From cbfsb!att!ucbvax!ihlpm.UUCP!rats Tue Oct 1 23:47:21 EDT 1991 Article: 10184 of rec.radio.shortwave Path: cbfsb!att!ucbvax!ihlpm.UUCP!rats From: rats@ihlpm.UUCP Newsgroups: rec.radio.shortwave Subject: Realistic PRO-2022 Cellular Restoration Message-ID: <9109301350.AA24169@ucbvax.Berkeley.EDU> Date: 30 Sep 91 13:50:04 GMT Sender: daemon@ucbvax.BERKELEY.EDU Lines: 49 Cellular Restoration on the Realistic PRO-2022 The Realistic PRO-2022 certainly is a look-alike for the all-time popular, but now-discontinued, PRO-2005. But is the similarity only cosmetic? What tricks can be done to increase the utility of the lower-cost 2022, now availible from Radio Shack and Grove Enterprises? Of the greatest interest, can cellular phone coverage, censored at the factory, be restored? Yes. After removing the two upper back screws and the top lid, locate the black cable just behind the front panel. Adjacent to the cable are four diodes locations: D42, D43, D44 and D45. D42 is not present; installed, it adds the 68-88 MHz European mid band (which includes the US 76-82 MHz mid band), removing the US 30-54 MHz low band. Even if a switch were installed to allow the diode to be selected, additional components and realignment are necessary for that higher frequency coverage. Don't do it! D43 is present, allowing the 800 MHz band to be received; the diode may be deleted so that the same microprocessor may be used in scanner modles which don't have that 800 MHz capability. Don't touch it! D44 is present, deleting the cellular mobile and base frequencies. If one lead is cut, total 806-960 frequency is restored, including 30 kHz steps in the cellular band. Keep in mind, however, that mobile telephone eavesdropping is prohibited by the Electronic Communications Privacy Act! This modification may void your warrenty; it is best to cut the lead carefully, gently separating the gap slightly so that it may be resoldered in case the radio needs warrenty repair later. D45 is not present; installed, it makes the cellular 30 kHz increments change to 12.5 kHz. A small SPST switch connected in series with one lead of a 1N914 or 1N4148 could allow selection of the 25 kHz step interval in those areas which utilize that channel spacing. To do this, it is necessary to unsolder a shield under the circuit board which covers the solder pads for the diodes. Such a modification should only be attempted by someone familiar with electronic circuitry. [Excerpted from Monitoring Times, June 1990, page 89.]