[ARC5] T-17 Microphone

[Mark K3MSB]

Good info Jeep, but alas I don't have an amplified D-104 on hand.

Someone sent me an email (which was mistakenly deleted so I can't reply in
person.....) that I could use a mic such as the Motorola HMN1080A.  He said
to ensure the bias voltage is positive before using it.

Checking the SCR-274N schematic, it looks like 28V is applied as the bias
voltage to the mic output through the primary of T-51.

There is a TON of information on the HMN1080A on the web, but I can't find
a single tech spec that tells me the impedance.

The mic is pretty cheap on eBay, but I want to make sure I don't nuke T-51
in the BC-456 if I get one of these hand mics.

Thanks

Mark K3MSB

Sent from my Android phone
On Jun 13, 2014 3:10 PM, "D. Platt" <jeepp at comcast.net> wrote:

> The mic under discussion is the T-32. I have two of them and they are
> outstanding.  Its a modified telephone with the off-hook switch and
> earpiece hanger modified for PTT.  Modern elements can be installed with no
> issues, whatever.  In fact, I have taken to installing the guts of an
> amplified D-104 in a T-32 and use it for carbon and otherwise operation.
>  It works swell... in old parlance!!!
>
> Jeep - K3HVG
>
> On 6/12/2014 8:07 PM, Todd, KA1KAQ wrote:
>
>> On Thu, Jun 12, 2014 at 5:52 PM, Mike Everette via ARC5 <
>> arc5 at mailman.qth.net <mailto:arc5 at mailman.qth.net>> wrote:
>>
>>
>>
>>     If you can find one, there was a WW2 "desk mic" which looked like
>>     an old candlestick phone less the receiver... these were often
>>     used in airfield control towers.  This mic has a good bit of room
>>     inside, so a Motorola element might do well in it.  Good luck
>>     finding one, though....
>>
>>
>> They actually show up on ebay fairly often.. The trick is to check the
>> telephone section. Often the seller thinks it's a partial phone and sells
>> it as parts. I've got a couple of the typical 'bulldog' style seen often
>> and one with the removable mouth piece which appears to have once been a
>> phone. It came with an old Abbott TR4 in a box of stuff years ago. Another
>> has a smaller swivel head and PTT lever on the side.
>>
>> The military versions usually have the orange Signal Corps stamp on the
>> base if the felt is still intact.
>>
>> ~ Todd/KAQ
>>
>>
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