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Radio Noise
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rdmac(at)swbell.net
Guest

Posted: Fri Feb 05, 2010 1:58 pm Post subject: Radio Noise

I need some opinions from the List. I run a Rotax 912s in a model 7 and it has developed a noise in the radio every time I transmit. It would best be described as a crackling popping noise in the headset. It is connected some way with the engine sense it varies with the RPM of the engine and quits altogether when I shut the engine down. I was up flying the other day and after I landed I called the FBO and asked for a radio check and he said I was a little static’y but I was readable. Could I have a bad spark plug or plug wire? The engine seems to be running fine. Do I have a bad ground some where...opinions?  

   

Roger McConnell, Duncan, OK  

Model 7 Trigear, Rotax 912uls   

Flying sense Jan. 06  

   

       [quote][b]

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Fri Feb 05, 2010 6:43 pm Post subject: Radio Noise

Possible bad ground in the antenna system... but I doubt it because you would have very poor transmit strength and you didn’t mention that.  

   

You can look for a bad ground on the shield that covers the mag P-Leads.  That certainly would cause your problem...  That shield should be well grounded at the base of the engine.  

Finally look for a resistor plug that may have the resistor shorted. Or a plug cap that has arced inside. (It will be loose)  

   

Noel  

       

From: owner-kitfox-list-server(at)matronics.com [mailto:owner-kitfox-list-server(at)matronics.com] On Behalf Of Roger McConnell

 Sent: February 5, 2010 6:26 PM

 To: kitfox-list(at)matronics.com

 Subject: Radio Noise  

  

  

   

I need some opinions from the List. I run a Rotax 912s in a model 7 and it has developed a noise in the radio every time I transmit. It would best be described as a crackling popping noise in the headset. It is connected some way with the engine sense it varies with the RPM of the engine and quits altogether when I shut the engine down. I was up flying the other day and after I landed I called the FBO and asked for a radio check and he said I was a little static’y but I was readable. Could I have a bad spark plug or plug wire? The engine seems to be running fine. Do I have a bad ground some where...opinions?  

   

Roger McConnell, Duncan, OK  

Model 7 Trigear, Rotax 912uls   

Flying sense Jan. 06  

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_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

Guy Buchanan

Joined: 16 Jul 2006
Posts: 1204
Location: Ramona, CA

Posted: Sat Feb 06, 2010 6:43 am Post subject: Radio Noise

At 01:56 PM 2/5/2010, you wrote:

  	  Quote: 	
		  I need some opinions from the List. I run a Rotax 912s in a model 7 and it has developed a noise in the radio every time I transmit. 	


 I have problems with the grounding of my antenna to the frame. A couple of times after getting the airframe washed the ground degraded and reception and transmission suffered. I simply cleaned up the connection, restoring the ground plane, and reception was great again.



 

 Guy Buchanan

 San Diego, CA

 K-IV 1200 / 582-C / Warp / 400 hrs. and counting    [quote][b]

_________________
Guy Buchanan
Deceased K-IV 1200
A glider pilot too.

rdmac(at)swbell.net
Guest

Posted: Sun Feb 07, 2010 6:25 am Post subject: Radio Noise

Guy and Noel,  

Thanks for the advice. After old man winter eases up around here I will check these out. I really think it’s something to do with the ignition system or a bad ground on a P-lead.  

DO NOT ARCHIVE  

     

Roger McConnell, Duncan, OK  

Model 7 Trigear, Rotax 912uls   

Flying sense Jan. 06  

  

         

  

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Paul A. Franz, P.E.

Joined: 02 Dec 2008
Posts: 280
Location: Bellevue WA

Posted: Mon Feb 08, 2010 4:49 am Post subject: Radio Noise

On Sun, February 7, 2010 6:23 am, Roger McConnell wrote:

 	  Quote: 	
		   Guy and Noel,



 Thanks for the advice. After old man winter eases up around here I will

 check these out. I really think it's something to do with the ignition

 system or a bad ground on a P-lead.


	


That's a possibility, for sure. I'm certainly not a radio expert but from my reading

and personal experience, I'll put my money on a loose or corroded connection at one of

four places:



1) Radio power lead.



2) Radio ground wire.



3) Antenna ground connection to the ground plane.



4) Antenna cable connection especially at the end points of RG-58 coax.



Be sure to inspect crimped connectors for 1) and 2) carefully. Any corrosion at these

connectors introduces capacitance and can act as an amplifier to introduce ignition

noise into the power side of the radio.



