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OT Mystery QRM Help (Video)

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David Ahrendts

OT Mystery QRM Help (Video)

Stumped. Need your guesses. What is this mystery, rhythmically pulsing, urban S7 QRM: https://vimeo.com/152779708 <https://vimeo.com/152779708>

Factors: captured 5:30pm Friday (Sunset was 5:15). Densely packed Los Angeles neighborhood — could be next door or a block away. Occurs regularly at night or near dusk and not prime 20M day time. Occurs only on 20M. I’ve noticed it from Fall on to current Winter time. Seems to be a mechanical device (pool pump?). 60-degrees falling to 50-degrees tonight -- a heater system? Eventually just fizzles away slowly. Elecraft K3S + P3, SteppIR DB-11.

David A., KK6DA (formerly KC0XT), LA

David Ahrendts [hidden email]

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Ken G Kopp

Re: OT Mystery QRM Help (Video)

Hi Dave!

In a past life I was a noise technician for a large electric utility.....

WAG's:

Solar cell controlled street light. Had one a block away about a year
ago. Came on dimly and slowly got to normal brightness and noise
diminished as got brighter.

Is your area cold enough that someone has placed a heat tape in an eve
trough or downspout?

A timer or photo cell controlled flood light that might not be making good
contact in some manner?

Electrically heated floor? Once hosted in a state park that had yurts with
electrically heated floor tiles.

Touch lamps are notorious noise sources.

On-demand water heater that is activated when someone gets home from work.

Are there any heated critter drinking pans or tanks nearby? How about a
hot pad or electric blanket in a dog house? Had one next door some years
ago.

A neighbor with grow lights? A heated bed for plants in a green house?

The possibilities are infinite ....

73!

K0PP
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Barry K3NDM

Re: OT Mystery QRM Help (Video)

In reply to this post by David Ahrendts

David,
I'm going to make a wild guess based on an experience I had about 10
or so years ago. See if there is a commercial establishment not too far
away that has an external air handler as a part of its HVAC system. Some
of these used solid state controllers that weren't too clean. You may
have one near by. In my case, it took a while to find it and get it
fixed. First, we needed to figure out what it was and next where it was.
Figuring out what it was was the hardest as no one had ever seen this
before. And, the way we found it was by eliminating all other possible
sources. I wish that you have less trouble locating your problem than we
had.

73,
Barry
K3NDM

------ Original Message ------
From: "David Ahrendts" <[hidden email]>
To: "[hidden email]" <[hidden email]>
Sent: 1/22/2016 9:16:36 PM
Subject: [Elecraft] OT Mystery QRM Help (Video)

>Stumped. Need your guesses. What is this mystery, rhythmically pulsing,
>urban S7 QRM: https://vimeo.com/152779708
><https://vimeo.com/152779708>
>
>Factors: captured 5:30pm Friday (Sunset was 5:15). Densely packed Los
>Angeles neighborhood — could be next door or a block away. Occurs
>regularly at night or near dusk and not prime 20M day time. Occurs only
>on 20M. I’ve noticed it from Fall on to current Winter time. Seems to
>be a mechanical device (pool pump?). 60-degrees falling to 50-degrees
>tonight -- a heater system? Eventually just fizzles away slowly.
>Elecraft K3S + P3, SteppIR DB-11.
>
>David A., KK6DA (formerly KC0XT), LA
>
>
>
>David Ahrendts [hidden email]
>
>
>
>
>______________________________________________________________
>Elecraft mailing list
>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>Help: http://mailman.qth.net/mmfaq.htm
>Post: mailto:[hidden email]
>
>This list hosted by: http://www.qsl.net
>Please help support this email list: http://www.qsl.net/donate.html
>Message delivered to [hidden email]

Fred Townsend-2

Re: OT Mystery QRM Help (Video)

Gentlemen:
That is not a dirty signal. It's very clean with about a 2 KHz wide SSB. The sidebands are very clean. I'd say you have a beacon or some other intentionally caused signal. It may be modulated by some grey line effect but the pulses are consistent as I can tell hearing only 4.

