Home

R. L. Drake Company, Miamisburg, OH

R - 4 B

Logo
travel radios
portable receivers
communication receivers
classic commercial receivers
"boatanchors"
military equipment
 
Drake
 
Drake 2 - C
Drake R - 4 B
Drake R - 4 C
Drake RR - 1
Drake MSR - 2
Drake SPR - 4
Drake SSR - 1
 
receiver list
receiver manuals
 

überarbeitet am 19.10.2010

After the amateur band receivers Drake 1 - A and the 2 - A to 2 - C series, Drake presented the R - 4 in 1964, a double conversion set covering the amateur bands, ten additional 500 kHz - segments can be added using plug in crystals, the set has an analog circular dial with an accuracy of 1 kHz. The R - 4 and R - 4A sets have been completely tube equipped, the only semiconducter beeing the demodulation diode, the R - 4 B is a composite set with nine tubes, several transistors and even an early integrated circuit used in a frequency divider stage.

Double conversion, 1st IF 5,645 MHz, 2nd IF 50kHz

linear analog dial 1 kHz

Amateur bands and additional 10 crystal controlled 500 kHz segments,
continuous covering with the FS-4 frequency synthesizer added

AM, USB/LSB

Sensitivity 5 MHz
AM / SSB < 0,25 uV

Selectivity -6/-60 dB
0,4/2,6 kHz, 1,2/4,8 kHz, 2,4/8,2 kHz, 4,8/20 kHz

RF-Gain, AGC 2x, PBT, Notch, (NB optional)

The dimensions of the metal cabinet of the Drake R - 4 B are 14 x 27,3 x 29,7 cm, it's weight is 7,3 kg, as the set has no closed rear cover, You can see the tubes glowing when You look inside or even through the holes of the sides of the cabinet, do never touch inside the set, when it's powered on.
In the bright grey upper segment of the front panel, You find from the left side the signal strenght meter calibrated in S units and decibels over S9, the main switch to set the receiver in standby and operation mode and to activate the Noise blanking circuit and the Crystal calibrator. At it's right, You find the Passband tuning control to shift the passband of the IF filter to the side of a signal, which is less compromised by an interfering adjacent channel signal. A small metal handle lets You chose one of the LC IF filters, the skirt selectivity of the LC bandwidth filters is suboptimal, but the set offers a wide choice from 400 Hz / 1,2 / 2,4 and 4,8 kHz. At the right, You find the analog frequency dial and the main tuning knob.

In the lower dark grey part of the front panel, You find six more controls at the left hand and the volume knob, the so called AF (audio frequency) gain in the right lower corner. In the upper row of the six controls, You will find the XTALS band selector for the additional crystal controlled 500 kHz segments and underneath the selector for the amateur bands, active when XTAL switch is set to NORM position. In the middle, You find the preselector control with it's small red metal pointer, this has to be thoroughly set to the signal peak when tuning in a station; the RF Gain underneath is usually set to the most clockwise position. The controls at the right activate the NOTCH filter to eliminate an unwanted interfering carrier signal and the reception modes selecting the AM and SSB modes with AGC activated or off for full manual RF gain control.

At the rear of the set, You find the RCA / chinch connectors for the external speaker, the antenna (!) and connectors used in transceive operation together with the matching transmitter, the MUTE connector should normally be short circuited. At the right, You find the sockets for the accessory crystals. With a plain R-4B, continuous coverage from 1,5 - 30 MHz is not possible, You would need 55 crystals. To correct this shortcoming, Drake did develop a solid state frequency synthesizer, the FS-4 plugs in in the socket of one crystal, You can chose the desired waveband by simply turning the knobs until the start frequency of the 500 kHz segment is displayed.

To use the R-4B as a standalone receiver, You first have to make sure, that the MUTE connector is shorted by a special short circuit plug connecting the center pin and shielding, otherwise You won't hear anything from Your muted R-4B.
As a second step, You have to attach an external speaker, the MS-4 was the matching speaker with identical dimensions as the R-4B's cabinet. Now plug in an antenna to the RCA-type antenna socket and You are ready for take-off. The R-4B will cope with strong signals.

When the receiver is switched on, the dial and S-meter will be illuminated with bright blue light. Now select the desired amateur radio band with BAND switch, the XTALS switch should remain in the normal position. In case You want to receive a signal from the 49m broadcast band, a matching crystal has to be fitted in the connector at the rear, a table in the operating manual will tell You about the correct settings of Bandswitch and Preselector. Adjust the preselector for maximum noise or signal strength; remember to adjust the preselector when cruising through a band - as long as the preselector is adjusted precisely, the receiver performs with an excellent sensitivity and rejection of unwanted and spurious signals. You can read frequencies from the round dial calibrated in 25 kHz steps and the 1 kHz lines on the tuning knob with an accuracy of about 1 kHz, which was an above average value in the sixties, that normally could only be found in high end commercial receivers.
The internal crystal marker gives You a calibration signal every 25 kHz to adjust the main dial for 1 kHz accuracy. Set the receiver to SSB mode, tune in to the calibrating signal and adjust for "zero beat", move the red line poiner on the dial to match the 25 kHz mark on the main dial, then hold the main tuning knob in zero beat position and slide the ring with the 1 kHz lines exactly to 0.

After You have set the receiver to the desired frequency, in reality this step is mach faster then You might expect from this description, You have a choice of tools to improve a faint signals readibility. The coil IF filters have not the really steep skirts as found in crystal filters. You can shift the filter passband to the direction of the less disturbed sideband, this PASSBAND tuning in the Drake receivers became a legend. There is another legendary tool: the RF NOTCH will help You suppressing in anwanted interfering signal by carefully tuning its control until the hiss will disappear.

Performance on the shortwave bands is still good compared with modern middle class world band receivers. When the preselector is tuned carefully, sensitivity and selectivity are good and the stability is sufficient to copy radioteletype transmissions. With it's LC filters, the R-4B will give You a very pleasant audio; as the filters can be selected independently from the reception mode, the R-4B is considered a little bit more versatile then it's successor R-4C.
There is one major drawback: coverage depends on the availability of accessory crystals and bandswitching to compare parallel frequencies of one major broadcaster takes a lot of time, the receiver is suited much better for DXing in one specific band or for amateur use.

weitere Lektüre:
d/e: Drake R-4B at www.radiomuseum.org
e: The Drake R-4B and R-4C, Two Receivers From the Past, Jon Williams, fine tuning's proceedings 1989

© Martin Boesch 15.12.2008