My favored resource for help with this kind of problem is the Aeroelectric list. If

you are using the forum for this list (Kitfox), you can also read and post to the

Aeroelectric forum or any other Matronics forum.

-- 

Paul A. Franz

Registration/Aircraft - N14UW/Merlin GT

Engine/Prop - Rotax 914/NSI CAP

Bellevue WA



"We the People of the United States, in Order to form a more perfect

Union, establish Justice, insure domestic Tranquility, provide for

the common defence, promote the general Welfare, and secure the

Blessings of Liberty to ourselves and our Posterity, do ordain and

establish this Constitution for the United States of America. ...

Done ... the seventeenth day of September, in the year of our LORD

one thousand seven hundred and eighty seven."

-- George Washington and the Signers



"The Modern Liberal believes in the supremacy of the state, thereby

rejecting the principles of the Declaration and the order of the civil

society, in whole or part. For the Modern Liberal, the individual's

imperfection and personal pursuits impede the objective of a utopian

state. In this, Modern Liberalism promotes what French historian Alexis

de Tocqueville described as a soft tyranny, which becomes increasingly

more oppressive, potentially leading to a hard tyranny (some form of

totalitarianism). As the word 'liberal' is, in its classical meaning,

the opposite of authoritarian, it is more accurate, therefore, to

characterize the Modern Liberal as a Statist. ... The Statist ... knows

that despite his successful usurpations, enough citizens are still

skeptical and even distrustful of politicians and government that he

cannot force his will all at once. Thus he marches in incremental

steps, adjusting his pace as circumstances dictate. Today his pace is

more rapid, for resistance has slowed. ... The Conservative does not

despise government. He despises tyranny. This is precisely why the

Conservative reveres the Constitution and insists on adherence to it.

An 'effective' government that operates outside its constitutional

limitations is a dangerous government. ... The Conservative is alarmed

by the ascent of a soft tyranny.... He knows that liberty once lost is

rarely recovered. He knows of the decline and eventual failure of past

republics. And he knows that the best prescription for addressing

society's real and perceived ailments is not to further empower an

already enormous federal government beyond its constitutional limits,

but to return to the founding principles. A free people living in a

civil society, working in self-interested cooperation, and a government

operating within the limits of its authority promote more prosperity,

opportunity, and happiness for more people than any alternative.

Conservatism is the antidote to tyranny precisely because its

principles are the founding principles."

-- author and radio talk-show host Mark Levin in his book "Liberty and Tyranny"

_________________
Paul A. Franz, P.E.
Registration/Aircraft - N14UW/Merlin GT
Engine/Prop - Rotax 914/NSI CAP
Bellevue WA
425.241.1618 Cell
425.440.9505 Office

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Mon Feb 08, 2010 5:37 am Post subject: Re: Radio Noise

Roger I sent this on sunday but it bounced back form matronics mail server. looks like my ISP is blocked for mail



The original message was received at Sun, 7 Feb 2010 10:35:35 -0500

from node152.wl-a.pppoe.execulink.com [209.213.225.152]



   ----- The following addresses had permanent fatal errors -----

<kitfox>

    (reason: 554 Service unavailable; Client host [smtp2.execulink.net] blocked using Barracuda Reputation; http://bbl.barracudacentral.com/q.cgi?ip=209.213.225.152)





From: Dave Fisher 

To: kitfox-list(at)matronics.com 

Sent: Sunday, February 07, 2010 10:35 AM

Subject: Re: Kitfox-List: Radio Noise

Roger, 



I common fault is using the chassis as a ground. Even though the chassic may be grounded to the ground bar or to the battery you can still have issues.



All grounds should be at one point . Don't ever consider  the chassis ground to be perfect consistently.



Dave 

no radio troubles here currently

----- Original Message ----- 

From: Roger McConnell 

To: kitfox-list(at)matronics.com 

Sent: Sunday, February 07, 2010 9:23 AM

Subject: RE: Kitfox-List: Radio Noise

_________________
Realtime Kitfox movies to separate the internet chatter from the truth
http://www.youtube.com/user/kitfoxflyer
Hundreds of Kitfox Movies
Most viewed Kitfox on youtube
Most popular on youtube
Highest rated on youtube

MDKitfox(at)AOL.COM
Guest

Posted: Mon Feb 08, 2010 5:45 am Post subject: Radio Noise

Paul,



Thank you for placing those two paragraphs at the end of your email.  They caught my attention and I'm glad they did.  I've heard of Mark Levin, but had no idea he was such a brilliant writer.  I just may have to get his book!



