morning everyone . I am in the need of some advise from you learned people out there , I am putting up a ground mounted multiband vertical antenna up, the problem is that I can only put radials out at 180 degrees & not 360 , would that be ok .
or would it be better to raise it & use elevated radials.
many thx mark.

I only have mine laid out at 180 degrees and seems to make very little difference, it might slue the radiation pattern very slightly on the higher frequencies, but only by about a db or so, you wouldn't notice. If they are ground mounted they are not resonant, just lay as many as you can down it doesn't matter how long they are, in fact, don't make them too long.

thx for that paul , that will make the xyl happy , not to see another antenna in the air.
i'll put loads down then would 10m long radials be ok paul.
thx mark.

There is an optimal length depending on the band you use. If I remember rightly, without running my little program, the optimal length for 40M is about 5Mtrs long. Much longer than this and the efficiency started to decrease, not by much admittedly. I use 33 radials all varying lengths from about 5 Mtrs to 10 Mtrs and I very happy the way the antenna is performing.

great that will do for me paul , cheers mate .
thx mark.

The difference you're talking about is 1 S point in the direction there aren't any at the most.

ok cheers conor .

A useful guide is to try to make the radials about the same length as the vertical. Another rule of thumb is that, for a given total length of copper, more short radials are better than a few long ones.

That said, they'll probably end up where the XYL tells you

Steve G3TXQ

ya not wrong steve. thx for the advice will get it sorted .
many thx mark.

I have 36 radials on my butternut vertical
just get as many down as you can and as long as you can, you will find the bandwith becomes narrower and the vswr becomes higher the more you put down
A vertical like the butternut/hustler types without radials is a waste of time trust me
This is the radial plate i use, also the crimps too now the antenna is more efficient
http://www.antennaengineering.co.uk/radial-plate/

Paddy 2E0TXP

thx for that paddy.
cheers mate.

You might be interested in some loss measurements I did as I added radials one by one to the ground system for a 40ft 160m vertical:



The radials were between 30ft and 40ft long. Things will be different for other bands and vertical lengths, but it gives some idea of how things vary. The curve was getting pretty flat by 16, and I was getting tired

73,
Steve G3TXQ

that's great steve , now I understand what you mean , so in theory somewhere around 20 ish radials would do .
cheers steve .
thx mark.

lots of interesting reading here

http://w4rnl.net46.net/gr.html

With the homebrew ground mounted vertical I have here the biggest improvements achieved so far have been adding random length radials in a 360 degree pattern, average radial length is 16 ft to span the width of the garden with radials getting longer to fill in a rough rectangle the full 30ft width of the graden again but extending out to 33 ft in the far corners from the antenna base... the radials are obviously pretty close together at the feed point and connect to a small tinned brass earth block that is normally used for connecting supplementary earths in a domestic electrical installation.

Increasing the amount of radials in my case raised the signal level against the background hash however the major improvement made was in raising the effective electrical height of the antenna by lengthening it towards the text book 5/8th wavelength, this significantly improved the performance by raising signal levels markedly and put me back in the game as it were although there has sadly been a vote of no confidence from the neighbours so the antenna is currently in an inverted L.

Cheers, Dave.