DRAKE R-4A Specifiche

III CONTROL FUNCTIONSA. FRONT1. MAIN TUNING - The MAIN TUNING knob of the R-4A determines thefrequency on which you are receiving. The vernier skirt a

by the transmitter. When in the N. B. position the noise blankeris energized,and when in the CAL position, the noise blanker isswitched off and the ca

11.12.For CW reception on the .4 position the signal is tuned for mostpleasing note with the frequency knob and is then peaked with thePASSBAND tuning

C. SIDE CONTROLS & JACKS1.2.3.4.S-METER ZERO -This control is the front-most adjustment on theright side of the R-4A chassis and is for the purpos

IV OPERATIONA. Preliminary Control SettinqsFor all modes of operation set these controls as follows:FUNCTION--BAND--XTALS--PRESELECTOR--NOTCH--R.F. Ga

Under crowded band conditions it will be advantageous to use the.4 KC selectivity position and reposition the Passband knob formaximum S-Meter reading

F. Adjustinq Dial CalibrationThe calibration of the main tuning dial on the R-4A may vary slightlyfrom band to band due to the tolerance limits of the

H.Operation of NOTCH controlThe notch control on the R-4A consists of a permeability-tuned T-notchfilter in the 50 KC I. F.This filter is capable of p

I. Accessory Frequency CoverageIn addition to reception on 80, 40, 20, 15, and the 28.5 - 29.0 portionof 10 meters, the R-4A can be programed to recei

The following table shows the correct crystal frequency, and Bandsetting for ranges between 1.5 and 30 mc (excluding 5.0 - 6.0 mc) NOTE that if you in

TABLE OF CONTENTSGeneral Specifications3I General Description5II Installation InstructionsA. Unpacking6B. Location 6C. Power Requirements6D. Antenna R

J.Fixed Frequency OperationThe R-4A can be locked to a specific frequency by plugging theappropriate crystal in the crystal lock socket, located on th

V THEORY OF OPERATIONA. R.F. AmplifierA signal entering the antenna is applied to the grid of the low noise12BZ6 R. F. amplifier tube (Vl) through the

c.Second ConverterThe 5645 KC output of V2 is applied to the grid of the 12BE6 secondconverter (V3) through a crystal filter. This gives excellent cro

2030cnii3W0 405060FREQUENCYKILOCYCLESBFO-8 -6 -4 -2 0 2 4 6 8IONOTE‘PASSBANDS ARECONTINUOUSLYMOVABLE ABOVEAND BELOW EIFO,FREQUENCY.FIGURE X 6 - SELECT

F,GAudio OutputAudio signal from the AF GAIN potentiometer is applied to the grid of the6EH5 audio output tube V-7 through two stages of AF amplifiers

The S-Meter sensitivity control R-40 varies the sensitivity of the meterfor calibration purposes by varying the resistance in series with it.I. Noise

The negative bias supply uses a IN3194 diode to provide -60 voltsto the AVC system for minimum bias, muting, and control of RF Gain.An OB2 voltage reg

VI SERVICE DATAWe will check and factory align your R-4A for a nominal fee of $10 .OO plustransportation charges if the set has not been tampered with

Figure #9 VOLTAGE CHART9Number Type 1 2 3 4 5 6 7Vl 12BZ6 -1.1 1.66 0 12.6* 140 129 0v2 6HS6 0 0 6.3* 12.6* 140 80 2.8v3 12BE6 -11.5 2.7 12.6* 0 140 1

VI Service Data27A, Removing Top Cover27B. Removing Bottom Cover27C. Tube Replacement27D. Troubleshooting27VII Alignment InstructionsA.B.c.D.E.F.G.H.I

Figure #l0 RESISTANCE CHARTNumberVlv2v3v4V5v7V8v9VlOVllv12Note s:Type12BZ66HS612BE612BA612BA66EH56HS612BA612AX7.OB212BA6--A4.4M2.2M4.2M3.7M100350K2.6M

VII ALIGNMENT INSTRUCTIONSAlignment of the R-4A will require the following equipment.1.2.3.4.5.A reasonably stable signal generator having a frequency

C. Crystal Filter and Filter Match Transformer Aliqnment1.2.3.4.5.6.7.8.9.Attach signal generator to pin #l of V2 and set generator frequencyto 5645 K

E. Antenna, RF, and Injection Circuit Aliqnment1.2.3.4.5.6.7.Turn off receiver and temporarily connect a 10K resistor fromthe side rotor contact of S

F. 100 KC Calibrator Alignment1. Attach the antenna to the R-4A and tune in WWV at the frequencymost reliable in your area. For crystal selection see

band tuning knob should be pointing horizontally to the left asviewed from the front. If it is not, loosen the knob set screwand reposition the knob.3

GENERALSPECIFICATIONSFREQUENCY COVERAGE: 3.5-4.0 MC, 7.0-7.5Mc, 14.0-14.5, 21.0-21.5,and 28.5-29.0 MC with crystals supplied. Ten accessory crystal so

TUBES AND SEMICONDUCTORS:TUBE12BZ612BA66HS66HS612BE612BA612BA62N33942 -2N33946EH512BA612AX 7A2N7062N38582N3394lN7140B2 and lN483A2 -lN3194lN3194lN270

I GENERAL DESCRIPTIONThe DRAKE R-4A is an extremely versatile communication receiver de-signed to bring you every feature desirable for the ultimate i

II INSTALLATION INSTRUCTIONSA. UNPACKINGCarefully remove your R-4A from the packing carton and examine it closelyfor signs of shipping damage. Should

Antenna connection to the R-4A is provided at the jack on the rear of thechassis marked ANT.It is recommended that when the R-4A is used with a transm

TR-4AC-4/MS-4 or RV-4y--- -- - ---IThis switch must bein the TCVR positionfor transceiving andin the RCVRposition for separatereceiver use.lower Cable