How many copper straps and how far do the extend from the tower base?
What frequency are they at?
Hey MRAM: I dont remember the exact number but certainly not 120. Most runs were about 200 feet long. Some runs were bent around the building. The frequency is 1350 KHZ. The tower is 205 feet high. Interesting story about that. In 1954 when WDCF went on the air, the tower was the tallest structure in Pasco County, FL. The new owner was proud of this fact so when he learned that the FAA required lighting on anythnig over 200 feet, he had it built at 205 feet so he could put a light on the top. True story.
There is some very useful information in this thread, but it is not the entire story on the subject of "buried radials," although the information covers plenty.
I will return to the subject of oddly placed and strangely shaped radial sets in future posts.
Whilst on the subject of ground radials, i have been looking at my permanent installation of ground radials, instead of my temporary 12x 3 metre wires laid on the grass.
Whilst looking at options i saw a post by Ermi Roos that stated an article by Trainotti that said a 1.5 metre diameter metallic ground shield offered good performance for a part 15 antenna system.
The resistance of this ground at 1700khz was 3.5 ohm for average soil of 10mS/m.
This does look good for a compact area, so i am wondering if galv concrete reinforcement mesh of similar size would match this, or would solid plate metal be better ?
If solid is better for the rf resistance, then i would buy a large stainless sheet, and silver solder 32 radials from the outer edges to maximise performance.
Thanks,
Paul.
Moments ago I spotted a paragraph that goes right to the question just asked by BOARDMAKER. It comes from "Radio Handbook" by William I. Orr, W6SAI.
"A perfectly conducting ground can be simulated by a ground screen placed under an antenna. The screen should have a small mesh compared to the size of the radio wave and should extend for at least a half wavelength in every direction from the antenna."
I have started to cut slits in the ground to install a permanent ground radial system.
The antenna is equally 3 metres from two boundaries that are 90 degrees from each other.
This means that my radial lengths towards these boundaries are limited to 3 metres, but away from these boundaries i can use longer radials approx 14+ metres.
But i wondering wether i should have all my radials 3 metres long, or to increse the radials where i can ?
Compared to all being 3 metres, i would expect the lopsided radials to enhance signal toward the extended radial direction, and keep the shorter side unaffected ?
My concern is, would the lopsided radial system cause negative effects, such as increased rf on the buried supply/audio cable, due to incomplete phase cancellation of the radials ?
I don't want to get this wrong so i would appreciate advise on this.
I intend to later place the metal disc around the base of the antenna, on top of the ground radials, and bond them together at the base.
Thanks,
Paul.
BOARDMAKER posted: "Compared to all being 3 metres, i would expect the lopsided radials to enhance signal toward the extended radial direction, and keep the shorter side unaffected?"
Based on a single experience I would expect the signal to be enhanced toward the direction of the longer radials.
I have an installation with only two radials, pointing south and north. My signal goes farther in the south north directions.
But hold on until others give their viewpoints about this.