Icom IC-720A Instruction Manual page 7

For AC operation it is recommended that the optional
BC-10A be used.
3-5 ANTENNA
Antennas play a very important role in radio communi-
cation.
give you the best performance. With a good antenna and
feeder cable having 50 ohms impedance, you should easily
get the desired matching and performance. Carefully install
a high performance antenna that suits the frequency band(s)
you wish to operate on and place it as high as possible. Be
especially careful
of the condition
of the connectors
as
loose connections will deteriorate the performance. Be sure
to connect the ground terminal of a whip antenna, if used,
to the body of your car.
As the output is quite high, avoid connecting the antenna
connector to open lines and do not transmit under mis-
matched conditions. Otherwise the final stage could be
overloaded and cause a malfunction of the unit.
Since the 1С-720А has a General Coverage receiver it is
recommended that а long-wire general coverage antenna апа
an antenna coupler be used. Тһе antenna's impedance
should be 50 ohms. To attempt to use the Ham band
antenna for general coverage reception could result in
mismatching, and attendant poor reception.
When receiving lower than 1600KHz, connect the antenna
to the "СОМ BAND ANT" terminal.
(Refer to page 21.)
3-6 GROUND
In order to prevent electrical shocks, ТУІ, BCI and other
problems, be sure to connect a heavy wire ground, as short
as possible, from a good earth point to the ground terminal
on the rear panel.
3-7 MICROPHONE
The microphone supplied with the 1С-720А is the ІС-НМ7
which contains а pre-amplifier. The optional electret
condenser type stand microphone IC-SM5 can be used.
Their circuit diagrams are shown.
Should you wish to use a different microphone, make
certain it has a proper рге-атр ћег.
If the antenna is inferior, your transceiver cannot |
Schematic diagram of 1С-НМ7
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00047
00047
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Schematic diagram of ІС-5М5
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Microphone plug exploded View
3-8 CW KEY
When operating CW, connect the Key to the Key Jack
with
the plug supplied.
The connection
of the plug is shown
below.
| Kev Wiring Diagram