Matronics Email Lists :: View topic

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

Noisy Comm Radio

Matronics Email Lists Forum Index -> Europa-List

View previous topic :: View next topic

Author Message

Troy Maynor

Joined: 10 Jan 2006
Posts: 162

Posted: Sun Apr 27, 2014 6:25 pm Post subject: Noisy Comm Radio

Hi All,

I know this has been discussed before on the forum. I have looked til I bleary eyed and can't find the answer I'm looking for.

When I key the mike I have started getting a loud static noise or feedback that wasn't there before. I have near radio silence of incoming traffic until I am in the pattern and then it's scratchy. It sounds ok with the engine off but I don't know how far I'm transmitting or receiving on the ground. I am running an ICOM A200 and Bob Archer antenna. The antenna is mounted on the fuselage wall behind the D panel port side. It has always performed well until recently but can't pin down what has changed. I have checked the security of all the grounds on and forward of the firewall, as far as I can tell. I was thinking it is time to pull the instrument panel but got to thinking about these torroids or suppressors. Can I just string some of these onto the RG58 coax back near the antenna and maybe help matters? 

I'd really appreciate any pointers to look at specifically. I have a Sigtronics intercom with the music switcher also.

Can the presence of an IPAD communicating with a Stratus ADSB cause this?

Most of what I found on the forum dealt with the transmitter affecting other equipment. This is not the case. I am hearing huge noise when I key the mike and can't here others calling me until I'm very near, like in the landing pattern. I can also hear the electric gyros in the headsets a little but that has always been there but not too noticeable, a little pop from the strobes faintly, but I can live with that. I just need to kill the giant, not the little noises necessarily. I'd like to figure out what change took place. 

Thanks, 

Troy Maynor

240 TT hours to date

- The Matronics Europa-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?Europa-List

brian.davies(at)clara.co.
Guest

Posted: Mon Apr 28, 2014 12:17 am Post subject: Noisy Comm Radio

Hi Troy,



How are you powering the iPad?  If you are using a cigarette lighter socket

with a cheap USB power converter it could be generating a large amount of

noise .  Try running the iPad off its internal battery to see of this is the

case.  



Before diving into the wiring and checking for bad connections/ bad earths

it is always worth standing back and saying "what have I changed?"  It is

then a good idea to get a pal to communicate with you on an unused frequency

using a hand held to help you trouble shoot.  First try switching things off

in a systematic way to see what makes a difference.  Try switching off the

intercom.  Most intercoms have a direct radio transmit feature to allow for

intercom failure.



Good luck!



Brian Davies



--

- The Matronics Europa-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?Europa-List

Bill & Sue

Joined: 10 Jan 2006
Posts: 48
Location: Malvern, Worcs. UK (Defford, Croft Farm)

Posted: Tue Apr 29, 2014 1:33 am Post subject: Re: Noisy Comm Radio

Troy,



I had a similar problem with my a200/sigtronics/rotax setup - a loud rough whine on transmit- and it was the earthing.  I was pretty certain it was the earthing but it took a couple of attempts to find the culprit- it may not be the radio earth itself, in fact your description sounds as though the radio earth is OK, poor power earths can induce the noise  too. Good luck! 

I'm not sure about the reception side of your problem other than my A200 sometimes seems a bit deaf and other times is fine - I never did entirely resolve this but I suspect it may be sensitive to stations slightly off frequency.



Regards

Bill

- The Matronics Europa-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?Europa-List

frans(at)privatepilots.nl
Guest

Posted: Tue Apr 29, 2014 2:04 am Post subject: Noisy Comm Radio

-----BEGIN PGP SIGNED MESSAGE-----

Hash: SHA1



On 04/28/2014 04:25 AM, Troy Maynor wrote:

 	  Quote: 	
		   

 <wingnut54(at)charter.net>

 

 Hi All, I know this has been discussed before on the forum. I have

 looked til I bleary eyed and can't find the answer I'm looking

 for.


	


Looks to me (experienced HAM) that you have a failure in your antenna

or the coax cable. Get it checked with a SWR meter to see if it is

still ok.

If it is not ok it can cause the symptoms you described.

The SWR of the antenna can also go wrong if you change something close

to the antenna, like adding another antenna or a piece of metal.



