From r55stan at gmail.com  Wed Sep  4 14:50:10 2019
From: r55stan at gmail.com (r55stan at gmail.com)
Date: Wed, 4 Sep 2019 11:50:10 -0700
Subject: [RFI] SolarEdge Solar Panel RFI Update
In-Reply-To: <26de4934-5c65-97f2-9cfe-f9cc9f16c5dd@optonline.net>
References: <1112899013.1024461.1566600334305.ref@mail.yahoo.com>	<1112899013.1024461.1566600334305@mail.yahoo.com>	<CA+z+1iwcw9QOqwRbppgJyhO5bafoTxs4MJ3Z+9F7V-AxYJoMbg@mail.gmail.com>
	<26de4934-5c65-97f2-9cfe-f9cc9f16c5dd@optonline.net>
Message-ID: <020801d56351$9463ffe0$bd2bffa0$@gmail.com>

Hi Tony,

The SolarEdge optimizer I tested was Model P320.  If other members of this
list want to see the spectrum plot I measured, feel free to send me an email
and I will send it to you (the list bounced it when I sent an embedded
jpeg).

A comment regarding high RFI levels after SolarEdge comes out and "fixes" a
neighbor's installation is they may have missed one or more optimizers.
Even one optimizer without ferrites will radiate a lot of RFI.  SolarEdge
had to come out four times for one of my neighbors until they finally
filtered every optimizer.

 

73,

 

Randy, KQ6RS

 

 

-----Original Message-----
From: RFI <rfi-bounces at contesting.com> On Behalf Of Tony
Sent: Thursday, August 29, 2019 1:33 PM
To: Rfi List <rfi at contesting.com>
Subject: Re: [RFI] SolarEdge Solar Panel RFI Update

 

On 8/23/2019 7:50 PM, Randy Standke wrote:

> I picked up a SolarEdge optimizer on eBay and fed it with a power supply
in place of a solar panel.  Even though it was in idle mode, on a spectrum
analyzer I saw the same RFI that I see on the air.

 

Randy:

 

Would you happen to have the model number of that eBay Optimzer? I spoke to
one of the SolarEdge field techs today and he said there's a "quiet" 

model SP350 that they install whenever they receive an RFI complaint.

 

This is the same model they used to replace the optimizers on my neighbors
installation in 2017 which did little to reduce the noise.

 

Tony -K2MO

 

_______________________________________________

RFI mailing list

 <mailto:RFI at contesting.com> RFI at contesting.com

 <http://lists.contesting.com/mailman/listinfo/rfi>
http://lists.contesting.com/mailman/listinfo/rfi


From k4sbz.stan at gmail.com  Wed Sep  4 18:19:54 2019
From: k4sbz.stan at gmail.com (Stan Zawrotny)
Date: Wed, 4 Sep 2019 18:19:54 -0400
Subject: [RFI] Canadian Solar
Message-ID: <CAPPCcb7Tc99Py4z7KbbMSb5CQTZph3LeQJkVY63on+j8iCB1EA@mail.gmail.com>

My son-in-law, who owns the house that I live in, has received a quote for
a solar installation for our house. "This system would use 74, 300 watt
mono-crystalline panels from Canadian Solar, and 74 grid tied IQ7
micro-inverters from Enphase." Does anyone have any experience with
Canadian Solar panels or  IQ7 micro-inverters from Enphase?
___________________
Stan , K4SBZ

From dana.roode at gmail.com  Thu Sep 19 15:12:41 2019
From: dana.roode at gmail.com (Dana Roode K6NR)
Date: Thu, 19 Sep 2019 12:12:41 -0700
Subject: [RFI] Name that Noise
Message-ID: <CAEhu_sy4D8fxkzLyihomPTppJ4Qk1=EV6xB5s+N9V4oCrvu8Gg@mail.gmail.com>

I reviewed some of my postings to RFI over the years, and am reminded that
my QRN is not new.  Back in 2010 I wrote about the easterly noise that is a
problem on 20 meters, getting worse in the afternoons.  I've never tracked
that down, its hard to locate when I get in the car.

