CONNECTIONS
Power Source:
Use any well-filtered DC power supply or battery pack with output in the
8-15 VDC range and capable of 1.5-Amps or more.
DO NOT connect the MFJ-9200 to a
source exceeding 15 VDC or permanent damage may result.
Power Connection:
Use a standard 2.1-mm concentric power plug with plus (+)
connected to the center and ground (-) connected to the outer sleeve. The MFJ-9200
has a built-in series diode to protect against accidental reverse-polarity connection, but
we also strongly recommend
fusing the plus (+) lead of your power source at 2-A
to
provide over-current protection in the event of an accidental short or component failure.
+
_
2-A Fuse
2.1-mm Plug
Antenna:
The antenna jack accepts a standard BNC male connector or BNC-to-UHF
adapter, as required. Connect any coax-fed resonant antennas with SWR measuring
under 2:1 directly to the radio. Antennas exhibiting higher SWR or using balanced
feeders should be matched to 50-Ohm unbalanced line using an external antenna tuner
(ATU). Never intentionally transmit into high-SWR loads, as extreme mismatch may
cause the radio to emit out-of-band signals exceeding FCC guidelines. A prolonged
high-SWR condition may also damage internal components.
Headphones:
Use any 8 to 32-Ohm stereo headset outfitted with a 3.5-mm stereo plug.
Note that the radio’s audio output circuit
is not wired to accept monaural plugs.
Connecting phones or a speaker wired with a monaural plug will shunt the audio signal
to ground. To obtain monaural output, use a 3.5-mm stereo plug and leave the ring
disconnected.
Tip
Ring
Sleeve
Right
Left
Ground
Tip
Ring
Sleeve
Ground
NC
Audio
Stereo Phones
Monaural Phones
Paddle or Straight-key Wiring:
Configure paddles with a 3.5-mm stereo plug. Connect
the dot contact to the tip, dash contact to the ring, and ground to the sleeve. Configure
manual keys using a monaural plug with the contactor connected to the tip. If using a
stereo plug with a manual key, connect both the ring and sleeve to ground.
Tip
Ring
Sleeve
Dot
Dash
Ground
Tip
Sleeve
Ground
Contactor
Paddles
Manual Key - Monaural Plug
Tip
Ring
Sleeve
Ground
Ground
Contactor
Manual Key - Stereo Plug