MFJ-9420 Installation Manual
20-Meter SSB Travel Radio
STEP-BY-STEP INSTRUCTIONS USING YOUR MFJ-9420
TRANSCEIVER
STEP 1. Connect a suitable microphone, power source, and 20-Meter antenna.
STEP 2. Turn VOLUME fully counter clockwise (down) and press ON switch to power up
radio. PWR indicator should light.
STEP 3. Turn VOLUME clockwise for a comfortable listening level.
STEP 4. If you are using an antenna tuner, adjust ATU controls for strongest received signals or
maximum background noise on the S-Meter. Then, press CARRIER to generate a
steady RF signal for final adjustment. Red XMIT indicator should light.
STEP 5. The VFO tuning range covers 14.150-14.350 MHz and the MFJ-9420 tuning dial was
carefully calibrated at the factory. However, by nature an analog frequency readout may
be subject to some inaccuracy or misinterpretation. To ensure compliance with FCC
rules, we suggest the following:
(a.) Periodically check the VFO dial with a digital transceiver or counter to confirm
location of band edges.
(b.) Avoid transmitting on the margins of your allocation unless you are certain the
station you are calling is in "in band."
STEP 6. To transmit, press the mic's PTT switch and speak at normal conversational level with
the mic held about 2 inches from your mouth. The MFJ-9420 has a very potent speech
processor and will pick up your voice at full intensity. Avoid the natural temptation to
yell or close talk this will only overload the processing circuit and hurt the intelligibility
of your signal!
SPECIAL OPERATING NOTES
The MFJ-9420 does not have automatic high VSWR shutdown and you must provide a
"reasonable" 20-Meter antenna to ensure proper operation. Whenever possible, use a low SWR
resonant type antenna such as a dipole or tuned vertical. If you use an ATU (or a high Q loop
such as the MFJ-1786 or Isopole 10 30), carefully rough tune first for maximum S-Meter
readings before activating the CARRIER switch.
Under FCC Rules, licensed amateurs are solely responsible for the frequency of operation of
their transmitters. MFJ cannot be held responsible for out of band operation due to
misinterpretation or miscalibration of the MFJ-9420 analog VFO dial.
