OT: Anyone use a noise canceller?

[Mark Hampton]

Hi all,
        I have a S-9 noise level across the bands and despite some detective work, I have been unable to locate the source.    

I feel that I may have to resort to using a noise canceller in order to use the bands at the home QTH.

Before I purchase one, I'm wondering if any of the subscribers to this list use one and if so, how effective are they?

Apologies for the off-topic post but I though I'd canvass opinions before I buy one.

Thanks, Mark M5MDH
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[Paul Fletcher]

Hi Mark,

I use a Timewave ANC-4 which is very effective against certain types of
noise (e.g. my neighbours plasma TV) but not sure about wideband noise -
best bet is to see if you can try one on loan). It needed a bit of tweaking
with the sense antenna to get the best out of it. Other units to consider
are the MFJ one and DX engineering have released on as well. Can't comment
of these but if DXE's other products are anything to go by it should be the
dog's b's

73 Paul M1PAF

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Mark Hampton
Sent: 22 September 2007 11:40
To: Elecraft list
Subject: [Elecraft] OT: Anyone use a noise canceller?

Hi all,
        I have a S-9 noise level across the bands and despite some detective
work, I have been unable to locate the source.    

I feel that I may have to resort to using a noise canceller in order to use
the bands at the home QTH.

Before I purchase one, I'm wondering if any of the subscribers to this list
use one and if so, how effective are they?

Apologies for the off-topic post but I though I'd canvass opinions before I
buy one.

Thanks, Mark M5MDH
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[David Pratt-2]

In a recent message, Mark Hampton <[hidden email]> wrote ...
>I feel that I may have to resort to using a noise canceller in order to
>use the bands at the home QTH.
>
>Before I purchase one, I'm wondering if any of the subscribers to this
>list use one and if so, how effective are they?

It might be wise to hold off buying one for a while, Mark. I believe
there has been discussion on here about the possibility of a noise
canceller being built into the K3, possibly as an optional module. That
would indeed be very useful for people in situations like your own.

73
--
David G4DMP
Leeds, England, UK
------


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[David Woolley (E.L)]

Mark Hampton wrote:

> I have a S-9 noise level across the bands and despite some detective
> work, I have been unable to locate the source.

Noise cancelers would better be described as interference cancelers.
They work by creating a null in the antenna pattern.  They cannot
suppress thermal or undirected sky noise.

As such, if you don't know the direction of the source now, but
successfully "noise" cancel it, you will have established some
information about the direction, and could, in theory, have used other
means to do that more directly.

A possible other approach would be to use a separate, receive antenna,
positioned for minimum interference.  My impression is that noise
cancelers only work well at frequencies where external noise and
interference dominate receiver noise, so one should not need as
efficient an antenna for receive as one does for transmit.

> Apologies for the off-topic post but I though I'd canvass opinions
> before I buy one.

I've removed the OT tag, as this appears, to me, to be on topic
according to the guidelines, which allow more than just Elecraft
hardware related articles.

--
David Woolley
Emails are not formal business letters, whatever businesses may want.
RFC1855 says there should be an address here, but, in a world of spam,
that is no longer good advice, as archive address hiding may not work.
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[Edward Dickinson, III]

Hi Mark.

The noise canceling units use phase inversion to cancel noise.  They work
okay on noise coming from a singe point source.  However, they don't seem to
work well on noise generated from multiple sources or a spread out source as
noise will then arrive in different phases.

DX Engineering's '2 Channel' feature might allow canceling from a second
source, but that's a bit beyond my understanding.

If it is possible to determine the type of noise you are receiving, you may
save yourself some money.  Some investigation with some noise detecting
equipment (if you don't have to pay for the equipment) may be fruitful.


Regards,
Dick - KA5KKT/4


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Mark,

I would get a hold of your power company and ask for the Ghost Squad.  Here is the Wichita Kansas area there is a dedicated truck and two guys that look for power line noise from anywhere.  They will track it down to a pole...and fix it....or they will track it down to a house and tell you where it is coming from.  I think that most power companies worth their salt have a Ghost Squad that tracks these things down.

