Oa Output

MOC5005/6 digital optocoupler schematic.

OK 's PRB-1 digital ioglc probe.

CSC's 500-MHz prescaier.

The Communicator II from Pace.

a reusable case with complete troubleshooting instruction booklet. It is available at local electronics distributors and retailers or directly from O.K. Machine and Tool CorporationP 3455 Conner Street, Bronx NY 10475; phone (212)-994~66Q0> Reader service number OS.


Continental Specialties Cor poration first previewed their new PS-500 500-M Hz frequency prescaier at spring's NEWCOM show, then officially introduced it at summer's WESCON show. Actual production began in late summer, and quantities are now in stock for immediate delivery.

The PS-500 prescaier has been designed to complement CSC's MAX-50 and MAX 100 frequency counters.

For additional information, contact Continental Specialties Corporation, 70 Fulton Terrace, New Haven CT 06509; (203)-624-3103, TWX (710)-465-1227. Reader service number C9.



Electra Company has announced a breakthrough development in scanner technology that allows a single scanning monitor to receive not only public safety, marine, ham, and other FM frequencies, but also the AM aircraft frequencies. The new Bearcat 220 scanner is the first scanning monitor which combines AM and FM reception capability. Until now. two of the most popular monitoring activities-listening to aircraft and listening to police calls—had to be received on separate monitor receivers. But now, six VHFand UHF FM public service bands plus the AM aircraft band are covered by this single radio.

The new Bearcat 220 also features three search operations for finding active local frequencies. It has the normal search operation where frequency limits are set and the scanner searches between them. All active aircraft and marine frequencies are pre* programmed into the scanner's search memory so frequency limits aren't necessary. The user simpty pushes the aircraft or the marine search button and the BC 220 seeks out the aircraft or marine frequencies being used locally.

CrystaMess push-button frequency entry which was pioneered in the Bearcat 210 scanner is used in the Bearcat 220, The actual frequencies be^ ing monitored are shown on a bright digital display. Up to 20 frequencies can be in any sequence or mix of bands. A priority function is also provided, Instantly alerting the listener when a call is made on the priority frequency programmed into the channel one position. Channels can also be activated in banks of 10, permitting the operator to "cail up" a group of 10 channels with one pushbutton.

Olher features included In the Bearcat 220 are patented selective scan delay, scan speed selection, acfdc operation, automatic and manual squelch, individual channel lock out, and direct access to any programmed channel without the need to manually step through channels. Electra Company's patented "track tuning" is used to provide op timum reception across entire frequency bands. Complete details are available from Bearcat suppliers or by writing to Electra Company, PO Box 29243, Cumberland IN 46229. Reader service number E40.


Pace Communications Division of Pathcom1 Inc,, has been known for its superb CB and commercial FM two way radio products for many years. A few months ago. the Amateur Radio Products Group of Pace intro duced Us Communicator line. Top of the line is a 4-MHz, 800-channel, all-synthesized two meter FM mobile, the Communicator II.

By using three knobs (MHz, 100 kHz. and 10 kHz) and an in-out push-button for 5 kHz, the receive frequency is rapidly dialed into the unit and displayed on the .375" 6-digit LED readout. Transmit is selected by a 5*position rotary switch giving simplex, ±600-kHzT and ±1-MHz splits. When the PTT is depressed, the digitaf readout automatically shifts from receive frequency to transmit frequency, leaving no doubt as to where the unit is set. Also of note is a push-on, push-off power switch that relieves the user of having to reset the volume control The Communicator II weighs 6,6 pounds and is 6.41S Wx 2.8" Hx 10.2" L. Current draw is 1+1*5 A receive and 1.5 A {1 WJ^.O A <25 W) transmit.

Using 52 diodes, 8 LED units, 32 transistors, 6 FETs, and 18 ICs the Communicator ll operates in a 16F3 mode. Power output is 1 or 25 Watts push-batton controlled (with the 25 Watts being adjustable for those who wish QRP). Frequency deviation is ±5 kHz maximum. Spurious harmonics are 65 dB below carrier. Frequency stability is ±5 ppm for - 30 Mo + 60 * C,

The receiver is a double superheterodyne using 16,9MHz and 455-kHz i-fs. Sensitivity is less than .4 microvolts for 20 dB quieting (.20 microvolts for 12 dB SI NAD), image and receiving spurious rejection is 65 dB down; selectivity is 65 dB down at ± 12 kHz. The internal 8-Ohm speaker allows 1.2 Watts at 10% THD, One of the 8-mm plug jacks on the rear mutes the internal speaker when an external speaker is connected. The other 8-mm jack allows not only an external speaker to be used,

Continued on page T63

New Bearcat 220 scanner.

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