From: rats
Newsgroups: rec.radio.shortwave

Subject: Realistic PRO-2022 Cellular Restoration

Message-ID: <9109301350.AA24169
Date: 30 Sep 91 13:50:04 GMT

Sender: daemon
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.



D42is 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!

 

D43is 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!

 

D44is 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.



D45is 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.]






SOURCE: The QRZ Windows Ham Radio CDROM