Made by R. L. Drake.\ Also sold as Debeg 7220, Hagenuk EE421, SAIT MR1541, ITT Mackay Marine 3022A or CRM 3702.

For use in maritime radio, a professional version of the popular receiver based on the SPR-4 was available from Drake after 1973.

The Drake RR-1 was sold as a 19-inch rack-mount unit or in a tabletop case and covered the maritime shortwave ranges, so it did not have a continuous frequency coverage. Continuous reception is possible as with the R-4B / R-4C when an external frequency synthesiser FS-4 is connected, this technology was integrated in the marine radio receiver RR-2.

• Principle: Double conversion, IF 5.645 MHz, 50 kHz
• Operation modes: A1 with BFO, USB/LSB, AM (A3)
• Frequency Range LW (150-535 kHz), SW (1.5-4, 4-4.5, 6-6.5, 8-9, 12-13.5, 16-17.5, 22-23, 25-26 MHz, 4 more 500 kHz - ranges optional); continuous with FS-4
• Frequency display: linear analogue display, 1 kHz
• Frequency memory: none
• Signal strength indicator: S-meter
• Signal processing
• Features: RF gain, notch filter, noise blanker optional, attenuator
• Sensitivity AM (A3) < 5 μV, SSB < 1 μV / Selectivity: AM 4.8/10 kHz, SSB (A1-broad) 2.4/7.2 kHz, CW (A1-narrow) 0.4/2.7 kHz (-6/-60 dB)

• Mains operation: 110, 220 V

• 510 x 210 x 300 mm, weight kg

With the SPR-4 Drake launched a communications receiver in the early 70s that made the hearts of many shortwave listeners beat faster, it covered the most common shortwave broadcast bands with its number of crystal controlled 500 kHz ranges.

The professional variant of this set, the RR-1 was used onboard ships or in coastal radio stations, for which it came equipped with crystals for the maritime communication bands. Four empty crystal slots can be equipped to cover additional bands, alternatively the FS-4 external oscillator can be used for continuous coverage.

The Drake RR-1, which I could acquire from DL1SDQ, was sold by DEBEG as DEBEG 7220 with a front panel with German lettering and measures 51 x 21 x 30 cm (wxhxt) with the grey sheet steel desktop housing. On the left half of the front panel are the controls in the arrangement found in the SPR-4, on the right are the internal speaker and some specific controls for maritime communications.

Below the left display window of the S-meter, which is calibrated in S-units, there is the range selector switch on the lower left, a little above it on the right the control of the preselector with the small coarse preselector dial typical for Drake, and further down on the right the combined mains switch / volume control. It is a double potentiometer, the outer ring controls the RF gain.

Below the middle display window is the band segment switch, in the dial window the band segment is displayed and the setting of the band range switch and the optimal preselector position are suggested. These settings have to be made manually on the RR-1, in contrast to Collins - sets.

In the large dial window in the centre, the kHz digits of the reception frequency are displayed on two coupled plexiglass discs. Even though the control elements of the Drake receivers appear dispersed on the front panel without too much structure, the main tuning knob forms the centre of the front panel. To the left below the tuning knob is the operating mode switch, which on the DEBEG set is labelled A2/A3 (AM), A1 (CW-N), A1 (CW-B)/LSB and USB. To the right below the tuning knob is the switch for the receiver's various „goodies“; the large inner knob switches and operates the notch filter, which can be used to selectively fade out an interfering frequency at RF level. The small switch on the outer axis operates the crystal calibrator CAL and the noise blanker.

To the right of it, in a horizontal row, the typical maritime radio controls. At the top the switch for the internal loudspeaker, below it a 20 dB attenuator. The operating voltage switch can be used to switch from mains to 24 V DC operation, the AGC switch below it is used to switch from automatic to manual control of the HF gain.

The loudspeaker radiating to the front is located at the top right, the loudspeaker of the SPR-4 radiates to the side in the wall of the unit. The mains and DC fuses, accessible from the front, are located below the loudspeaker.

At the rear of the unit there is only the antenna input, plus a muting connector that protects the receiver from excessive RF input voltages from a transmitter operating in the vicinity.

In practical operation, the RR-1 is typical for Drake sets. After the receiver is switched on with the AF gain control, a hiss is audible. For boradcast reception, the mode switch should be set to A3 (AM). Now select the corresponding 500 kHz segment with the band segment switch, for example 12 (MHz). Use the main tuner to tune to 95 kHz or 5 divisions below the 100 kHz mark. According to the information in the band segment switch, the band range F is set and the preselector is moved to the position between 6 and 7 according to the suggestion. With a little search, you can find the position where the noise becomes stronger and the BBC London can be heard with full S-meter deflection. After switching to A1 LSB or USB, you can retune to zero beat or until the whistling tone disappears and listen to the upper or lower sideband of the radio station in ECSS mode.

The performance is corresponding to a SPR-4 receiver, the radio has a high sensitivity and, thanks to the preselector a good large-signal behaviour - which, however, complicates the handling of the recevier because you have to operate the preselector and preselector range switch.

Double conversion, crystal controlled 500 kHz ranges covered by a VFO linear in this range.

The set is solid state.

• Drake Reserve Receiver RR-1 on the website of www.radiomuseum.org