That should have been more radials DECREASE the bandwidth.
Sorry,

Jon W3JT

On Tue, 30 Aug 2005 09:29:49 -0400, J. Teske
wrote:

On Mon, 29 Aug 2005 15:17:01 GMT, Paul Hinman
wrote:

I came across an interesting antenna the other day on the web. It
called for four radials for each band that one would want to use it on.
In order to protect the lawn mower I would like to bury the radials. If
I use insulated wires for the radials can I bury multiple radials for
different frequencies in the same trench. I would rent a small trencher
like they use for underground power and utility feeds, make four
trenches and drop in the radials, then cover them.

Thanx for any responses.

Paul VE6LDS

A trencher is far overkill. Any sufficiently hard disk can cut through
the turf and inch or so. That is all that is needed for burying a
radial. I have about 30 radials for a Butternut Ground plane. I used
an old circular saw blade which I put on an improvised axle to cut
through the turf. I used whatever wire I had on hand at the time, some
bare, some insulated. It works fine. One thing to notice though is
that more radials will somewhat increase the bandwidth of the antenna,
but not anything which can't be overcome with a transmatch. The
radials do have to be radial from the antenna. If you crave super
efficiency though you may have to go to the extremes of Jerry Sevcik
(sp) who wrote a series of articles and books on vertical antennas in
the 70's. I have nearly 200 countries though with just the Butternut
and about 100 watts so you will get out.

Jon W3JT

That should have been more radials DECREASE the bandwidth.
Sorry,

====================================

It may be considered by some that a decrease in bandwidth is a
disadvantage. What really matters is that more radials result in an
improvement in power radiating EFFICIENCY.

Albeit with a diminishing rate of return.

In ordinary garden soil, first lay about 3 or 4 shallow buried radials
and test the results using the receiver S-meter.

Then increase the number of radials by 50 percent and look for an
improvent. If there is no measurable improvement then, to be certain,
increase the number of radials by another 50 percent.

Keep increasing number of radials until there is no improvement and
then do a final increase of 20 or 30 percent. Even with very poor
garden soil, in all probability you will not exceed 20 or 30 radials.

Just ignore the ridiculous instructions in the handbooks and
magazines, and from old-wives, to lay the magic number of 120 radials
at the outset.

Due to reciprocity, any improvement on receive, as indicated by your
S-meter, will be exactly followed by the same improvement on transmit.
----
Reg, G4FGQ