REVIEW OF ICOM IC228H 2M TX/RX ============================== PRODUCT REVIEW: ICOM IC-228H 2M TRANSCEIVER by Bob Parnass, AJ9S Part 2 of 2 Icom took cues from the Kenwood TM2530 series to improve the LCD display panel and make the front panel controls visible in the dark. The display on the IC228 makes use of colored backgrounds for various fields, and is easier to read than the display in the IC28. Unlike the IC28, the IC228 emits a beep tone each time a key is depressed. Although some people find this feature annoying in walkie-talkies, the beeps make it more convenient to operate the IC228 while driving. Icom recognizes freedom of choice, and permits the user to disable the beep. The volume, squelch, and tuning knobs, as well as several buttons, are now backlit - an improvement over the IC28. The IC28 contained a photocell which automatically varied the LCD backlighting with changing ambient light levels, however the newer IC228 permits the user to select from 4 fixed levels of backlighting. There is no free lunch, and Icom fans had to give up something in exchange for the new control backlighting: the plastic front panel and tuning knob on IC228 feel chintzier than the metal panel and rubber padded knob on the IC28. Another new feature is a "lock" pushbutton, which disables the radio's front panel controls. I haven't found this as useful as the lock slide switch on the DTMF up/down microphone. The up/down pushbuttons on the microphone can be bumped accidentally in the mobile environment, and the slide switch prevents unplanned frequency changes. The IC228's scanning features are on par with, or slightly above those of other 2 meter transceivers, but not as well implemented as in "real" scanners. The IC228 scans at the same speed as the 28 - rather slowly. A reasonable memory scan, with channel lockout, is provided. This is an improvement over the early Kenwood TH-215 walkie-talkie memory scan, which lacked a lockout feature, so one was forced to scan ALL channels.(2) The timer operated scanning in the IC228 causes the radio to resume scanning 2 seconds after the carrier drops, or after 15 seconds - whichever occurs first. Too bad the IC228 lacks a carrier operated mode, like the feature in the Kenwood TM2530, so the receiver would "stay put" until the carrier drops. The IC228 includes the ability to search between 2 frequency limits, and users of the American versions can select tuning steps of 5KHz or more. The search limits are programmed into a special register pair, so they don't tie up memory channels. The search will pause as soon as the squelch opens, which usually brings the receiver to a halt off the center of the station you want to hear. Unfortunately, Icom didn't adopt the Kenwood "center tuning" or Bearcat ZeromaticTM feature, which forces the searching to stop right on the center frequency. The Bearcat window detector circuit employs operational amplifiers, fed by the discriminator signal, to generate a logic level when the receiver is tuned within 2.5 KHz of center frequency. When the IC28 was first introduced, it was offered with either the standard or DTMF microphones, at two different prices. Apparently, most people wanted DTMF mikes, and a DTMF microphone is provided with the IC228. Except for the high heat sink temperatures, the IC228 performed well during a recent cross country trip. With the radio bolted to the center console of my truck, the receiver audio output was ample, the display easy to read day and night, and stations in Pennsylvania and Ohio praised the transmitted audio quality. I'm pleased with the IC228, and recommend it. 1. See "RF Hybrid Modules: Building with Bricks," by Bill Olson W3HQR, in July 1988 QEX. 2. Late vintage Kenwood TH-215 walkie-talkies now come with upgraded firmware which permits channel lockout. A new CPU chip may be retrofitted into earlier units, but Kenwood charges for this service. Bob Parnass AJ9S, AT&T Bell Laboratories (Downloaded from GB7SYP)