My bigger problem is a dreaded 40m noise from the South; that is coming
from a group of houses about 1200 ft away.  Earlier this week I was
orienting a Pixel loop antenna to null the noise and made the following
video of my KX2 as I tuned through the band:

https://drive.google.com/open?id=1haecP3Dvz-sckJj7V4GPhAK3DVj74dUR

Its AM, and there is some wind noise you have to ignore.  The signal is
strongest around 7mhz, peaking every 300khz or so.  Its weaker at 10mhz,
and even weaker at 14mhz.  I think I hear it at 3.5 but there is lots of
other QRN to hear as well.

Any thoughts on what this is?  A friend traced it once to a house with an
electric fence, but I wouldn't think those would have peaks ever 300khz.

  Dana

From jim at audiosystemsgroup.com  Thu Sep 19 15:25:02 2019
From: jim at audiosystemsgroup.com (Jim Brown)
Date: Thu, 19 Sep 2019 12:25:02 -0700
Subject: [RFI] Name that Noise
In-Reply-To: <CAEhu_sy4D8fxkzLyihomPTppJ4Qk1=EV6xB5s+N9V4oCrvu8Gg@mail.gmail.com>
References: <CAEhu_sy4D8fxkzLyihomPTppJ4Qk1=EV6xB5s+N9V4oCrvu8Gg@mail.gmail.com>
Message-ID: <b7e4ddbd-9baf-ccff-80a1-6fcf9c5d4d13@audiosystemsgroup.com>

The most useful footprint for noise is its RF spectrum with a waterfall. 
See my applications notes on the topic at k9yc.com  Also, see NK7Z's 
excellent work on his website.

73, Jim K9YC

On 9/19/2019 12:12 PM, Dana Roode K6NR wrote:
> Its AM, and there is some wind noise you have to ignore.


From gwj at wb9jps.com  Fri Sep 20 14:44:40 2019
From: gwj at wb9jps.com (Gary Johnson)
Date: Fri, 20 Sep 2019 11:44:40 -0700
Subject: [RFI] Name that Noise
In-Reply-To: <mailman.5.1568995202.12177.rfi@contesting.com>
References: <mailman.5.1568995202.12177.rfi@contesting.com>
Message-ID: <A21A0403-498E-466C-B115-4380507B045D@wb9jps.com>

I think you?ll need to walk around with a DFing loop and try to triangulate the source. There is a design on my RFI pages that would work nicely with your KX2. http://wb9jps.com/Gary_Johnson/RFI_files/Handheld_DF_Antenna.pdf <http://wb9jps.com/Gary_Johnson/RFI_files/Handheld_DF_Antenna.pdf> 

Offhand, it sounds like it has some modulation on it that makes me think it?s not just a simple switching supply (e.g., a lighting device) but rather something associated with a more complex system. For instance, the SolarEdge system next door sounds a bit like that because it?s leakage from their control signals. But who knows...

-Gary NA6O

> Date: Thu, 19 Sep 2019 12:12:41 -0700
> From: Dana Roode K6NR <dana.roode at gmail.com>
> To: rfi at contesting.com
> Subject: [RFI] Name that Noise
> 
> My bigger problem is a dreaded 40m noise from the South; that is coming
> from a group of houses about 1200 ft away.  Earlier this week I was
> orienting a Pixel loop antenna to null the noise and made the following
> video of my KX2 as I tuned through the band:
> 
> Its AM, and there is some wind noise you have to ignore.  The signal is
> strongest around 7mhz, peaking every 300khz or so.  Its weaker at 10mhz,
> and even weaker at 14mhz.  I think I hear it at 3.5 but there is lots of
> other QRN to hear as well.
> 
> Any thoughts on what this is?  A friend traced it once to a house with an
> electric fence, but I wouldn't think those would have peaks ever 300khz.
> 
>  Dana
> 


From dana.roode at gmail.com  Fri Sep 27 15:07:37 2019
From: dana.roode at gmail.com (Dana Roode K6NR)
Date: Fri, 27 Sep 2019 12:07:37 -0700
Subject: [RFI] Name that Noise - K6NR Victorville Receive Interference
In-Reply-To: <CAEhu_sy4D8fxkzLyihomPTppJ4Qk1=EV6xB5s+N9V4oCrvu8Gg@mail.gmail.com>
References: <CAEhu_sy4D8fxkzLyihomPTppJ4Qk1=EV6xB5s+N9V4oCrvu8Gg@mail.gmail.com>
Message-ID: <CAEhu_sysEMiJTfYt_zUaSF4=1uQKCX5Q-XiX7bz9PdtjdwVAVA@mail.gmail.com>

