[Milsurplus] MT-171

[Michael Hanz]

On 8/26/2019 3:37 PM, Hubert Miller wrote:
>
> I am going to put an MT-171/U on Epay.
> But first I want to ask,
>
> is this called "standard ATR format" ?
>

Short answer is yes.  It is one of the ARINC series, Hue.  They were 
standardized in a set of different widths and lengths, which the 
military (naturally) converted to letter code sizes.  The MT-171/U is 
referred to as a B-1/D-1 size, associated with what was probably the 
most common width and length for aircraft sets.  There was also an 
A-1/D-1 size (typified by the MT-167/U) that was the same length but 
half the width, used for power supplies and smaller avionics sets.  Then 
they started adding features like rear connectors (used with the AN/ARC- 
1 and AN/ARC-4), swapping out the shock units for heavier equipment.  
(The MT-52/U had shock units about twice the size to accommodate heavier 
sets like the AN/APT-4 magnetron jammer at 
https://aafradio.org/countermeasures/AN-APT-4_jammer.htm
  but used the same aluminum frame as the MT-171/U.)  Standardization is 
fine until the stuff being fielded gets outside of the envelope. Then 
you have to start being creative.

> What radios does it fit, other than ARR-5, 7,   ARQ-1  ?  Fits ARC-1, 
>  APT-series ?
>

For some reason the WWII ECM community designers focused on the ARINC 
standards pretty much right out of the box - probably because of the 
need to constantly swap sets in and out for each mission. The ARINC 
standard was a godsend for them, not to mention making it less expensive 
to field.  Even the early (1942) use of commercial equipment like the 
Halli SX-28 went to war on mounts that were derived from the standard - 
see https://aafradio.org/garajmahal/APA-6X_shock_mount.html for an 
adaptation to support the venerable HP 200C audio oscillator used with 
the AN/APT-6 pulse analyzer.  Almost all of the sets on my 
countermeasures page uses one variation or another of the ARINC 
specification to support the sets.  The rest of the military avionics 
community was slower to adapt, but eventually  signed on to the concept.

    73,
  - Mike  KC4TOS



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