I had the problem too....and they found quite a few bad poles.  The crew fixed it pronto because they are wasting power before it gets to the meter so you have to pay for it.  I have a quite location now right in town.

Lee - K0WA



In our day and age it seems that Common Sense is in short supply.  If you don't have any Common Sense - get some Common Sense and use it.  If you can't find any Common Sense, ask for help from somebody who has some Common Sense.  Is Common Sense divine?
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[n6wg]

Hi Mark
If you cannot locate the noise source, can you at least
determine it's direction from you?  A simple untuned
loop should allow you to do that.
An antenna noice canceller (ANC) works best if you
can get a pickup antena as close as possible to the
source, relative to the communication antenna, even
if it is just to the edge of your property.
I have both the ANC-4 and the MFJ-1026, and they
both work well on a single noise source.  They can't
cope with multiple noise sources, though, or a single
source spread out over an area, such a power line
that is radiating along its length.
Good luck and 73
Bob N6WG

----- Original Message -----
From: "Mark Hampton" <[hidden email]>
To: "Elecraft list" <[hidden email]>
Sent: Saturday, September 22, 2007 3:39 AM
Subject: [Elecraft] OT: Anyone use a noise canceller?


Hi all,
        I have a S-9 noise level across the bands and despite some detective
work, I have been unable to locate the source.

I feel that I may have to resort to using a noise canceller in order to use
the bands at the home QTH.

Before I purchase one, I'm wondering if any of the subscribers to this list
use one and if so, how effective are they?

Apologies for the off-topic post but I though I'd canvass opinions before I
buy one.

Thanks, Mark M5MDH
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[David Cutter]

Bob

Wonder if you (or anyone) has mixed the outputs from 2 or more noise
cancellers, perhaps using different antennas for each.

David
G3UNA


----- Original Message -----
From: "Robert Tellefsen" <[hidden email]>
To: "Mark Hampton" <[hidden email]>; "Elecraft list"
<[hidden email]>
Sent: Saturday, September 22, 2007 2:36 PM
Subject: Re: [Elecraft] OT: Anyone use a noise canceller?

> Hi Mark
> If you cannot locate the noise source, can you at least
> determine it's direction from you?  A simple untuned
> loop should allow you to do that.
> An antenna noice canceller (ANC) works best if you
> can get a pickup antena as close as possible to the
> source, relative to the communication antenna, even
> if it is just to the edge of your property.
> I have both the ANC-4 and the MFJ-1026, and they
> both work well on a single noise source.  They can't
> cope with multiple noise sources, though, or a single
> source spread out over an area, such a power line
> that is radiating along its length.
> Good luck and 73
> Bob N6WG
>
> ----- Original Message -----
> From: "Mark Hampton" <[hidden email]>
> To: "Elecraft list" <[hidden email]>
> Sent: Saturday, September 22, 2007 3:39 AM
> Subject: [Elecraft] OT: Anyone use a noise canceller?
>
>
> Hi all,
>        I have a S-9 noise level across the bands and despite some
> detective
> work, I have been unable to locate the source.
>
> I feel that I may have to resort to using a noise canceller in order to
> use
> the bands at the home QTH.
>
> Before I purchase one, I'm wondering if any of the subscribers to this
> list
> use one and if so, how effective are they?
>
> Apologies for the off-topic post but I though I'd canvass opinions before
> I
> buy one.
>
> Thanks, Mark M5MDH
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>
> _______________________________________________
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[David Woolley (E.L)]

Mark Hampton wrote:

> I have a S-9 noise level across the bands and despite some detective
> work,

One other thing to consider is whether the interference is actually
coming in on the "earth" connection.  With the K2, on 80m, I find that
the noise drops drastically when I disconnect from the mains power
supply (a very old one that has high leakage and therefore needs to be
earthed and the secondary side) and run on a battery.  It drops from
about S9 to about S2 (although my S meter calibration is suspect).  This
is using a crude indoor doublet, with a BL-1 and with a clamp on ferrite
ring on five or six turns of the DC supply cable.

