KX3 Grounding w/dipole

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KX3 Grounding w/dipole

jreedbum
Page 9 of the manual seems to say that creating a ground for the KX3 is
necessary in all cases.  Is this really true when you're using a Buddipole,
Yo-Yo dipole or any dipole fed with coax?
Thanks
Reed AA1RB
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Re: KX3 Grounding w/dipole

Jim Brown-10
On 3/26/2012 10:19 AM, Reed Bumgarner wrote:
> Page 9 of the manual seems to say that creating a ground for the KX3 is
> necessary in all cases.  Is this really true when you're using a Buddipole,
> Yo-Yo dipole or any dipole fed with coax?

This has nothing to do with the radio, but rather comes down to a matter
of antenna fundamentals. First, any antenna needs an earth ground for
lightning safety.

Second, to function effectively as an antenna, any "single-ended"
antenna that looks like a long wire needs some sort of counterpoise to
carry the return current (and serve as a return for the electric and
magnetic fields).  A typical mobile antenna, most verticals, and a wire
thrown into a tree all fall into this category.

When the rig is tied to ground via the AC power supply and ground rods
associated with the shack, that wiring and connection functions as a
counterpoise of sorts.  When an antenna is mounted on a vehicle and the
coax shield bonded to the body, the body acts as a counterpoise. When
you use a rubber duck on a VHF or UHF talkie, your body,
capacity-coupled via your hand to the talkie, functions as a counterpoise.

When operating battery portable with a rig like a KX3, a good practice
would be to carry lengths of #22 wire that are a bit shorter than a
quarter wave on the frequencies where you plan to operate, and that can
be laid out on the ground around you to serve as a counterpoise.  K2AV
has also written about a "folded counterpoise" system that you can put
together that is more compact than simple wires.

73, Jim K9YC
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Re: KX3 Grounding w/dipole

Don Wilhelm-4
In reply to this post by jreedbum
Reed,

I see reference to Ground on page 6, but none on page 9 - is that a typo?

The problem is we here in the US have too many definitions for ground,
the British use "Earthing" which helps a little.

The references on page 6 are to "the other half of the antenna"  which
is taken care of when using a dipole,
I believe those points were made in the manual to indicate that an
antenna consisting only of a wire connected to the KX3 antenna jack
center will not be very effective - there has to be something connected
to the BNC shell too, and that is not necessarily mother earth ground.

Note that the references are for portable or pedestrian mobile operation
- an antenna at the home station should have a DC path on both
conductors to mother earth ground to drain off static charge buildup.

73,
Don W3FPR


On 3/26/2012 1:19 PM, Reed Bumgarner wrote:
> Page 9 of the manual seems to say that creating a ground for the KX3 is
> necessary in all cases.  Is this really true when you're using a Buddipole,
> Yo-Yo dipole or any dipole fed with coax?
> Thanks
> Reed AA1RB
>
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Re: KX3 Grounding w/dipole

jreedbum
Don,
That is a typo.
Thanks for the reply.
73
Reed AA1RB

On , Don Wilhelm <[hidden email]> wrote:
> Reed,





> I see reference to Ground on page 6, but none on page 9 - is that a typo?





> The problem is we here in the US have too many definitions for ground,  
> the British use "Earthing" which helps a little.





> The references on page 6 are to "the other half of the antenna" which is  
> taken care of when using a dipole,


> I believe those points were made in the manual to indicate that an  
> antenna consisting only of a wire connected to the KX3 antenna jack  
> center will not be very effective - there has to be something connected  
> to the BNC shell too, and that is not necessarily mother earth ground.





> Note that the references are for portable or pedestrian mobile operation  
> - an antenna at the home station should have a DC path on both conductors  
> to mother earth ground to drain off static charge buildup.





> 73,


> Don W3FPR








> On 3/26/2012 1:19 PM, Reed Bumgarner wrote:




> Page 9 of the manual seems to say that creating a ground for the KX3 is


> necessary in all cases. Is this really true when you're using a Buddipole,


> Yo-Yo dipole or any dipole fed with coax?


> Thanks


> Reed AA1RB








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