MFJ-9412 Instruction Manual
12-Meter SSB Transceiver
4
QUICK-START OPERATING INSTRUCTIONS
•
Power Supply:
Use any regulated 13.8-Volt 3-Amp supply or comparably-rated 12-
Volt battery. Connect power via a 5.5 OD x 2.1 mm coaxial power plug (Radio Shack
274-1569):
[+] lead must be attached to the connector center pin.
+
-
•
Microphone:
The MFJ-290 dynamic microphone compliments your radio's speech
processor, but other 600-ohm PTT microphones may be used with a 5-pin DIN
connector installed as shown below (use Radio Shack 274-003). Amplified
microphones
should not
be used with the MFJ-9412.
1
4
2
5
3
Pin 3 = PTT Line
Pin 4 = Mic Line
Pin 1,2,5 = Ground
Mic
PTT
Gnd
•
Antenna Selection:
Use any vertical or horizontal 12-meter antenna exhibiting a
VSWR of 2:1 or less. A simple dipole or groundplane is adequate for casual
operation, but a 3-element yagi or 2-element quad yields better DX performance.
Important Note:
Avoid using antennas with unknown or high VSWR. The MFJ-9412
does not provide automatic high-VSWR shutdown circuitry. Operation into extremely
reactive loads may result in out-of-band spurious emissions in violation of FCC rules!
•
Speech Processing:
The MFJ-9412 processor rapidly readjusts transmitter IF gain for
each spoken syllable. For best results, hold the Mic about 1-2" from your lips and
speak normally. The S-meter should deflect 1/2 scale as you speak.
Important Note:
Transmit meter deflection will be affected by high-VSWR loads. If the
meter deflects beyond S9 or holds below S4 with normal speech, check your antenna. A
VSWR of 2:1 or less is normally considered acceptable for amateur service.
•
Connecting a Power Amplifier:
The MFJ-9412 provides a built-in FET switch to
key an external amplifier. Be sure to follow all manufacturer's instructions carefully
when installing an amplifier at your station. The
Ext Amp
jack provides closure to
ground during transmit.
•
Choosing an Operating Location:
Set your station up in a sheltered and dry
location. Avoid operating in direct sunlight--the radio's black case may absorb
excessive heat that can impair normal operation or damage internal components.
