The Davco DR-30 Communications Receiver

    A high performance, dual-conversion, communications receiver for amateur applications utilizing solid-state components and featuring field-effect transistor RF stage for greater sensitivity, better image rejection and exceptional freedom from cross modulation or overloading on strong signals.   The DR-30 provides the maximum in communication effectiveness under the most rigorous operating conditions. Full amateur band coverage on SSB, CW or AM, Collins mechanical filter, crystal stability and extra built-in QRM-cutting features make the DAVCO DR-30 the finest and most reliable receiver for use on today's crowded bands.

Performance Features...

FIELD-EFFECT RF STAGE: Field-Effect transistors are the revolutionary new solid-state devices that make cross-modulation and overloading problems a thing of the past; they also allow superior image rejection and extreme sensitivity for weak-signal reception.

FULL COVERAGE: Complete ham-band coverage of 80 through 10 meters, the first half-megacycle of 6 meters, WWV and the 31 meter SWL band on 9.50-10.050 Mc, and optional coverage of any two additional 550 kc segments between 3.5 and 54 Mc (for CB, MARS, further 6-meter coverage, etc.)

VARIABLE SELECTIVITY: Front-panel selection of your choice of a wide IF for AM reception (6 selective elements giving a nominal 5 kc bandwidth), or a Collins 2.1 kc mechanical filter for superb SSB selectivity, or an ultra-sharp crystal filter for crowded-band CW use.

DETECTORS: Linear AM detector, separate product detector for SSB and CW utilizing a crystal-controlled BFO and carrier generator for USB and LSB.

NOISE LIMITER: True blanking action occurs before selectivity lengthens noise pulses; extremely effective on power-line and ignition-type interference.

REJECTION NOTCH: Tunable notch provides more than 50 db rejection of undesired carrier. Pulls SSB and AM stations through under otherwise impossible conditions.

AGC: Full automatic gain control action on all modes, with selection of fast, medium or slow release time.

PLUS ALL THESE PERFORMANCE EXTRAS: Transmitter-type VFO - Crystal-controlled 1st oscillator - Separate RF and AF Gain controls - Illuminated dial and S-meter - Built-in 100 kc. crystal calibrator - Fully solid state - operates directly from 12-15 volts DC or accessory AC supply.

        3.5 -   4.050 Mc
        7 0 -   7.550 Mc
        9.5 - 10.050 Mc
      14.0 - 14.550 Mc
      21.0 - 21.550 Mc
      28.0 - 28.550 Mc
      28.5 - 29.050 Mc
      29.0 - 29.550 Mc
      29.5 - 30.050 Mc
      50.0 - 50.550 Mc

Plus two extra switch positions for other 550 kc segments optional.

SENSITIVITY: better than 1 uv for 10 dB s/n; 1 uv for .3 watts audio.

SELECTIVITY:
      SSB: 2.1 kc Collins mechanical filter.
      AM: nominal 5 kc broad IF.
      CW: 200 cycle xtal filter in series with mechanical filter for improved skirt rejection.

STABILITY: negligible warm-up change; less than 100 cps change per hour; less than 25 cps for 20% power supply variation.

TUNING: spring-loaded split-gear drive unit, backlash-free; flywheel loading for large band excursions; adjustable dial drag and lock.

CALIBRATION: internal 100 kc crystal calibrator supplied; slide-rule dial has 5 kc markings, hairline pointer; tuning knob has 2 kc marks on perimeter; internal frequency shift for sideband compensation.

SPURIOUS RESPONSES: images and IF down at least 60 db below 22 Mc, at least 35 db 22-54 Mc Internal spurious less than equivalent 1 uv signal at input in ham bands.

FREQUENCY READOUT: significant figure (Mc) appears in indicator window, is color coded as to whether .000-.550 Mc or .500-1.050 section is in use. Can provide direct calibration with accessory crystals.

DETECTORS: linear AM detector; separate product detector for SSB and CW; crystal controlled BFO- carrier generator for USB and LSB.

AGC: full action on all modes of operation has fast- attack characteristic; panel switch selects fast release (.015 seconds) for AM or break-in, medium (.2 sec.) or slow release (.8 sec) for SSB and CW. Audio output varies 8 db for 80 db change in RF input. AGC action is delayed to 5 microvolts.

NOISE LIMITER: true blanking type action occurs before selectivity lengthens pulses; has separate ANL amplifier and detector, diode noise gate. Front panel control.

RF STAGE: low-noise premium field-effect RF amplifier and mixer; input and output circuits employ high-Q toroidal inductors.

REJECTION NOTCH: tunable notch provides up to 60 db rejection of undesired carrier.

INTERMEDIATE FREQUENCIES: 1st IF: 2.405- 2.955 Mc (variable, tracked), 2nd IF: 455 kc.

SEMICONDUCTOR COMPLEMENT:
      23 - bi-polar transistors
        2 - field-effect transistors
      10 - signal diodes
        1 - power diode
        2 - zener regulator diodes

AUDIO: .6 watt at 5% distortion; max 1 watt. Output impedance 8 to 45 ohms speaker; 600 ohm earphones preferred.

SIZE: 4" H, 7-1/8" W, 6" D. Weight 7 pounds.

POWER REQUIREMENTS: 12 volts DC 300 ma. maximum, 150 ma. maximum without panel lights (switch provided).

DR-30 Receiver ... $389.50 (1966)

Front Panel Detail With descriptions of each control
Block Diagram
Construction Details
Technical Features & Theory of Operation
Schematic Diagram

   Through a philosophy - both imaginative and conservative - which combines the newest, improved components with the most sophisticated circuit techniques, DAVCO has been able to conceive and produce some of the finest equipment available to the amateur today.

   Our constant and continuing attention to the requirements of the amateur fraternity and our use of only the highest quality materials result in equipment which provides full performance capability ... great pleasure and confidence in operation ... and full flexibility for the amateur's every application.

Terms...

   The DR-30 is fully guaranteed for 6 months.

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Copyright © 1998-WA3KEY & 1966-Davco Electronics, Inc.
This Home Page was created by wa3key, Wednesday, September 23, 1998
Most recent revision Wednesday, September 23, 1998