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Posted (edited)
1 hour ago, Geoff_H said:

I think that you maybe right.  Is there a difference between the shield and the ground plane.  My experience is  with instruments.  

Hi Geoff - from one electronically blind pilot to another :

 

  • The Ground Plane on a metal aircraft is usually the fuselage.
  • On a composite aircraft, one must be installed. For best transmit/receive, the composite GP will have dimensions compatible with the system wave length. Sometimes the GP dimensions are compromised by the physical limitations of the aircraft shape/dimensions.
  • A GP can be made of almost any metal eg aluminium/copper foil./sheet. Can be arranged in a cross shape ie not a solid plate.
  • The shield, as in co-axial cable, is to prevent stray current (from any source) effecting the quality of the reception/transmission.

😈

Edited by skippydiesel
  • Informative 1
Posted
1 minute ago, skippydiesel said:

Hi Geoff - from one electronically blind pilot to another :

 

  • The Ground Plane on a metal aircraft is usually the fuselage.
  • On a composite aircraft, one must be installed. For best transmit/receive, the composite GP will have dimensions compatible with the system wave length. Sometimes the GP dimensions are compromised by the physical limitations of the aircraft shape/dimensions.
  • A GP can be made of almost any metal eg aluminium/copper foil./sheet. Can be arranged in a cross shape ie not a solid plate.
  • The shield, as in co-axial cable, is to prevent stray current (from any source) effecting the quality of the reception/transmission.

😈

my antenna from mendehlsons came with foil tape to make a ground plane if needed.    i am thinking my fuse tube may not have a good earth to the battery so on  the weekend i will try a jumper wire from antenna mount to bat neg.

Posted

as far as voltage regulators go, its pity powermate regs are not made anymore.  very robust and i get a constant 14v

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Posted (edited)

Geoff is confusing shielding as you would do to a signal wire to an instrument or P Lead with the outer braid of an Antenna coax which as well as providing shielding of the inner also has to form a baseplane and is connected both ends

Edited by Red
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Posted (edited)
54 minutes ago, BrendAn said:

my antenna from mendehlsons came with foil tape to make a ground plane if needed.    i am thinking my fuse tube may not have a good earth to the battery so on  the weekend i will try a jumper wire from antenna mount to bat neg.

It's actually better for the antenna if it's baseplane is independent to the aircraft ground, though in many aircraft it isn't.

P.s. re questioning your airframe grounding, get yourself a cheap multimeter ....no need to go trying jumping stuff blindly

Edited by Red
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Posted

Note to admin, can we have a longer time to edit posts, I know it's to preserve context in replies but its ridiculously  short.

Admittedly its a fault of mine that I often don't explain things properly in my posts and need to edit.

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Posted
30 minutes ago, Red said:

It's actually better for the antenna if it's baseplane is independent to the aircraft ground, though in many aircraft it isn't.

P.s. re questioning your airframe grounding, get yourself a cheap multimeter ....no need to go trying jumping stuff blindly

it takes a minute to run a jumper wire to earth. and that will tell me straight away.  why do i want a cheap multimeter , i already have 2 good ones,😁

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Posted (edited)
15 minutes ago, BrendAn said:

it takes a minute to run a jumper wire to earth. and that will tell me straight away.  why do i want a cheap multimeter , i already have 2 good ones,😁

What an odd way of thinking, running a jumper doesn't tell you whether it actually changed anything if the thing you are trying to fix doesnt show change....unless you put a meter on it before and after

Edited by Red
Posted
2 minutes ago, Red said:

What an odd way of thinking, running a jumper doesn't tell you whether it actually changed anything if the thing you are trying to fix doesnt show change....unless you put a meter on it before and after

So you say if I chuck a jumper on there and the radio comes good I have achieved nothing.

Its a quick job on my xair. Battery and antenna are only a meter apart.

Posted

No read my post again.

What I'm saying is if you jump it and it doesnt fix the radio you still dont know if you have a bad airframe ground.

Multiple problems in electrics are common.

