[ARC5] WWII Navy RU- Receiver Coils.

[Lenox Carruth]

Interesting Dave,

I am curious to know if something is connected to all of the pins in the
first and second cans from the left.  It looks to me like the four pin
trapezoidal configuration of male pins would plug into four of the pins on
the cans with the six pins in a circle.  The only place this would not work
is in the second can from the left in the middle set of coils where the
circular pins are "upside down" compared to the others.  

If there is nothing connected to the odd pins in the circular configuration,
then it is possible that the 6-pin can bottoms might have been used if they
ran out of the four-pin configuration.  If this is the case, it seems
possible that the second can in the middle coil set has been installed
upside down.

It looks like only the BFO can has more than four connectors.  I am not
familiar enough with these sets to know which can is the BFO.  It may be
that the cans for the sets with BFOs won't plug into receivers intended for
navigation use? Although, I thought the receivers were interchangeable but
the RU-2 is obviously different from most of the others. Looks like the BFO
cans need five connectors.

Curious what you find out.

Lenox Carruth
WA5OVG


-----Original Message-----


Re: Coil sets for the WWII Aircraft RU-series receivers.

Have manuals for RU-2A, -5, -8, -13 and -16.
The coil sets for all of these, when examined with the coil rightside-up,
label to the right, counting the coil contacts from front to back, are:
4, 4, 4, 4, 6Dn (contact gap down, BFO coil).
This is also the configuration in my RU-15 receiver.

I made the assumption that all the RU coil sets from RU-2A and following
were the same configuration.  Finally piled-up my stash of RU coils and
surprise- there are three seemingly incompatable coil configurations.
In this photo, the "front" of the coils is to the right and I count them
right-to-left.

https://goo.gl/photos/Lh4PRy9WiHQn4DWt9

One configuration looks like that
for SCR-183 and will plug into that rig, though I don't know if it works
there.
It would seem there is no BFO in these.
That configurtion is 4-4-4-4-4.
The third has two 6-contact: 4-4-4-6Up-6Dn.

I have coils for:

4-4-4-4-6Dn
RU-5, RU-7, RU-12, RU-13, RU-15,
RU-16, RU-17, RU-18.

4-4-4-4-4
RU-7, RU-11, RU-12, RU-18, RU-19

4-4-4-6Up-6Dn
RU-6, RU-12, RU-16, RU-18

Note that RU-7, RU-12, RU-16 and RU-18 all have multiple configurations, -12
and -18 having all three.
-18 and -19 were supposedly for Liaison use, so "No BFO winding" makes no
sense.
The coil nomenclature tags give the "correct" 
coil numbers.  
i.e. RU-16 4-4-6 and RU-16 4-6-6 have
the manual-listed coil numbers like CW-47112.

The 4-4-4-6Up-6Dn coils do show some
evidence of being "Ham-burglered."  Was there some CQ article on modifying
these with an extra BFO coil?
However, the 4-4-4-4-4 coils do not look as though they have been molested.
A mod to get them to work in SCR-183 receivers?
The RU-16 manual does not show
the 4-4-4-6-6 configuration.

What do you think?  Is there an explaination  or did someone "ham-bone"
these coils? 

Does anyone have RU-6, RU-7, RU-11,
RU-12. RU-18 or RU-19 manuals
that can shed light on the original coil contacts or explain the multiple
configurations?  There's usually a photo of the contact side of the receiver
coil set somewhere in the first 14 to 18 pages.

TNKS OM ES 73 DE Dave AB5S