[ARC5] arc-5 BCB RX seen

[Mike Morrow]

I wrote:

> The C-26 control box outboard the ATC is for the R-26. In this
> particular installation, isn't it likely that the R-26 is the 
> receiver normally used with the ATC, not the RAX-1?  Within its
> tuning range, the R-26 wouldn't be much inferior to the CG-46116.

Dave wrote:

> Check the antenna leads.  Both the R-26 and the ARB are wired to
> the ATB.  Therefore, since the ATB has an internal antenna relay,
> the R-26 antenna is not switched by the ATC, but by the Command Set.
> ...
> I think it likely that, in this installation, the R-26 acted as a
> second Command receiver

Mike wrote:

> ...the R-23 is fed by the same ATB antenna.
>
> Just for discussion's sake, I put up three of the series at 
> http://aafradio.org/sidebar/PB4Y2_Line_Maintenance_Manual.html
> - the photos are all dated 20 July 1944.

Mike, you have some very interesting documentation!  The photo of the cockpit radio installation in your latest link (above, which appears to have removed the first link from yesterday) shows the control box for the ATB, control box and dial for the ARB, and the C-26 control for the R-23, a SCR-269 ADF control box, and an AN/APS-2 indicator.  Great stuff!

Dave, I was initially thinking that, yes, the R-26 could have been used as a second command set receiver, allowing the ARB to be set on one of the two ATB channels and the R-26 to cover the other ATB channel.  But the cockpit photo shows no C-26 for the R-26...that C-26 was back near the ATC.  So even though the R-26 antenna is the same as the ARB and is switched by the ATB, my best guess remains that the R-26 was controlled only by the radio operator, in order at times to function with the ATC.  But it does seem strange that the R-26 is not switched by the ATC.

No doubt somewhere an ABK IFF is installed, but I wonder at the lack of VHF homing and communications gear.  By 1944, I'd have thought an AN/ARR-2 and a SCR-522 or AN/ARC-4 would have been installed.

The excellent SCR-269 appears to have been very commonly installed on USN aircraft such as this one.  It's odd that the USN couldn't come up with anything better than the DZ dinosaur, but at least they recognized and used the superior USAAF unit in this and many other instances.

Mike / KK5F