06-07-2012, 04:28 PM
AM BROADCAST TRANSMITTER AM1
[attachment=27009]
INTRODUCTION
Many times we wish to be heard via wireless communications. Whether
transmitting music or voice, what’s required is a stable transmitter tunable to
an unused frequency on the broadcast band. Here at Ramsey, we have
produced several models of FM wireless units for years. Recent requests for
an AM type transmitter have been answered with this kit.
The Ramsey AM1 transmitter is a true broadcast transmitter, which any
person may build and use in accordance with the rules of one’s national
telecommunications authority. For U.S. residents, that authority is the
Federal Communications Commission (FCC). The AM1’s low power
broadcasting capabilities make it practical for many uses, but one should
remember that this transmitter is definitely not a toy. We will refer to the FCC
regulations frequently in this manual and provide you with some information
necessary to enjoy the AM1’s capabilities in accordance with the law.
Typical uses for the AM1 include:
• Student operated school radio stations.
• Re-broadcasting received audio for shortwave or HAM radio use.
• Listening aid for auditoriums, churches, or other events.
• Short range experimentation.
We think that you will be very pleased with the transmitting range, audio
quality, and frequency stability of this build it yourself AM transmitter. If you
follow our assembly instructions carefully and use your AM1 in accordance
with applicable FCC rules, a whole new world of sharing news, views, and
music with friends and neighbors awaits you.
AM1 CIRCUIT DESCRIPTION
Before we dive into the circuit description of the AM transmitter, first we’ll
describe exactly what we mean when we say “AM”. An (A)mplitude (M)
odulated signal is actually a combination of two signals. The high frequency
carrier is the frequency that one will tune on the radio receiver’s dial, from
530 to 1750 KHz. The modulation is the audio information that rides “on top”
of the high frequency carrier, resulting in a changing of the level, or
amplitude, of the output waveform. Take a glance at the schematic and
follow along at how we produce this AM waveform.
ASSEMBLY INSTRUCTIONS
There are numerous solder connections on the AM1 printed circuit board.
Therefore, PLEASE take us seriously when we say that good soldering is
essential to the proper operation of your transmitter!
• Use a 25-watt soldering pencil with a clean, sharp tip.
• Use only rosin-core solder intended for electronics use.
• Use bright lighting, a magnifying lamp or bench-style magnifier may
be helpful.
• Do your work in stages, taking breaks to check your work. Carefully
brush away wire cuttings so they don't lodge between solder
connections.
[attachment=27009]
INTRODUCTION
Many times we wish to be heard via wireless communications. Whether
transmitting music or voice, what’s required is a stable transmitter tunable to
an unused frequency on the broadcast band. Here at Ramsey, we have
produced several models of FM wireless units for years. Recent requests for
an AM type transmitter have been answered with this kit.
The Ramsey AM1 transmitter is a true broadcast transmitter, which any
person may build and use in accordance with the rules of one’s national
telecommunications authority. For U.S. residents, that authority is the
Federal Communications Commission (FCC). The AM1’s low power
broadcasting capabilities make it practical for many uses, but one should
remember that this transmitter is definitely not a toy. We will refer to the FCC
regulations frequently in this manual and provide you with some information
necessary to enjoy the AM1’s capabilities in accordance with the law.
Typical uses for the AM1 include:
• Student operated school radio stations.
• Re-broadcasting received audio for shortwave or HAM radio use.
• Listening aid for auditoriums, churches, or other events.
• Short range experimentation.
We think that you will be very pleased with the transmitting range, audio
quality, and frequency stability of this build it yourself AM transmitter. If you
follow our assembly instructions carefully and use your AM1 in accordance
with applicable FCC rules, a whole new world of sharing news, views, and
music with friends and neighbors awaits you.
AM1 CIRCUIT DESCRIPTION
Before we dive into the circuit description of the AM transmitter, first we’ll
describe exactly what we mean when we say “AM”. An (A)mplitude (M)
odulated signal is actually a combination of two signals. The high frequency
carrier is the frequency that one will tune on the radio receiver’s dial, from
530 to 1750 KHz. The modulation is the audio information that rides “on top”
of the high frequency carrier, resulting in a changing of the level, or
amplitude, of the output waveform. Take a glance at the schematic and
follow along at how we produce this AM waveform.
ASSEMBLY INSTRUCTIONS
There are numerous solder connections on the AM1 printed circuit board.
Therefore, PLEASE take us seriously when we say that good soldering is
essential to the proper operation of your transmitter!
• Use a 25-watt soldering pencil with a clean, sharp tip.
• Use only rosin-core solder intended for electronics use.
• Use bright lighting, a magnifying lamp or bench-style magnifier may
be helpful.
• Do your work in stages, taking breaks to check your work. Carefully
brush away wire cuttings so they don't lodge between solder
connections.