On Jan 18, 4:23*pm, dave wrote:
On 01/18/2011 02:17 PM, D. Peter Maus wrote:







On 1/18/11 16:05 , bpnjensen wrote:
On Jan 18, 10:57 am, John wrote:
On 1/18/2011 10:44 AM, bpnjensen wrote:

...
Actually, no, and I am sorry if there was a misunderstanding - I meant
an inline (in the coax) RFI reduction system.

Baluns/ununs really are NOT an RFI reduction system. They provide
proper impedance matching between antenna and feedline. Coax, with an
rf choke (can be a balun/unun) allows the feedline to run though noisy
areas and not pick up the noise there, such as when it enters a house
with noise present.

Baluns/ununs/rf-transformers, because of the use in gaining a superior
match (transfer of signal energy) improves signal to noise ratio, in
most instances, and this can appear to be functioning as a "RFI
reduction system."

Some useful
links:http://users.belgacom.net/hamradio/s...ongwire%20Balu...

Regards,
JS

OK, understood, but I have always thought (based on what I have read)
that one of these matching transformers, properly deisgned and
grounded, can bleed off some noise to ground. Am I misled?

Local environmental noise, and static, yes. Man made noise, or noise
radiated into the antenna space, not so much, no.

A properly designed matching transformer will improve the transfer of
antenna output to the receiver. And it will help drain off static
buildup on the antenna, and help reduce the noise floor. But, if noise
is being radiated into the air, as from powerlines, digital toys, and
dimmers and similar sources, and your antenna is picking that up, it
will depend on the antenna's ability to discriminate between desired and
undesired frequencies whether or not you see a reduction in undesired
signals.

It sounds as though much of your noise problem is related to your
connection to the mains. Mains borne noise is a big problem in radio
hobbycraft. Most of the noise in my own area is brought in through the
mains. The remainder is radiated from the hundreds of devices throughout
the neighborhood.

It's possible, though a PITA to do so, to bypass the mains with safety
caps between .1 - .01mfd (safety caps are essential, here, for fire
prevention) to reduce the irregular impulses on the line. And isolation
transformer, balanced to ground will also produce significant results in
reducing your noise, but that can be expensive.

Your least difficult path may be in isolating your radios from the
mains, entirely, and move to battery power.

You need to embrace ferrites. They're like putting a low pass filter is
series with your mains. Shunt caps are scary. MOVs, sure.

Thanks - Maybe, but I think ferrites on the RF cables might be more
critical than on the power cables. The radios are nice and quite when
I disconnect the antennae; no noise level at all even with the
multiple preamps all the way up.

On 1/18/11 21:59 , bpnjensen wrote:
On Jan 18, 2:17 pm, "D. Peter wrote:
On 1/18/11 16:05 , bpnjensen wrote:









On Jan 18, 10:57 am, John wrote:
On 1/18/2011 10:44 AM, bpnjensen wrote:

...
Actually, no, and I am sorry if there was a misunderstanding - I meant
an inline (in the coax) RFI reduction system.

Baluns/ununs really are NOT an RFI reduction system. They provide
proper impedance matching between antenna and feedline. Coax, with an
rf choke (can be a balun/unun) allows the feedline to run though noisy
areas and not pick up the noise there, such as when it enters a house
with noise present.

Baluns/ununs/rf-transformers, because of the use in gaining a superior
match (transfer of signal energy) improves signal to noise ratio, in
most instances, and this can appear to be functioning as a "RFI
reduction system."

Some useful links:http://users.belgacom.net/hamradio/s...ongwire%20Balu...

Regards,
JS

OK, understood, but I have always thought (based on what I have read)
that one of these matching transformers, properly deisgned and
grounded, can bleed off some noise to ground. Am I misled?

Local environmental noise, and static, yes. Man made noise, or
noise radiated into the antenna space, not so much, no.

A properly designed matching transformer will improve the
transfer of antenna output to the receiver. And it will help drain
off static buildup on the antenna, and help reduce the noise floor.
But, if noise is being radiated into the air, as from powerlines,
digital toys, and dimmers and similar sources, and your antenna is
picking that up, it will depend on the antenna's ability to
discriminate between desired and undesired frequencies whether or
not you see a reduction in undesired signals.

It sounds as though much of your noise problem is related to your
connection to the mains. Mains borne noise is a big problem in radio
hobbycraft. Most of the noise in my own area is brought in through
the mains. The remainder is radiated from the hundreds of devices
throughout the neighborhood.

It's possible, though a PITA to do so, to bypass the mains with
safety caps between .1 - .01mfd (safety caps are essential, here,
for fire prevention) to reduce the irregular impulses on the line.
And isolation transformer, balanced to ground will also produce
significant results in reducing your noise, but that can be expensive.

Your least difficult path may be in isolating your radios from
the mains, entirely, and move to battery power.

Thanks, Peter - This may be all true - but for the record, with the
radios plugged in, I disconnected the antennas and kept the grounds
connected. The radios got very quiet; based on this, I don't think
it's the mains.


