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 |
