[Elecraft] K3 - MH2 mic switch mechanical noise

[Richard Fjeld]

Bill,

I sent that last post a bit too soon.  I thought of something else.

Some mic switches kill the mic lead by grounding it, maybe some open it.  I 
don't know if it is done with electret elements.  There are people who are 
more familiar with the nature of this.

Here is my though; If the PTT contacts are make-before-break, etc, check to 
see if they are adjusted properly.  Due to having bias voltage, you will 
want to do some research before adjusting contacts.

Perhaps the mic lead is becoming 'hot' too soon so that you hear what you 
don't want to.  I realize this is a stretch, but maybe a possibility.  If I 
had a MH2, I'd know.

Rich, n0ce

----- Original Message ----- 
From: "Bill" <bill at w2blc.net>
To: "Richard Fjeld" <rpfjeld at embarqmail.com>
Sent: Monday, November 12, 2012 6:12 PM
Subject: Re: [Elecraft] K3 - MH2 mic switch mechanical noise


> Thanks Rich for the kind reply. I am looking at ways to re-engineer the 
> MH2. Basically, it involves a very cheap switch and plastic sliding on 
> plastic. Two distinct problems.
>
> I am working on using bubble switches as replacements and have tried a 
> silicone lubricant.
>
> I expect the combo of both tactics will relieve the problem.
>
> Thanks again,
>
> Bill W2BLC
>
>
>
> On 11/12/2012 6:18 PM, Richard Fjeld wrote:
>> Bill,  you said in part:
>>
>>> It is a mechanical problem within the mic, as other mics do not do this.
>>
>> You are partially right.  The word is *SOME*  mics do not do this.  I 
>> have had both hand-mics and desk-mics do it.  AND, it was not only a 
>> spike; it was during transmit if I changed the pressure on the PTT.  The 
>> buttons should be soft material.   Yes, it is annoying.  It is one of the 
>> reasons I went to a boom-mic (CM500). No way for a mechanical noise 
>> pickup from a detached PTT.
>>
>> Now, it is so quiet I get complaints that my rag-chew group can't tell 
>> when I release the PTT.  (Longevity affects the hearing.)  I wrote in 
>> awhile back at their request to see if the K3 could do a short 'dit' when 
>> I released the PTT. (That opened up a can of worms)
>>
>> I don't know what the innards of the MH2 looks like, but you may try to 
>> improve what the element is cushioned in to reduce the microphonics. If 
>> it is audible noise, the electret element will 'hear' it.
>>
>> Rich, n0ce
>>
>>
>> ----- Original Message ----- From: "Bill" <bill at w2blc.net>
>> To: <elecraft at mailman.qth.net>
>> Sent: Saturday, November 10, 2012 9:55 AM
>> Subject: [Elecraft] K3 - MH2 mic switch mechanical noise
>>
>>
>