At 08:15 AM 3/5/98 -0600, T A RUSSELL wrote:
>N4KG response below -
>
>> Raised resonant radials radiate like crazy and couple
>>to EVERYTHING else in the near field (including lossy soil below the
>>antenna) no matter how much time is wasted pruning and tuning. The
>>fields from each radial only cancel completely hundreds of feet away,
>>and that is where they don't cause power loss. (W8JI)
bit snipped about the tower
>>Raised radials are a great idea if they are installed a hundred feet
>>in the air, but place anything (including good ole dirt) within a
>>pretty large distance and the radials couple like crazy to
>>whatever the other conductor is. And that's true no matter how
>>much time is wasted "tuning and pruning" them for equal currents.
>>
>>73, Tom W8JI
>>w8ji.tom@MCIONE.com
>>
>Hi Tom -
>
>I agree that my elevated GP antennas have losses due to
>the earth connection and low radials, but you make it sound
>like such antennas are not much better than a dummy load
>and on this point I must STRONGLY DISAGREE.
>
>(My GUESS at WORST CASE losses compared to a full size ground based
>vertical with lots of radials is 6 dB. My HUNCH is that it is actually
>much LESS.)
How about the performance of the 6Y4A elevated radial antennas
during last year's contests? See Feb and March CQ-Contest. Used
Force 12's verticals, and Tom raised the radials, only two or three
feet, were "completely" decoupled from the ground; impedance
came right into the 30 ohm area as it should for 1/4 wave verticals.
Also set world class scores with them down there.
Or consider W1XT's score in the recent CQWW CW test: 792,438 points,
916 Q's and 289 multis: all using monoband Gladiator verticals, with
the antennas raised about 10 feet, from which elevated, resonant
radials, four per antenna are run out. He was on poor ground, in
Arizona; even got 23 Q's and 18 multis on 160 using the 38 foot
top loaded Gladiator; 76 and 34 on 80; 296/65 on 40; 271/77 on 20;
192/63 on 15 and 58/32 on 10 meters. All done in 30 hours of
operating using monoband verticals only. No one else
on the desert in the SW has apparently reported better scores,
at least as far as I know.
So they do work pretty well!!
73, Jim, KH7M
On the Garden Island of Kauai and putting up a complete
suite of Gladiators!
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