[ARC5] [Milsurplus] DU-1 Loop Assembly,

[Mike Hanz]

Well, as long as we're speculating, perusal of that 1936 chapter on Navy 
aircraft DF techniques that I posted on my website gives me some pause 
to ponder.  There are a number of approaches listed in that review of 
technology, from Bellini-Tosi loops, to the "GI Type" cross field 
goniometers used in the DZ DF receivers, to classic Adcock arrays, as 
well as the familiar small loop antennas we all know and love.  While 
the "climax vegetation" for the majority of the fleet appears to have 
been small loops of the Bendix manual and automatic direction finder 
category, it's hard to second guess the requirements guys in 1943 when 
the AN/ARC-5 receiver specifications were initially established without 
knowing what inputs they had to work with.  As AB5S suggested, there may 
have even been some allied forces input.  I don't have a good feel for 
the British side of the DF equation, for example.  We just don't know at 
this point without a document covering those "like to haves", and from 
our perspective seventy years later, it's perhaps easy to question their 
justification.  Having sat on requirements boards like they had for such 
equipment, I can confirm that an incorporation issue sometimes hinges on 
the cost versus the pushback from the particular advocate if the 
requirement isn't incorporated.   The marginal cost of providing the 
capability doesn't seem to be particularly onerous and the design cost 
may well have been eaten by ARC in contract negotiations.  To put it 
another way, politics often intrudes... :-)

73,
Mike  KC4TOS

On 7/24/2012 1:11 PM, Todd, KA1KAQ wrote:
> On Mon, Jul 23, 2012 at 3:00 AM, Mike Morrow <kk5f at earthlink.net> wrote:
>> Loop connections were restored (for God knows what reason) on the 1943
>> R-23*
>> and R-24/ARC-5 receivers.  I don't know of any documented purpose or use of
>> them...they appear simply to be atavistic anachronisms.
> If I had to make a SWAG as to why, I'd bet it was something as simple as
> redundancy. Not knowing where a piece was going or specifically how or what
> it would be used with along the way, it was probably a simple and cheap way
> of adding some additional [potential] utility. A set might end up being
> used at some out-of-the-way location with other dated/obsolete pieces. Or
> end up with some ally who wasn't as up to date as us. If not - no harm
> done.
>
> Beyond that, I agree - it's difficult to justify.
>
> ~ Todd,  KA1KAQ/4