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überarbeitet am 14.12.2008
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Drake's maritime receiver MSR-2 has been introduced in 1977, it has certain
similarities to sets of the R-4 series, but it has an integrated 1 MHz segment
synthesizer instead of using separate quartzes for each band and a nixie tube
display with it's typical orange glowing characters.
This 19 inch rack model has been used as secondary receiver for maritime communications,
the German maritime communications equipment companies Debeg sold it under
their designation 7202, Hagenuk called the set EE-334 (as shown), it came with
a front panel with german language lettering and a german translation of the
user's manual.
The set has some similarities with Drake's DSR-2, which comes without adjustable preselector
for the VLF segments and internal monitor speaker.
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Double conversion, 1st IF 50,5 MHz, 2nf IF 50 kHz
Digitala frequency readout, 100 Hz
10 - 30'000 kHz
AM, USB, LSB, ISB
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Sensitivity 5 MHz SSB < 0,5 uV
Selectivity -6 dB
AM 6 / 1,2 / 0,3 kHz; SSB 2,4 MHz
Separate preselector circuits for VLF and SW, RF-Gain
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As it's mainly used as commercial maritime receiver, Drakes MSR-2 comes as a 19 inch
rack receiver, the mains connectors are found at the rear of the set, the MSR-2
accepts voltages of 120 or 220-240 volts and can be operated from 12 - 24 V DC by use of an inverter.
Also at the rear of the receiver, You will find the connectors for AF signals and
for the AF of the second band for independent side band reception. The RCA / chinch
connectors for 50 kHz IF output, speaker AF output and muting as well as the
SO-239 antenna socket do not really match a commercial grade receiver and might
remember that the set's realtives are found in the high end amateur radio class.
The MSR-2 as a 19 inch rack model comes with dimensions of 480 x 133 x 380 mm
and a weight of 11,5 kg.
On the front panel, You find in the right upper area the very impressive nixie
tube digital frequency display with it's characteristic orange glow. Two rotary
switches let You select the 10 MHz and 1 MHz segments, You tune in the kHz and 0,1 kHz
digits with the large VFO knob; a mechanical lock prevents the receiver to be detuned,
when You find Yourself with Your vessel in a severe thunderstorm. In the right lower corner,
You find the 6,3 mm headphones jack.
Left to the frequency display, You find the signal strength meter, three pushbuttons
just underneath set the receiver to fast AVC, noise blanker and stand by mode. Next to these
buttons, You find the preselector control for the 0,5 - 10 MHz shortwave ranges.
Below You find the knobs to control signal processing: The volume control
is combined with the mains switch, the two modes switches (left one let's You chose
IF bandwidths, upper or lower sideband an the ISB (independent side band) modes; use the right
one to select AM and SSB modes). The following two knos are marked brown to indicate,
that additional features are activeted, when the knob is pulled: Pull the RF gain
knob to activate manual gain control, pull out the BFO knob to activate the beat frequency oscillator.
Use the "Vernier tuning" control for fine tuning between 100 Hz increments.
In the left upper corner, You find the monitor speaker and the switch to activate ist,
just below the controls for the VLF preselector. In the 0,01 - 0,03 MHz segment, no
further tuning is required, in the 0,03 - 0,5 MHz segments tweak the VLF preselector for
signal maximum, so You should never miss a faint VLF beacon signal again...
The slightly odd arrangement of the MSR-2's controls are explained by that the fact
that the construction of this receiver is based on the chassis of the Drake R-4 and
SPR-4 receiver series. The signal strenght meter, digital frequency display, the main
preselector and the lower row of controls including AF / RF gain and modes control
have identical locations as found in the DSR-2, which was an improved version of the
SPR-4 with a frequency synthesizer and digital display added. The monitor speaker and the VLF
preselector part has been added later.
As this set has been used in maritime communications, it is worthing consulting
the operator's manual before switching it on:
To listen to a station in the 49 m shortweave band, the left preselector control
should be in the 0,5 - 30 (MHz) position, You don't need the 0,03-0,5 MHz preselect
control. Turn the knobs for the first two digits of the frequency to "0" and "6",
and use the main tuning knob to tune in to 155,0 kHz. Th If bandwidth should be set to 6 MHz,
and the mode switch to "AM", push in the RF gain control to activate automatic
gain control. Just in case, the MGC is activated and the knob is in the most
counterclockwise position, You won't hear anything. Use the volume / AF gain control
to chose optimal volume und tweak the preselector 0,5 - 10 MHz for maximum signal
strength and optimum rerading of the meter.
© Martin Bösch 15.12.2008
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