AMERITRON AWM-20 User manual

This SWR & Power meter is a highly accurate RF meter for measuring Forward Power,
Reflected Power, and VSWR.
Main Features:
Large meter display for easy reading.
Forward RF power readings, switchable to indicate either average power of Peak
Envelop Power (PEP) for SSB and AM transmitters.
Reflected RF power readings.
VSWR ratios.
Illuminated meter.
Convenient control for easy operation.
Model AWM-20
Frequency Range 1.6 - 60 MHz
Power Range 1W to 3KW
Power Scale 30W, 300W, 3KW
Maximum Power 3KW (up to 1 minunte maximum)
Accuracy +/- 10% (AVG)
VSWR Min Power required = 3 Watt for F.S.D.
Input/Output Impedance 50 Ohms
Input/Output Connectors SO-239
Dimensions (W/H/D) in 7.5 X 4.25 X 3
Weight (lbs) 1 lb 11oz
Accessories Instruction Manual & Lead wire with DC Plug
Front Panel
Explanation of Features:
1. Meter Display: Indicates Forward/Reflected Power in Watts and SWR ratio.
2. Function Switch: Selects Forward Power, Reflected Power, SWR SET, and SWR.
3. Range Switch: Selects RF Power Ranges of 30W, 300W, and 3KW.
4. SWR SET Control Knob: Sets full scale deflection when measuring SWR.
5. AVG/PEP M onitor: Selects Average or PEP RF Power Readings.
6. Meter Zero adjust: Mechanical zero adjustment for meter needle.
7. TX Connector: Coax connector to transmitter 50 Ohm RF output.
8. ANT Connector: Coax connector to 50 Ohm antenna system.
9. 13.8V DC connection for meter illumination.
Note: If meter lighting is required, use the DC cable enclosed and connect it to a 13.8V DC
source.
Back Panel

FORWARD POWER MEASUREMENT
1. Set the FUNCTION switch to the ‘FWD’ position.
2. Set the radio transceiver to transmit and read the scale corresponding to the Power
range selected (30W, 300W, or 3 KW)
3. When the AVG/PEP button is ‘out’ the meter reads average RF power. When the
AVG/PEP button is depressed the meter reads Peak Envelope Power for use with SSB
and AM transmissions. In this mode there will be a slow rise and decay time.
REFLECTED POWER MEASUREMENT
1. Set the FUNCTION switch to the ‘REF’ position.
2. Set the radio transceiver to transmit and read the scale corresponding to the Power
range selected (30W, 300W, or 3 KW)
3. When the AVG/PEP button is ‘out’ the meter reads average RF power. When the
AVG/PEP button is depressed the meter reads Peak Envelope Power for use with SSB
and AM transmissions. In this mode there will be a slow rise and decay time.
VSWR MEASUREMENT
1. Set the FUNCTION switch to the ‘SWR SET’ position.
2. Set the radio transceiver to transmit mode.
3. Slowly turn the “SWR SET” Contol Knob clockwise until the meter point is at the
‘CALt’ position. This should be full scale.
4. Set the FUNCTION switch to the ‘SWR’ position while transmitting. The meter will
now indicate the SWR ratio.
CAUTION
1. Since the meter movement is very sensitive, avoid excess ive vibration or mechanical
shock to the unit.
2. The absolute maximum power that should be applied to the meter is 3KW. Also
observe maximum power inputs of 30W and 300W when unsing the lower two ranges.
3. The transceiver and antenna connections to the meter must never be reversed.
Always observe the correct connections to the transmitter and the antenna as
indicated on the back panel and in this Instruction Manual.
4. The meter has been carefully calibrated at the factory. Tampering with any of the
internal circuitry or sensors may cause damage and will degrade the accuracy of the
meter.
5. Do not expose the meter to excessive temperatures, high humidity, or strong magnetic
fields.
6. Power capability (measures short -term RF power up to 3KW):
SECONDS
WATTS
0
500
1000
1500
2000
2500
3000
60 70 80 90 100 150 200 600