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microphone noise

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klehman(at)albedo.net
Guest

Posted: Sat Jul 15, 2006 3:52 am Post subject: microphone noise

Good day.



I've tried a couple of headsets but I have a lot of static whenever I 

key the transmit button with the headset microphone plugged in. I can 

hear it on my headset and it is being transmitted. No static if I key it 

with the mic unplugged. So it would seem that the mic is picking up 

cockpit noise. However clasping my hand over the boom mic or changing 

its orientation does not change the static which seems to suggest it is 

not cockpit noise. Any suggestions?



This is an Icomm A-200 radio and an intercom but bypassing the intercom 

with its "pilot/all" switch doesn't change anything. The headset jacks 

are mounted in a plastic box. Separate shielded wires are used for the 

mic and the earphones with the shields carrying the grounds.



thanks

Ken

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ceengland(at)bellsouth.ne
Guest

Posted: Sat Jul 15, 2006 5:07 am Post subject: microphone noise

Ken wrote:



 	  Quote: 	
		   



 Good day.



 I've tried a couple of headsets but I have a lot of static whenever I 

 key the transmit button with the headset microphone plugged in. I can 

 hear it on my headset and it is being transmitted. No static if I key 

 it with the mic unplugged. So it would seem that the mic is picking up 

 cockpit noise. However clasping my hand over the boom mic or changing 

 its orientation does not change the static which seems to suggest it 

 is not cockpit noise. Any suggestions?



 This is an Icomm A-200 radio and an intercom but bypassing the 

 intercom with its "pilot/all" switch doesn't change anything. The 

 headset jacks are mounted in a plastic box. Separate shielded wires 

 are used for the mic and the earphones with the shields carrying the 

 grounds.



 thanks

 Ken 


	


If you have a noisy cockpit, covering the mic with your hand probably 

won't make much difference.



Is it electronic static or cockpit noise?



Does it change in pitch with engine rpm? (ignition or alternator)

Is it quiet it you key the mic with the master & all accessories on but 

without the engine running? (cockpit noise)



If it's there with the engine & all other accessories off, you might 

have radio problems.



If it's there but quieter & no pitch change with the engine idling, it's 

probably cockpit noise.

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FLYaDIVE(at)aol.com
Guest

Posted: Sat Jul 15, 2006 6:10 am Post subject: microphone noise

In a message dated 7/15/06 7:55:03 AM Eastern Daylight Time, 

klehman(at)albedo.net writes:



 	  Quote: 	
		   Good day.

  

  I've tried a couple of headsets but I have a lot of static whenever I 

  key the transmit button with the headset microphone plugged in. I can 

  hear it on my headset and it is being transmitted. No static if I key it 

  with the mic unplugged. So it would seem that the mic is picking up 

  cockpit noise. However clasping my hand over the boom mic or changing 

  its orientation does not change the static which seems to suggest it is 

  not cockpit noise. Any suggestions?

  

  This is an Icomm A-200 radio and an intercom but bypassing the intercom 

  with its "pilot/all" switch doesn't change anything. The headset jacks 

  are mounted in a plastic box. Separate shielded wires are used for the 

  mic and the earphones with the shields carrying the grounds.

  

  thanks

  Ken

=============================
	


Ken:



You have a good question ... Problem their ...  My next question in the 

diagnosis would be:

Is the static their when you use any other Headset - Mic Jacks?

If not then the problem is only associated with the Mic Jack you are using.

If the problem still exists on ALL jacks then you have to go back to the 

common points - PTT Switch, Intercom and Radio.



Barry

"Chop'd Liver"



"When all the possibilities are eliminated then the only thing left is the 

probability"

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klehman(at)albedo.net
Guest

Posted: Sun Jul 16, 2006 6:59 pm Post subject: microphone noise

Thank you Charlie and Barry for your thoughts.



It seems that it is cockpit noise that the mic is picking up. 

Interestingly I have a flighttech intercom which uses a hot mic and 

processes the mic audio to remove the cockpit noise from the intercom. 

That works well and there is no noise in the intercom. However when 

transmitting, the mic signal (and noise) goes directly to the radio and 

is transmitted regardless of whether the intercom is on or off.. 

Speaking loudly helps for the time being 



Ken

Charlie England wrote:



 	  Quote: 	
		   

 <ceengland(at)bellsouth.net>



 Ken wrote:



> 

>

> Good day.

>

> I've tried a couple of headsets but I have a lot of static whenever I 

> key the transmit button with the headset microphone plugged in. I can 

> hear it on my headset and it is being transmitted. No static if I key 

> it with the mic unplugged. So it would seem that the mic is picking 

> up cockpit noise. However clasping my hand over the boom mic or 

> changing its orientation does not change the static which seems to 

> suggest it is not cockpit noise. Any suggestions?

