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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