[ARC5] FWIW: RU, RU/GF, and RAJ Receiver Coil Set Range Letter Designations

[Mike Morrow]

RU receivers (with two exceptions) have ganged tuning capacitors that provide a nominal top-end frequency that is 1.5 times the nominal low-end frequency.  There are 15 out of the 17 different RU/RAJ "Navy Type" receivers between 1931 and 1941 which have that characteristic.  The design of the 1934 RU-3 CBY-46036 was mature for the remaining models, with only relatively small improvements made thereafter.  The following is a list of those post-1933 receivers which could use the same coil sets;

CBY-46036  - RU-3/GF-1
CBY-46041  - RU-3A/GF-2
CBY-46046  - RAJ
CBY-46048  - RU-4
CBY-46048A - RU-5
CBY-46048B - RU-6
CBY-46048C - RU-10, early RU-11, early RU-12
CBY-46048D - RU-11, RU-12
CW -46048D - RU-18, RU-19
CBY-46051  - RU-4A/GF-3
CBY-46051A - RU-5A/GF-4, RU-7/GF-5, RU-13/GF-8, RU-14/CF-9
CW -46051A - RU-16/GF-11, RU-17/GF-12

Here is a lising of the associated range designations and frequency coverage:

RANGE       NOMINAL 1.5:1.0
LETTER    FREQUENCY RANGE (kHz)
  A            224 -   350
  B            350 -   545
  C            545 -   850
  D            850 -  1330
  E           1330 -  2040
  F           2040 -  3000
  G           3000 -  4525
  H           4000 -  6000
  I           5400 -  8100
  J           8100 - 12500
  K           9050 - 13575
  L            400 -   600
  M           5200 -  7700
  N *         6000 -  9050
  O *          195 -   290
  P *          290 -   435
  Q *          540 -   830 (For ZB homing adapter output)
* Range exists only on dual-range coil set.

There are ten dual-range coil sets with the following ranges:
 A plus B,
 F plus G,
 F plus N,
 F plus Q,
 G plus L,
 G plus Q,
 L plus M,
 L plus N,
 M plus Q,
 O plus P.

The coil sets above will not work in these receivers:
CBA-46000  - RU-1
CBY-46006  - GF
CBY-46012  - RU-2/GF
CBY-46012A - RU-2A
CBY-46064  - RU-8/GF-6, RU-9/GF-7, RU-15/GF-10

The last two receivers shown have ganged tuning capacitors that provide a nominal top-end frequency that is 2.0 times the nominal low-end frequency.  (Note:  All 19 different SCR-A*-183/-283 receivers have a 2.0:1.0 tuning ratio.)

The CBY-46064 is identical to the CBY-46051A except for the tuning ratio.  Its tuning ranges are designated by two letters, the first of which is Z.

RANGE        NOMINAL 2.0:1.0
LETTERS    FREQUENCY RANGE (kHz)
 ZA *          200 -   390
 ZB            200 -   400
 ZD *          530 -  1000  (For ZB homing adapter output)
 ZE           1000 -  2000
 ZF *         2000 -  3700
 ZG *         3100 -  5600
 ZH *     '   5500 -  9050
 ZR *          200 -   394
* Range exists only on dual-range coil set.

There are nine dual-range coil sets with the following ranges:
 ZA plus ZF (two different Navy Type numbers),
 ZA plus ZG (two differnet Navy Type numbers),
 ZA plus ZH,
 ZD plus ZF (two different Navy Type numbers),
 ZH plus ZR,
 ZG plus ZR.
 
Mike / KK5F