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überarbeitet am 26.12.2008
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After several year's of absence, Drake returned to the shortwave receiver
market in 1991 with it's R - 8 receiver, the set has been upgraded several times
in the following years:
- R - 8: first version:
You cannot directly select the different recepetion modes or IF bandwidth
filters, but You have to circle through the selection by pressing the
MODE or BANDWIDTH buttons several times without a "back" option. So You will have
to press the button once to change from USB to LSB but it will take five
times to press the button to switch back to USB. In addition, the receiver
switches the bandwith automatically when changing reception modes to Drake's
recommended fitler setting, the selection has not been accepted by all DXers...
- R - 8A:
direct switching of all reception modes and filters with 6 pushbuttons
for MODE and BANDWIDTH each, 440 alphanumeric programmable frequency memories
- R - 8B:
synchroneous detection with selectable sidebands, 1000 memory channels
- R - 8E : European version of the original R - 8
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Double Conversion, 1st IF 45 MHz, 2nd IF 50 kHz
Digital frequency display, 10 Hz resolution
AM, AM-Sync, USB/LSB, CW/Data, FM-n
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Sensitivity 5 MHz
AM <1 uV, SSB <0,25 uV
Selectivity
-6 (-60) dB 0,5/1,5 kHz, 1,8/3,6 kHz, 2,3/4,5
kHz, 4/8 kHz, 6/12 kHz
RF-Gain, Attenuator, AGC 2x, PBT, Noise Blanker, Notc Filter
440 alphanumeric memory channels, RS-232 port.
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The front panel of this black coloured receiver has very clear structures.
In the left upper corner of the pront panel, You find the analog signal strength meter
and a big green backlit LCD display. When the set is switched off, the set displays
local or UTC time. When the receiver is switched on, the display will show You the
reception frequency with an accuracy of 10 Hz, the selected IF bandwidth filter and
the reception mode. There are also indicators for the settings of all six menue
pushbuttons, the A or B VFO channel, preamplifier / attenuator, AGC speed, IF bandwidth
and reception mode. At the right hand, You find the switch to activate the synchroneous detector
and the main power switch.
In the lower half of the front panel, You find the concentric controls for tone
and Notch filter and the number keys for the direct frequency entry keaypad. These
keys are arranged like on a telephone keypad. Four light grey buttons let You
activate VFO operations, two bigger grey buttons are used for fast tuning through
the shortwave bands. The main tuning knob is quite lightweight, it has an electronic
flywheel effect switching tuning steps from 1 kHz, 100 Hz and 10 Hz according to the
speed, the knob is rotated. Another two concentric knobs at the right will give
You control over passband shift and squelch functions and RF / AF gain.
The LCD frequency display is not as colourful as the display of the NRD receivers,
but it gives very low interfering radiations in the shortwave bands.
At the rear of the set, You find two antenna connectors, Ant 1 is a PL259 connector,
Ant2 are terminals for a long wire antenna, You can select the antenna connectors
from the front panel using the menue buttons. There are connectors for external
12V DC powering, and the mains cable. A very useful connector is the integrated
serial RS-232 socket, You can connect the set directly to a computer (as long as
this comes with a COM1 connector) for software rig control without having to buy
a computer interface card.
An integrated monitor speaker gives You the possibility to check the reception
functions without using headphones, the MS - 8 external 2,5 Watt sounds acceptable.
Operation is quite straightforward: Use the mains switch to turn on the
set, use the first menue button to select VFO A or B. To chose the appropriate
reception mode and IF filter, use the BANDWIDTH and MODE menue pushbuttons.
It's a peculiarity of a several Drake receivers, that the "optimal bandwidth"
setting is coupled to the reception modes switch. If You don't agree with Drake's
choice, You have to circle through the selection by pressing the MODE or BANDWIDTH
buttons several times without a "back" option. So You will have to press the button
once to change from USB to LSB but it will take five times to press the button
to switch back to USB. By pressing the AM/SYNC button, You switch to automated
ECSS tuning, You hear a short hiss, until the Sync detector locks on to the
station's carrier. You can shift
the IF filter passband to eliminate interferences from carriers on adjacent
channels, You can also eliminate a annoying hiss using the notch filter.
