PRO2004.5 Part 2/4 Searching The SEARCH facility found on most programmable scanners allows the entry of a pair of frequencies, then by pressing a key, the radio searches frequencies between those limits. The PRO-2004 allows for 10 pairs of lim- its! These pairs of limits are stored in their own memory, and don't use up any of the conventional 300 memory channels. One can set up several search pairs, for instance: - 46.610-46.970 MHz: cordless telephones - 144-148 MHz: the 2 meter ham band - 30.01-30.56, 32-33, 36-37 MHz: US Govt Another unique feature is the MONITOR key, which stops the search and stores the frequency in one of ten special monitor memories. These memories are separate from the 300 main memory channels. The search can be restarted from where it left off by striking the up or down arrow key. The user can select the search direction (up or down), and step size of 5, 12.5, or 50 KHz, although the PRO- 2004 is intelligent enough to select a default step size based on the frequencies being searched. The owner's manual claims that a step size of 30 KHz is also available, but apparently this step size was disa- bled when the cellular telephone frequency coverage was removed. The selected parameters are displayed on the LCD panel. Search speed is switchable between slow and fast, with fast search being about 14 increments/second (versus 12 for the 800XLT). For a 12.5 KHz increment, this translates to 11.2 MHz/minute (versus 9.6 MHz/minute for the 800XLT). The DIRECT key allows one to start searching up or down from whatever frequency is on the display. Let's say the scanner is in MANUAL mode, and set at channel 26, which contains 460.100 MHz. Striking the DIRECT then UP-ARROW keys starts the PRO-2004 searching upwards from 460.100. This is a nice feature. The PRO-2004 contains a "window detector" circuit, which is called into play during a SEARCH operation. This circuit tries to detect when the radio is tuned close to the center frequency of a station, and prevents the search from halting prematurely, off to the side of the signal. The AFC (automatic frequency control) circuit of the Bearcat 800XLT often causes a search of 850 MHz signals to halt prematurely. Even though the signal sounds on frequency, the display reads the wrong frequency. The PRO-2004 does not have this problem. Another interesting feature is the SOUND SQUELCH, which may be used during scan or search operations. With the the sound squelch enabled, signified by a red lamp above the pushbutton, the scanner will skip over unmo- dulated signals. This is handy for skipping over "bir- dies", or link signals with a constant carrier. According to the owner's manual: - "When the PRO-2004 stops at a frequency which has no sound, it remains there for 0.5 seconds, and then goes to the next frequency if" no sound is detected "within that time." "When a frequency which contains sound is received, it halts at the frequency. But, a. If the sound ceases during the reception, it stays on the frequency for 5 seconds, and resumes scanning." b. "If the [station] stops sending a carrier, the unit reverts to scan [or search] immedi- ately if DELAY is off, after 2 seconds, if the DELAY is active." The manual warns that the sound squelch may be fooled by signals with low modulation, and skip over them. The PRO-2004 SOUND SQUELCH tries to detect the presence or absence of modulation (not human speech), so unfor- tunately, it thinks that mobile phone idle tones, digi- tal data signals, and paging tones are worth monitoring and will stop the scanner to listen to them.  Downloaded From P-80 International Information Systems 304-744-2253