Valves for the Racal RA17 and RA117 series of H.F. Receivers
by Andy Cowley, M1EBV

The Racal RA17/117 series of valve/tube H.F. receivers evolved considerably over its long production lifetime. More than 70 versions were produced. Not all versions, even of the same model, used the same valve complement. In some cases substitution of a valve from one set to another might cause damage to the valve and the receiver - see warning.
     The tables below give the 'official' valve designations either from Racal or from British Military (NATO) manuals. 'NA' or 'C12' indicates a North American Model. Where the model designation is an active link, it leads to a table of equivalents.

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RA17 series valve complement
See also: equivalents list
Function RA17 Mk2 RA17L RA17C12
1 Crystal Oscillator CV138 CV138 6AU6
2 Harmonic Generator CV138 CV138 6AU6
3 R.F. Amplifier CV3998 CV5331 6ES8
4 Harmonic Mixer CV2209 CV2209 6AS6
5 First V.F.O. CV138 CV138 6AU6
6 37.5 Mc/c Amplifier CV138 CV138 6AU6
7 First Mixer CV3998 CV3998 6688
8 37.5 Mc/s Amplifier CV138 CV138 6AU6
9 Second Mixer CV3998 CV3998 6688
10 37.5 Mc/s Amplifier CV138 CV138 6AU6
11 Third Mixer CV453 CV4012 6BE6
12 Second V.F.O. CV138 CV138 6AU6
13 Divider/Mixer CV453 CV4012 6BE6
14 First I.F. Amplifier CV454 CV454 6BA6
15 Multiplier CV454 CV454 6BA6
16 Second I.F. Amplifier CV454 CV454 6BA6
17 I.F. Output CV454 CV454 6BA6
18 A.V.C. and T.C. CV140 CV140 6AL5
19 B.F.O. CV138 CV138 6AU6
20 Power Rectifier CV378 CV1377 _
21 Detector and Noise Limiter CV140 CV140 6AL5
22 A.F. Outputs (Local) CV138 CV138 6AQ5
23 A.F. Output (Remote) CV138 CV138 12AT7
24 Clamping Diode _ CV469 _

RA117 valve complement
Function RA117 RA117 NA
1 Crystal Oscillator/Amplifier CV4010 6AK5W
2 Harmonic Generator CV4010 6AK5W
3 R.F. Amplifier CV5531 6ES8
4 Harmonic Mixer CV4011 6AS6
5 First V.F.O. CV4009 6BA6
6 37.5 Mc/c Amplifier CV4009 6BA6
7 First Mixer CV3998 6688
8 37.5 Mc/s Amplifier CV4009 6BA6
9 Second Mixer CV3998 6688
10 37.5 Mc/s Amplifier CV4009 6BA6
11 Second V.F.O. Amplifier CV4010 6AK5W
12 Second V.F.O. CV4024 12AT7
13 Calibrator CV4012 6BE6W
14 First I.F. Amplifier CV4009 6BA6
15 Calibrator CV4009 6BA6
16 Second I.F. Amplifier CV4009 6BA6
17 I.F. Output CV4009 6BA6
18 A.V.C. and T.C. CV4007 6AL5
19 B.F.O. CV4010 6AK5W
20 none _ _
21 Detector and Noise Limiter CV4007 6AL5
22 A.F. Output CV4019 6AQ5
23 A.F. Amplifier and Output CV4024 12AT7
24 Clamping Diode CV469 5704
25 Third Mixer CV3998 6688
26 Fourth Mixer CV4012 6BE6W
27 1.7 Mc/s Crystal Oscillator and Amplifier CV4010 6AK5W

There are two distinct models of RA17L, the British Military version, which uses CV numbered valves and the North American model, which uses U.S. commercial valves. The valve sets for these two models are different. Several valves, while similar in function, have a different pin-outs. Inserting the valve from the other set could result in the destruction of the valve, and might cause damage to other components. In particular, many substitution guides give 6AS6 or its variants as equivalents for the S6F33 (special 6F33 - V4). In fact the connections to G2 and G3 are reversed and the connections to the base must be changed to do this substitution.

 Andy Cowley, M1EBV, 2002

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