MFJ-216 Instruction Manual Deluxe Amplifier Saver
5
mode and depress the pulse tune button on the MFJ-216 Deluxe Amplifier Saver.
Tune the amplifier for peak output power.
Note:
Due to the response time of most non-peak-reading RF watt meters, the
meter will read a low average power, but the amplifier will be tuned for
full peak power.
While momentarily pressing the carrier tune button, the RF watt meter should
read full power of the amplifier. The amplifier is now tuned for full power.
For best linearity, it is best to reduce the transceiver's power slightly after tuning
the amplifier.
Testing QSK Systems
The MFJ-216 Deluxe Amplifier Saver can be used to evaluate QSK systems. In
one test configuration, a continuous signal source is loosely coupled to the
dummy load. The receiver is tuned to this signal source, and the MFJ-216
Deluxe Amplifier Saver controls are adjusted until the test signal is clearly
audible. The maximum QSK receive speed is found by measuring the PULSE
RATE, and multiplying the PULSE RATE by 2.4. The DUTY CYCLE should
be set for normal sounding CW dots during this test, or a 1:1 ratio.
The transmission wave shape can be checked by looking at the RF output on a
scope, with the scope triggered or synchronized to the keying line signal. A
normal CW signal has a smooth rise and fall time of about one millisecond, with
no overshoot or undershoot. Switching from manual operation to full QSK
should not disturb the keying wave form, or change the on and off time period.
Testing Watt meters
Watt meters can be tested by measuring the single tone power with a barefoot
exciter running off of a regulated supply, and adjusting an oscilloscope to read
near full screen with that carrier. By activating the MFJ-216 with the PULSE
RATE set approximately mid-range, and adjusting the DUTY CYCLE control
until the full peak envelope voltage is just displayed on the scope, the meter can
be evaluated. A good peak reading meter should indicate the same amount of
peak power with the MFJ-216 pulsing the carrier as it indicates with a
continuous carrier, as long as the maximum scope deflection remains the same.
RFI and TVI Troubleshooting
