[ARC5] Advice requested. AN/ARN-7 Controls

[Mike Morrow]

John wrote:

> The Control Box is for an ARN-6 or ARN-7... I never remember which is wich.

No, there is never any confusion made between the C-4/ARN-7 and the C-149/ARN-6.
Those are very different visually.

What is often confused is the BC-434-* control box for the BC-433-* (SCR-269-*) ADF,
versus the C-4/ARN-7 control box for the R-5/ARN-7 ADF.  The AN/ARN-7 ADF is just
a SCR-269-* ADF with a fourth band from 100 to 200 kHz added, plus a CW-VOICE switch
on the control box.

Just remember...
Three bands on the control box = SCR-269-*
Four bands on the control box = AN/ARN-7

The presence of the CW-VOICE switch is a little less of a distinction since many
BC-434-* control boxes had a CW-VOICE switch added.

So Ken's control box is the C-4/ARN-7.

And with all that in mind, the control box on ebay that was cited at

   http://www.ebay.com/itm/261172459854

is obviously NOT the item that Ken has.  It is a BC-434-* (three-band, no CW-VOICE
switch).

The AN/ARN-6 (R-101/ARN-6) is a considerable advance over the R-5/ARN-7.

> The Junction Box is for a more complex system with more than an ADF.

Well...it's for systems using *ONE* ADF (here, R-5/ARN-7) with *TWO* control boxes
C-4/ARN-7.  One control is located in the pilot's cockpit, the other at the
navigator's (or rarely radio operator's) position.  The "CONTROL" pushbutton on
a control box is pushed momentarily to assume control of the common R-5/ARN-7
at that particular control box.

The SCR-269-* and most other USAAF ADFs utilized the same type of control transfer
system.

> The MN-52J is for either a MN-26 or much more likely an RA-10. The second
> toggle is a dead giveaway for te RA-10...  it's for the Loop Relay in the
> RA-10 front panel mounted switch box.

Yes...RA-10** Receiver with MR-11* Loop Relay Unit and MN-20* Loop, controlled
by MN-52* Loop Control box.  This item has nothing to do with the MN-26 RDF,
nor the AN/ARN-7 ADF components shown.

Mike / KK5F