After some correspondence with Charles Counselman, W1HIS, I have been
made aware of serious short comings in my testing procedure. Charles
pointed out that I could not make accurate enough to insure that what I
was
measuring was in fact TI and not common mode effect due to micro
imbalances
in my equipment.

Upon further thought and reflection, the fact that placing a number of
ferrite beads
along coax stops the "ingress" suggests that Charles is correct and
that it is
common mode effects I am measuring.

From some simple tests to check the balance of my BALUNs, I am
convinced that
I have errors of at least 15%. Even my trusty R390's balanced input is
far from a
"perfect" balance over the 5000KHz to 30MHz frequency range.

Charles Counselman's research into common mode effects and how to
reduce
it are a God send to my receiving pursuits.
http://www.yccc.org/Articles/W1HIS/C...S2006Apr06.pdf
I am grateful for his help in understanding where I went wrong. And I
am sorry
for any confussion I may have caused.

For a very inexpensive aid in RFI/EMI reduction, check out
http://www.hosfelt.com/,
scroll down to filters and take a look at the CURTIS, Mfg.# -
F1600CA03, 3A filters.
These have been a great help in stomping RFI before it gets started

Terry

wrote:
After some correspondence with Charles Counselman, W1HIS, I have been
made aware of serious short comings in my testing procedure. Charles
pointed out that I could not make accurate enough to insure that what I
was
measuring was in fact TI and not common mode effect due to micro
imbalances
in my equipment.

Upon further thought and reflection, the fact that placing a number of
ferrite beads
along coax stops the "ingress" suggests that Charles is correct and
that it is
common mode effects I am measuring.

From some simple tests to check the balance of my BALUNs, I am
convinced that
I have errors of at least 15%. Even my trusty R390's balanced input is
far from a
"perfect" balance over the 5000KHz to 30MHz frequency range.

Charles Counselman's research into common mode effects and how to
reduce
it are a God send to my receiving pursuits.
http://www.yccc.org/Articles/W1HIS/C...S2006Apr06.pdf
I am grateful for his help in understanding where I went wrong. And I
am sorry
for any confussion I may have caused.

For a very inexpensive aid in RFI/EMI reduction, check out
http://www.hosfelt.com/,
scroll down to filters and take a look at the CURTIS, Mfg.# -
F1600CA03, 3A filters.
These have been a great help in stomping RFI before it gets started

Terry

Terry -

Thanks, good info. The good news is the solution works for either
reason.... although Devoldere's/Bryants chokes remain a terrific tool
as well as the distributed beads.

Bob

Bob wrote:

Terry -

Thanks, good info. The good news is the solution works for either
reason.... although Devoldere's/Bryants chokes remain a terrific tool
as well as the distributed beads.

Bob

Don't forget to look at John Bryant's pdf showing another way to build
a
an effective common mode choke for receiving applications. Bryant's
torroid will over heat with as little as 10W on Tx!

http://www.dxing.info/equipment/coax_leadin_bryant.pdf

I have found that the most effective way to reduce your QTH noise level
is:
Step 1: Use a portable SW receiver, I use a DX398, with a simple loop
to check every circuit, and every device in your home and outbuildings.
Be certain to check everything. Doorbell, Smoke alarm, water heater,
PIR lights, coldcathode florescents lamps, telephone devices, TVs, VCRs
DVD/CD players, audio cassette decks(I had a pioneer that had a nasty
spur on ~5.1 @ S9), battery chargers, well you get the idea. Check
every
thing. A lot of the RF noise, in every case I have worked with, comes
from
within or very close to your home.
Step2:After finding and logging the noise, start fighting it. The
Curtis RFI
filters I mentioned are easily made into "things" to go between the AC
mains
and the device. They use PC style IEC power cord for inputs, so it will
be
useful to gather at least one per filter. For those devices with it
will take two
cords per filter, one for the AC in and another that you simply cut the
male
end off and solder to the filter's outputs. Other devices will need the
IEC input
cord and either have the device hard wired to the filter output, or the
use of a
suitable female connector.

