[ARC5] M-15 type microphone

[hwhall at compuserve.com]

Thanks everyone for the info. Turns out this mike is not proper vintage for the Link Trainer restoration project, though it might be a parts donor for a future T-17. So I won't be trying to pretty it up anymore. I did try to test the sound and it sounded pretty bad in my simple circuit but it gave decent output levels and probably would sound somewhat better in a proper audio amp.
 

 Wayne
WB4OGM

 

-----Original Message-----
From: DSP3 <jeepp at comcast.net>
To: arc5 <arc5 at mailman.qth.net>
Sent: Wed, Nov 5, 2014 10:40 am
Subject: Re: [ARC5] M-15 type microphone



On 11/3/2014 4:24 PM, hwhall at compuserve.com wrote:
> I have a couple of questions about a microphone, a noise-cancelling type that 
looks much like a T-17 mike, that is labeled M-15/UR...
>
> a) What was the period that the M-15 was in military service?
>
> b) Has anyone ever disassembled the black carbon mike element part? I'd like 
to know how far I can take it down for cleaning without getting to a point the 
carbon grains might fall out.
>
> Thanks!
>
> Wayne
> WB4OGM
>
It appears the M-15/URoise-cancelling mic came out in the 50's, to 
replace the venerable T-17.  I know they were in the USAF inventory in 
the late 50's as I saw the (used them) as a cadet on C-47s and C-53s.  
The M-15, as a hand mic (USAF) was used up until the USAF moved over to 
dynamic mics and headsets.  Our MART-Cart (mobile automatic radiating 
trailer) was an ARC-27 installed and an M-15 was installed, circa 1964.  
They were still listed in USAF stock catalogs in the mid-1960's.   The 
thing is, carbon/carbon compatible mics went over to the old-family 
connectors for most all ground equipment.  The PL-68/PJ-068 mic plug 
(used on T-17 and M-15/UR mics) became passe for GRC/VRC/PRC equipment.  
However, those connectors are still used in many aircraft, especially 
GA.  Headset became the norm in aircraft in the in the 60's, IMHO.  That 
said, on a trip from ADW to Wright-Patt in the 1970's, I recall that the 
C-47 had RS-38 type hand mics installed up front.  Beginning with the 
H-78/AIC headset in the early 60's,  dynamic mics were the standard, 
employing the MX-1646 carbon/dynamic mic adaptor for use with the older 
radios like the ARC-27, 55, ad infinitum.

Regarding taking the M-15 apart.  The front assy can be un-bolted from 
the main assy, but that's all.

Jeep - K3HVG
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