73
Fred, AE6QL
-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Barry LaZar
Sent: Friday, January 22, 2016 7:52 PM
To: David Ahrendts; [hidden email]
Subject: Re: [Elecraft] OT Mystery QRM Help (Video)

David,
I'm going to make a wild guess based on an experience I had about 10 or so years ago. See if there is a commercial establishment not too far away that has an external air handler as a part of its HVAC system. Some of these used solid state controllers that weren't too clean. You may have one near by. In my case, it took a while to find it and get it fixed. First, we needed to figure out what it was and next where it was.
Figuring out what it was was the hardest as no one had ever seen this before. And, the way we found it was by eliminating all other possible sources. I wish that you have less trouble locating your problem than we had.

73,
Barry
K3NDM

------ Original Message ------
From: "David Ahrendts" <[hidden email]>
To: "[hidden email]" <[hidden email]>
Sent: 1/22/2016 9:16:36 PM
Subject: [Elecraft] OT Mystery QRM Help (Video)

>Stumped. Need your guesses. What is this mystery, rhythmically pulsing,
>urban S7 QRM: https://vimeo.com/152779708
><https://vimeo.com/152779708>
>
>Factors: captured 5:30pm Friday (Sunset was 5:15). Densely packed Los
>Angeles neighborhood — could be next door or a block away. Occurs
>regularly at night or near dusk and not prime 20M day time. Occurs only
>on 20M. I’ve noticed it from Fall on to current Winter time. Seems to
>be a mechanical device (pool pump?). 60-degrees falling to 50-degrees
>tonight -- a heater system? Eventually just fizzles away slowly.
>Elecraft K3S + P3, SteppIR DB-11.
>
>David A., KK6DA (formerly KC0XT), LA
>
>
>
>David Ahrendts [hidden email]
>
>
>
>
>______________________________________________________________
>Elecraft mailing list
>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>Help: http://mailman.qth.net/mmfaq.htm
>Post: mailto:[hidden email]
>
>This list hosted by: http://www.qsl.net Please help support this email
>list: http://www.qsl.net/donate.html Message delivered to
>[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email]

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David Ahrendts

Fwd: OT Mystery QRM Help (Video)

In reply to this post by David Ahrendts

A bit more: I watched this mystery QRM pretty closely for an hour Friday evening as 20 meters closed for the day (by 6:30pm PST). The cadence of this noise changed. It slowed. Then faded away with the band. I’m scratching my brain to try think of a mechanical device that would create that kind of rhythm. And as always as I check 20 meters at 11am Saturday, there is no sign of the QRM.
Will listen again late afternoon today. May experiment moving the DB-11 around to see if it is directional.

> Begin forwarded message:
>
> From: David Ahrendts <[hidden email]>
> Subject: OT Mystery QRM Help (Video)
> Date: January 22, 2016 at 6:16:36 PM PST
> To: "[hidden email]" <[hidden email]>
>
> Stumped. Need your guesses. What is this mystery, rhythmically pulsing, urban S7 QRM: https://vimeo.com/152779708 <https://vimeo.com/152779708>
>
> Factors: captured 5:30pm Friday (Sunset was 5:15). Densely packed Los Angeles neighborhood — could be next door or a block away. Occurs regularly at night or near dusk and not prime 20M day time. Occurs only on 20M. I’ve noticed it from Fall on to current Winter time. Seems to be a mechanical device (pool pump?). 60-degrees falling to 50-degrees tonight -- a heater system? Eventually just fizzles away slowly. Elecraft K3S + P3, SteppIR DB-11.
>
> David A., KK6DA (formerly KC0XT), LA
>
>
>
> David Ahrendts [hidden email] <mailto:[hidden email]>
>
>
>
>

David Ahrendts [hidden email]

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Bob McGraw - K4TAX

Re: Fwd: OT Mystery QRM Help (Video)

If one is serious about finding noise, I've found this item to go a long
way in identifying down to the building or site from which it
originates. It takes a bit of practice and time to triangulate but does
work well. I'm sure there's other equipment and methods available as well.

http://www.mfjenterprises.com/Product.php?productid=MFJ-856

This is always a good item for a club to have and own for its members.

