Subject: Realistic PRO-2022 Cellular Restoration

From: [email-masked]
Date: 30 Sep 91 13:50:04 GMT

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.]