Earthing
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Aussiescanners takes no responsibility for any modification undertaken, these are to be done at your own risk and should only be performed by those with good knowledge of radio and soldering.
Aussiescanners takes no responsibility for any modification undertaken, these are to be done at your own risk and should only be performed by those with good knowledge of radio and soldering.
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beaconboy
- Registered User
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- Joined: Wed Jan 01, 2014 7:29 am
Earthing
Okay they say there's not such thing as a silly question, just silly mistakes so here goes. Is a metal ground plane the same as a Earthing ? I wanted to install my new antenna on the roof but it is not earthed is this okay or not?
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Comint
- Senior Member
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- Joined: Sat Mar 22, 2008 5:17 pm
Re: Earthing
For UHF and VHF antennas, a metal "ground-plane" generally serves the same purpose as an "earth", assuming of course, your antenna is actually connected to the "ground-plane" and not just sitting above it.beaconboy wrote:Okay they say there's not such thing as a silly question, just silly mistakes so here goes. Is a metal ground plane the same as a Earthing ? I wanted to install my new antenna on the roof but it is not earthed is this okay or not?
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Comint
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beaconboy
- Registered User
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Re: Earthing
Thanks Comint, the iron roof it is then.
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mpep74
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- Joined: Fri Jan 27, 2012 10:54 am
- Location: Chch, NZ
Re: Earthing
Earthing can also imply Lightning protection, where-as ground-plane is an RF term.
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_Art_
- Newly Registered Users
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- Joined: Mon Jul 21, 2014 1:49 pm
Re: Earthing
That all depends on they type of antenna you have.
All antennae on Earth still fall into the two general categories of Marconi or Hertz antennas.
Marconi: One hand slapping the ground to make noise, Hertz: two hands clapping together to make noise.
If you try to earth any Hertz antenna (dipole, J-Pole, etc.) you're doing it wrong
If you are talking about an ex-mobile whip antenna, you could try some quater wave radials which won't be too much trouble to come up with for VHF/UHF, and would allow mounting on the edge of a roof rather than (ideally) toward the centre.
All antennae on Earth still fall into the two general categories of Marconi or Hertz antennas.
Marconi: One hand slapping the ground to make noise, Hertz: two hands clapping together to make noise.
If you try to earth any Hertz antenna (dipole, J-Pole, etc.) you're doing it wrong
If you are talking about an ex-mobile whip antenna, you could try some quater wave radials which won't be too much trouble to come up with for VHF/UHF, and would allow mounting on the edge of a roof rather than (ideally) toward the centre.
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Spectre
- Registered User
- Posts: 76
- Joined: Sat Oct 06, 2012 11:40 am
- Location: Sunraysia, Australia.
Re: Earthing
An antenna ground plane is not an earth but simply a reflective surface/component to permit the antenna to perform as designed.
Example:
The outer coaxial shield ensures the antenna is electrically grounded through your radio/PSU to the wiring of your home, this approach does not provide protection to lightening strike damage, generally the mast itself is grounded to earth either intentionally (by design) or by simply being mounted from the ground surface itself.
An RF ground essentially acts as a counterpoise.
A tin roof makes an excellent RF ground for mobile antennas, I have been using this approach for years for secondary antenna systems, I'm currently running a 9 ft copper antenna off my shed roof now for 27Mhz.
Example:
The outer coaxial shield ensures the antenna is electrically grounded through your radio/PSU to the wiring of your home, this approach does not provide protection to lightening strike damage, generally the mast itself is grounded to earth either intentionally (by design) or by simply being mounted from the ground surface itself.
An RF ground essentially acts as a counterpoise.
A tin roof makes an excellent RF ground for mobile antennas, I have been using this approach for years for secondary antenna systems, I'm currently running a 9 ft copper antenna off my shed roof now for 27Mhz.
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