I found it helpful to add a 0.1uF 1KV disk cap across the filter's
output. I
used liquid tape to unsulate the filters hot end, and in most cases I
used
large diameter heatshrink to protect the whole filter assembly. Regular
electrical tape would work, and the really industrious can build the
filters
into mini-boxes. For our HiFi/"Home Theatre" center I built my own
fitlered
power "strip" with 10 RFI filters in one metal box with 1 heavy AC
input
cord that I fan out to each filter input. I use some 1" square females
because
I had a chasies punch. I got fancy and added some relays to allow the
power
to be remoted. Most modern devices don'e have real power switches as
something
is always left alive, so by really turning everything off I reduce the
off state noise
and as important, reduce the chances of AC line spikes damaging
something.

For Wall Wart, I try to pick RF quite units to begin with, then add
ferrite on the
output, and in extreme cases I crack the case open and bypass the
diodes
with 1000pF/0.0001uF caps. As Telemon pointed out, it would be more
effective
to design and build a snubber for that specific circuit, but I have
found the 1000pF
to almost always work very well.

Be sure to check the phone line at the NID/demarcation box. A friend
had
nasty RFI coming down the phone line. With more DLS being added all the
time, I check mine once a week or anytime I hear a new constant RFI
source.
Ferrite will keep it out of your home.

Use a real RF ground and do not rely on the house hold electrical
ground.
Use good quality coax.
If you are using a "wire" antenna, be certain a matching transformer.
If you are using a non-dipole acitve antenna you will almost certainly
have
to use a lot more ferrite then you first would think. Active dipoles
are
much more imune, but still need some common mode filtering.

!!ALL of the active non-dipoles that I have played with require a very
good
ground at the base of the antenna.!! Good means at least a 4' ground
rod into moist soil. 8' is better, but awkward to move. I plan on using
a 4' until I find the quitest spot then switch to an 8' rod.


Sorry for the length of this, but I thought you mind find it useful.

Terry

wrote:

Don't forget to look at John Bryant's pdf showing another way to build
a
an effective common mode choke for receiving applications. Bryant's
torroid will over heat with as little as 10W on Tx!
__________________________________________________ ________________________
That's what I meant by Devoldere/Bryant, but I wasn't clear enough...
Devoldere's book (ARRL Low Band DXing) is where Bryant & Nelson got the
info from originally.
__________________________________________________ ________________________

http://www.dxing.info/equipment/coax_leadin_bryant.pdf

I have found that the most effective way to reduce your QTH noise level
is:
Step 1: Use a portable SW receiver, I use a DX398, with a simple loop
to check every circuit, and every device in your home and outbuildings.
Be certain to check everything. Doorbell, Smoke alarm, water heater,
PIR lights, coldcathode florescents lamps, telephone devices, TVs, VCRs
DVD/CD players, audio cassette decks(I had a pioneer that had a nasty
spur on ~5.1 @ S9), battery chargers, well you get the idea. Check
every
thing. A lot of the RF noise, in every case I have worked with, comes
from
within or very close to your home.
Step2:After finding and logging the noise, start fighting it. The
Curtis RFI
filters I mentioned are easily made into "things" to go between the AC
mains
and the device. They use PC style IEC power cord for inputs, so it will
be
useful to gather at least one per filter. For those devices with it
will take two
cords per filter, one for the AC in and another that you simply cut the
male
end off and solder to the filter's outputs. Other devices will need the
IEC input
cord and either have the device hard wired to the filter output, or the
use of a
suitable female connector.

I found it helpful to add a 0.1uF 1KV disk cap across the filter's
output. I
used liquid tape to unsulate the filters hot end, and in most cases I
used
large diameter heatshrink to protect the whole filter assembly. Regular
electrical tape would work, and the really industrious can build the
filters
into mini-boxes. For our HiFi/"Home Theatre" center I built my own
fitlered
power "strip" with 10 RFI filters in one metal box with 1 heavy AC
input
cord that I fan out to each filter input. I use some 1" square females
because
I had a chasies punch. I got fancy and added some relays to allow the
power
to be remoted. Most modern devices don'e have real power switches as
something
is always left alive, so by really turning everything off I reduce the
off state noise
and as important, reduce the chances of AC line spikes damaging
something.

For Wall Wart, I try to pick RF quite units to begin with, then add
ferrite on the
output, and in extreme cases I crack the case open and bypass the
diodes
with 1000pF/0.0001uF caps. As Telemon pointed out, it would be more
effective
to design and build a snubber for that specific circuit, but I have
found the 1000pF
to almost always work very well.

