i have a few known good hf rigs. after all is hooked up i notice over
time as i've made 'hookup' changes... that i seem to dectect rf energy
leaking from somplace

it might be the case or my coax perhaps the grounds lastly it's
possible rf is just going into the ac lines

I know this as my tv in the room hasn't changed and lately is pickng up
rf on keydown (i've isolated to not being from my roof antenna)

sometimes when rig a is on i can pick up a little of it from rig b
(even w/a bandpass filter) so it's shack related

Question:

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

can i use a instrument? trial and error?

ml wrote:
i have a few known good hf rigs. after all is hooked up i notice over
time as i've made 'hookup' changes... that i seem to dectect rf energy
leaking from somplace

it might be the case or my coax perhaps the grounds lastly it's
possible rf is just going into the ac lines

I know this as my tv in the room hasn't changed and lately is pickng up
rf on keydown (i've isolated to not being from my roof antenna)

sometimes when rig a is on i can pick up a little of it from rig b
(even w/a bandpass filter) so it's shack related

Question:

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

can i use a instrument? trial and error?

ml:


after all is hooked up i notice over
time as i've made 'hookup' changes...

I hope that didn't take you a LONG time.

I know this as my tv in the room hasn't changed ...

The only change you will ever see is, it grows older and outdated.
But, I am curious, what changes have you seen occurring with the tv's in
your other rooms?

sometimes when rig a is on i can pick up a little of it from rig b

Apparently, you have long arms. Why you can only pick "rig a" up in
such a sporadic fashion and time frame baffles me. Again, I am curious,
can you pick "rig b" up from "rig a" any more consistently?

so how does one go about finding out what i did wrong ...

My crystal ball is non-functioning at the moment, perhaps another can
assist you?

can i use a instrument?

Perhaps, give me a clue, are you a musician?

JS

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

dear rich


thank you again for helping, i was just beginning to think it was all
related, and yah i hate loops.

was thinking about just rewiring everything but now i sorta want to
find out what specifically is the culprit and fix it, seems more like a
chinese puzzle i have a alot of wires all neet thou , no rats nest's

one thing that riddles me, you mentioned in the past i've heard others
say this about putting stuff on a seperate breaker (or fuse?)

i don't get that so their is a main feed (one) and many breakers off
that so how does a plain ol' breaker "isolate' anything if they are all
so 'close' and connected to the main feed?

thanks again , i have a lot of work to do



In article ,
Richard Clark wrote:

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

On Tue, 14 Nov 2006 00:01:17 GMT, ml wrote:

i don't get that so their is a main feed (one) and many breakers off
that so how does a plain ol' breaker "isolate' anything if they are all
so 'close' and connected to the main feed?

Hi Myles,

It is like any parallel circuit. At one point they are all together,
but they all fly off in different directions and different lengths to
reach the various outlets and switches throughout your apartment.

By code, all of your power demand is spread out and BALANCED so that
no one breaker/fuse is carrying the whole load. This means that your
clothes dryere is not on the same circuit as the oven. They each have
their own wires that goes back to the breaker panel, and each has
their own breaker. Likewise, each room's outlets and lights goes on
its own wire back to its own breaker at the breaker panel. Sometimes
it might be two rooms sharing the same path. This is where you get
into trouble by injecting RF from your shack into the light dimmer in
the bath room.

73's
Richard Clark, KB7QHC