[Elecraft] KX3 Grounding w/dipole

[Jim Brown]

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