[Milsurplus] CRV-46123...what is it?...

[Morrow, Michael A.]

Hi Mike,

>  > Does anyone know if the USN developed a more capable
>  > airborne DF set than the DZ in WWII
>
> That's an interesting question, and I can think of two sides to the=20
> issue, both of which are based on the definition of "more=20
> capable."=20

Of course, I should actually had written "more modern" instead of "more =
capable."  But automatic DF with electronic loop and remote indicator =
positioning of the SCR-269 seems to be an important capability that the =
DZ lacks.

> Of the DF equipments available, the DF performance of the DZ was=20
> reportedly superior to all of them, but a big part of its accuracy was =

> apparently the complex loop head with its nested loops, compensation,=20
> and ability to tune lower frequencies.

I suspect the only aircraft which could use a DZ would have been a =
large, well-crewed craft like a PBY.  The DZ is labor intensive to use, =
and it can't actually be operated or directly utilized by the pilot.

> There is one school of thought that would=20
> suggest that the AAC actually inherited their SCR-269 and=20
> variants from the Navy, since the Navy heavily subsidized Bendix
> in developing and purchasing their commercial products for use on
> Navy aircraft in the 1930s.

I have a Bendix-made USAAC BC-310 (1937 contract date, SCR-242) which =
seems well advanced over the USN DZ, which was made well into the early =
1940s, judging from contract dates in my DZ-1 manual copy.

> They didn't even bother to nomenclature them with Navy tags.=20
> The Bendix gray wrinkle was a common sight on Navy aircraft, and the=20
> ubiquitous MN-26 DF unit was apparently a fixture on Navy patrol=20
> aircraft long before the AAF began to use it as an alternative to =
their=20
> SCR-269 and later ARN-7.

I never understood the reason for the common use of the completely =
manual DF MN-26 with its hand-cranked loop and mechanical spline-coupled =
indicator.  Maybe the MN-26 was the set of choice when 400 cps AC wasn't =
available.  (Something I read somewhere indicated that the MN-26 later =
became officially known as the AN/ARN-11.)  The SCR-269 and the later =
ARN-7 aren't that much larger, and have a completely automatic compass =
mode, but require 400 cps AC.

>  > The USAAF seems to have been leaps ahead of the USN in airborne ADF
>  > and ILS technology by the end of WWII.
>=20
> I don't hold a particular bias on either Service being a=20
> better avionics developer,

Neither do I.  I come from a USN family and served in the USN myself.

> but a tour through the NRL history books
> will likely show a significant program for DF and ILS far earlier than
> the US Army - and they were worried about locating and landing on a =
much=20
> smaller landing field that the AAC/AAF!

But what examples are there of the equipment the USN developed or used?  =
I've seen no USN equivalent to the USAAF ILS/MB sets, which are very =
commonly found.  Did the USN use the RC-103/ARN-5/RC-193 (and SCS-51 on =
the ground) systems of the USAAF when such capability was needed?

>  > OTOH, maybe the
>  > USN's ZB/YG homing system was all the USN really needed.
>=20
> As an interesting aside, the ARR-1 was a standard piece of=20
> gear on AAF aircraft later in the war.  Also known as the ZB-*,
> the AAF must have considered it useful for something...  :-) =20

I've wondered where and how commonly that occurred.  It's hard to find =
much info on what the USAAF really did with all those BC band BC-946 =
receivers.  But most of the ARR-1 sets I've seen or owned have USAAF =
contract numbers on them, so the USAAF must have had some intent to use =
the system.  One suspects the USAAF use of the ARR-1 and BC-946 sets =
must have been mainly in the Pacific Theater.  But then, what associated =
ground set did the USAAF use, or intend to use?  The USN's YG set??  I =
don't think there's a JAN- or SCR-nomenclature equivalent of a YG-type =
of homing transmitter.

> my impression from documents here is that the Navy usually had
> programs going far earlier than the Army.  'Course, with that
> and $3 you can get a Starbucks coffee.

In WWII and the post-war era, the ATC, AN/ARC-1 (and even the early UHF =
RT-58/ARC-12), AN/ARC-2, and AN/ARR-15 are classic sets with a strong =
USN heritage behind them.  Yet, I still think the best airborne HF =
receiver (BC-348) and ADF receiver (SCR-269 and ARN-7) of WWII had, at =
least officially, a USAAF pedigree on them. =20

By the way (unrelated aside), I found a cockpit photo of a F7F aircraft =
with C-45/ARC-1, C-38/ARC-5, and C-26/ARC-5 (3 to 6 mcs dial) control =
boxes.  Apparently the C-38 and C-45 were used to control the =
RT-18/ARC-1, the C-38 and C-26 to control a R-26/ARC-5, and the =
remaining C-38 section to control a AN/ARR-2.  I thought this was =
interesting, because I had never seen the C-38 being used with any =
VHF-AM set other than the R-28 and T-23/ARC-5.  I saw no HF transmitter =
control box (not even a VHF/HF C-30/ARC-5), so I wonder why the =
R-26/ARC-5 was installed.

Thanks so much for an interesting and informative reply.  Pardon my =
often uninformed speculations and questions.  I really learn a lot from =
you and the several other list members who have actually well researched =
the history of this technology.

73,
Mike / KK5F


=20