[ARC5] ZB, AN/ARR-1 vs. ARA, ARB, SCR-274-N, AN/ARC-5, SCR-269, AN/ARN-7

[Mike Morrow]

Jay wrote:

>There are pictures of my setup on the MRCG website.I built up a display 
>that included the ZB-* and the DU-*.

One of the interesting details of the ARB and ZB installation is that it
does not require the use of the ZB (or AN/ARR-1) control box, antenna relay,
and other little doo-dads that are required to use the ZB with the RU-series
of aircraft receivers.  Mike Hanz has information on his site about this
feature of the ARB:

http://aafradio.org/docs/atb-arb.html

Only the ZB unit, a three-conductor power cable from the ARB to the ZB,
and a RF connection from the ZB to the ARB's LOOP connections are required.

To select the ARB/ZB combo, the operator just selects the 560 to 1600 HOMING
band on the ARB control box and the input of the ARB will be switched to the ZB
through the ARB's LOOP connections.  If the operator wishes to use that band
normally, he just selects the 560 to 1600 COMMUNICATION band on the ARB control
box and the ARB inputs swaps to the normal antenna connection.

The use of the ZB or AN/ARR-1 with the CBY-46145, BC-946-B, or R-24/ARC-5 BCB
receivers would use similar philosophy:  Install the BCB receiver in the rack
in place of the beacon band receiver (both would not be needed), connect the ZB
RF output to the input of the BCB receiver, and connect a three-conductor power
cable between the power adapter on the BCB receiver and the ZB.  WHenever the
ZB homing system was required, it was right there by turning up the audio
on the BCB receiver.

I have a Handbook of Flight Operating Instructions (the "dash 1") for the B-29,
B-29A, and B-29B.  Some of these aircraft carried the AN/ARR-1 ZB-homing adapter.
Instead of directing the AN/ARR-1 output to a BC-946-B, it was directed to the
ANT connection of the SCR-269 or AN/ARN-7 ADF receiver.  The instructions tell
the operator to select ANT on the ADF control box, select CW mode, and select
the desired freqeuency in the 410 to 850 KC band to use the AN/ARR-1.

The fact that the ZB and AN/ARR-1 control and relay boxes were superfluous to
all but early installations likely explains why there are many ZB adapters but
few of the other components around today.  The adapter was about the only thing
needed.

Mike / KK5F