I had a noise I couldn't get rid of, a few years ago. Everything
pointed to some radiated phenomenon. Tried disconnecting the antenna.
Things got very quiet. Finally tracked it down with a Zenith transistor
radio. It was, in fact, noise on the mains, radiated into the antenna
space. Filtered the line and modded an offending device that was putting
the spike on the line. Cleaned it right up.

A transitor radio can be useful in tracking down the source. Follow
the noise, turn off each implement one at a time, and you'll find the
source or sources of noise.

You sound like you're living in the noise equivalent of the Little
Big Horn.



FWIW, I have an RFI filter on the 115 VAC - this item:

ICE:

http://www.iceradioproducts.com/imag...ersarticle.pdf

The difference between using it and not using it is slight, but
noticeable.

Such a device is best used as close to the source as practical.

On 1/18/2011 10:10 PM, Bob Dobbs wrote:

...

GAWD!

And, I thought I had it bad ...

Regards,
JS

On Jan 18, 8:21*pm, "D. Peter Maus" wrote:
On 1/18/11 21:59 , bpnjensen wrote:









On Jan 18, 2:17 pm, "D. Peter *wrote:
On 1/18/11 16:05 , bpnjensen wrote:

On Jan 18, 10:57 am, John * *wrote:
On 1/18/2011 10:44 AM, bpnjensen wrote:

...
Actually, no, and I am sorry if there was a misunderstanding - I meant
an inline (in the coax) RFI reduction system.

Baluns/ununs really are NOT an RFI reduction system. *They provide
proper impedance matching between antenna and feedline. *Coax, with an
rf choke (can be a balun/unun) allows the feedline to run though noisy
areas and not pick up the noise there, such as when it enters a house
with noise present.

Baluns/ununs/rf-transformers, because of the use in gaining a superior
match (transfer of signal energy) improves signal to noise ratio, in
most instances, and this can appear to be functioning as a "RFI
reduction system."

Some useful links:http://users.belgacom.net/hamradio/s...ongwire%20Balu...

Regards,
JS

OK, understood, but I have always thought (based on what I have read)
that one of these matching transformers, properly deisgned and
grounded, can bleed off some noise to ground. *Am I misled?

* * Local environmental noise, and static, yes. Man made noise, or
noise radiated into the antenna space, not so much, no.

* * A properly designed matching transformer will improve the
transfer of antenna output to the receiver. And it will help drain
off static buildup on the antenna, and help reduce the noise floor.
But, if noise is being radiated into the air, as from powerlines,
digital toys, and dimmers and similar sources, and your antenna is
picking that up, it will depend on the antenna's ability to
discriminate between desired and undesired frequencies whether or
not you see a reduction in undesired signals.

* * It sounds as though much of your noise problem is related to your
connection to the mains. Mains borne noise is a big problem in radio
hobbycraft. Most of the noise in my own area is brought in through
the mains. The remainder is radiated from the hundreds of devices
throughout the neighborhood.

* * It's possible, though a PITA to do so, to bypass the mains with
safety caps between .1 - .01mfd (safety caps are essential, here,
for fire prevention) to reduce the irregular impulses on the line.
And isolation transformer, balanced to ground will also produce
significant results in reducing your noise, but that can be expensive.

* * Your least difficult path may be in isolating your radios from
the mains, entirely, and move to battery power.

Thanks, Peter - This may be all true - but for the record, with the
radios plugged in, I disconnected the antennas and kept the grounds
connected. *The radios got very quiet; based on this, I don't think
it's the mains.

* *I had a noise I couldn't get rid of, a few years ago. Everything
pointed to some radiated phenomenon. Tried disconnecting the antenna.
Things got very quiet. Finally tracked it down with a Zenith transistor
radio. It was, in fact, noise on the mains, radiated into the antenna
space. Filtered the line and modded an offending device that was putting
the spike on the line. Cleaned it right up.

* *A transitor radio can be useful in tracking down the source. Follow
the noise, turn off each implement one at a time, and you'll find the
source or sources of noise.

* *You sound like you're living in the noise equivalent of the Little
Big Horn.



FWIW, I have an RFI filter on the 115 VAC - this item:

ICE:

http://www.iceradioproducts.com/imag...ersarticle.pdf

The difference between using it and not using it is slight, but
noticeable.

* *Such a device is best used as close to the source as practical.

This one is plugged into the wall between the radio and the socket.
Can you get any closer than that?

I also know factually that a MW radio brought near things like wall
switches and plugs results in a 60 Hz hum on the radio. It is really
noticeable with a little loop antenna swiveled around - whenever it
points to the wall switch, you hear that hum. The hum is not apparent
on the SW bands at all; but on powerhouse MW stations like KGO locally
here, the hum is solidly behind the audio.

On Jan 18, 10:10*pm, Bob Dobbs wrote:
D. Peter Maus wrote:

* You sound like you're living in the noise equivalent of the Little
Big Horn.

