(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 mike's PTT switch and speak at normal conversational level with the mike
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.
COAXIAL FED DIPOLES: A wire dipole for the phone band should measure about 32'10" (16'5" per leg).
Feed with RG 58U or RG 8X; raise high and in the clear for best performance. If you have only one high
support, make an inverted V. The "full sloper" (sloping dipole) is also an excellent single support antenna
with some directivity.
MFJ 1772 PORTABLE DIPOLE: As an alternative to making a coax-fed dipole, consider purchasing the
pre assembled MFJ 1772 antenna. This is a no compromise 20 Meter folded dipole complete with 30' of
feedline all made from ultra light weight 300 Ohm twinlead. Connect a random length of coax from the
MFJ 1772 feedline to your rig and let the antenna's built in 50 Ohm matching network do the rest. The
antenna is pre tuned, easy to handle, and sufficiently broad banded to cover both the CW and phone band.
WARNING: CONSTRUCTING OR ERECTING AMATEUR RADIO ANTENNAS IN
LOCATIONS WHERE THEY MAY COME INTO CONTACT WITH ELECTRICAL POWER LINES
MAY RESULT IN ACCIDENTAL INJURY OR DEATH!
While spanning the globe with a small portable rig like the MFJ 9420 may SOUND difficult, it really isn't.
High power and big antennas have never been a requirement for world wide radio communication and still
aren't. Despite the vast distances involved, hams consistently reach every corner of the planet running far
less power than your MFJ 9420. How do they do it? Here are some proven tips guaranteed to work:
GROOM YOUR ANTENNA:
Inspect and clean all traps and contacting surfaces. Replace corroded hardware, dirty connectors, and aging
coax. Retune for minimum SWR in the phone band.
Raise wire dipoles high and in the clear 40 to 60 feet is far better than 10 or 20. Carefully prune for
minimum SWR. If you have only one high support, install an inverted V or sloper.
Multiband verticals (1/4 wave types) require at least 4 good 14 MHz radials add them if needed. Clean up
corrosion and adjust your top section for minimum SWR in the phone band.
Avoid "compromise" antennas. When it comes to pure operating enjoyment, every dB you gain at the
antenna pays big dividends!
USE PROVEN DX OPERATING TECHNIQUES:
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