My impression is that the BL-1 isn't terribly effective on an
electrically short (about 10m either side, although not in a straight
line) antenna at 80m, even though the KAT-2 can tune it.  I'm going to
have to do more research on indoor antennas.

I'm in a first floor flat and running a separate functional (RF) earth
is not possible, and it would be electrically long if I ran it, anyway.
  Note, make sure that you understand the issues about protective
multiple earthing, and know how your electricity supply is done, before
providing any alternative earthing.

--
David Woolley
Emails are not formal business letters, whatever businesses may want.
RFC1855 says there should be an address here, but, in a world of spam,
that is no longer good advice, as archive address hiding may not work.
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[n6wg]

No, David, can't say I've done that.
I don't think it would be too successful, though,
because when you tune away from the frequency
where you have nulled a noise source, it comes
back.  The null will only hold over a certain
frequency spread, sepending on the band.  Then
you have to redo the null.  So with two nulls
on two sources, when you move into one null you
would be moving out of another.  The noise might
not show any improvement overall.
73, Bob N6WG

----- Original Message -----
From: "David Cutter" <[hidden email]>
To: "Elecraft list" <[hidden email]>
Sent: Saturday, September 22, 2007 7:08 AM
Subject: Re: [Elecraft] OT: Anyone use a noise canceller?

> Bob
>
> Wonder if you (or anyone) has mixed the outputs from 2 or more noise
> cancellers, perhaps using different antennas for each.
>
> David
> G3UNA
>
>
> ----- Original Message -----
> From: "Robert Tellefsen" <[hidden email]>
> To: "Mark Hampton" <[hidden email]>; "Elecraft list"
> <[hidden email]>
> Sent: Saturday, September 22, 2007 2:36 PM
> Subject: Re: [Elecraft] OT: Anyone use a noise canceller?
>
>
> > Hi Mark
> > If you cannot locate the noise source, can you at least
> > determine it's direction from you?  A simple untuned
> > loop should allow you to do that.
> > An antenna noice canceller (ANC) works best if you
> > can get a pickup antena as close as possible to the
> > source, relative to the communication antenna, even
> > if it is just to the edge of your property.
> > I have both the ANC-4 and the MFJ-1026, and they
> > both work well on a single noise source.  They can't
> > cope with multiple noise sources, though, or a single
> > source spread out over an area, such a power line
> > that is radiating along its length.
> > Good luck and 73
> > Bob N6WG
> >
> > ----- Original Message -----
> > From: "Mark Hampton" <[hidden email]>
> > To: "Elecraft list" <[hidden email]>
> > Sent: Saturday, September 22, 2007 3:39 AM
> > Subject: [Elecraft] OT: Anyone use a noise canceller?
> >
> >
> > Hi all,
> >        I have a S-9 noise level across the bands and despite some
> > detective
> > work, I have been unable to locate the source.
> >
> > I feel that I may have to resort to using a noise canceller in order to
> > use
> > the bands at the home QTH.
> >
> > Before I purchase one, I'm wondering if any of the subscribers to this
> > list
> > use one and if so, how effective are they?
> >
> > Apologies for the off-topic post but I though I'd canvass opinions

before

> > I
> > buy one.
> >
> > Thanks, Mark M5MDH
> > _______________________________________________
> > Elecraft mailing list
> > Post to: [hidden email]
> > You must be a subscriber to post to the list.
> > Subscriber Info (Addr. Change, sub, unsub etc.):
> > http://mailman.qth.net/mailman/listinfo/elecraft
> >
> > Help: http://mailman.qth.net/subscribers.htm
> > Elecraft web page: http://www.elecraft.com
> >
> > _______________________________________________
> > Elecraft mailing list
> > Post to: [hidden email]
> > You must be a subscriber to post to the list.
> > Subscriber Info (Addr. Change, sub, unsub etc.):
> > http://mailman.qth.net/mailman/listinfo/elecraft
> >
> > Help: http://mailman.qth.net/subscribers.htm
> > Elecraft web page: http://www.elecraft.com
>
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[Vic K2VCO]