Greetings RFI folks,

Richard, K6RBS, and I have done some additional investigating of my receive
interference described in this thread.  I have summarized everything in
this google doc:

https://docs.google.com/document/d/1k9-XJLehKoATtCEtdRMa-fkRkQtLds3VKu68KxrPWiI/edit?usp=sharing

The doc has links to SDR graphs and sound files.  I have two
persistent noise sources, at least.  The southerly one we have DF'd and
tracked south of me to one of two houses.  We found the electrical pole
where it is the strongest.  However, I am no expert, but the nature of the
noise may suggest a switching power supply or other device and not
electrical power lines.  You tell me.  It *amazingly* well wipes out 40
meters, as if it had been designed to do so.  And just for fun, has a wide
range of artifacts below and well above.  On AM it is a pulsating buzz
sound.

I have submitted a trouble ticket with Southern California Edison to verify
its not them, perhaps help with contracting the residents, and hopefully to
look at my second, easterly noise.  I have also reached out to the
residents at the two homes, but they are surrounded by locked fences so I
am starting by writing them letters.

The easterly noise I reported here in 2010, sounds like static crashes, but
is on pretty much every day.  There are intermittent noises as well, but I
will get to them if we make progress on these two.

I used a Alex Loop to get bearings on the southerly noise; its so strong
that it was not hard.  I am not able to hear the easterly noise on the Alex
Loop from my house, I will have to drive around more to see if I can locate
it.  I will also do some SDR graphs of it when I get a chance.

     Dana, K6NR


On Thu, Sep 19, 2019 at 12:12 PM Dana Roode K6NR <dana.roode at gmail.com>
wrote:

> I reviewed some of my postings to RFI over the years, and am reminded that
> my QRN is not new.  Back in 2010 I wrote about the easterly noise that is a
> problem on 20 meters, getting worse in the afternoons.  I've never tracked
> that down, its hard to locate when I get in the car.
>
> My bigger problem is a dreaded 40m noise from the South; that is coming
> from a group of houses about 1200 ft away.  Earlier this week I was
> orienting a Pixel loop antenna to null the noise and made the following
> video of my KX2 as I tuned through the band:
>
> https://drive.google.com/open?id=1haecP3Dvz-sckJj7V4GPhAK3DVj74dUR
>
> Its AM, and there is some wind noise you have to ignore.  The signal is
> strongest around 7mhz, peaking every 300khz or so.  Its weaker at 10mhz,
> and even weaker at 14mhz.  I think I hear it at 3.5 but there is lots of
> other QRN to hear as well.
>
> Any thoughts on what this is?  A friend traced it once to a house with an
> electric fence, but I wouldn't think those would have peaks ever 300khz.
>
>   Dana
>
>

From jim at audiosystemsgroup.com  Fri Sep 27 15:19:34 2019
From: jim at audiosystemsgroup.com (Jim Brown)
Date: Fri, 27 Sep 2019 12:19:34 -0700
Subject: [RFI] Name that Noise - K6NR Victorville Receive Interference
In-Reply-To: <CAEhu_sysEMiJTfYt_zUaSF4=1uQKCX5Q-XiX7bz9PdtjdwVAVA@mail.gmail.com>
References: <CAEhu_sy4D8fxkzLyihomPTppJ4Qk1=EV6xB5s+N9V4oCrvu8Gg@mail.gmail.com>
	<CAEhu_sysEMiJTfYt_zUaSF4=1uQKCX5Q-XiX7bz9PdtjdwVAVA@mail.gmail.com>
Message-ID: <52fcea58-adeb-2242-e4e6-7d6a960f073c@audiosystemsgroup.com>

On 9/27/2019 12:07 PM, Dana Roode K6NR wrote:
> The doc has links to SDR graphs and sound files.

I'll repeat my advice to use NK7Z's LONG and BROAD waterfall 
observations of the sources.

