On Sun, 09 Jan 2005 11:33:44 GMT, news wrote:

I need to improve my ground system, and am thinking of burying some
radials under the lawn.

[I realise this is not the most efficient way to do it from an
electrical point of view,

Why not?

Some practical questions:

~~~~~~~~~~~~~~~~~~~~~~~~~
1. What is the "best" type of wire (or braid) to use for the radials?

Something that is cheap (so you can have lots of it) and non-corroding
(so you don't have to re-lay it every year).

2. How do I bond the radials together? (I guess my 15-watt soldering
iron won't be up to the job ...).

Use a car battery clamp and plenty of grease.

3. What kind of solder and flux should I use?

None at all. See above.

4. What precautions should I take to minimise the effects of corrosion
at the joints?

See above.

5. How deep should I bury the radials? Two inches, six inches, 12
inches?

Whatever you find most convenient.

6. Is there anything else I should know?

You will never lay enough radials to turn your garden into a
highly-conductive metallic mirror, the next best thing you can do is
to provide the lowest ohmic contact for your vertical. If your
vertical has a radiation resistance of R ohms and the ohmic contact
with the ground is Z ohms, the efficiency of your system is given by
R/(R+Z). Consider a short vertical with a ground rod might have R = 10
and Z = 150, you can see the efficiency is pretty low at ~6 percent.
So 94 percent of your RF is heating up the earthworms &c.

We are on heavy clay soil that alternates between being very dry and
very wet.

I suggest you start with a couple of tons of well-rotted farmyard
manure. You need to work on that clay and turn it into something
better both horticulturally and electrically.

My main interest is in the lower hf bands (40/80/160) and possibly
136kHz.

In that case at 136 kHz R above might be .0001 ohms or worse, and your
efficiency will be very low. Get as much metal in the ground as
possible. Avoid loops.

--
from
Aero Spike