I found an easy way to drive in earth rods made from copper water pipe is like this: I found a steel rod of a slightly bigger diameter than the pipe, put a point on the end, and hammered it in to the ground. When it is in deep enough, it can be pulled out, and the copper pipe tapped into the hole. When driving the steel rod, it helps to pull it out occasionally, and pour some soapy water into the hole. This makes it easier to drive in, and easier to get the rod out afterwards. You need to fix something to the rod to hold on to when you are pulling it out. I used "Mole grips".

Al alternative to 'brute force' to get a pipe in the ground is to use water :
connect one end to a garden hose, put the pipe vertical (with the garden
hose end up) and let the water flow. The pipe will gently slide into the
ground, unles you have a very 'rocky' ground. Reduce the water flow for
when you get the last meter in the ground and secure the pipe for some days
(weeks) to avoid a 'China syndrome'.
For a picture of this procedure have a look at :
http://www.qsl.net/on7yd/136ant.htm#Radials

BTW : if prefer galvanized iron pipes, if you have 'acid soil' it will
'eat' your copper pipe.

73, Rik  ON7YD