Icom IC-22S PLL Synthesized 2-Meter Transceiver
Instruction Manual and Service Notes
5
impedance is recommended for fixed or mobile operation. In VHF as well as HF, every watt
o ERP effective radiated power will make a difference. Therefore, 10 watts output into a 3
db gain antenna yields 20 watts effective radiated power, assuming a low VSWR, of course.
Therefore the few more dollars invested in a gain type antenna is well worth it.
When adjusting your antenna – mobile or fixed – by all means follow the manufacturer’s
instructions. There are some pitfalls to be aware of. For example, do not attempt to adjust
the antenna for lowest VSWR when using an SWR bridge not intended for VHF use. Some
instruments will give readings with as much as a 40% error. A Drake WV-4, Bird model 43,
or Sierra model 164B with VHF cartridges
The RF coaxial connector on the rear chassis mates with a standard PL-259 connector.
Some models may have metric thread. In any event, the RF connector will mate with almost
any PL -259 connector if care is taken to seat them properly.
Microphone
A high quality dynamic microphone is supplied with your transceiver. Merely plug it into the
proper receptacle on the front panel. Should you wish to use a different microphone, make
certain it is of the high impedance type; at least 500 ohms or better. Particular care should
be exercised in wiring also, as the internal electronic switching system is dependent upon it.
See the schematic for the proper hookup. Under no circumstances use a “gain preamp” type
microphone. The audio system in your transceiver is more than adequate and additional
pre-amplification is unnecessary. To use this class of microphone is to invite distortion.
Synthesizer Programming
Your transceiver does not need crystals to set the frequency. It has 22 channels selected by
the channel selector switch. In addition, the channel selected has three options of how the
Offset is handled: receive and transmit on the programmed frequency (SPX), receive 600
kHz higher than the programmed frequency (DPX A), and transmit 600 kHz above the pro-
grammed frequency (DPX B). The programming is done on the diode matrix board by
soldering computer grade diodes into the boards in the locations indicated on the diode
matrix diagram. Please refer to the chart on pages 22~24 for the locations.
