At 03:31 AM 3/22/98 EST, Earl W Cunningham wrote:
>John, K4IQ wrote:
>
>The question is: what further improvement is realized by using more than
>two 1/4 wave radials when the "ground" 66 ft below is the ocean?
>
> |
> ____|____ _ 1/4L Vert. w /two res. radials at 66 feet
>_______________ _ H2O + NaCl
>For what it's worth, here's the EZNEC results:
>
>1/4-wave 160m vertical mounted at the ocean surface with beaucoup radials
>(zero ground loss): Gain = 4.67 dBi @ 7.3 degrees TOA
>
>Raising the vertical to 66' above the salt water with two radials:
>
> Gain = 5.70 dBi @ 5.3 degrees TOA (off the end of the radials)
> 5.76 dBi @ 5.9 degrees TOA (perpendicular to the
>radials)
>
> 66' above salt water, 4 radials: Gain = 5.84 dBi @ 5.6 deg
> 8 radials: Gain = 5.89 dBi @ 5.6 deg
> 16 radials: Gain = 5.91 dBi @ 5.6 deg
> 32 radials: Gain = 5.93 dBi @ 5.5 deg
> 64 radials: Gain = 5.96 dBi @ 5.5 deg
>
>All wires in the models were #12 gauge. Radials were kept at 140' long.
>
>73, de Earl, K6SE
Thanx very much Earl, for running this.
Looks like a lot of work for a quarter of a db, to me ; )
This establishes a base constant for plannng elevated radial systems, imo.
Now that I know there is an advantage, both in terms of gain and toa, there
is no question to me that resonant, elevated, systems are the way to go.
Now to improve my ground, or, better yet, move to the beach!
73,
John K4IQ
--
FAQ on WWW: http://www.contesting.com/topband.html
Submissions: topband@contesting.com
Administrative requests: topband-REQUEST@contesting.com
Problems: owner-topband@contesting.com
|