AWM-35B/H Mobile SWR/Wattmeter Instruction Manual
AMERITRON AWM-35B/H
MOBILE SWR/WATTMETER
INSTRUCTION MANUAL
PLEASE READ THIS MANUAL BEFORE OPERATING THIS EQUIPEMENT!
Version 2B
116 WILLOW RD
STARKVILLE , MS 39759 USA
662-323-8211
www.ameritron.com
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AWM-35B/H Mobile SWR/Wattmeter Instruction Manual
OPERATION
The AWM-35B/H SWR/Wattmeter’s unique two-unit design, with a
control unit and a remote sensor, permits convenient “remote” placement
of the sensor in both mobile and home stations.
The AWM-35B/H’s cross needle meter displays peak or average
FORWARD power, peak or average REFLECTED power, and SWR, all
simultaneously. The control unit’s REF IND (Reflected Indicator) is a
warning lamp for low and high-power operation; the lamp illuminates
when a factory setting of 2:1 VSWR is reached. To change the factory
default see ADJUSTING REF IND.
A 12 volt DC power source is required for the meter to function. An
external 12 VDC source can be provided via a jack on the sensor unit, or
a 9 VDC battery can be installed inside the control unit. When an
external power source is used the unit is enabled at all times and comes
on when RF is sensed. When battery power is used, the battery is
connected by the PWR ON/OFF pushbutton. Under battery power, the
meter lamp and REF IND indicator lamp do not function, to conserve
battery life.
Full scale forward and reflected power range is selected by the RANGE
HIGH/LOW pushbutton. If your transmitter runs more than 300 (H100)
watts of peak output power, set this switch to the 3000 (H to 1000) watt,
HI position (in). If your transmitter runs less than 300 (H100) watts peak
output power, set the push button to the 300 (H to 100) watt, LOW
position (out). Peak envelope power (PEP) is measured by placing the
PEAK/AVG switch in the “in” position.
Peak and average power values are equal with steady unmodulated
carriers such as closed-key CW, RTTY, FSK, or FM. The meter reading
on these modes will be the same in either peak or average modes. On
SSB, the ratio of PEP to average power varies with different voice and
modulation characteristics. With most voices the PEP reading is three to
five times higher than the average voice power reading.
The left hand FORWARD meter scale displays forward power in a scale
from 0 to 300 (H to100) watts. In the LO power position the reading is
made directly; (H model is a division of 10). Each picket (scale mark)
represents 5 (H2.5) watts below 10 (H 20) watts, 10 (H5) watts between
10 (H20) and 100 watts, and 25 watts between 100 and 300 watts. In the
HIGH power position, multiply the meter reading by ten (H reading is
directly).
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