You can change the AGC decay time from fast (AM) to slow (CW, SSB), when the AGC is completely switched off, You have to
gain manually using the RF gain control, use this carefully for the reception
of very faint SSB signals. In VFO operation, You can switch between the two
electronic VFO's like between two memory channels, that's the simple way.
The set offers You 100 memory channels saving not only the frequency but also
the mode, filter, AGC and antenna settings.
Performance on the Shortwave Bands:
The R-8 seem a little bit less sensitive then the JRC receivers, this will only
be of any importance in extremely low signal level situations in an empty band
segment without interfering channels. Connected to a long wire antenna, the
sensitivity of all high grade communications receivers is sufficient to make poor
signals audible. Usually, the readibility of a signal is not limited by a receivers
sensitivity but by it's selectivity, tho capability of pulling out as much
of the modulated signal as possible out of a sum of interfering carriers and
background noise.
The selectivity is depending on the quality of the IF filters used in the receiver.
With the R-8, Drake relied on the classic technology of using coil filters on
a low intermediate frequency. The skirt selectivity of these filters is not as good
as the one of crystal or mechanical filters, but the passband of the filter seems
to fit the human ear very nicely, the audio reproduction is convincing in DXers
ears.
Drake offers a reasonable choice of onboard IF bandwidths, for AM reception
with little interference, You use the 6 kHz filter, in crowded bands the 4 kHz
filter gives sufficient audio, in conjunction with passband shift, I use the 2,3 kHz
filter for AM in the tropical bands. For SSB, I use the 4 kHz filter in no interference situations, the 2,3 and 1,8
kHz filters are well suited for single sideband reception and the 500 Hz filter
is very helpful for CW reception. As the second intermediate frequency of Drake's
R-8 is uncommon, there is no choice of trying optional IF filters from third party
manufacturers.
Even with narrow band filters, the audio reproduction of the R-8A remains acceptable,
longtime listening is less tiring with the R-8 then with the NRD-525 with it's
high pitch background hiss. It sounds more like a classic American hollow state receiver.
Under difficult reception conditions, the 2,3 kHz filter as well as the Passband
tuning offering a wide passband shift range are extremely helpful. As long as there
is only one interfering carrier either at the higher or lower side of the reception
frequency, You can try to eliminate it with the passband tuning and by selecting the
less disturbed sideband. That's the way to cope with a sandwich situation, to
copy Radio Korea's Relay on 3970 kHz between RFI and R.Budapest.
In contrast to the excellent Sonychroneous Detector found in Sony's ICF-2001D,
You cannot select the sideband in SYNC mode, only the later R-8B will offer this
opportunity. The SYNC mode of the R-8 improves readibility in situations of
selective fading, in my experience, the situation was not improved significantly
over the use of SSB mode and tuning manually to zero beat for ECSS reception.
In automatic SYNC mode, You can select sidebands only by use of the Passband tuning
control, You hear a howling noise when PBT is adjusted and the receiver is
readjusting.
In conclusion I consider the Drake R-8 as a fully featured desktop
communications receiver well suited for the ambitious shortwave listener and
tropical band enthousiast.
The arrangement for IF filters and mode switching with the "carousel" pushbuttons
without "back" function, selecting various bandwidth and sideband combinations
is extremely cumbersome - so when You have to possibilty to acquire an R-8,
go for the A or B versions.
Keep in mind that the R-8E is the German variant of the original R-8 with
all it's backdrawals and in addition German shortwave band restrictions,
and not an improved A or B version, so I would rather
stay away from one of these either - it's not a poorer performer, but has very
awkward ergonomics.
There is one dark point like with all recent Drake sets: it's limited availability
in Europe makes it rare in Switzerland. The importer had a very good trading profit,
this means: all Drake sets have been overpriced in Germany and Switzerland.
© Martin Bösch 25.7.1999 / translated 26.12.2008
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