Be sure to check the phone line at the NID/demarcation box. A friend
had
nasty RFI coming down the phone line. With more DLS being added all the
time, I check mine once a week or anytime I hear a new constant RFI
source.
Ferrite will keep it out of your home.

Use a real RF ground and do not rely on the house hold electrical
ground.
Use good quality coax.
If you are using a "wire" antenna, be certain a matching transformer.
If you are using a non-dipole acitve antenna you will almost certainly
have
to use a lot more ferrite then you first would think. Active dipoles
are
much more imune, but still need some common mode filtering.

!!ALL of the active non-dipoles that I have played with require a very
good
ground at the base of the antenna.!! Good means at least a 4' ground
rod into moist soil. 8' is better, but awkward to move. I plan on using
a 4' until I find the quitest spot then switch to an 8' rod.


Sorry for the length of this, but I thought you mind find it useful.

Terry

Not too long for the info given! I am working on these exact things
courtesy of information passed to me by your friend Will. You didn't
know you were helping somebody in Syracuse, NY, but you have been.
Will has been kind enough to send me a lot of details on how you showed
him your "noise audit" procedure and ways to kill the noise. I just
received 20 of the Curtis filters from Hosfelt.
You helped Will and a bunch has "trickeled down" to me. Thank you very
much.

Bob

Bob wrote:
Not too long for the info given! I am working on these exact things
courtesy of information passed to me by your friend Will. You didn't
know you were helping somebody in Syracuse, NY, but you have been.
Will has been kind enough to send me a lot of details on how you showed
him your "noise audit" procedure and ways to kill the noise. I just
received 20 of the Curtis filters from Hosfelt.
You helped Will and a bunch has "trickeled down" to me. Thank you very
much.

Bob

Glad to have helped. As people have helped me over the years,
I try to pass my bits of useful knowledge on to those who can
use them.

An often overlooked source of ferrite material is computer "stuff".

Keyboards, and mouses often have small ferrite beads inside.

VGA monitors often have big ferrite beads on the cable at the HD15
and right inside the monitor. They also often have other ferrite beads
inside and the better ones they have pretty good single stage RFI
filters on the power lead.

The switch mode power supplies have at least one, and often several,
ferrite toroids.

Even junk like VCRs and DVD players often have ferrite on the AC mains
and the PS unit often has ferrite cores.

Dead light dimmers are also good sources of ferrite torroids.

I have made it a point to scavenge every piece of ferrite I can lay my
hands on.

As W1HIS points out transmitting requires the selection of the correct
ferrite. But for receiving we want extra lossy ferrite. The lossier the
better.
Lossy ferrite wastes power by absorbing it and getting hot. And if your
receive ferrite gets hot you are too darn close to a MW power house!

Even iron dust cores do a suitable job of suppressing common mode
on coax, power lines and telephone lines.

And don't be saddened when you find the noise reduction process is
multi step. The first pass will get the big RFI sources, each succesive
pass will reduce the next level of RFI.

Another trick is to find some GE MOVs and disassemble them and add
a 1000pF cap across the hot to neutral and maybe hot to ground. And to
add a 1000pF across the light switches. This last step will stop, or
greatly
reduce the "pop" as lights are turned on or off. On unexpected
advantage
of adding MOVs across every circuit was the reduction of damage from
nearby lightning strikes.

You might find it usefull to make a sketch of your home showing every
outlet, switch and light fixture. Number them. Don't forget the smoke
alarm and door bell. Then number your circuit breakers and make a chart
showing which outlet is controlled by which breaker. Very handy when
non RFI troubles pop up.

Terry

wrote:
Bob wrote:

Terry -

Thanks, good info. The good news is the solution works for either
reason.... although Devoldere's/Bryants chokes remain a terrific tool
as well as the distributed beads.