73, Jim K9YC

From matt at nq6n.com  Sun Sep 29 22:00:27 2019
From: matt at nq6n.com (Matt NQ6N)
Date: Sun, 29 Sep 2019 21:00:27 -0500
Subject: [RFI] tips for finding the source of broadband mixing products
Message-ID: <CANth69isB9oyvEgW3dNzCMhL_9dPb=aAiznxZF+8UPzEKYWCrw@mail.gmail.com>

Hello,

I'm noticing that the second harmonic of my transmitted signal is
accompanied by all sorts of broadband noise.

I am in the process of ruling out the equipment inside the shack as a cause
of this noise.

But I want to be prepared to begin the search outside the shack for things
(wall warts, etc.) that might be generating the broadband noise when
exposed to RF.

What are some techniques for localizing the causes of this kind of
broadband noise?

A screen shot of the pan adapter and a recording of the audio of the third
harmonic + noise is attached via the below link:

https://www.dropbox.com/sh/2639h09dhr8qxkf/AADr4-Nl4GS7e-Cl3TKSuq5aa?dl=0

Any advice would be much appreciated.

73,
Matt NQ6N

From jim at audiosystemsgroup.com  Sun Sep 29 22:48:23 2019
From: jim at audiosystemsgroup.com (Jim Brown)
Date: Sun, 29 Sep 2019 19:48:23 -0700
Subject: [RFI] tips for finding the source of broadband mixing products
In-Reply-To: <CANth69isB9oyvEgW3dNzCMhL_9dPb=aAiznxZF+8UPzEKYWCrw@mail.gmail.com>
References: <CANth69isB9oyvEgW3dNzCMhL_9dPb=aAiznxZF+8UPzEKYWCrw@mail.gmail.com>
Message-ID: <bbbada51-97be-84c5-4f7e-8a662827a0fc@audiosystemsgroup.com>

On 9/29/2019 7:00 PM, Matt NQ6N wrote:
> Hello,
> 
> I'm noticing that the second harmonic of my transmitted signal is
> accompanied by all sorts of broadband noise.
> 
> I am in the process of ruling out the equipment inside the shack as a cause
> of this noise.
> 
> But I want to be prepared to begin the search outside the shack for things
> (wall warts, etc.) that might be generating the broadband noise when
> exposed to RF.
> 
> What are some techniques for localizing the causes of this kind of
> broadband noise?

Hi Matt,

As with any source, try to use antenna directivity. Transmit on a 
directional antenna that excites it and listen on another RX to see 
where it peaks. Use the minimum antenna on the RX that hears the 
product. Likewise, use a portable RX, again with minimal antenna, to DF 
the source. My app note and slide set on the topic of chasing RX noise 
lists several useful candidates.

W3LPL has observed that mixing products often occur within antenna 
rotators.

73, Jim K9YC

From jwin95 at yahoo.com  Sun Sep 29 22:48:47 2019
From: jwin95 at yahoo.com (JW)
Date: Mon, 30 Sep 2019 02:48:47 +0000 (UTC)
Subject: [RFI] tips for finding the source of broadband mixing products
In-Reply-To: <CANth69isB9oyvEgW3dNzCMhL_9dPb=aAiznxZF+8UPzEKYWCrw@mail.gmail.com>
References: <CANth69isB9oyvEgW3dNzCMhL_9dPb=aAiznxZF+8UPzEKYWCrw@mail.gmail.com>
Message-ID: <1087360026.746283.1569811727104@mail.yahoo.com>

 How are you determining all this - you do realize, in close proximity to
a transmitting rig, much (albeit low-level) RF comes straight out the 
power leads and can 'modulate'/be modulated by the power supply 
energy that also escapes, including simple rectifier supplies using only 
diodes?

We demonstrated this at Heathkit several different ways, including using
a spectrum analyzer to 'sniff' the stray RF coming back out via the radio's 
power cable WHICH in turn was modulated and showed 120 Hz sidebands ...

de AA5CT 

     On Sunday, September 29, 2019, 9:00:49 PM GMT-5, Matt NQ6N <matt at nq6n.com> wrote:  
 
 Hello,

I'm noticing that the second harmonic of my transmitted signal is
accompanied by all sorts of broadband noise.