>

> This is an Icomm A-200 radio and an intercom but bypassing the 

> intercom with its "pilot/all" switch doesn't change anything. The 

> headset jacks are mounted in a plastic box. Separate shielded wires 

> are used for the mic and the earphones with the shields carrying the 

> grounds.

>

> thanks

> Ken 

 If you have a noisy cockpit, covering the mic with your hand probably 

 won't make much difference.



 Is it electronic static or cockpit noise?



 Does it change in pitch with engine rpm? (ignition or alternator)

 Is it quiet it you key the mic with the master & all accessories on 

 but without the engine running? (cockpit noise)



 If it's there with the engine & all other accessories off, you might 

 have radio problems.



 If it's there but quieter & no pitch change with the engine idling, 

 it's probably cockpit noise.

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ceengland(at)bellsouth.ne
Guest

Posted: Sun Jul 16, 2006 7:23 pm Post subject: microphone noise

Ken wrote:



 	  Quote: 	
		   



 Thank you Charlie and Barry for your thoughts.



 It seems that it is cockpit noise that the mic is picking up. 

 Interestingly I have a flighttech intercom which uses a hot mic and 

 processes the mic audio to remove the cockpit noise from the intercom. 

 That works well and there is no noise in the intercom. However when 

 transmitting, the mic signal (and noise) goes directly to the radio 

 and is transmitted regardless of whether the intercom is on or off.. 

 Speaking loudly helps for the time being 



 Ken 


	


<snipped>



Check with the headset maker on whether the mic has a gain control 

(usually a screwdriver-adjust miniature potentiometer in the mic 

itself). Also ask the comm radio mfgr the same question; there may be a 

mic amplifier gain control in the radio (also a screwdriver adjustment) 

as well.



You can achieve better *system* signal to noise ratio by lowering the 

mic gain & keeping it as close to your lips as possible. Lowering the 

gain lowers the noise volume & keeping the mic close raises the signal 

volume. Result: better system signal to noise ratio.

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FLYaDIVE(at)aol.com
Guest

Posted: Thu Jul 20, 2006 3:18 pm Post subject: microphone noise

In a message dated 7/16/06 11:02:12 PM Eastern Daylight Time, 

klehman(at)albedo.net writes:



 	  Quote: 	
		   Thank you Charlie and Barry for your thoughts.

  

  It seems that it is cockpit noise that the mic is picking up. 

  Interestingly I have a flighttech intercom which uses a hot mic and 

  processes the mic audio to remove the cockpit noise from the intercom. 

  That works well and there is no noise in the intercom. However when 

  transmitting, the mic signal (and noise) goes directly to the radio and 

  is transmitted regardless of whether the intercom is on or off.. 

  Speaking loudly helps for the time being 

  

  Ken

=====================================
	


Ken:



Thank you for the follow up to your problem.  I would have never thought of a 

HOT MIC as being the problem.



Is it possible to increase the Squelch by external knob or maybe internal 

adjustment to shut off the continually on Hot Mic?

I would give a call to the manufacture and see what they say about the 

problem.  If you have this problem with their product. I'm sure there are others.  

There might be a solution from the manufacture.



Barry

"Chop'd Liver"

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klehman(at)albedo.net
Guest

Posted: Thu Jul 20, 2006 6:42 pm Post subject: microphone noise

Barry

No the hot mic works fine for the intercom. This particular intercom 

processes the hot mic signal such that it eliminates the background 

cockpit noise from my mic on the intercom. A different concept than the 

more common voice actuated intercom and so far it seems to work as 

advertised although I'm mostly flying solo right now.

When I transmit, the mic is connected directly to the radio (bypasses 

the intercom) and that was when the objectionable noise was being picked 

up and transmitted. As per Charlie's suggestion, I reduced the mic gain 

adjustment on the radio and that seems to have helped quite a bit.

Ken

FLYaDIVE(at)aol.com wrote:

 	  Quote: 	

In a message dated 7/16/06 11:02:12 PM Eastern Daylight Time, 

klehman(at)albedo.net writes:

>Thank you Charlie and Barry for your thoughts.

> 

> It seems that it is cockpit noise that the mic is picking up. 

> Interestingly I have a flighttech intercom which uses a hot mic and 

> processes the mic audio to remove the cockpit noise from the intercom. 

> That works well and there is no noise in the intercom. However when 

> transmitting, the mic signal (and noise) goes directly to the radio and 

> is transmitted regardless of whether the intercom is on or off.. 

> Speaking loudly helps for the time being 

> 

> Ken

>    

>

=====================================

Ken:

Thank you for the follow up to your problem.  I would have never thought of a 

HOT MIC as being the problem.

Is it possible to increase the Squelch by external knob or maybe internal 

adjustment to shut off the continually on Hot Mic?

I would give a call to the manufacture and see what they say about the 

problem.  If you have this problem with their product. I'm sure there are others.  

There might be a solution from the manufacture.

Barry

"Chop'd Liver"

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