizon more than a single
“CP” antenna.
Half
Wave Spaced Antenna
These
are spaced approximately half that of a full wave system. Antenna
Doing so will decrease the overall gain of the system about half.
Therefore you would need to double power transmitter. Why in the
world would you want to do this? On the surface it sounds like you
would just be generating a larger power bill. But the resulting beam
from the half wave system will be more narrow with very little or no
radiation above and below the antennas, instead you will have a tight
signal heading off toward the horizon. This is perfect if you are in
an area with flat land (Florida anyone?) and distant transmission.
The
Cable – It’s just wire
Don’t
fall for the myth that any cable will do the job. Your coaxial cable
is a very important link in the RF chain. Cheap cable can eat up your
transmitter power, meaning less power gets to the antenna. If less
gets to the antenna, less is radiated. There are many types of cable
out there, choosing the wrong cable can really cause serious problems
with your station. Be sure to use a qualified broadcast Engineer to
determine the proper type of cable. Many factors influence this
including, power output of transmitter, length of cable, etc. Suffice
it to say that most installations of an LPFM station need at a
minimum ½ inch Andrew heliax or LMR 600 from Times Microwave.
Who
needs Processing? It’s just a 100 watt station.
The
best thing about radio is the average Joe Public doesn’t even begin
to know the meaning of a watt. If they can hear you and they like
what you are playing, they listen. But you can SOUND like those big
stations, wattage has nothing to do with it. Good audio processing
can make you sound as loud and strong as the flame thrower down the
street. So it’s important to spend as much as you can on a good
audio processor. We suggest the Inovonics OmegaFM or the Omnia 6.
Then you have the lower cost alternatives Inovonics, DAVID III. This
is a quality audio processor that can give you that loud punch to be
competitive with the other stations.
EAS
– Who needs it
You
do and it’s the law! FCC rules require LPFM's to only have a
Decoder. These units allow interruption of your broadcast for
national emergencies, inclement weather and even Amber alerts or
children abduction notices. We have several systems available. Each
unit will have two radios which monitor other radio stations or NOAA
for distributed alerts. It is very important to have and maintain
your EAS system.