Frans

 	  Quote: 	
		   When I key the mike I have started getting a loud static noise or

 feedback that wasn't there before. I have near radio silence of

 incoming traffic until I am in the pattern and then it's scratchy.

 It sounds ok with the engine off but I don't know how far I'm

 transmitting or receiving on the ground. I am running an ICOM A200

 and Bob Archer antenna. The antenna is mounted on the fuselage wall

 behind the D panel port side. It has always performed well until

 recently but can't pin down what has changed. I have checked the

 security of all the grounds on and forward of the firewall, as far

 as I can tell. I was thinking it is time to pull the instrument

 panel but got to thinking about these torroids or suppressors. Can

 I just string some of these onto the RG58 coax back near the

 antenna and maybe help matters? I'd really appreciate any pointers

 to look at specifically. I have a Sigtronics intercom with the

 music switcher also. Can the presence of an IPAD communicating with

 a Stratus ADSB cause this? Most of what I found on the forum dealt

 with the transmitter affecting other equipment. This is not the

 case. I am hearing huge noise when I key the mike and can't here

 others calling me until I'm very near, like in the landing pattern.

 I can also hear the electric gyros in the headsets a little but

 that has always been there but not too noticeable, a little pop

 from the strobes faintly, but I can live with that. I just need to

 kill the giant, not the little noises necessarily. I'd like to

 figure out what change took place. Thanks, Troy Maynor 240 TT hours

 to date

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=422480#422480

 

 

 

 

 

 

 

 

 

 


	


-----BEGIN PGP SIGNATURE-----

Version: GnuPG v2.0.22 (GNU/Linux)



iQIcBAEBAgAGBQJTX3diAAoJEC+zXxqs0ZzVtMcQAKzDoiil4QmepAbQ9+nr83hY

ZFrlB2VVfyXi3t8Shy9HyIKgi7m8/tpv/aW8D7fECwaiBQb4jAIrdEG98Rqg9pg6

Wo76V2ogueKlgvjqjwbetie4DP4BQhzFwCrekJwxsD754OUUj8M/Z3ugGeoejUPl

I8KMvJRnhTr8ZYd1NO7E4dWRvaGA3v+Ha0HlFWX+8WgzZHlS3ze7qq3NcFLLTzkz

2/mOOTT/lY1sMQUV8uprvggfb0Lwp0M6bXyqt8XuZ6UPDaOOtFRZLd7HkK2eytSl

ZjYvo7TMehNiEBrDL/40xM4nqNbqdaILnBiNt04BwAYi1WmQc3Aws6RVw8QYEe9h

KfoF/drcOp9zdFjhhEyrDDE77luIcIvTwJ+87Dii65749+9CnLuxtmvsDUCwj4hH

m4nQLdNRwTw5OZSgtGpqxXHsurCgZC8dr/x+aWdgZTlTRVTwW/plM2SqJMTt69PH

ej2LzYNB5rq2NPE5Do3GWj6Mh+lX72kQKL9wuQFv2sBJqo8w1nQr0As4S3qVEyIP

rFGElTvTqBAVvZQ0OA69CNKTNDC0jZm8jc0U3LL0C7K/nev4YvstdQxYkT5jXZmU

1yHOaxQ82ZEBIXzWwIjNeGVT3cc3z6RWTKpoR/dUnBOW0zndBJPphxCGKSj8bpa0

sK48y6sBFfNatBuvMpPG

=uQ8T

-----END PGP SIGNATURE-----

- The Matronics Europa-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?Europa-List

christoph.both(at)acadiau
Guest

Posted: Tue Apr 29, 2014 9:33 am Post subject: Noisy Comm Radio

Radio Troubled Europas:

I had exactly the same symptoms. I just replaced the entire antenna cable

and even more importantly, remade a new BNC connector (soldered type) into

my MGLV6 radio. This helped significantly to reduce the screeching noise.

Later this week I will replace the ROTAX912 regulator/rectifier which

introduced low frequency spikes to my bus. I hope this is the cure as the

spikes froze my radio and electric VSI as soon as RPM goes up.