 Rick Weiss

N39RW Series V Speedster, 912ULS

SkyStar S/N 1

Port Orange, FL

 

 

On Feb 7, 2010, at 11:19 PM, Paul Franz - Merlin GT wrote:

 	  Quote: 	
		  --> Kitfox-List message posted by: "Paul Franz - Merlin GT" <paul(at)eucleides.com (paul(at)eucleides.com)>



On Sun, February 7, 2010 6:23 am, Roger McConnell wrote:

 	  Quote: 	
		  Guy and Noel,



Thanks for the advice. After old man winter eases up around here I will

check these out. I really think it's something to do with the ignition

system or a bad ground on a P-lead.

	


That's a possibility, for sure. I'm certainly not a radio expert but from my reading

and personal experience, I'll put my money on a loose or corroded connection at one of

four places:



1) Radio power lead.



2) Radio ground wire.



3) Antenna ground connection to the ground plane.



4) Antenna cable connection especially at the end points of RG-58 coax.



Be sure to inspect crimped connectors for 1) and 2) carefully. Any corrosion at these

connectors introduces capacitance and can act as an amplifier to introduce ignition

noise into the power side of the radio.



My favored resource for help with this kind of problem is the Aeroelectric list. If

you are using the forum for this list (Kitfox), you can also read and post to the

Aeroelectric forum or any other Matronics forum.

-- 

Paul A. Franz

Registration/Aircraft - N14UW/Merlin GT

Engine/Prop - Rotax 914/NSI CAP

Bellevue WA



"We the People of the United States, in Order to form a more perfect

Union, establish Justice, insure domestic Tranquility, provide for

the common defence, promote the general Welfare, and secure the

Blessings of Liberty to ourselves and our Posterity, do ordain and

establish this Constitution for the United States of America. ...

Done ... the seventeenth day of September, in the year of our LORD

one thousand seven hundred and eighty seven."

-- George Washington and the Signers



"The Modern Liberal believes in the supremacy of the state, thereby

rejecting the principles of the Declaration and the order of the civil

society, in whole or part. For the Modern Liberal, the individual's

imperfection and personal pursuits impede the objective of a utopian

state. In this, Modern Liberalism promotes what French historian Alexis

de Tocqueville described as a soft tyranny, which becomes increasingly

more oppressive, potentially leading to a hard tyranny (some form of

totalitarianism). As the word 'liberal' is, in its classical meaning,

the opposite of authoritarian, it is more accurate, therefore, to

characterize the Modern Liberal as a Statist. ... The Statist ... knows

that despite his successful usurpations, enough citizens are still

skeptical and even distrustful of politicians and government that he

cannot force his will all at once. Thus he marches in incremental

steps, adjusting his pace as circumstances dictate. Today his pace is

more rapid, for resistance has slowed. ... The Conservative does not

despise government. He despises tyranny. This is precisely why the

Conservative reveres the Constitution and insists on adherence to it.

An 'effective' government that operates outside its constitutional

limitations is a dangerous government. ... The Conservative is alarmed

by the ascent of a soft tyranny.... He knows that liberty once lost is

rarely recovered. He knows of the decline and eventual failure of past

republics. And he knows that the best prescription for addressing

society's real and perceived ailments is not to further empower an

already enormous federal government beyond its constitutional limits,

but to return to the founding principles. A free people living in a

civil society, working in self-interested cooperation, and a government

operating within the limits of its authority promote more prosperity,

opportunity, and happiness for more people than any alternative.

Conservatism is the antidote to tyranny precisely because its

principles are the founding principles."

-- author and radio talk-show host Mark Levin in his book "Liberty and========================nbsp;       - The Kitfox-List Email Fortronics.com/Navigator?Kitfox-List">http://www.matronics.com/Navigator?Kitf========================p;            ================================================nbsp;      - List Contribution Web Site -http://www.matronics.com/contri=========================================



	


=  [quote][b]

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Mon Feb 08, 2010 2:02 pm Post subject: Radio Noise

Just to be sure...  There should be a grounded shield on the P-Leads The only time the P-Leads themselves should be grounded is to shut off the mags.  When the engine is in operation they should be adrift meaning they are actually like little transmitter antennas.  It is important they be shielded.  

