Especially if you have elevated radials you will need a choke otherwise
the coax and your shack will become part of the ground plane. . In my
case I have a choke ( for common mode currents) and UNUN to match the 25
ohm impedance of the antenna to 50 ohms. In some installations the
common modes� can be quite large . The choke on my� 60'-"t" is eight
ft-240-31 cores with 4 turns of coax. At 4 cores, the cores would get
hot enough after 10 minutes at legal limit that were too hot to touch.
With ground mounted radials the common mode problem is usually a lot lower.
YMMV
Dave
NR1DX
On 12/10/2020 2:17 PM, Jim Brown wrote:
On 12/10/2020 4:33 AM, Rob Atkinson wrote:
I've never understood what is gained by using a balun at the feedpoint
in this application.�� The feedline is unbalanced as is the load.
What's the point of a balun.
That's the problem with the word "balun." A CHOKE is needed at the
feedpoint so that the feedline does not become a radial.
73, Jim K9YC
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