REVIEW OF ICOM IC228H 2M TX/RX
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PRODUCT REVIEW:
ICOM IC-228H 2M TRANSCEIVER
by Bob Parnass, AJ9S

(Part 1 of 2 parts)

My Icom IC28A performed very well, and giving it to my wife afforded me the
opportunity to buy another 2 meter radio.

What do I look for in a 2 meter transceiver?  Being a scanner enthusiast, I
look for wide frequency coverage on receive, and reasonable scanning
facilities. Reliability and ease of obtaining schematics and parts are
important, and Icom, Kenwood, and Yaesu score well here.

I prefer 25 watt radios to 45 watt radios for a few reasons:

1.  I believe manufacturers overrate their transmitters' power specifications.
    Most models use hybrid modules for the driver/final amplifier stage. As a
    recent QEX article points out, the hybrid modules are only 25% - 50%
    efficient, which means the bulk of the power is dissipated in the form of
    heat.(1)

    The heat sinks on today's radios are just not big enough to dissipate
    the kind of heat developed during my typical QSO (conversation).  The
    heatsink on my old 25 watt Motorola MetrumTM never got nearly as hot as
    the heat sinks on late model 25 watt Japanese radios.  My 25 watt Kenwood
    TR-7800 and IC28A became very hot during QSOs.  Pity those who bought
    Kenwood's "45 watt" TM-221A transceiver.
    It's not until they read the owner's manual that they learned Kenwood
    recommends against transmitting for more than 1 minute out of 3.

    Heat shortens the already finite life of the hybrid modules, and I've 
    been forced to replace these modules on various radios, to the tune of
    over $55 apiece (not including my labor).

2.  It's easier to find power supplies for 25 watt radios, because they
    require only 6 - 7 amperes,  versus 9 - 10 amperes for their 45 watt 
    counterparts.  The smaller power supplies are less expensive and are
    easier to find surplus.

3.  Signals from 25 watt transmitters are almost as strong as those from 45
    watt radios.

The IC228A/H series is Icom's replacement for the IC28A/H two meter radios.  The tradition of offering two models at different transmitter power levels
continues, with the 25 watt IC228A and 45 watt IC228H.

The IC228 contains a single VFO, and 20 memory channels.  All the memory
channels behave the same, as contrasted with some Kenwood designs which limit
the flexibility of certain memory channels, while permitting special
operations with others.  Each IC228 memory channel can store receive
frequency, CTCSS tone, transmit frequency offset, and scan list lockout.

Unlike Yaesu radios, the IC228 comes equipped with a synthesized CTCSS (PLTM)
tone encoder, which is almost a necessity for using repeaters in the
Chicagoland area.  Any one of 32 tone frequencies can be selected from the
front panel, and associated with a memory channel or VFO.

Repeater offsets are selectable from 5KHz through 10MHz, and can be stored in
memory.  You could conceivably store 20 different repeater frequencies in the
 IC228, each with a different offset and tone.

I wanted the 25 watt IC228A, but only IC228H models were available at the
time.  I'm glad I bought the IC228H high power model, because an internal
potentiometer made it easy to reduce power output from 45 watts down to 25
watts.  The large heat sink affords extra cooling capacity, and the final
amplifier should last longer.  Even so, the heat sink becomes too hot to hold
during a moderately long QSO!  Heat is eventually transferred from the heat
sink to the entire radio case, making the entire radio "untouchable."

The major changes in IC228 circuitry from the IC28 design involve the
microprocessor.  The RF circuits remain similar, using the same transistor
lineup in the transmitter stages  and the now familiar Motorola MC3357 IF
detector/squelch chip popular in scanners.

Cont'd in part 2 of 2

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