The ground mounted vertical

1/4,1/2,5/8 or full wave

This is personal choice. The simplest and easiest to match is probably the 1/4 wave . Again you must remember this is only half the antenna and a good ground must be used for best efficiency. Because the feedpoint of the 1/4 wave is a low voltage and high current point this will present a low inpedence feed in the region of 30 to 40 ohms at resonance.BELOW you can see the current (red line) and voltage (blue line) distribution of the 1/4 wave vertical, the bottom of the diagram being the feedpoint. On a 1/2 wave vertical things change and the feedpoint will present a high voltage and low current point.This in turn presents a high feedpoint impedence and would then be a voltage fed antenna needing some form of matching for 50 ohm coax. You may of heard the term voltage and current fed antennas.This simply describes the condition at the feedpoint. current high or voltage high.There are however lengths that would put the current/voltage at mid points.Loading also has an effect on the current/voltage distribution.

Earthing the antenna

This is probably the most important aspect of the ground mounted vertical. You may of heard people talking about the good results obtained over or near salt water,this is due to salt water being a very good conductor and thus providing a good earth. Most gardens are not over salt water so it's best to presume the earth we have is a bad conductor. So what does this mean? Simply we have to make it a good conductor. Laying radials is one way to lower the ground resistance and a general rule of thumb is the more the better.

In the top example you will see the antenna is trapped. We can assume (with good quality traps/design)that during design the traps were tuned against a good earth and you will probably of been given these figures with any tech notes on the antenna.(It's good to keep in mind not all manufacturers make antennas and/or traps with efficiency in mind,simply showing a low vswr) you will need to reproduce this good earth if your going to have the traps work as they should at the specified impedence. Laying 1 radial per band is probably not a good idea. You may get away with this if the antenna was above ground and using a tuned radial as far as matching goes but using buried radials will probably not work given the fact that the minute you bury a tuned radial the ground itself will de tune it. Some people will make adjustments to the length of the radial to account for this but what happens when the ground properties change due to rain or ice and the like. So basically the ground system for the ground mounted vertical is every bit as important as the vertical section. You need to lower the ground resistance to obtain a low impedence current return for the antenna to work efficiently.Simple as that. I have worked europe on 5 watts ssb with a simple 1/4 wave ground mounted vertical using 1 tuned radial suspended a couple of inches above the ground during summer when i wanted a quick antenna to have a play around with when using the 817 in the garden.This was probably more to do with good conditions than the efficiency of the antenna.

There are many ways to build the ground mounted vertical. 1/4 wave 1/2,5/8 or full, wire or poles and tubing. Mono band or multiband using matching sections or amu's. All have one very important thing in common. They should all have as good a ground as you can possibly lay. This really will pay off both in terms of matching and efficiency.