How a Radio Station Works

How A Radio Station Works

We'll start with the microphone and
take you through the whole equipment chain ...
(This is a "composite station" made up of pictures
of many different radio stations !)

Click on pictures to enlarge


This is a typical radio studio
with a control console
mike, CD Players,
digital audio system, etc.

We start at the Microphone
(EV RE-20)
which feeds into:

a microphone processor
(Valley 401)
which equalizes,
compresses and limits
the disk jockey's voice to
make it louder and clearer

then into the studio console
(Radio Systems RS/12)
there are ON/OFF buttons
and a 'pot' to
adjust the volume

so the meters always
read 100% and
to let the DJ talk
over the music

these are the main
controls on the console
that allow the DJ
to adjust his speaker
and headphone volume

we then send the signal
out of the studio to an
equipment room and into
an audio processor to
tailor the sound, then

to the Studio Transmitter Link
(STL) system (Marti STL-10)
to the transmitter on the
950 mHz band, on two channels
one for left, one for right

via this high-gain
antenna (Scala PR-950)

Meanwhile,
at the transmitter ...

The STL signal is
picked up here ...

and turned back into
left and right audio
by these receivers (Marti STL-10)

and fed into this
audio processor/stereo generator
Orban Optimod 8100A

and then into the exciter
which is actually the heart
of the transmitter
creating 10-50 watts on the
FM frequency of the station


This is a high power
Eimac 4CX20000
transmitter tube
capable of amplifying the
input signal up to 30,000 watts

it would be found inside
the transmitter in a
tuned 'cavity' like this

looking in the back
of the transmitter
notice the large
4000 volt transformer
at the bottom

this is the back of
the final cavity
the pipe is the output
to the antenna

the large transformer
on the left powers the
filament of the final tube

a transmitter has a metering
and control panel to read
operating voltages and currents

and to turn it on and off
and adjust the power output

there is also a remote control
system to allow the DJ at the studio
control the transmitter
(this is a Burk ARC-16)


the FM signal leaves the
transmitter and goes
up the tower on a big cable

to the antenna
on top of the tower
(this is an ERI 4 bay)
and out to the listeners

we now pick the FM signal out
of the air and listen to
it on a tuner and amplifier

and monitor the levels
with a modulation monitor
(QEI 691)