SWR-3 SWR/POWER METER INSTALLATION MANUAL
POWER METER AND STANDING WAVE BRIDGE
The SWR-3 is a handy, compact device for the
amateur radio station in checking transceivers
operator. For SWR measurements, Model SWR-3
uses the bridge method of comparing the voltage
supplied to and reflected from the antenna systems.
The operation can accurately and quickly match the
antenna to the transmitter. For RF power
measurement, the average voltage form a carrier
detector is measured. Continuous monitoring of
the transmitter output is possible by having the instrument in the circuit at all times. The indicator can also be used as a
field strength meter by disconnecting it from the feed line and attaching the small pickup antenna, included.
OPERATION
SWR Measurement
1. Turn the transmitter of and disconnect the antenna coaxial cable at the output.
2. Connect the SWR-3 “TRANS” connector to the transmitter output, and “ANT” to antenna connector. As short
cable equipped with male connectors on both ends will be required between the transmitter and the meter.
3. Set the slide switch to “SWR” and “FWD”. Rotate the “SET & FS ADJ” counterclockwise to near minimum
position.
4. Turn the transmitter on, rotate the “SET & FS ADJ” for full scale, “SET” position on meter.
5. Next, set the slide switch FWD/REF to “REF” and read the meter scale. The meter will give the SWR reading
directly.
6. A 1:1 ratio is the ideal match. Adjustments on the antenna system should be made so that the SWR is as low as
possible. A SWR of 2.0 is considered satisfactory, taking into account the line losses and slight mismatching.
The operator is referred to the numerous articles in radio magazines and books dealing with various proper
matching methods of different types of antennas. NEVER attempt to adjust the set to the antenna.
7. The power required for the SWR bridge operation is dependent on the frequency; about 25 watts of 3.5 MHz, 15
watts at 7 MHz, and proportionately lower power at higher frequencies. If the transmitter power is not sufficient
and a full meter swing cannot be achieved, adjust the antenna system for the lowest possible swing at the “REF”
position of the slide switch.
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