[ARC5] T-17 Microphone

[Jim Falls]

My best T -17 is perforated that way. I rejuvenated it and several others by tuning a radio with BFO to ~900Hz ( an apparent sweet spot these have), cranking the volume, then keying the TX into a dummy load while rotating the mic along an axis perpendicular to the face of the element. 6 out of 8 had significant improvement. YMMV

Cheers!
Jim K6FWT 

> On Jun 11, 2014, at 8:41, "Kenneth G. Gordon" <kgordon2006 at frontier.com> wrote:
> 
>> On 11 Jun 2014 at 8:49, Mark K3MSB wrote:
>> 
>> I successfully used my BC-456 ( with the dynamotor) for the first time this
>> weekend in my SCR-274N system!
> 
> Good on ya. That is just the sort of stuff we like to hear. Keep it up, 
> Mark.
> 
>> I´ll get a post out on that saga hopefully
>> later on today.  Alas, I was not able to test AM as I found (and had
>> suspected) that my NIB T-17 mic wasn´t ready for use.
> 
> Ha! Why am I NOT surprised?
> 
>> First, can the carbon mic element be salvaged?
> 
> My understanding is, "No". "Never", might be a better and more accurate 
> word.
> 
>> I´ve read that an telephone
>> mouthpiece mic element will work,
> 
> Well...yes....
> 
>> but I no longer have a "vintage" phone
>> handset.....
> 
> Most of us don't.
> 
>> The matching transformer looks to be in good shape;
> 
> Hmmmm....that sounds odd to me. I didn't know the T-17 HAD a matching 
> transformer. Are you certain your T-17 has not been modified?
> 
>> The capacitor - I assume that´s what´s on the piece of phenolic?  What is
>> the value supposed to be?
> 
> Dunno. Purpose is to cut out the "highs". Audio quality from a T-17 was 
> always "crappy" to my way of thinking: supposed "communications quality 
> in an extremely noisy environment" stuff.
> 
> Although I have always liked the looks of the T-17 and the way it worked 
> (that big round button on the side), I have never liked what it sounded 
> like, even back in the day when they were commonly used with mobile rigs.
> 
> There are ways, which have been published over the years, to replace that 
> carbon-element with a more modern and far better sounding unit withOUT 
> having to do any modification to whatever you wish to plug it into.
> 
> One thing that I do remember is that the T-17 has only three small holes 
> in the cover. Many folks back then used to, carefully, increase the 
> number of holes by quite a few to both increase the amount of audio 
> reaching the element and to improve the audio quality by quite a bit.
> 
> Ken W7EKB 
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