[ARC5] Mystery RU Receiver Coil

[Ben Hall]

Perhaps one of the most interesting things to do with the BC-xx-229 and 
RU-xx series is to compare the similarities and differences.

Recently, I came into an assortment of RU parts and a plug-in tuning coil.

This coil was weird - it was marked Range Q/G for RU-16, but the 
oscillator coil assembly only had *four* contacts, not the usual six.

This would be the expected configuration for a BC-xx-229 coil set, not 
an RU coil set.  I took the coil set apart and got out the manuals to 
see what was going on here.

Army BC-xx-229 coil sets (referred to from here on out as "Army coil 
sets") have the following modules:

89 - tuned input
92 - band-pass
90 - "tuned coupling"
90 - "tuned coupling"
90 - "tuned coupling"

Navy RU-xx coil sets (referred to from here on out as "Navy coil sets") 
have the following modules:

89 - tuned input
92 - band-pass
90 - "tuned coupling"
90 - "tuned coupling"
91 - "OSCILLATOR COIL ASSY"

Further investigation looking at the Navy coil parts lists to drawing 
numbers table notes that in this CW-47107 Range Q/G coil set, #89 is 
drawing number 2858, as is #90.  These are the same part.

Same thing with Army coil parts lists.  On a C-379 coil set, the #89 
tuned input coil has the same part number as the #90 tuned coupling coils.

I suspect that this mystery coil, made from Navy parts, will operate 
properly in a BC-xx-229.  Next step is to compare the schematics.

thanks much and 73,
ben, kd5byb