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Thread: Another grounding question

  1. #1

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    Default Another grounding question

    I wish to set up an antenna in my garden, purely for using my FT-450D downstairs, when circumstances permit.
    I have read various articles on grounding, and, have conflicting ideas.
    Some articles advocate the use of copper rods, others copper pipe.
    During my Foundation Course, every one I spoke to, advocated 'ground spikes', in the form of copper rods.
    What are the thoughts of others here? My main station is a spare bedroom, upstairs, grounded by an old copper pipe which goes into the ground, buried in a wall. There is no water connected, and, it seems to work fine.
    Any suggestions are gratefully accepted.
    Many thanks.

  2. #2
    K7KBN's Avatar
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    Whether you need to worry about "grounding" an antenna depends on the antenna, mainly. A properly-sized center-fed dipole installed at least a quarter-wavelength (half-wavelength is better) above the ground and away from metallic structures does not require any grounding to work well. An end-fed wire, on the other hand, needs a ground plane or counterpoise to work against.

    If by "ground" you're looking for some means of protection from nearby lightning strikes, that's a different matter.

    What kind of antenna are you going to install?
    73
    Pat K7KBN
    Semper ubi sub ubi.

  3. #3

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    I have inherited a Sandpiper MV4+2, vertical with radials.
    Sandpiper suggest mounting the aerial on a metal post, 18"-24" above ground, with ground radials.
    They also recommend attaching a 'ground post/earth rod' for improved performance.
    Hope this clarifies the question better.

  4. #4
    Super Moderator pmh's Avatar
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    As your house will no doubt have a PME supply, it's worth reading up on this first.

    The RSGB have produced a leaflet on this, which can be downloaded for free from here:-

    http://rsgb.org/main/files/2012/11/EMC07-final.pdf

    Kind regards,



    Phil

  5. #5

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    Many thanks, Phil.
    I have received that from RSGB, and read their technical sections....
    Just wondered what others felt about it, and any experiences/suggestions....

  6. #6

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    Hi,
    There is often a lot of confusion about grounding with antennas. There are two main points to bear in mind. Firstly, if the antenna works against a ground then what you're looking for is a counterpoise or a set of radials or even a ground mat. This isn't usually necessary for a balanced antenna like a dipole, G5RV or a Cobwebb but is essential for a vertical/monopole.
    Secondly, earthing is absolutely essential to discharge any static buildup (not a common issue in the UK as it's usually too damp for a charge to build up) and to provide a DC path for lightning protection.

    In general, a ground spike(s) will not form a sufficient connection into the Earth to provide decent grounding for a vertical antenna, usually a more significant amount of wire is needed to form a system of radials or an earth mat. However, a decent ground spike is just fine for a lightning route or for static discharge.

    Hope this helps!

    Jason G7RUX

  7. #7

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    Many thanks for all the replies....
    I am about to embark on setting up the antenna in the garden, and, having taken on board all the answers, I intend to build a 'ground mat', from some steel mesh, and install the antenna in that.

  8. #8
    K7KBN's Avatar
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    A suggestion, Eamonn: I suspect you'll be using galvanized steel mesh, which is something like we here in the US call "chicken fencing" - mainly because that's often what it's used for. If you're burying it, don't expect it to last more than 12-18 months if the soil is very moist. Galvanized or not, it rusts quickly when it's constantly damp. Also, if you buy it in rolls of, say ten meters long by one meter wide and you plan to use two or three lengths side by side, be sure to bond areas where the strips come in contact; this can create a bit of noise.

    Good luck...
    73
    Pat K7KBN
    Semper ubi sub ubi.

  9. #9

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    Pat, thanks for the advice.
    That was my intention, and your comments are most welcome on this.

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