On Sat, 26 Jul 2008 15:12:27 +0100, "Andy"
wrote:

I have used some conductive grease for the first time on the beam. I've
never used grease before, do you think this might be the problem?

Hi Andy,

It is not the problem.

The other thing is, that the beam is at apex roof height and mounted on the
back of the house. I have no where else to try it out to see if this is a
problem.

You are closer to noise in the home.

The centre fed dipole has the element that connects to the centre pin of the
PL259 at house end and I don't suffer any noise hiss on that like I do on
the beam

However close one arm of the dipole is to the house, I will bet the
feedline is far, far away from the noise source.

and the Cobwebb is at the bottom of the garden away from the house
and that has a very quite receive on it.

Even further away from the noise source.

So far, no one has asked, and you haven't offered a comprehensive
meaning to this noise.... hiss is not remarkably unique at HF. For
comprehensive you do not state what frequencies it inhabits. OK, its
on the five bands, but is it everywhere else? Is it equally
strengthed?

A portable radio is a must for noise troubleshooting. If the S-9
noise covers 5 bands, this freestanding radio should hear it all. The
noise seems to be uniquely near the house, but can you wander the
neighborhood with a transistor radio and hear it other places? Can
you bring a transistor radio near the point the antenna is mounted and
hear the noise? If you hear it there, do you hear it in the garden?

On the other hand, if you cannot hear noise on a portable; then it is
not over-the-air, it is conducted noise. Severely corroded joints
could do that, but you already state this is a new(?), greased (that
is what the grease is for) joint antenna. Is the feedpoint choked?
(This is common advice.) Does the feedline pass near noise sources?
(Use your portable along the length of the line.)

How do you ground your shack? Some folks think that ground wires
everywhere does the job - often that is the problem. Could that hiss
be a hum? Poor antenna connections would be more like a sizzle.
Descriptive terms are not often reliable symptom indicators.

You have a ground loop with your new installation.

73's
Richard Clark, KB7QHC