   

Noel  

       

From: owner-kitfox-list-server(at)matronics.com [mailto:owner-kitfox-list-server(at)matronics.com] On Behalf Of Roger McConnell

 Sent: February 7, 2010 10:53 AM

 To: kitfox-list(at)matronics.com

 Subject: RE: Radio Noise  

  

  

   

Guy and Noel,  

Thanks for the advice. After old man winter eases up around here I will check these out. I really think it’s something to do with the ignition system or a bad ground on a P-lead.  

DO NOT ARCHIVE  

     

Roger McConnell, Duncan, OK  

Model 7 Trigear, Rotax 912uls   

Flying sense Jan. 06  

  

         

  

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_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Mon Feb 08, 2010 3:12 pm Post subject: Radio Noise

In the interest of opening a can of worms, Noel........shielding  

grounded on one end or both?  (ducking) : )

Lynn Matteson

Kitfox IV Speedster, taildragger

Jabiru 2200, #2062, 849.1 hrs

Countdown to 1000 hrs~151 to go

Sensenich 62"x46" Wood (summer)

Sensenich 55.5" x 46" Wood (winter)

Electroair direct-fire ignition system

Rotec TBI-40 injection

Status: flying (and learning)

do not archive



On Feb 8, 2010, at 4:58 PM, Noel Loveys wrote:



 	  Quote: 	
		   Just to be sure...  There should be a grounded shield on the P- 

 Leads The only time the P-Leads themselves should be grounded is to  

 shut off the mags.  When the engine is in operation they should be  

 adrift meaning they are actually like little transmitter antennas.   

 It is important they be shielded.



 Noel



 From: owner-kitfox-list-server(at)matronics.com [mailto:owner-kitfox- 

 list-server(at)matronics.com] On Behalf Of Roger McConnell

 Sent: February 7, 2010 10:53 AM

 To: kitfox-list(at)matronics.com

 Subject: RE: Radio Noise



 Guy and Noel,



 Thanks for the advice. After old man winter eases up around here I  

 will check these out. I really think it’s something to do with the  

 ignition system or a bad ground on a P-lead.



 DO NOT ARCHIVE



 Roger McConnell, Duncan, OK



 Model 7 Trigear, Rotax 912uls



 Flying sense Jan. 06



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

 forums.matronics.com http://www.matronics.com/contribution   http:// 

 www.matronics.com/Navigator?Kitfox-Listhttp:// 

 forums.matronics.comhttp://www.matronics.com/contribution

 ============================================================ _- 

 ============================================================ _- 

 contribution_- 

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

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

rdmac(at)swbell.net
Guest

Posted: Mon Feb 08, 2010 4:42 pm Post subject: Radio Noise

Wow, lots of food for thought, thanks fellows. I will for sure check my

radio power and ground connects and the RG-58 connection.

DO NOT ARCHIVE

Roger McConnell, Duncan, OK

Model 7 Trigear, Rotax 912uls 

Flying sense Jan. 06



--

Paul A. Franz, P.E.

Joined: 02 Dec 2008
Posts: 280
Location: Bellevue WA

Posted: Mon Feb 08, 2010 5:51 pm Post subject: Radio Noise

On Mon, February 8, 2010 3:08 pm, Lynn Matteson wrote:

 	  Quote: 	
		   



 In the interest of opening a can of worms, Noel........shielding

 grounded on one end or both?  (ducking) : )


	


I've a lot of experience with RG-58 cabling with ethernet networks. The proper way is

a ground on one end and the last connection on the other should be a T with a 50 ohm

terminator. With ethernet, having the terminator on one or both ends seems sufficient,

i.e., no grounds at all. I believe you should ground only one end of the shielded coax

when used as an antenna lead. I don't know if a terminator should be used on the other

or not though.



-- 

Paul A. Franz

Registration/Aircraft - N14UW/Merlin GT

Engine/Prop - Rotax 914/NSI CAP

Bellevue WA



Per list moderators' directive my taglines will from here on out will be more limited

in scope and volume. Here's a couple though.



"The cause of America is in a great measure the cause of all mankind."

-- Thomas Paine, Common Sense, 1776



There is no such thing as society: there are individual men and women,

and there are families.

