überarbeitet am 19.10.2010
In 1979, Drake presented the earliest version of their R-7 shortwave receiver,
it was primarily designed as a amateur band receiver with analog frequency dial.
Soon, the integrated digital frequency display was a standard feature of the
sets sold to the public, due to several accessories integrated in the receiver
as stanard, the price of this fine set did rise from 1295 to 1800 US$:
- DR - 7: Digital display frequency counter and extended frequency
coverage from 0,5 - 30 MHz
- AUX - 7: Additional borad to give direct access to 8 additional 500
MHz segments using the AUX switch, diodes on RRM - 7 band segment modules
were used to define the respective band segment.
- Filter - Board: beside the standard 2,3 kHz filter, there has been
an option to install additional IF bandwidth filters, a recommended filter selection
was 6 or 4 kHz for AM, 1,8 MHz for SSB, 500 / 300 Hz for CW.
- NB - 7A: Noise Blanker<
- RV - 75: an externel VFO, a second tuning to unit which allows You to
switch between two operating frequencies quickly.
- MS - 7: the matching external speaker.
Tripple conversion, IF 48,05 MHz, 5,645 MHz, 50 kHz
Digital frequency display, 100 Hz resolution
AM, USB, LSB
AM <2 uV, SSB <0,5 uV für 10 dB S+N/N
-6/-60 dB 0,5/1,5 kHz, 1,8/3,6 kHz, 2,3/4,4
kHz, 4/8 kHz
RF-Gain, Preamplifier and Attenuator, AGC 3x, PBT, optional Noise Blanker, Notch
The anthracite -black coloured frontpanel of the desktop receiver with the dimensions
of 340 x 121 x 315 mm is dominated by the analod dial and S-meter with their blue
backlight and the red LED frequency display.
In the upper part, above an aluminum edging, You find at the left the blue illuminated
signal strength meter calibrated in S units (You won't expect to find something else in
a Drake receiver), some indicator lights for RIT and fixed frequency operation, the UP / DOWN
buttons to switch the 500 kHz segments and the red LED frequency display giving You
the reception frequency information with an accuracy of 100 Hz.
In the lower part of the front panel, below the aluminum edging, You find leftmost the
preselector range control, the preselector will let only frequencies between the orange
fiures pass the preselector stage.
At it's right, You find two rows of bushbuttons activating several special functions,
and underneath the bandswitch for 8 directly accessible "auxiliary" band segments,
the bandwidth filter selector and the passband tuning / sideband selector control active when
the receiver ist set to SSB operation with the "AM / SSB/CW" pushbutton. The inner knob
of this double control is used for RIT (receiver incremental tuning), a fine tuning
option to adjust the receiver between 100 Hz steps for CW, SSB and radioteletype operation.
At the right, You find the main tuning knob and the analog frequency dial giving You
an accuracy of around 5 kHz and most righthand an antenna selector (the R-7A allows
You to conect two antennas individually to itself and an axternal secondary receiver),
the Notch filter control and the double control for RF gain and AF gain / volume
combined with the mains switch.
For practical operation, connect an external antenna to the MAIN antenna connector
(a chinch RCA connector like fond on several older Drake receivers), set the antenna
selector switch to the second (MAIN/ALT) or third position.
Turn on the set using the AF gain control and make sure, the outer ring (RF Gain)
is set to the most clockwise maximum position. Following the description in the
user's maunal, only the AM button should be activated, all other bushbuttons should
not be pressed in. The AUX PROGRAM selector should be set to OFF and the selectivitiy
to 4 (or 2.3) kHz for AM reception. To tune in to Austrian Radio Vienna on 6155 kHz,
set the BAND (preselector range) switch to 5 (because of 6155 kHz lying in the 4,5-7 MHz
slot) and press the UP / DOWN buttons several times to reach the 6000 - 6500 kHz
range, now use the main tuning knob to tune to 6155,5 kHz. For single sideband
reception, switch from AM to SSB/CW and select the desired sideband using the
In it's days, the shortwave performance of the Drake R-7A receiver was absolutely
superior, it can still match the demands of todays DXer, the operation scheme
is a bit outdated as You have no programmable frequency presets.
Depending on the choice of IF filters, You can cope with nearly all signals
found on the shortwave bands, from faint CW and radioteletype to very strong
signals of nearby mediumwave transmitters.
In contrast to modern receivers like AOR's AR-7030,
the modern NRD-525 or -535
receivers or Drake's R-8A, checking parallel frequencies
of one major External Service on different bands is a little bit more cumbersome,
as the R-7A has no direct frequency input keypad. But the number of stations
transmitting on 5 - 8 parallel frequencies has decreased significantly. But for
scanning a shortwave or tropical broadcast band, the R-7A is a great rig not often
found on the used market.
d/e: Drake R-7A at www.radiomuseum.org
e: Drake SSR-1, © Drake Virtual Museum
d: Drake R-7 Testbericht © Horst Marx, Rudi Waurich, addx kurier
e: THE DRAKE R7 COMMUNICATIONS RECEIVER REVISITED, Jerry Strawman, fine
tuning Proceedings 1988
e: THE DRAKE R-7 / R-7A RECEIVER: An Outline of Major Features,
Modifications and Accessories, David Clark, Jon Williams, fine tuning Proceedings 1988
© Martin Bösch 14.8.2003