parnass@ihuxf.UUCP (10/10/83)
- 1 - I recently purchased a Radio Shack PRO-30 synthesized handheld scanner. Here are some details: o+ Price: $300. o+ Batteries are not included. The PRO-30 requires 3 "hearing aid type" batteries for memory retention and 6 AA batteries. o+ Frequency coverage is fixed. The manual states: "In case you're wondering, the tuning range of your PRO-30 is permanently stored in the microprocessor chip. There's no way it can be extended or altered - even by a skilled electronics technician. So if you try to enter a frequency not in the PRO-30's tuning ranges, you'll get an error message every time!" o+ 30 - 54 (includes entire 6 meter ham band) o+ 108 - 136 (AM commercial aircraft band) o+ 138 - 174 (includes some military frequencies below the 2 meter ham band) o+ 380 - 512 (several military and "secret" US government frequencies in this range) o+ Semiconductor components: 1 LSI microprocessor, 1 LSI PLL chip, 3 CMOS chips, 5 other chips, 39 transistors, and 75 diodes! o+ Selectivity: +-9 KHz @ 6 db., +-15 KHz @ 50 db. o+ Scanning rate: Fast = 10 channels/second, Slow = 5 channels/second. o+ IF frequencies: 10.7 MHz and 455 KHz. o+ Current drain (not including memory backup cells): 55 mA squelched, 100 mA unsquelched at full volume. o+ Priority Sampling: 2 seconds. o+ BNC antenna connector. A multi band semi-flexible antenna is supplied. o+ The case is plastic, with a hinged, spring loaded belt clip on the rear. The inside of the case has been sprayed with some type of gold colored RFI shielding material. - 2 - o+ The keyboard buttons are made of a rubber type material, that compress slightly when depressed. An audio tone is used to confirm key depression. o+ Three pushbutton switches on the top of the unit dupli- cate functions on the front mounted keypad: a. Scan b. Manual c. Speed This allows the user to manipulate these functions while the scanner is worn on the belt. o+ The PRO-30 is made in Japan by GRE, the same company that makes Radio Shack's crystal controlled scanners. o+ The owner's manual contains a block diagram, but no schematic. I am told that a service manual, with schematic, will be available for sale. The owner's manual contains a list of "birdies." Some early impressions: o+ The scanner works quite well.1 o+ The instruction manual is pretty good, although a schematic should be included. o+ The scanner is bigger than the Bearcat BC-100. No leather case is available to protect the PRO-30, so the scanner could be "bruised" in heavy service. o+ The LCD display contains several status indicators, including a low battery warning message.2 The display __________ 1. The PRO-30 being reviewed is one of the first available in the northern Illinois area. Early models of complex radio equipment from other companies have been plagued by several problems. Examples are the Drake TR-7 transceiver, the Bearcat BC-100 and BC-300 scanners, and the Collins KWM-380 transceiver. 2. The user is also warned of failing batteries by a audio alarm. - 3 - is quite crisp and clear in good light, and when the internal dial light is activated. It is difficult to read under low lighting conditions and at various angles, a characteristic of LCD technology. o+ Striking a key does not always actuate the desired function. If a key is struck off center, the rubber key top compresses without actuating the switch mechan- ism. The user is made aware of this situation when no audio tone is heard after a key depression. A nice aspect is that the keyboard is less prone to damage if it is struck against the corner of a desk. o+ Sensitivity on UHF is at least as good as the several crystal controlled portable scanners I've aligned, maybe even better! o+ The internal construction looks decent. There are two printed circuit boards in the radio, connected via a multi pin connector rather than messy wiring harnesses. The component designations (e.g. R102, C212, etc.) are printed on the board. Resistors are 1/8 watt and mounted vertically. Layout appears clean, not over- crowded. o+ The priority scan feature works well and uses a "rea- sonable" algorithm, like that used in most Bearcat and Regency scanners.3 o+ Audio output circuitry uses the LM386 audio amplifier chip, producing about 220 milliwatts of audio power out.4 This is a bit on the weak side if your using the scanner in a truck, or wearing it in a noisy situation without benefit of an earphone. The audio is crisp and clean, without synthesizer noise. o+ The 2nd IF, FM detector and squelch circuitry is imple- mented using a Motorola MC3357 IC, now quite common in scanners.5 __________ 3. The algorithms used in most Japanese 2 meter ham radio transceivers, discussed in a previous article, are not very useful to American amateurs. 4. The LM386 is also used in the PRO-24 crystal controlled handheld scanner, reviewed in a previous article. 5. The squelch function works quite well and is not plagued by the hysteresis problem found in the PRO-24. -- ============================================================================ Robert S. Parnass, AT&T Bell Laboratories, ihnp4!ihuxf!parnass (312)979-5760