 

  • Informative 1
Posted
51 minutes ago, Red said:

Note to admin, can we have a longer time to edit posts, I know it's to preserve context in replies but its ridiculously  short.

Admittedly its a fault of mine that I often don't explain things properly in my posts and need to edit.

Many of us have asked this. Not going to happen. You've got 15 minutes and then all your mistakes are locked in forever 😄

Posted
1 minute ago, danny_galaga said:

Many of us have asked this. Not going to happen. You've got 15 minutes and then all your mistakes are locked in forever 😄

Become a first class member and you get 30 minutes

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Posted
12 minutes ago, danny_galaga said:

Many of us have asked this. Not going to happen. You've got 15 minutes and then all your mistakes are locked in forever 😄

Dagnabbit!!!.......condemned to become the laughing stock of generations to come🤪

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Posted
3 hours ago, BrendAn said:

    i am thinking my fuse tube may not have a good earth to the battery so on  the weekend i will try a jumper wire from antenna mount to bat neg.

I am a long time advocate of running dedicated earth return/neutral wire rather than relying on the airframe/chassis. The added weight, cost & complexity is minimal and you are assured of a good low resistance return at all times. Improves the performance and service life, of all 12V systems.😈

  • Informative 1
Posted
3 minutes ago, skippydiesel said:

I am a long time advocate of running dedicated earth return/neutral wire rather than relying on the airframe/chassis. The added weight, cost & complexity is minimal and you are assured of a good low resistance return at all times. Improves the performance and service life, of all 12V systems.😈

I agree. I am going to check where all my earths are running too .

Posted
5 minutes ago, skippydiesel said:

I am a long time advocate of running dedicated earth return/neutral wire rather than relying on the airframe/chassis. The added weight, cost & complexity is minimal and you are assured of a good low resistance return at all times. Improves the performance and service life, of all 12V systems.😈

Ground loops await

Posted
1 hour ago, Red said:

Dagnabbit!!!.......condemned to become the laughing stock of generations to come🤪

Why don't you pay a few dollars a year . It supports the running of this site and you will get your 30 minutes.

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Posted

Stop!

There is a big difference between a battery earth and an antenna ground plane.

Get some real knowledge before you do anything else.

 

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Posted
38 minutes ago, BurnieM said:

Stop!

There is a big difference between a battery earth and an antenna ground plane.

Get some real knowledge before you do anything else.

 

That's a big help . Why don't you explain  what you are talking about.

The xair antenna is on a metal bracket on the fuse boom so it should be earthed to the battery anyway. 

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Posted (edited)
3 hours ago, BrendAn said:

Why don't you pay a few dollars a year . It supports the running of this site and you will get your 30 minutes.

A full 30 minutes 😲

 

Here's a post of mine on a different forum. 2004. Notice the link in the first post?

 

https://forum.arcadecontrols.com/index.php/topic,20073.0.html#msg161529

 

Edited by danny_galaga
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Posted

In the 1970's when we first used computers in industry for control we would get many failures, almost always on computer  board connections, we would always carry an ink rubber to remove oxides, more often happening in we weather.  We were told by plug manufacturers that 30,000 psi connection pressure was needed to prevent high resistance connections.   I  believe that earth connections should be checked regularly, particularly after a wet period like the east coast is experiencing 

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Posted
14 hours ago, Red said:

Ground loops await

In theory, possible. In practise, unlikly.

 

The return, to -battery terminal,  is connected to all major metal components (airframe in a metal aircraft, engine & subframes in composite). All electrical systems are connected to the return (various ways eg buss) & by default, airframe/subframes.

 

Most home mechanics, working with 12V systems, are unaware of just how little corrosion can increase resistance or even completely interrupt a connection, making a system operate below optimum to not operate at all. They tend to pay more attention to +posative/power connections, not realising that for the current to flow (well)/ system to work, the  -negative is just as important.😈

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Posted

Just a reminder, do not remove oxide from electrical contract surfaces with carborundum (emery) it attaches small quantities to the surface and will oxidise with electrical current. 

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