Matronics Email Lists :: View topic - intercom noise (was radio noise)

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

intercom noise (was radio noise)

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

uuccio(at)gmail.com
Guest

Posted: Fri Aug 22, 2014 8:39 am Post subject: intercom noise (was radio noise)

When my (Rotax 912) engine goes over 3800 RPM it breaks the squelch on the

radio, the radio goes in RX mode and I hear a bunch of white noise, which

for all intents and purposes makes receiving transmissions very difficult.

I have been through several iterations of this problem (see previous posts,

involving a noisy Autopilot on the 130Mhz which is our local frequency) but

yesterday I realized that if I turn the intercom off the problem disappears

(the radio doesn't go into RX mode).  



So it appears that there is some kind of noise source which makes its way

into the Intercom (it's a GMA 240).  What steps can I take to get rid of

this problem?  I have already shielded the magneto wires.   



sacha

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

uuccio(at)gmail.com
Guest

Posted: Fri Aug 22, 2014 8:53 am Post subject: intercom noise (was radio noise)

When I say "white noise" I mean interference noise that seems related to

engine RPM.



--

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

saylor.dave(at)gmail.com
Guest

Posted: Fri Aug 22, 2014 9:08 am Post subject: intercom noise (was radio noise)

I'm not associated with any avionics manufacturer, but I know from experience with several Garmin audio panels that they just don't reject noise as well as PS Eng audio panels.  In several cases, changing to a PS got rid of whines, buzzes, static, etc. that extra shielding and ground loop witch hunts just didn't fix.  What you're hearing may just not be resolvable with a Garmin.  I really like a lot of their other products, but the audio panels aren't as good.  



--Dave



On Fri, Aug 22, 2014 at 9:37 AM, Sacha <uuccio(at)gmail.com (uuccio(at)gmail.com)> wrote:

  [quote]--> AeroElectric-List message posted by: "Sacha" <uuccio(at)gmail.com (uuccio(at)gmail.com)>

   

 When my (Rotax 912) engine goes over 3800 RPM it breaks the squelch on the

 radio, the radio goes in RX mode and I hear a bunch of white noise, which

 for all intents and purposes makes receiving transmissions very difficult.

 I have been through several iterations of this problem (see previous posts,

 involving a noisy Autopilot on the 130Mhz which is our local frequency) but

 yesterday I realized that if I turn the intercom off the problem disappears

 (the radio doesn't go into RX mode).

 

 So it appears that there is some kind of noise source which makes its way

 into the Intercom (it's a GMA 240).  What steps can I take to get rid of

 this problem?  I have already shielded the magneto wires.

 

 sacha

 

 

 ===========

  -

 Electric-List" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List

 ===========

  FORUMS -

 _blank">http://forums.matronics.com

 ===========

 b Site -

           -Matt Dralle, List Admin.

 target="_blank">http://www.matronics.com/contribution

 ===========

 

 

 

 [b]

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Sat Aug 23, 2014 4:19 am Post subject: Re: intercom noise (was radio noise)

Breaking the radio squelch would not make it more difficult to hear incoming radio transmissions.  The symptoms that you describe are from breaking the intercom squelch.  The white noise is cockpit noise.  As the engine RPM increases, the cockpit noise increases until it reaches a point where the intercom squelch is broken.  Try adjusting the intercom squelch at cruise RPM using the large knobs, left knob for pilot and right knob for copilot.

Joe

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

_________________
Joe Gores

uuccio(at)gmail.com
Guest

Posted: Sat Aug 23, 2014 5:55 am Post subject: intercom noise (was radio noise)

Hi Joe,

Thanks for your suggestion.  What you say makes perfect sense.  I tried

turning up the pilot intercom squelch before but I may have inadvertently

left the copilot squelch low and the copilot headset connected.  I'll check

that next time I'm in the plane.

Sacha

 

--

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

uuccio(at)gmail.com
Guest

Posted: Thu Aug 28, 2014 12:56 pm Post subject: intercom noise (was radio noise)

Joe,

I can confirm that you hit the nail on the head.  Yesterday and today I

unplugged the copilot headset and the intercom squelch problem went away.

Thank you again!

Sacha



--

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Thu Aug 28, 2014 2:10 pm Post subject: Re: intercom noise (was radio noise)

You are welcome, Sacha.

Do not archive

Joe

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

_________________
Joe Gores

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum