Topband: elevated radials question
Jim Brown
jim at audiosystemsgroup.com
Mon Oct 25 18:58:41 EDT 2021
On 10/25/2021 9:17 AM, Grant Saviers wrote:
> Don't connect elevated radials to on/in ground radials.
>
> There is a huge ground loss for 4ft high radials on 160m. 7ft is far
> better and 10 ft is pretty good.
When I first installed radials this low, there was, indeed, high ground
loss. N6BT, an excellent antenna designer who has done extensive work on
verticals, advised me that 16-20 feet was a minimum height, and when I
raised them to about 20 ft, efficiency improved significantly.
>
> There are "W" shaped radial feeds with the base near to the ground but
> IMO it is better to elevate the feedpoint to radial height and add a bit
> of wire to the top load to get back to resonance.
>
> Radials can be a bit shorter than 1/4wl ~ 85% for 4, even shorter for
> more. see antennasbyn6lf.com Or a single high Q inductor to shorten
> them more, but modeling is needed.
I've followed Rudy's advice and made them slightly shorter than a
quarter wave.
73, Jim K9YC
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