Bob

Don't forget to look at John Bryant's pdf showing another way to build
a
an effective common mode choke for receiving applications. Bryant's
torroid will over heat with as little as 10W on Tx!

http://www.dxing.info/equipment/coax_leadin_bryant.pdf

I have found that the most effective way to reduce your QTH noise level
is:
Step 1: Use a portable SW receiver, I use a DX398, with a simple loop
to check every circuit, and every device in your home and outbuildings.
Be certain to check everything. Doorbell, Smoke alarm, water heater,
PIR lights, coldcathode florescents lamps, telephone devices, TVs, VCRs
DVD/CD players, audio cassette decks(I had a pioneer that had a nasty
spur on ~5.1 @ S9), battery chargers, well you get the idea. Check
every
thing. A lot of the RF noise, in every case I have worked with, comes
from
within or very close to your home.
Step2:After finding and logging the noise, start fighting it. The
Curtis RFI
filters I mentioned are easily made into "things" to go between the AC
mains
and the device. They use PC style IEC power cord for inputs, so it will
be
useful to gather at least one per filter. For those devices with it
will take two
cords per filter, one for the AC in and another that you simply cut the
male
end off and solder to the filter's outputs. Other devices will need the
IEC input
cord and either have the device hard wired to the filter output, or the
use of a
suitable female connector.


And for things like PC's,that already use the IEC sockets,you could
(should!) replace them with the type that have the built in filters.

PC's are horribly noisy beasts. And all the SMPS's used everywhere don't
help either..anyone actually use a scope to look at their 120V waveform
lately? I'll bet it looks nasty.
Beware of those nasty light-dimmers too..Those suckers can spew noise
for blocks,and spread noise through your entire house's wiring!

(I once had a "glitch" in a signal on my O'scope,couldn't figure it
out..it was noise from a light dimmer in the bedroom,on the other end of
the house,on a different circuit even..It's supposedly a "low EMI/RFI"
dimmer also. PFfft.)

Ferrite,Filters,and bypass caps for everyone!




I found it helpful to add a 0.1uF 1KV disk cap across the filter's
output. I
used liquid tape to unsulate the filters hot end, and in most cases I
used
large diameter heatshrink to protect the whole filter assembly. Regular
electrical tape would work, and the really industrious can build the
filters
into mini-boxes. For our HiFi/"Home Theatre" center I built my own
fitlered
power "strip" with 10 RFI filters in one metal box with 1 heavy AC
input
cord that I fan out to each filter input. I use some 1" square females
because
I had a chasies punch. I got fancy and added some relays to allow the
power
to be remoted. Most modern devices don'e have real power switches as
something
is always left alive, so by really turning everything off I reduce the
off state noise
and as important, reduce the chances of AC line spikes damaging
something.


And those nasty "Phantom Loads" ie: something that's powered on,even
though the button on the front says "off"..
Nowadays "Standby" has replaced "off".
And put the "wall warts" on a switched-strip too,turn them off when you
don't need them.Save a bit on the power bill too while you're at it.




For Wall Wart, I try to pick RF quite units to begin with, then add
ferrite on the
output, and in extreme cases I crack the case open and bypass the
diodes
with 1000pF/0.0001uF caps. As Telemon pointed out, it would be more
effective
to design and build a snubber for that specific circuit, but I have
found the 1000pF
to almost always work very well.

Be sure to check the phone line at the NID/demarcation box. A friend
had
nasty RFI coming down the phone line. With more DLS being added all the
time, I check mine once a week or anytime I hear a new constant RFI
source.
Ferrite will keep it out of your home.



Another trick I've used on the phone line is to earth-ground all the
unused conductors in the cable.
They wired our house with Cat-5,and we had 2 phone lines.
So we had 2 pairs used,and 2 pairs unused..I grounded the unused pairs
at the junction box outside the house,and that killed a bunch of noise
and crosstalk between the lines. The 56K modem would connect at faster
speeds also.



Use a real RF ground and do not rely on the house hold electrical
ground.
Use good quality coax.
If you are using a "wire" antenna, be certain a matching transformer.
If you are using a non-dipole acitve antenna you will almost certainly
have
to use a lot more ferrite then you first would think. Active dipoles
are
much more imune, but still need some common mode filtering.

!!ALL of the active non-dipoles that I have played with require a very
good
ground at the base of the antenna.!! Good means at least a 4' ground
rod into moist soil. 8' is better, but awkward to move. I plan on using
a 4' until I find the quitest spot then switch to an 8' rod.


Speaking of grounds,go around your house with a wrench and
screwdriver,tighten the ground wire connections at the service
box,ground rod,etc. Those connections can become corroded,and noisy.

If there are any light-poles around with transformers on them,go tighten
the ground connections on those up too. Those can spew noise for
blocks,or even miles.
(or have the utility come do it,but that might take a month.)



Sorry for the length of this, but I thought you mind find it useful.