-- Margaret Thatcher

_________________
Paul A. Franz, P.E.
Registration/Aircraft - N14UW/Merlin GT
Engine/Prop - Rotax 914/NSI CAP
Bellevue WA
425.241.1618 Cell
425.440.9505 Office

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Mon Feb 08, 2010 6:24 pm Post subject: Radio Noise

Shielding... grounded only to the end closest to the source..  If you ground

the shield at both ends what you have done is made an unbalanced conductor

like a piece of coax.  As with coax there is a capacitance in the line when

it is grounded at both ends.  This is why they say to only ground at one end

and that end usually has the best ground at the source end.



Years ago I was involved in a volunteer position at the local cable station.

We did several programs which were all recorded on 1/2" Beta video machines

and then edited down to the program length.  Our editing suite had a problem

that after a video dub of five minutes we would get a glitch in our video.

The suite was in a room with a faraday screen that was connected to a close

to perfect ground ( a 4X8'piece of steel buried ten feet below the surface

of the ground...  The steel had 20'radials attached to it)  Sony was so

upset over this they actually sent technicians from Japan to check out our

installation.  After a week of trying everything they could think of one of

the technicians attached an additional ground between the frame of the video

board and one of the audio boards and the glitch stopped.  No one knows why

since both boards were properly grounded.  The bond between the two boards

worked so well that future models of the Beta editing suite had the extra

ground included.



When it comes to electronics there are rules and just like everything else

there are exceptions that make the rules.



Noel



--

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Mon Feb 08, 2010 7:02 pm Post subject: Radio Noise

Antennae are a bit different they are unbalanced conductors where the

shielding carries up to half the power.  Antennae should be grounded at both

ends.  On a vertical antenna the shield should have a ground plane equal to

at least 1/4 the wave length being transmitted. The groundplane is located

at the base of the vertical radiator and 90 deg to it.  On transmitting

coaxes generally the centre radiator is not in any way grounded...  Note the

word "Generally".  There are some antennas that may use a resistor between

the radiator and the shield.



Noel



--

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

Paul A. Franz, P.E.

Joined: 02 Dec 2008
Posts: 280
Location: Bellevue WA

Posted: Mon Feb 08, 2010 7:54 pm Post subject: Radio Noise

On Mon, February 8, 2010 7:02 pm, Noel Loveys wrote:

 	  Quote: 	
		   



 Antennae are a bit different they are unbalanced conductors where the

 shielding carries up to half the power.  Antennae should be grounded at both

 ends.


	


Noel, are you certain of that? I am looking at the installation guide for a Narco

VOR/COM given to me from the Paine Field Radio shop and it says to ground the Com coax

on one end only at the radio end of the shielding of the coax. I seem to recall

reading the same advice on the AeroElectric list. I'm not speaking from Engineering

knowledge just regurgitating so I definitely won't feel hurt if I'm corrected on this.

-- 

Paul A. Franz

Registration/Aircraft - N14UW/Merlin GT

Engine/Prop - Rotax 914/NSI CAP

Bellevue WA



"It is an object of vast magnitude that systems of education should

be adopted and pursued which may not only diffuse a knowledge of the

sciences but may implant in the minds of the American youth the

principles of virtue and of liberty and inspire them with just and

liberal ideas of government and with an inviolable attachment to

their own country."

-- Noah Webster, On Education of Youth in America, 1790



"Absolute power corrupts even when exercised for humane purposes. The

benevolent despot who sees himself as a shepherd of the people still

demands from others the submissiveness of sheep. The taint inherent in

absolute power is not its inhumanity but its anti-humanity."

-- American author Eric Hoffer (1902-1983)



"That [tyrannical government] power is absolute, minute, regular,

provident and mild. It would be like the authority of a parent if,

like that authority, its object was to prepare men for manhood; but

it seeks, on the contrary, to keep them in perpetual childhood: it

is well content that the people should rejoice, provided they think

of nothing but rejoicing. For their happiness such a government

willingly labors, but it chooses to be the sole agent and the only

arbiter of that happiness; it provides for their security, foresees

and supplies their necessities, facilitates their pleasures, manages

their principal concerns, directs their industry, regulates the

descent of property, and subdivides their inheritances: what

remains, but to spare them all the care of thinking and all the

trouble of living?"

-- French historian Alexis de Tocqueville (1805-1859)

_________________
Paul A. Franz, P.E.
Registration/Aircraft - N14UW/Merlin GT
Engine/Prop - Rotax 914/NSI CAP
Bellevue WA
425.241.1618 Cell
425.440.9505 Office

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Mon Feb 08, 2010 8:24 pm Post subject: Radio Noise

This all boils down to my favorite thought:



If it don't work, try something else.