Christoph Both

#223 TRI 912ULS 75+ hours

Nova Scotia, Canada

On 2014-04-29, 6:56 AM, "Frans Veldman" <frans(at)privatepilots.nl> wrote:



 	  Quote: 	
		  



-----BEGIN PGP SIGNED MESSAGE-----

Hash: SHA1



On 04/28/2014 04:25 AM, Troy Maynor wrote:

> 

> <wingnut54(at)charter.net>

> 

> Hi All, I know this has been discussed before on the forum. I have

> looked til I bleary eyed and can't find the answer I'm looking

> for.



Looks to me (experienced HAM) that you have a failure in your antenna

or the coax cable. Get it checked with a SWR meter to see if it is

still ok.

If it is not ok it can cause the symptoms you described.

The SWR of the antenna can also go wrong if you change something close

to the antenna, like adding another antenna or a piece of metal.



Frans

> When I key the mike I have started getting a loud static noise or

> feedback that wasn't there before. I have near radio silence of

> incoming traffic until I am in the pattern and then it's scratchy.

> It sounds ok with the engine off but I don't know how far I'm

> transmitting or receiving on the ground. I am running an ICOM A200

> and Bob Archer antenna. The antenna is mounted on the fuselage wall

> behind the D panel port side. It has always performed well until

> recently but can't pin down what has changed. I have checked the

> security of all the grounds on and forward of the firewall, as far

> as I can tell. I was thinking it is time to pull the instrument

> panel but got to thinking about these torroids or suppressors. Can

> I just string some of these onto the RG58 coax back near the

> antenna and maybe help matters? I'd really appreciate any pointers

> to look at specifically. I have a Sigtronics intercom with the

> music switcher also. Can the presence of an IPAD communicating with

> a Stratus ADSB cause this? Most of what I found on the forum dealt

> with the transmitter affecting other equipment. This is not the

> case. I am hearing huge noise when I key the mike and can't here

> others calling me until I'm very near, like in the landing pattern.

> I can also hear the electric gyros in the headsets a little but

> that has always been there but not too noticeable, a little pop

> from the strobes faintly, but I can live with that. I just need to

> kill the giant, not the little noises necessarily. I'd like to

> figure out what change took place. Thanks, Troy Maynor 240 TT hours

> to date

> 

> 

> 

> 

> Read this topic online here:

> 

> http://forums.matronics.com/viewtopic.php?p=422480#422480

> 

> 

> 

> 

> 

> 

> 

> 

> 

> 



-----BEGIN PGP SIGNATURE-----

Version: GnuPG v2.0.22 (GNU/Linux)



iQIcBAEBAgAGBQJTX3diAAoJEC+zXxqs0ZzVtMcQAKzDoiil4QmepAbQ9+nr83hY

ZFrlB2VVfyXi3t8Shy9HyIKgi7m8/tpv/aW8D7fECwaiBQb4jAIrdEG98Rqg9pg6

Wo76V2ogueKlgvjqjwbetie4DP4BQhzFwCrekJwxsD754OUUj8M/Z3ugGeoejUPl

I8KMvJRnhTr8ZYd1NO7E4dWRvaGA3v+Ha0HlFWX+8WgzZHlS3ze7qq3NcFLLTzkz

2/mOOTT/lY1sMQUV8uprvggfb0Lwp0M6bXyqt8XuZ6UPDaOOtFRZLd7HkK2eytSl

ZjYvo7TMehNiEBrDL/40xM4nqNbqdaILnBiNt04BwAYi1WmQc3Aws6RVw8QYEe9h

KfoF/drcOp9zdFjhhEyrDDE77luIcIvTwJ+87Dii65749+9CnLuxtmvsDUCwj4hH

m4nQLdNRwTw5OZSgtGpqxXHsurCgZC8dr/x+aWdgZTlTRVTwW/plM2SqJMTt69PH

ej2LzYNB5rq2NPE5Do3GWj6Mh+lX72kQKL9wuQFv2sBJqo8w1nQr0As4S3qVEyIP

rFGElTvTqBAVvZQ0OA69CNKTNDC0jZm8jc0U3LL0C7K/nev4YvstdQxYkT5jXZmU

1yHOaxQ82ZEBIXzWwIjNeGVT3cc3z6RWTKpoR/dUnBOW0zndBJPphxCGKSj8bpa0

sK48y6sBFfNatBuvMpPG

=uQ8T

-----END PGP SIGNATURE-----

- The Matronics Europa-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?Europa-List

tennant

Joined: 19 Apr 2011
Posts: 121

Posted: Tue Apr 29, 2014 11:47 pm Post subject: Re: Noisy Comm Radio

I have the reverse problem.



