[Boatanchors] [Milsurplus] T-17 microphone

[Mike Hanz]

And the outside diameter of the stack of late WECO drop-in elements I 
have around here is 1.820" (not sure if they are F1s, but the date code 
on them is the _late_ 1960s/early 70s and they have screw terminals for 
connection), which simply requires a small counterbored enlargement of 
the T-17 on a milling machine for a perfect fit.  It takes longer to 
fixture and zero the T-17 in the mill than it does to bore it out.  Done 
it numerous times - as did the old timers.  It could be done with a 
1-13/16" hole saw on a drill press if you don't have a friend with a 
mill, but will require the same careful clamping of the microphone 
body.  I use some resilient vise inserts made for gun work that don't 
leave a mark on the black plastic or soft aluminum of the T-17 variants.
73,
Mike

On 8/27/2014 11:13 PM, hwhall at compuserve.com wrote:
>> What are the dimensions of that element?
> The outside diameter of the pictured unit is 1.75 inches.
>
>   Wayne
>
>   
>
> -----Original Message-----
> From: Jim Haynes <jhhaynes at earthlink.net>
> To: hwhall <hwhall at compuserve.com>
> Cc: milsurplus <milsurplus at mailman.qth.net>; boatanchors <boatanchors at mailman.qth.net>
> Sent: Wed, Aug 27, 2014 8:29 pm
> Subject: Re: [Milsurplus] T-17 microphone
>
>
> What are the dimensions of that element?  Wonder if a modern telephone
> handset carbon mike element would fit in there.  (I know people used to
> substitute the old F1 telephone mike elements, but they were too big
> and had to be taped on to the front of the T-17.  Very non-authentic.
>
> A modern (for 1960) carbon mike element is the T-1 used in the Bell 500
> type phones, G-type handset.  I just measured one to be 1 3/4" in
> diameter at the rim, then the rim part is about 1/4" thick, then the
> total thickness is about half an inch.  Without a T-17 mike to look
> at I'm guessing that might fit inside.  Much easier than trying to take
> the original apart and replacing the carbon.  Also you can get an
> electret replacement for the telephone carbon transmitter.
>
> Now the T-17 mikes were remarkably insensitive even when new.  I don't
> have the facts, but it's my belief that was done intentionally so that
> the user had to yell into the mike to be heard over the engine noise
> in an airplane.  The T1 should be a lot more sensitive.
>
> Jim W6JVE
>
> jhhaynes at earthlink dot net
>
>   
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