Nissei RS-50M User Manual

WHAT IS IT?

The RS-50M SWR Power Meter helps to ensure your radio
installation is transmitting at it's best possible performance. By
testing your VHF radio at the radio, and at each junction point of
your antenna cable, you will quickly be able to determine if there is
an issue with your radio, a cable segment, or antenna that is
preventing your radio from transmitting to its maximum range.

QUICK GUIDE

FWD – Forward Power is the amount of power being transmitted

from the radio to the antenna in Watts.

REF – Reflected Power is the amount of power being reflected back
from your antenna in Watts.

SWR –Standing Wave Ratio is the ratio of FWD to REF power.

HOW DOES IT WORK?

The RS-50M will detect when the microphone button on the VHF
radio also known as PTT (push to talk) has been pressed, and
measures the Forward Power, Reflected Power and Standing Wave
Ratio.

The Forward Power (signal output) from the VHF radio is shown in
Watts under FWD. The power reflected back from the antenna due
to incorrect impedance between the VHF radio, antenna cable,
connectors and antenna is shown under REF for Reflected Power.
The Standing Wave Ratio which is a measurement of how efficiently
your radio is radiating the power it produces when you transmit is
shown under SWR. It is generally referred to as the ratio of FWD to
REF power. The smaller the number, the better the SWR reading.

An SWR reading of 1.00 is ideal but rarely achieved, meaning 100%
of your signal is transmitted with no reflected power.

1.00 to 1.50

Very good reading.

1.50 to 2.00

Okay, some issue may exist.

2.00 to 3.00

Significant loss. Serious issue exists.

3.00 and up

Potentially damaging amount of REF power to the
transceiver.

Note: The highest SRW values occur when the antenna is
disconnected or short circuited. Operating a VHF radio with the
antenna disconnected or short circuited can damage the radio.
Testing the radio with the RS-50M without the antenna attached
can also damage the radio.