best length for ground radials on 5/8 wave

[davev8]

Hi i was just wondering what dictates the optimal length of ground radials on say a 5/8 wave sigma 2 type with a matching ring? if practical what will happen if say they are 1/2 wave or even 5/8 wave will the type of matching make a difference to the length needed ?
thanks Dave

 

[BOOTY MONSTER]

tried a few different ground elements on my home-brewed 5/8s . my results are from 2 different locations though so they are not a fair comparison .

my first 5/8 had a maco type tuning ring with four 12 gauge wires sloped down at 33 degrees and 108 inches long . it did surprisingly well just 8 feet off the ground next to a one story house and surrounded by several trees . the was the only 5/8 i made and tested there . at that height i was impressed . when i got it over the house i was actually very happy comparing my contacts/ears to what others near me were hearing and contacting

my next attempts were here on the deck about 6-7 ft off the ground , 2 story house with both more and bigger trees . using the same vertical and maco tuning ring ... but , with four 113 1/2 inch horizontal ground elements made from 3/8 inch solid aluminum rods , i wasnt particularly impressed

my next attempt was keeping just the vertical and eliminating the maco loop and using a beefy copper coil . i also changed the ground elements to 1/8 wavelength . i tried both horizontal and sloped and both together for a total of 8 1/8 wl ground elements . still nothing to write home about .

i think my build area here is just a very very bad place to build/test antennas . but its the only place open enough to raise and lower the antenna :sad: . but it did do better with the four 1/4wl horizontal elements . i think if i built another 5/8 id stick with 1/4wl ground elements and slope them down to get the tallest capture area i could .

certianly not a definitive or maybe even not even useful reply for you ........ but thats my story and im stickin' to it .

good luck

 

[Kamikaze]

Best length from a mechanical standpoint? Windload? Construction with available pieces?

From a simple matching standpoint?

From an electrical standpoint?

Answer for electrically is another 5/8 as vertical as possible. Provides max low angle gain and closest to a balanced feedpoint load.

Not sure about the others.

 

[davev8]

Answer for electrically is another 5/8 as vertical as possible. Provides max low angle gain and closest to a balanced feedpoint load.

Not sure about the others.

Well that interesting the resan am asking is long time ago i had a bog stranded 1/2 wave silver rod type approx 20 feet up,
i decided push it up to over 45 feet up (may be more it was a long time ago)
and it needed some guys, so i think i can have the first part wire and have them as ground planes (3 no) The roll of wire i had was long so i made them the same length as the silver rod so 1/2 wave
Well when it was up all the stations all say i must be running power of 30 to 50 watts when in fact it was only 7 or 8 watts
The thing was i did not know if it was the hight alone, or the ground planes helping a lot as i did both mods at the same time.
The one thing that made me think that the ground planes help a lot is that a town approx 35 miles away had anther station dead in-line with it from me but 10 miles closer.
His antenna was approx the same hight as mine except it was a SIRIO 5/8 wave the one with 12 radials and the coil in a jam jar so you can see it LOL and i always matched or beat his signal
He never believed the power i claimed to be running
But i am in the open
So if wire full size ground plans work so well why don't we see more of them on home modded antennae as they are much easy to play with than a ridged 1/4 wave stuck out
Has any body else had findings like this ?

 

[HomerBB]

I have tried both the 12 radials @ 3' GP, and the 4 radials @ 9', and at my place, the 9' produced a better antenna.

 

[loosecannon]

according to W8JI its about 3-10 miles.

HEY!!!
who threw that tomato?!

LC

 

[Captain Kilowatt]

according to W8JI its about 3-10 miles.

HEY!!!
who threw that tomato?!

LC

Actually he's right about that. Well maybe not 10 miles but certainly extending many wavelengths beyond the antenna. A good RF reflective surface where the incident wave reflects off the earth is highly desirable but highly impractical.

 

[loosecannon]

i know he's right CW, thats why its funny!
LC

 

[bob85]

im having a 1-1/4wave gainmaster moment,
20ft scaffold pole and a cut down vector

QUOTE=Kamikaze;281728]

Answer for electrically is another 5/8 as vertical as possible. Provides max low angle gain and closest to a balanced feedpoint load.

Not sure about the others.[/QUOTE]