PS-90 REVIEW ------------ HERE IS ANOTHER NIFTY MODIFICATION THAT YOU CAN MAKE TO YOUR PRO-2004 OR PRO-2005 RADIO SHACK SCANNERS, THIS IS A DRAMATIC ENHANCEMENT THAT I HAVE YET TO TRY... ARTICLE FROM: POPULAR COMMUNICATIONS JULY 1990, pg. 32. REVIEWED BY: BILL CHEEK REPRINTED BY: JOHN JOHNS0N, KWV8BP OF THE HOTLINE BBS.. 304-736-9169 PRODUCT REVIEW: AN AUTOMATIC POWER SEARCH & STORE MODULE FOR YOUR PRO-2004 OR PRO-2005. Pop'Comm readers were recently introduced to an innovation for the Realistic PRO-2004 and RO-2005 programmable VHF/UHF scanners, the Model SS-45 Search & Store Module, by Key Research Co. You will recall from my last review how the SS-45 provices a special SEARCH mode to STORE new found frequencies in the scanner's ten MONITOR channels. The S-45 Search & Store Module allows the scannist to "discover" up to ten new frequencies in a "hands-off" unattended mode while asleep or at work. The main limitation of the Search & Store Module is that a maximum of ten new frequencies can be found and stored in one session because there are only ten MONITOR CHANNELS available in the PRO- 2004/2005. Key Research Co. has done it again! There is now a Power Search & Store Module, Model PS-90, which takes up where the SS-45 leaves off. The PS-90 has two seperate modes of operation, the first being a SEARCH & STORE function exactly like the SS-45 module. In that mode the PS-90 can find and store up to ten new frequencies in the MONITOR CHANNELS, completely hands- off while the operator is away from the scanner. But then the PS-90 takes off into uncharted territory with its unique second mode, the POWER SEARCH & STORE function. This mode allows up to 255 newly found frequencies to be stored in the perm- anent MEMORY channels, the exact number of which is determined by the operat- or! In other words, the POWER SEARCH & STORE function transfers each new found frequency to a predesignated permanent MEMORY channel. When the allo- cated MEMORY channels are filled by the POWER SEARCH & STORE function, oper- ation automatically stops until the operator intervenes. Like the SS-45, the PS-90 is designed to work only with the Realistic PRO-2004 and PRO-2005 scanners. Electronically speaking, the PS-90 Power Search & Store Module performs the same actions that the operator would manually perform during a conventional SEARCH operation. For example, the conventional SEARCH mode halts on an active frequency for the time a signal is present. To store that frequency, the operator must first press the MONITOR button on the keyboard. Then the operator must press ENTER to store that frequency in a permanent MEMORY channel. SEARCH automatically resumes after the ENTER key is pressed. At the same time, the MONITOR channel and the MEMORY channel each advance by one to await the next operation. That's the manual way to fully utilize the SEARCH function of the scanner, but the PS-90 does it for you. Drawbacks or disadvantages of the Power Search & Store Module, like with the SS-45 are practically nonexistent, but there are limitations. One is that the PS-90 like the SS-45, will sometimes "hang up" or stop in the middle of its sequence if and when a very short burst of RF signal breaks the SQUELCH at the moment the SEARCH mode scans that frequency. If the RF signal disappears before the SEARCH & STORE sequence is completed (about a tenth of a second), the SEARCH & STORE operation will stop until the SQUELCH breaks again. It could be seconds, minutes, or even hours on quiet frequencies before another signal comes in to restart the SEARCH & STORE sequence. The operator can, of course, intervene at any time to manually restart the sequence. This limita- tion, as with the SS-45, is more a function of receiver and external factors, than any inherent short-coming of the PS-90. Operation of the PS-90 Power Search & Store Module is solely from the Key- board (at the touch of a key) and can be activated or deactivated at any time by the operator. All functions of the scanner remain normal and intact. There are no external switches or controls. The PS-90 circuit board comes fully sealed, fully assembled and ready to install. There are five integrated circuits, seven diodes, twenty resistors, six capacitors, an 8-segment DIP switch and ten interconnect wires, this makes for a sophisticated pakage of high technology! Installation is incredibly easy with ten wires to solder, and the solder points are very accessible. There is no mojor disassembly required; no holes to drill; no wires or circuit patterns to cut; and no controls to install. The installation process took me maybe twenty minutes, but it took that long because I was very careful and critical as I went along! The PS-90 lays flat against the back of the angled keyboard in the PRO-2004. In the PRO-2005, the PS-90 is installed behind and perpendicular to the key board panel. The installation instructions and procedures are clear and straightforward for both radios. When I installed the PS-90 Module in my PRO-2004, a problem was first en- countered that caused considerable dismay to Key Research Co. and me until we figured it out. Most hobbyists will not encounter this, but the details are related here for those scannists who have "turbocharged" their PRO-2004's or 2005's. One modification for increased SCAN and SEARCH SPEEDS calls for the 7.37 MHz clock oscillator resonator, CX-501, to be replaced with a cer- tain frequency quartz crystal. I had previously done this to obtain turbo speeds of 15 & 30 channelsper second for my PRO-2004. Then, when my PS-90 module didn't work properly, it took some time to determine that the turbo speed wasn't compatible with the electronic timing requirements of the PS-90 Module. When I removed the new crystal and reinstalled the stock CX-501 res- onator, voila: perfect operation of the POWER SEARCH & STORE function!! Subsequent experimentation revealed that a milder turbo speed was OK and I finally settled on another crystal which yielded CAN and SEARCH speeds of 12.5 & 25 channels per second, and the PS-90 Module still works great.. My PS-90 works fine now, but those who have modified their PRO-2004/2005's should be aware that some modifications might not be compatible with the POWER SEARCH & STORE function. There is a 30-day "no questions" guarantee and a 90-day guarantee against defects in parts or workmanship. The PS-90 Power Search & Store Module is available from: Key Research Company P.O. Box 5054 Cary, NC. 27511 This product was reviewed by: Bill Cheek in Popular Communications Magazine. Reprinted by: John Johnson, KWV8BP of The Hotline MBBS 304-736-9169