Plasma Sonics OM-1 Users Manual

OM-1 Transmitter

Plasma Sonics Ltd. Co

PLEASE READ THIS OPERATIONS MANUAL PRIOR TO
USAGE OF YOUR NEW OM-1 TRANSMITTER! FAILURE
TO FOLLOW INSTRUCTIONS CAN RESULT IN DAMAGE
TO YOUR NEW TRANSMITER !

Your new OM-1 Transmitter is designed as a pulsed RF driver for a variety of different
instruments. It is designed to either be used in stand alone usage, or to be used in
conjunction with an RF amplifier. Utilization of the OM-1 with an amplifier will
necessitate the addition of some sort of harmonic suppression to the amplifiers output.
The OM-1 is designed specifically for square wave audio modulation. Do not use less
than a 50% duty cycle, and preferably a 70% duty cycle, square wave, for modulation
purposes.

The front side of the OM-1 has an on-off switch, a BNC connector, and a 4 pin
microphone connector. The OM-1 is not designed for voice communication! The 4 pin
connector allows one to use a computer controlled relay system to automatically turn the
transmitter function on and off.

The OM-1 is extremely simple to use, there two primary rule to remember:

1. The OM-1 is extremely sensitive to the input square wave power level! Excessive
voltage and current can destroy the audio amplifier chip! Do Not !!! attempt to
operate your OM-1 until after reading all instructions and setting input voltage
from your frequency generator to an absolute minimum.

2. Do not operate (transmit) your OM-1 without being connected to some sort of
load!

Preparing The OM-1 For Use

1. Make certain all power switches are in the off position. This includes the power
supply , the OM-1 transmitter, and the frequency generator.

2. Most frequency generators will lack any ability to computer control the OM-1.
Use a BNC cable to connect your frequency generator output to the input BNC
connector on the OM-1. Make certain power output is set to a minimum! Many
frequency generators will have a –db button or buttons . Push ALL of these in.

3. Connect the power wire with the fuse in it, found on the back side of the OM-1,
to the positive side of a 13.8 volt, 5 ampere or greater , power supply.

4. Connect the negative power wire on the back of the OM-1 to the negative side of
a 13.8 volt power supply.

5. Connect a coaxial cable to the SO-239 connector on the back side of the OM-1.
The other end of the cable should be connected to an antenna tuner or some sort
of pre balanced load, such as an antenna, dummy load, laser plasma tube etc. .

6. Turn on the power supply, the fan should start running on the top of the OM-1.
Turn on transmitter with a connected appropriate load . It is important that SWR
values be balanced. The OM-1 has been tested for prolonged operational times
with poor SWR’s . It has survived 30 minutes operation with SWR’s of 3 to 3.5.
If your antenna or load is not balanced to the OM-1, you will risk damaging the
OM-1. It is highly suggested that you balance SWR using an impedance matcher
of some sort ( antenna tuner) between the OM-1 and it’s load.

7. Turn on frequency generator set to about 3000 Hz . Slowly start increasing output
power level of your frequency generator until power level of the OM-1
maximizes. This power level is best seen on the SWR meter of an antenna tuner.
Continue to increase audio level until power output of transmitter drops. Once a
drop in power level is noted, quickly reduce audio output level from the frequency
generator until power output of the OM-1 once again maximizes. Note where this
output is, then decrease output level of the frequency generator till power starts to
drop. Note where this level is. Operate the OM-1 at an output level half way
between these maximum and minimum audio output settings. Do not drive the
OM-1 on the edge of maximum audio input voltage!

8. In most applications the output level of a frequency generator can be set at
between 0.3 and 0.5 volts P-P using an oscilloscope. Some frequency generators
do not have much current output and these may take from 3 to 7 volts p-p to
maximize output of the OM-1.