Terry

wrote:
Glad to have helped. As people have helped me over the years,
I try to pass my bits of useful knowledge on to those who can
use them.

Thanks again!

In your discussions with Charles Counselman, has he added anything yet
to his document? He had some blank sections that were to come later,
just wondering if he mentioned anything.

Bob

Bob wrote:
wrote:
Glad to have helped. As people have helped me over the years,
I try to pass my bits of useful knowledge on to those who can
use them.

Thanks again!

In your discussions with Charles Counselman, has he added anything yet
to his document? He had some blank sections that were to come later,
just wondering if he mentioned anything.

Bob

We covered many topics, but it would be hard to extract anything to
post here.
He does intend to post info on his search antenna. A simple 20 turn
loop wound
on a pill bottle will suffice to get you started.

Is your Email valid? I will ask Charles if it is OK to forward you his
B-field noise
sensing diagram.

Depending on how serious, or demented, you are, you might benifit from
rereading
my prior posts on RF hunts. The 20 turn loop is good for finding noisy
devices. A
smaller loop made from a salvaged 100uH axial ferrite inductor is great
for sniffing
around inside a device to find the exact noise source. I built mine in
a old
Sharpie dry marker case. While I added BNC females connectors to all my
probes
because I was in the process of trading for a spectrum anylzer and
wanted to
be able to use my probes with that test gear, a cheaper and more
effective option for
most people would be to use ~3' of RG174 terminated in the coorect
connector for
your noise sniffing receiver. I choose to use a DX398 because I have
one and becuase
it it reasonbly well shielded and does a good job as a sniffer.

Maybe 99% of devices radiate RFI over a very wide frequency range.
Digital noise
tends to be very broadband. Every so often you will find a device that
produces a
strong signal on a specific frequency and does not radiate general RFI.

One common frequency is 3.58MHz, US color refference burst. I had one
early Apex
DVD that I never could quiten down enough to live with. I suppose I
ought to dig through
my notes and list the more common "CPU' frequencies. As NTSC goes away,
and
TV horizontal moves away from 15.73426KHz, (from a grass valley "NTSC
Studio
Timing:") the harmonics that we are used to at ~15.73KHz increments
will vanish.
ATSC can be a can of snakes. (http://www.atsc.org/standards.html)
Butfrom what I
have seen so far ATSC will bigger VHF/UHF RFI issue.

Plasma big screens have their own nasty noise signature. LCDs are cold
cathode
florescent illumintated and the drive oscillators tend to be in the
35~50KHz range
and are fairly well shielded and (most) don't radiate too badly.Perhaps
the best thing
for modern SWLs is the move from over the air TV to cable and
satellite. Older tube
sets had very poor internal shielding and radiated sweep and color
burst back out
the antenna and that 300 ohm ribbon lead made a pretty effective
antenna.

Good hunting

Terry

wrote:
Is your Email valid? I will ask Charles if it is OK to forward you his
B-field noise
sensing diagram.

Yes, it is valid, thanks.

Depending on how serious, or demented, you are, you might benifit from
rereading
my prior posts on RF hunts.

I am both serious and demented, and very proud of it ;-)
Actually, because Will had referred so much to what you had taught him,
I saved that info plus I searched this group for posts on noise,
grounding, etc., so you can assume that if you posted it here I have
probably read it. I have a Word document that started out in outline
form to collect radio info that I cut and paste info from the web and
messages into. It is getting rather large, around 60 pages or so, but
very helpful. I find that info that was confusing two mos ago is now
clear as I read it again after further learning. I need to figure out
how to expand and collapse sections in Word pretty soon!

I am a retired/disabled engineer with a good mind limited a bit by
various physical things, so physical work has to be hired out or
proceeds slowly.

Radio is fascinating to me. I was interseted as a kid, and at
intervals later, but family and too much work kept me from having much
time. Now I have it. Although an electrical engineer, I spent my
career at a steel mill, on things like 15 KV and 480V power
distribution, large DC motors and generators, relay logic, and later
solid state drives and computer stuff, but really not at the component
level. Later years were mostly managing engineering where I spent more
time on planning and budgets than on technical things. Learning about
this "stuff" is a refreshing change.

I believe anything Mr. Counselman has written would be interesting...

Bob

Terry -

Have you found any specific wall warts that you would consider
reasonably electrically quiet?

Thanks again, Bob