During my last flight I was told that my radio was reading 2 because of interferance. I could hear the airfield perfectly as usual.



I have been flying it now for 17 years without such a problem.



Any ideas please.



Barry

- The Matronics Europa-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?Europa-List

_________________
Barry Tennant
D-EHBT
At EDLM - Germany

Troy Maynor

Joined: 10 Jan 2006
Posts: 162

Posted: Tue May 06, 2014 2:50 am Post subject: Re: Noisy Comm Radio

I tried all the things suggested except the SWR check...no access to one yet. It made no difference running the Ipad and Stratus on self batteries. I check the integrity of all grounds and coax connections that were accessable. I did think I momentarily showed a short center to shield when I had my meter on the male pin in the back of the radio rack but could not repeat it. So now I have the panel at home in my garage. I built in such a way to have it out of the plane in about 30 minutes. 

I am planning to replace the RG58 with RG400 from the radio rack to the Bob Archer antenna on the port bulkhead aft.

So my questions now are:

1. Should I put ferrite torroids on both my electric attitude ind. and turn coord. power wires? What other consumers would need torroids on their power feed...engine monitor? AOA system? Transponder?  other?

2. Should I run a separate ground wire from the radio to the battery itself. Currently it is on one of the Bob Nuckoll's 20 or 30 point grounding strips connected to the negative battery cable inside the panel and would seem useless to run another wire to the same place anyway but maybe it would help. I do have one more spare pin on a connector to get thru the firewall of about a 20 gage wire size.

3. The Sigtronics intercom wires weren't shielded. Do they need to be wrapped up in some kind of shield foil or braid?

I just want to "carpet bomb" anything that could contibute to noise, static, cross interference while I've got the panel out. 

I am also trying to find a new 90 degree coax fitting that fits the ICOM rack. I may be able to just reuse the one there now. 

Thank you so much for your responses.

Troy

- The Matronics Europa-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?Europa-List

frans(at)privatepilots.nl
Guest

Posted: Wed May 07, 2014 8:17 am Post subject: Noisy Comm Radio

-----BEGIN PGP SIGNED MESSAGE-----

Hash: SHA1



On 05/06/2014 12:50 PM, Troy Maynor wrote:

 	  Quote: 	
		   

 <wingnut54(at)charter.net>

 

 I tried all the things suggested except the SWR check...


	


Well this is important. While you can get away for a light bulb with

just checking for proper connection and shorts, for RF things are more

complicated and not measurable with standard multimeters. You can't

measure moisture that has creeped into the coax spongy insulation, but

it would ruin the SWR and cause the coax to act as an antenna rather

than just a transporter. The same with kinks or other damages. Or

metal objects that are just a bit too close to the antenna and causing

the antenna to refuse to radiate and instead bouncing the energy back

into the coax cable.

Bottomline is that your problem looks like an SWR problem and if you

don't measure this, you won't get nearer to a solution.



 	  Quote: 	
		   I am planning to replace the RG58 with RG400 from the radio rack to

 the Bob Archer antenna on the port bulkhead aft.


	


RG400 is a waste of money so is the Bob Archer antenna. Just stick to

the RG58 and a standard dipole antenna. Fancy cables are intended for

losless transmission of frequencies in the GHz range over longer

distances, neither property is valid for your aircraft. For aircraft

purposes, nothing beats the good old dipole antenna (unless there is

not enough space for it but luckily in our Europa's a dipole fits just

fine in the sternpost and this is also the maximum distance away from

our sensitive equipment in the cockpit). No antenna can produce "gain"

without taking energy away from certain directions. But in your

airplane you don't want to favour certain bearings at the cost of

other bearings so a dipole is the ultimate radiator for your ship.

Think of a radiator as a light bulb. Sure there are lenses and

reflectors and you can produce "gain" with it, but is this really what

you want in an airplane?



