Welz SP-15M SWR Meter
- Thread starter heathkit
- Start date
G4HAA
Administrator
Hiya Graham
I couldn't find an original instruction sheet for the SWR meter you have there, but the operation of the unit is pretty much the same as many of the modern SWR meters.
1.8-150MHz Frequency Range
Up to 200 Watts
Three switched power ranges: 2.5W - 20W - 200W
To use the switched (i.e. pre-set) power ranges, place the "Function" switch in to the "Power" position, and select the appropriate power range (equal to or greater than your expected transmitter output level) using the "Range" switch.
Use the "Power" switch to select either forward power (energy supplied to the antenna), or reflected power (unradiated energy returning from the antenna). If you use a 50 Ohm dummy load, and the "Power" switch on the SWR meter is set in the "Forward" position, then you will be able to read off your transmitters' output power level.
It's better to use a dummy load for power measurement as reactive loads (like antennas) can give misleading results on some meters, especially as the amount of reflected energy increases (i.e. a high SWR).
To use the adjustable power range, place the "Function" switch in to the "Cal" (short for calibrate) position. Starting with the variable calibration control fully anti-clockwise, select a mode on your transceiver that will produce a continuous carrier e.g. CW, FM etc.
While transmitting, slowly rotate the Calibrate control clock-wise until the pointer on the meter scale just reaches the "Cal" marker (marked with a small triangle on the top scale of the meter movement).
Cease transmitting for a moment and change the "Function" switch to the "SWR" position.
Transmit again, while reading off either the level of reflected energy, or the SWR.
Best 73, Mark.
I couldn't find an original instruction sheet for the SWR meter you have there, but the operation of the unit is pretty much the same as many of the modern SWR meters.
1.8-150MHz Frequency Range
Up to 200 Watts
Three switched power ranges: 2.5W - 20W - 200W
To use the switched (i.e. pre-set) power ranges, place the "Function" switch in to the "Power" position, and select the appropriate power range (equal to or greater than your expected transmitter output level) using the "Range" switch.
Use the "Power" switch to select either forward power (energy supplied to the antenna), or reflected power (unradiated energy returning from the antenna). If you use a 50 Ohm dummy load, and the "Power" switch on the SWR meter is set in the "Forward" position, then you will be able to read off your transmitters' output power level.
It's better to use a dummy load for power measurement as reactive loads (like antennas) can give misleading results on some meters, especially as the amount of reflected energy increases (i.e. a high SWR).
To use the adjustable power range, place the "Function" switch in to the "Cal" (short for calibrate) position. Starting with the variable calibration control fully anti-clockwise, select a mode on your transceiver that will produce a continuous carrier e.g. CW, FM etc.
While transmitting, slowly rotate the Calibrate control clock-wise until the pointer on the meter scale just reaches the "Cal" marker (marked with a small triangle on the top scale of the meter movement).
Cease transmitting for a moment and change the "Function" switch to the "SWR" position.
Transmit again, while reading off either the level of reflected energy, or the SWR.
Best 73, Mark.