Before the last move three years ago I lived close to there.
Or so it seemedhttp://img.myph.us/Ar9.jpg
From the left is a Butternut 80/40 vertical then an Imax 2000 (CB antenna)
for 10, 12, 15 and also mounted on the back porch a Diamond V2000 for
6, 2, 440. then on the roof is a discone plus some UHF WX transponders.
In addition to Cox and Ma Bell were 4kv, 12kv distribution feeders,
and above that a 138kv tie line (not visible in pic). All of that wire either
radiated its own noise or parasitically re-radiated noise of the others
so it was often, but not always, difficult to get a precise source to use in the
phase noise canceler (ANC-4).
The TV antenna was useful to get OTA LA stations like KCAL9,
SoCal's premier car chase station. g

This looks bad, worse than my situation. I just have the local
residential feeder out front, probably 12 kv, and a set of parallel
feeders in back that probably range up to 138 kv that serves the
industrial park 500 feet west of me. I can often reduce noise from
one source with my MFJ-1026 (similar to the ANC-4), but just the one.
I hate the idea of piling up multiple MFJs and antennae to try to
catch all of the sources.

There are some high-tension lines out about 1/2 mile west or so, but
they are pretty far. They audibly crackle and snap all the time,
though, whenever I ride my bike past them.

On Jan 18, 9:34*pm, Bob Dobbs wrote:
bpnjensen wrote:
Maybe I'll try to match up the astronomy sessions with the radios.

Reminiscent of yesteryear when several friends and I would go
up to the local mountains or over to the desert for an evening
of various activities, astronomy included.
We would routinely take a load of optical gear plus star charts,
GPS units plus topo charts, amateur radio gear for tactical coordination,
as well as a few firearms, pyrotechnical devices, night vision viewers,
and so on. We had met through mutual interest in scanner/SWL activities.

BIG sigh - that sounds wonderful!

On Jan 19, 1:10*am, Bob Dobbs wrote:
D. Peter Maus wrote:

* You sound like you're living in the noise equivalent of the Little
Big Horn.

Before the last move three years ago I lived close to there.
Or so it seemedhttp://img.myph.us/Ar9.jpg
From the left is a Butternut 80/40 vertical then an Imax 2000 (CB antenna)
for 10, 12, 15 and also mounted on the back porch a Diamond V2000 for
6, 2, 440. then on the roof is a discone plus some UHF WX transponders.
In addition to Cox and Ma Bell were 4kv, 12kv distribution feeders,
and above that a 138kv tie line (not visible in pic). All of that wire either
radiated its own noise or parasitically re-radiated noise of the others
so it was often, but not always, difficult to get a precise source to use in the
phase noise canceler (ANC-4).
The TV antenna was useful to get OTA LA stations like KCAL9,
SoCal's premier car chase station. g

Oh,that's why some people started using alumium siding ! It is almost
a Faraday cage...

bpnjensen wrote:

On Jan 18, 10:10 pm, Bob Dobbs wrote:
D. Peter Maus wrote:

You sound like you're living in the noise equivalent of the Little
Big Horn.

Before the last move three years ago I lived close to there.
Or so it seemedhttp://img.myph.us/Ar9.jpg
From the left is a Butternut 80/40 vertical then an Imax 2000 (CB antenna)
for 10, 12, 15 and also mounted on the back porch a Diamond V2000 for
6, 2, 440. then on the roof is a discone plus some UHF WX transponders.
In addition to Cox and Ma Bell were 4kv, 12kv distribution feeders,
and above that a 138kv tie line (not visible in pic). All of that wire either
radiated its own noise or parasitically re-radiated noise of the others
so it was often, but not always, difficult to get a precise source to use in the
phase noise canceler (ANC-4).
The TV antenna was useful to get OTA LA stations like KCAL9,
SoCal's premier car chase station. g

This looks bad, worse than my situation. I just have the local
residential feeder out front, probably 12 kv, and a set of parallel
feeders in back that probably range up to 138 kv that serves the
industrial park 500 feet west of me. I can often reduce noise from
one source with my MFJ-1026 (similar to the ANC-4), but just the one.
I hate the idea of piling up multiple MFJs and antennae to try to
catch all of the sources.

There are some high-tension lines out about 1/2 mile west or so, but
they are pretty far. They audibly crackle and snap all the time,
though, whenever I ride my bike past them.

You need to flee your present location.

Karl Knows

On 01/18/2011 07:59 PM, bpnjensen wrote:

Thanks, Peter - This may be all true - but for the record, with the
radios plugged in, I disconnected the antennas and kept the grounds
connected. The radios got very quiet; based on this, I don't think
it's the mains.

FWIW, I have an RFI filter on the 115 VAC - this item:

ICE:

http://www.iceradioproducts.com/imag...ersarticle.pdf

The difference between using it and not using it is slight, but
noticeable.

http://www.radioshack.com/product/in...ductId=2103222

[read reviews]

On 01/18/2011 08:03 PM, bpnjensen wrote:


Thanks - Maybe, but I think ferrites on the RF cables might be more
critical than on the power cables. The radios are nice and quite when
I disconnect the antennae; no noise level at all even with the
multiple preamps all the way up.

Maybe you should just use 50 Ohm resistors in lieu of antennas. Very low
VSWR; should work great.