Mark Hampton wrote:

> Hi all, I have a S-9 noise level across the bands and despite some
> detective work, I have been unable to locate the source.
>
> I feel that I may have to resort to using a noise canceller in order
> to use the bands at the home QTH.
>
> Before I purchase one, I'm wondering if any of the subscribers to
> this list use one and if so, how effective are they?
>
> Apologies for the off-topic post but I though I'd canvass opinions
> before I buy one.

I have the MFJ. It is quite effective for noises generated by nearby
sources, although you have to fiddle with the knobs a bit for each
individual noise.

The biggest problem is that it has to be in the line to the antenna and
has to switch itself in and out on receive/transmit. This may not be a
big problem with PTT SSB, but it's a bother on CW and pretty much
prevents QSK -- unless you have a rig like the K3 with KXV3 which has
receiver antenna in and out connections.
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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[David Cutter]

Yes, I appreciate that controls have to be adjusted for each QSY, but when
trying to hear that weak signal amongst QRM you would be on one frequency
and spend time to set up the controls, (eg 3B7C).  It seems intuitive to me
that with more than one rx antenna and mixers it should be possible to null
more than one signal.

David
G3UNA


----- Original Message -----
From: "Robert Tellefsen" <[hidden email]>
To: "David Cutter" <[hidden email]>; "Elecraft list"
<[hidden email]>
Sent: Saturday, September 22, 2007 3:44 PM
Subject: Re: [Elecraft] OT: Anyone use a noise canceller?

> No, David, can't say I've done that.
> I don't think it would be too successful, though,
> because when you tune away from the frequency
> where you have nulled a noise source, it comes
> back.  The null will only hold over a certain
> frequency spread, sepending on the band.  Then
> you have to redo the null.  So with two nulls
> on two sources, when you move into one null you
> would be moving out of another.  The noise might
> not show any improvement overall.
> 73, Bob N6WG
>
> ----- Original Message -----
> From: "David Cutter" <[hidden email]>
> To: "Elecraft list" <[hidden email]>
> Sent: Saturday, September 22, 2007 7:08 AM
> Subject: Re: [Elecraft] OT: Anyone use a noise canceller?
>
>
>> Bob
>>
>> Wonder if you (or anyone) has mixed the outputs from 2 or more noise
>> cancellers, perhaps using different antennas for each.
>>
>> David
>> G3UNA
>>
>>
>> ----- Original Message -----
>> From: "Robert Tellefsen" <[hidden email]>
>> To: "Mark Hampton" <[hidden email]>; "Elecraft list"
>> <[hidden email]>
>> Sent: Saturday, September 22, 2007 2:36 PM
>> Subject: Re: [Elecraft] OT: Anyone use a noise canceller?
>>
>>
>> > Hi Mark
>> > If you cannot locate the noise source, can you at least
>> > determine it's direction from you?  A simple untuned
>> > loop should allow you to do that.
>> > An antenna noice canceller (ANC) works best if you
>> > can get a pickup antena as close as possible to the
>> > source, relative to the communication antenna, even
>> > if it is just to the edge of your property.
>> > I have both the ANC-4 and the MFJ-1026, and they
>> > both work well on a single noise source.  They can't
>> > cope with multiple noise sources, though, or a single
>> > source spread out over an area, such a power line
>> > that is radiating along its length.
>> > Good luck and 73
>> > Bob N6WG
>> >
>> > ----- Original Message -----
>> > From: "Mark Hampton" <[hidden email]>
>> > To: "Elecraft list" <[hidden email]>
>> > Sent: Saturday, September 22, 2007 3:39 AM
>> > Subject: [Elecraft] OT: Anyone use a noise canceller?
>> >
>> >
>> > Hi all,
>> >        I have a S-9 noise level across the bands and despite some
>> > detective
>> > work, I have been unable to locate the source.
>> >
>> > I feel that I may have to resort to using a noise canceller in order to
>> > use
>> > the bands at the home QTH.
>> >
>> > Before I purchase one, I'm wondering if any of the subscribers to this
>> > list
>> > use one and if so, how effective are they?
>> >
>> > Apologies for the off-topic post but I though I'd canvass opinions
> before
>> > I
>> > buy one.
>> >
>> > Thanks, Mark M5MDH
>> > _______________________________________________
>> > Elecraft mailing list
>> > Post to: [hidden email]
>> > You must be a subscriber to post to the list.
>> > Subscriber Info (Addr. Change, sub, unsub etc.):
>> > http://mailman.qth.net/mailman/listinfo/elecraft
>> >
>> > Help: http://mailman.qth.net/subscribers.htm
>> > Elecraft web page: http://www.elecraft.com
>> >
>> > _______________________________________________
>> > Elecraft mailing list
>> > Post to: [hidden email]
>> > You must be a subscriber to post to the list.
>> > Subscriber Info (Addr. Change, sub, unsub etc.):
>> > http://mailman.qth.net/mailman/listinfo/elecraft
>> >
>> > Help: http://mailman.qth.net/subscribers.htm
>> > Elecraft web page: http://www.elecraft.com
>>
>> _______________________________________________
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>>
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>> Elecraft web page: http://www.elecraft.com
>