73
Bob, K4TAX

On 1/23/2016 1:06 PM, David Ahrendts wrote:
> A bit more: I watched this mystery QRM pretty closely for an hour Friday evening as 20 meters closed for the day (by 6:30pm PST). The cadence of this noise changed. It slowed. Then faded away with the band. I’m scratching my brain to try think of a mechanical device that would create that kind of rhythm. And as always as I check 20 meters at 11am Saturday, there is no sign of the QRM.
> Will listen again late afternoon today. May experiment moving the DB-11 around to see if it is directional.
>

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Mike Maloney

Re: Fwd: OT Mystery QRM Help (Video)

Yes, but David says, "only occurs on 20M", so this may not hear it at 135MHz? Need portable like KX3 and small mag loop tuned to 20M.

On Saturday, January 23, 2016 2:14 PM, Bob McGraw K4TAX <[hidden email]> wrote:

If one is serious about finding noise, I've found this item to go a long
way in identifying down to the building or site from which it
originates. It takes a bit of practice and time to triangulate but does
work well. I'm sure there's other equipment and methods available as well.

http://www.mfjenterprises.com/Product.php?productid=MFJ-856

This is always a good item for a club to have and own for its members.

73
Bob, K4TAX

On 1/23/2016 1:06 PM, David Ahrendts wrote:
> A bit more: I watched this mystery QRM pretty closely for an hour Friday evening as 20 meters closed for the day (by 6:30pm PST). The cadence of this noise changed. It slowed. Then faded away with the band. I’m scratching my brain to try think of a mechanical device that would create that kind of rhythm. And as always as I check 20 meters at 11am Saturday, there is no sign of the QRM.
> Will listen again late afternoon today. May experiment moving the DB-11 around to see if it is directional.
>

______________________________________________________________
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Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

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Bob McGraw - K4TAX

Re: Fwd: OT Mystery QRM Help (Video)

Usually electrical noise is very broad band in nature. I use the MFJ
unit to find the general direction, triangulate to an area, and then
using a 24" reflector type microphone, equipped with a high gain audio
amp and headphones, go "listening to poles". {Yea the neighbors think
I'm crazy, but so what.} You can actually hear the arcing at connectors
for conductors, ground arcing or insulators arcing. I've even stood on
the ground with the crew from the power company and identified the exact
connector which is loose. Another handy item is an infrared
thermometer. A hot spot is likely a problem spot. This works to scan
ones breaker panel as well.

If the noise is inside a building or house, proceed with caution. Dogs
bite and occupants may shoot first.

If the noise is from a device oscillating this is more frequency
selective and a bit more of a challenge to find and isolate.

73
Bob, K4TAX

On 1/23/2016 4:29 PM, [hidden email] wrote:

> Yes, but David says, "only occurs on 20M", so this may not hear it at
> 135MHz? Need portable like KX3 and small mag loop tuned to 20M.
>
>
> On Saturday, January 23, 2016 2:14 PM, Bob McGraw K4TAX
> <[hidden email]> wrote:
>
>
> If one is serious about finding noise, I've found this item to go a long
> way in identifying down to the building or site from which it
> originates. It takes a bit of practice and time to triangulate but does
> work well. I'm sure there's other equipment and methods available as
> well.
>
> http://www.mfjenterprises.com/Product.php?productid=MFJ-856
>
> This is always a good item for a club to have and own for its members.
>
> 73
> Bob, K4TAX
>
> On 1/23/2016 1:06 PM, David Ahrendts wrote:
> > A bit more: I watched this mystery QRM pretty closely for an hour
> Friday evening as 20 meters closed for the day (by 6:30pm PST). The
> cadence of this noise changed. It slowed. Then faded away with the
> band. I’m scratching my brain to try think of a mechanical device that
> would create that kind of rhythm. And as always as I check 20 meters
> at 11am Saturday, there is no sign of the QRM.
> > Will listen again late afternoon today. May experiment moving the
> DB-11 around to see if it is directional.
> >
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email] <mailto:[hidden email]>
>
> This list hosted by: http://www.qsl.net/
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email] <mailto:[hidden email]>
>
>