 	  Quote: 	
		   So my questions now are: 1. Should I put ferrite torroids on both

 my electric attitude ind. and turn coord. power wires?


	


Probably not. These devices were designed for use in an airplane, and

virtually every airplane has a radio. It is unlikely the manufacturer

of your attitude indicator has "forgotten" to incorporate ferrite

torroids in their cables or even specs. If your system works as

intended, torroids are not needed anywhere else than on the end of

your coax cable. (They were included in the Europa radio plan to adapt

the asymmetric coax cable to the symmetric dipole).



 	  Quote: 	
		   2. Should I run a separate ground wire from the radio to the

 battery itself.


	


No. With a properly working antenna no RF is transported than via the

coax cable. The ground wire will only transport DC. But of course, if

your antenna (or the cable connecting it to your radio) is

malfunctioning the RF energy is desparate to find a way out and will

radiate over the ground wire, causing all kinds of interesting effects

in adjacent equipment which is now fed by RF rather than by DC.



 	  Quote: 	
		   3. The Sigtronics intercom wires weren't shielded. Do they need to

 be wrapped up in some kind of shield foil or braid?


	


Consult their manual. These things are designed for use in an airplane

with radio's. If the manufacturer doesn't specify this, it should not

be needed in a properly working system.



 	  Quote: 	
		   I am also trying to find a new 90 degree coax fitting that fits the

 ICOM rack.


	


This rings bells. Why do you need a new one? Or did you bend the coax

instead? You are probably not aware, but the distance between the

center of the coax and the outer shield is a crucial property of the

cable. Bend the cable and the center conductor will get closer to the

outer shield, ruining the impedance of the cable and causing all sorts

of problems.



One other test you can do: obtain a dummy load. This is just a fairly

big resistor of 50 ohms (It needs to be manufactured for RF use, other

resistors are just a wire coiled up but this is not suitable for RF).

It converts the radio energy into heat instead of radiation. Connect

it directly to the radio and transmit. Most likely the problem is

gone. Connect it to your coax cable instead of the antenna and test

again. Is the problem still gone? Then your antenna is the problem.

Does the problem reoccur? Then the cable is faulty.



Succes with troubleshooting!



Frans

-----BEGIN PGP SIGNATURE-----

Version: GnuPG v2.0.22 (GNU/Linux)



iQIcBAEBAgAGBQJTalqmAAoJEC+zXxqs0ZzVaFEQAIpx/2dbc5QlAQ0Yv15/Nn2J

Yx4GceJDbr9lnalpXLnSkztZYz3XPNK8rV9mcaJWShw4cEZTEav0A+ES0CEZEZGG

pk434BdmETHX2q9iWY88jd0hGE4hs/y6gV88hd7BaKDMRr/LyndNlAoQj1ufhDDC

DhHqwgxUHnfDWaZoK/LDOFVWpWY397ZUTA5YHXsxgtVDLuwrJqSxSbKFc/U83j/b

38mZBfgd6x3OHnIyH8po2oidYVV33RFu9BAjP733a97zQtnD7OP0WLe1R+ypf3v4

zb7d025oaebDDmj/2RsWfdPJ94J2yGbc39AohRgVWe3NtjnjZ7j+qmaQyh3htivC

f9ig42PkBlE1bC7zlkpXDrnGQ9hPUC4dBMzwWM+te0FaCDQPQjdQoKzjk7ZWO4Hg

MI0aZqQoa28mJwwPIXdhqXJfw1NDB1ZUUt6E0LcNaGwX5IHLcjfLajZcwYsxOmgd

yAkMyrrWk9pbyFcJFYqelYfElTIG+YV1/AWgdcHL7pcG97zxgB4jsiWruQu+iciR

a6CeWsKYMQxe3G0nI5VdHQeswQESfA3aQ+ARMVv/z1CShRUAmCXwR6JLmyp6JIEx

YVDgr1hSGWCs3jxGcHbDs5mveMBYctj7uZ+tTCQY36wj3Iho85LV8mIyeJletLmE

9mXXSD/Gj6xpg+LflB/Q

=/D8d

-----END PGP SIGNATURE-----

- The Matronics Europa-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?Europa-List

Display posts from previous:

	Matronics Email Lists Forum Index -> Europa-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