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[AC7AC]

CONTENTS DELETED

The author has deleted this message.

[Roelof Bakker]

Hello David etc,

When you use two noise cancellars to get rid of two noise sources, either
noise will be present at the output of one of the two cancellars, so nothing
is gained.

On an other note, as a lot of local noise is common mode noise, the first
thing to do is to establish if this is the case or not. Noise can also be
picked up on the shield of the coaxial feedline.

I am using a battery operated receiver outdoors for this purpose as a lot of
noise is contained inside a building.

Roelof Bakker, pa0rdt
Middelburg, Netherlands
JO11tm


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[David Woolley (E.L)]

David Cutter wrote:
> and spend time to set up the controls, (eg 3B7C).  It seems intuitive to me
> that with more than one rx antenna and mixers it should be possible to null
> more than one signal.

It's not that intuitive.  The sense antenna inputs will combine
linearly, which means that if you just control phase and amplitude, the
combination will be a third combination of them, not both
simultaneously.  If you want to cancel both simultaneously, you will
have to find two other variables, which would in practice, have to be
the antenna locations (x and y).  As the effect would be in wavelengths,
you would have to move at least one sense antenna with frequency.

You need two independent parameters for each simultaneously cancelled
source.

Getting the sense antennas close to the two sources will help, as once
you attenuate the sense signal to match the main signal, it will
re-introduce relatively little of the other interfering signal which
will not originate close to that sense antenna.

--
David Woolley
Emails are not formal business letters, whatever businesses may want.
RFC1855 says there should be an address here, but, in a world of spam,
that is no longer good advice, as archive address hiding may not work.
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[AC7AC]

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[Geoffrey Mackenzie-Kennedy-2]

Ron D'Eau Claire  <[hidden email]> wrote:

Those interested in noise canceling might be interested in what the rest of
the communications industry is doing with exotic integrated circuit systems
that kill noise by inverting and adding it to the signal at the antenna
input.

<snip>

The bad news for the casual homebrewer is that the chip measures less than
1mm (<0.04") on a side.

------------------------------------------------------------------

Thank you for the bad news Ron :-)  A circuit working at IF which involves
splitting, hard clipping, phasing and summing used in CW reception to reduce
zero beat QRM shows promise with noise, but much work still to be done for
use as a noise canceller.

73,
Geoff
GM4ESD



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