Lynn Matteson

Kitfox IV Speedster, taildragger

Jabiru 2200, #2062, 849.1 hrs

Countdown to 1000 hrs~151 to go

Sensenich 62"x46" Wood (summer)

Sensenich 55.5" x 46" Wood (winter)

Electroair direct-fire ignition system

Rotec TBI-40 injection

Status: flying (and learning)

On Feb 8, 2010, at 9:21 PM, Noel Loveys wrote:



 	  Quote: 	
		   



 When it comes to electronics there are rules and just like  

 everything else

 there are exceptions that make the rules.



 Noel

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Tue Feb 09, 2010 6:34 am Post subject: Radio Noise

Yes.  Com transmitters on aircraft use a basic vertical design antenna.

They require a ground plane to direct the radio waves in a horizontal,

omni-directional direction.  On metal aircraft the mounting lug for the

antenna has a place for the shield to be attached.  At the transmitter end

it is grounded to the frame of the radio.  On cloth planes there is usually

a steel support under the cloth for the mount to attach.  Again the coax is

connected to the ground side of the mount.  



On cloth planes it is recommended that a foil ground plane be installed on

the inside of the cloth.  Many times operators who find they have poor range

on their com radios will have installations with no ground plane.  When

attaching the ground plane to the inside of the cloth you really want to be

careful that the glue you use won't dissolve the dope on your cloth  my

recommendation would be to install the ground plane when the fuselage is

being covered so it will be held in place with the dope.



Newer composite planes may have their antennae actually moulded into the

skins of the planes.  For instance a jet liner may have the com antennae

moulded as a vertical dipole inside the leading edge of the vertical

stabilizer. In that case the ground plane may not be actually grounded but

the coax shield will be connected to a radiator equal in length to the

centre radiator.  Gone are the days of the loop antennas and sense wires out

in the breeze where they slow down the plane and increase fuel consumption.



In all the vertical antenna types with the different feeds the one thing

that is consistent is the centre radiator of the coax must never be

grounded!



Jet liners may also have complex antenna for HF (high frequency) operation.

Smaller planes may have a wire which is extended out behind the plane for HF

operation.  Designing ground planes for those antennae can be difficult.



Noel



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Noel Loveys
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Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Tue Feb 09, 2010 6:36 am Post subject: Radio Noise

Right on!



Noel



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helili(at)chahtatushka.ne
Guest

Posted: Tue Feb 09, 2010 7:00 am Post subject: Radio Noise

DC ground, or RF ground???

John Hart



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clint_bazzill(at)hotmail.
Guest

Posted: Tue Feb 09, 2010 11:02 am Post subject: Radio Noise

You have got to be joking.



 



Clint

 

[quote] From: noelloveys(at)yahoo.ca

 To: kitfox-list(at)matronics.com

 Subject: RE: Radio Noise

 Date: Mon C 8 Feb 2010 22:51:20 -0330

 

 

 

 Shielding... grounded only to the end closest to the source.. If you ground

 the shield at both ends what you have done is made an unbalanced conductor

 like a piece of coax. As with coax there is a capacitance in the line when

 it is grounded at both ends. This is why they say to only ground at one end

 and that end usually has the best ground at the source end.

 

 Years ago I was involved in a volunteer position at the local cable station.

 We did several programs which were all recorded on 1/2" Beta video machines

 and then edited down to the program length. Our editing suite had a problem

 that after a video dub of five minutes we would get a glitch in our video

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Tue Feb 09, 2010 2:47 pm Post subject: Radio Noise

I'm not too sure that I understand the question.  The whole airframe should

be DC grounded in as much as it should be bonded to the negative lug on the

battery.  All the cases of all the instruments should be grounded to this

and the it can also serve as the ground plane.   Battery operated

transmitters that have vertical antennas need not have the ground planes

attached to the negative terminal of the battery other than through the

coaxial shielding.



The rubber duck antennae that a lot of hand held radios use are a separate

antenna on their own they use a coil to approximate a load to the radio

without having a ground plane however I have used the side of a trailer as a

signal reflector on a vhf radio to be able to transmit over a hundred miles

on 1/10th of a watt.  The signal was strong enough to open a repeater site

and allow me to access an auto patch to make a phone call.



Noel



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