On Sun, 12 Nov 2006 16:23:22 GMT, ml wrote:

so how does one go about finding out what i did wrong how do you
trouble shoot? and isolate

Hi Myles,

This, again, goes to issues of ground loops (I bet you're tired of
hearing that).

What interference that does not arrive through the air, must arrive
through a wire. This second form is by conductance. If you share a
conductor, you will also share some of the RF at that common point,
especially if that common point is elevated above a true ground.

To understand what it means to "share" a conductor, you have to think
outside of the box. Look at your entire home/apartment/building
instead of just your rig and the wire to ground. Few ever step far
enough back to visualize the complete picture.

In that complete picture, your rig is being powered through a
connection to a wall plate that eventually finds its mains connection
at a breaker panel. If you were to consider the room (partially
outside of the box of rig and ground wire), you can (with x-ray
vision) see that conductor behind the wall tracing its way through
probably half a dozen other wall plates powering your computer in that
room, several lights, perhaps your modem, another charger for your
phone (yet another ground loop path to Ma Bell's ground), perhaps a
digital clock - need I go on?

If you turn up the x-ray vision to go further outside of the box of
rig, ground wire and shack, and look at the home/apartment/building,
you might see that conductor winding through the rooms to pick up
connections to your furnace control, maybe the door bell transformer,
and passing through the living room to power your TV and FM radio
(they could be on the opposite side of the wall of your shack). Then
after this winding around, it might finally hit the breaker panel. You
might also find your Amp is sharing the same panel circuit as the
kitchen range or your clothes dryer (more ground loops opportunities
there).

If your transmitter's power source is at the far end of that long
trail back to the panel, all those connections along the way are
sharing the same conduction leakage from your source. It doesn't take
much to make your TV image swim with modulation, or for the FM to go
screwy, it can also pulse your lights through their sensitive dimmers.

How do you cure this problem of conducted interference?
1. Break the path,
2. Shorten the path,
3. Change the path.

Basically isolate your RF activities to one breaker at the breaker
panel. Because all mains powers branch out from this point you are
simultaneous doing all three above when you choose one branch and
dedicate it to RF.

This requires you to map out every power switch and wall plate in your
home back to their breaker in the panel. With this map you are then
informed as to which devices might share the RF conduction path, and
you can then move either the devices, or the choose another RF path.

A simple test as to the degree of coupling of this conduction
interference is to simple choose one device that is especially
sensitive. Let's say it is the TV (and by that I mean the display and
ALL of its accessories like cable connection, Tivo, VCR, sound system
and the rest) and plug it into an extension cord that is in turn
plugged into another wall plate on a DIFFERENT branch. This often
means a long extension to another room, or better yet, to the outlet
nearest to the breaker panel.

This is why curing ground loops is so frustrating.

73's
Richard Clark, KB7QHC