General Coverage Communications Receiver
This series of the American designed and built McKay
Dymek receivers was produced in limited numbers from 1977 to 1980. They have a distinct
1970's hi-fi component style which is somewhat unique for a communications
receiver. Many early PLL type receivers exhibited phase noise and intermod
problems but the DR 22 and DR 22C were nothing short of excellent in these
areas, however they did have a price supporting this (and some). In 1979-80 the
DR 22C was available here in
Those who know of the DR 22 would be familiar
with its bullet proof front end and the strange tuning scheme used by its early
programmable divider circuit. A separate rotary switch is employed for
each decade of a 5 digit display, with the exception of the last digit. A ± 5
kHz Fine Tuning knob was mounted under the last digit for sliding ether side of
the 5 kHz minimum resolution step. Earlier model DR22's did not have a Noise
Limiter function, both the DR 22 and DR 22C are quite rare. There was also a DR
33 model but as far as I know none of these ever made it over here to
Phase locked loop, Digital synthesis tuning control with 5 digit LED display.
High level RF front end for excellent intermodulation rejection and sensitivity.
Class D AM envelope detection for low distortion at high modulation percentages.
Switch selectable Bandwidth filtering of 8 or 4 kHz in the 3rd IF (455 kHz).
Fixed 5000 Hz audio heterodyne Notch filter
NL, IF Output Jack, Mute Line, Fine Tuning.
Accessories: DS111 Speaker, DA100
Active Antenna, 19RM22 Rack Kit, DP40 RF Preselector.
Circuit Description and Block Diagram for the DR 22
Incoming RF energy from the antenna is passed through a steep roll off 30 MHz low pass filter to a Broad Band RF Amplifier with switching for through, bypass and attenuator operation (not shown on block diagram). A high level Double Balanced Mixer is driven by the 1st local oscillator which consists of a PLL frequency synthesizer and RF Amplifier. The use of a high level LO (5 - 10mW) and double balanced mixer arrangement works well in limiting intermodulation and receiver overload problems. The DR 22 synthesizer is controlled by a multi-switched programmable divider with frequency selection being displayed on a large 5 digit LED display.
A first IF of 30 MHz is employed, thus the
output of the double balanced mixer is passed through a 30 MHz Crystal filter.
The 2nd IF also employs
Detection for the AM mode is carried out using the Class D AM envelope detection method this provides for low distortion levels at high modulation percentages. Demodulation of SSB/CW signals is carried out by the conventional Balanced Demodulator and BFO (455 kHz) method. Prior to audio amplification all AF signals pass through a 5000 Hz audio heterodyne Notch Filter.
Made In United States 1977-1980
Coverage: 50 kHz - 29.700 MHz
Readout: Digital LED display.
Modes: AM / LSB / USB
Circuit: Triple Conversion (30MHz - 10.7MHz - 455kHz)
Selectivity: 8 kHz @ -6 dB or 4 kHz @ -6 dB (switchable)
Sensitivity: AM = 10 uV @ 100 kHz, 3 uV @ 300kHz & <1.5 uV @ > 400 kHz
Sensitivity: SSB = 5 uV @ 100 kHz, 1.5 uV @ 300 kHz & < 0.5 uV @ > 400 kHz
Intermodulation: 65 dB to 1 uV
Cross Mod: 65 dB to 1 uV
Image Rejection: 75 dB
Voltages: 110 -120 / 220 - 240 VAC
Physical: 43cm x 13cm x 37cm 6.8 kg (17.5x5.1x15" 20 Lbs)
In August 1979 the now defunked Electronics
Today International (ETI) magazine published a review of the DR 22 carried out
by Roger Harrison (VK2ZTB) and Phil Wait (VK2ZZQ). The radio was supplied by
VICOM Australia and had the serial number of 01519, it was later purchased by
Bill Trenworth VK3ATW from
The DR 22 is now in my care.
E-mail VK3CAE (Ex VK3JEG): email@example.com