I am in the process of ruling out the equipment inside the shack as a cause
of this noise.

But I want to be prepared to begin the search outside the shack for things
(wall warts, etc.) that might be generating the broadband noise when
exposed to RF.

What are some techniques for localizing the causes of this kind of
broadband noise?

A screen shot of the pan adapter and a recording of the audio of the third
harmonic + noise is attached via the below link:

https://www.dropbox.com/sh/2639h09dhr8qxkf/AADr4-Nl4GS7e-Cl3TKSuq5aa?dl=0

Any advice would be much appreciated.

73,
Matt NQ6N
_______________________________________________
RFI mailing list
RFI at contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
  

From jim at audiosystemsgroup.com  Sun Sep 29 23:28:44 2019
From: jim at audiosystemsgroup.com (Jim Brown)
Date: Sun, 29 Sep 2019 20:28:44 -0700
Subject: [RFI] tips for finding the source of broadband mixing products
In-Reply-To: <1087360026.746283.1569811727104@mail.yahoo.com>
References: <CANth69isB9oyvEgW3dNzCMhL_9dPb=aAiznxZF+8UPzEKYWCrw@mail.gmail.com>
	<1087360026.746283.1569811727104@mail.yahoo.com>
Message-ID: <7f7d7ad8-c602-19f0-17a0-2e187e15dafb@audiosystemsgroup.com>

On 9/29/2019 7:48 PM, JW via RFI wrote:
> How are you determining all this - you do realize, in close proximity to
> a transmitting rig, much (albeit low-level) RF comes straight out the
> power leads 

If that happens, there are errors in design and/or construction.

and can 'modulate'/be modulated by the power supply
> energy that also escapes, including simple rectifier supplies using only
> diodes?

Ingress/egress is a linear function, and depends strongly on details of 
both design and construction. Nearly all modern equipment fails to 
terminate cable shields and power green wires properly. They SHOULD go 
the the shielding enclosure (chassis), but they nearly always go first 
to the circuit board, THEN eventually find the chassis after wandering 
around return circuitry for a while. This equipment flaw, first 
discovered by a ham working in pro audio, is called "The Pin One 
Problem," because the designated shield contact of the connector 
commonly used for balanced audio circuits is Pin 1.

The method in which equipment is built usually makes it impractical to 
correct these design errors, so the best fix is a serious common mode 
choke on the cable(s) involved. And because the ingress/egress is via 
the green wire or the cable shield, conventional line filters are 
useless UNLESS they are internal, and with their shielding enclosure 
bonding the green wire to the equipment shielding enclosure! They treat 
only the differential voltage and current between phase and neutral, 
phase and ground, and neutral and ground.

The only effect of signal strength is on the strength of the mixing 
products.
> 
> We demonstrated this at Heathkit several different ways, including using
> a spectrum analyzer to 'sniff' the stray RF coming back out via the radio's
> power cable WHICH in turn was modulated and showed 120 Hz sidebands ...

So you added an AC line filter with its shielded enclosure bonded to the 
chassis, right? THAT would work.

73, Jim K9YC


From k7tjr at msn.com  Mon Sep 30 01:24:11 2019
From: k7tjr at msn.com (Lee STRAHAN)
Date: Mon, 30 Sep 2019 05:24:11 +0000
Subject: [RFI] tips for finding the source of broadband mixing products
In-Reply-To: <CANth69isB9oyvEgW3dNzCMhL_9dPb=aAiznxZF+8UPzEKYWCrw@mail.gmail.com>
References: <CANth69isB9oyvEgW3dNzCMhL_9dPb=aAiznxZF+8UPzEKYWCrw@mail.gmail.com>
Message-ID: <MWHPR05MB2816C035AFEC94C6EEBF2686F5820@MWHPR05MB2816.namprd05.prod.outlook.com>

  Hi Matt,
   It looks and sounds to me like you are simply overloading the SDR receiver and generating the spurs and noise inside it. What level of the fundamental signal is actually being applied to the SDR? I am guessing the largest pip shown is the third harmonic you refer to. 
   One way to find out is to lower the transmitter power by 10 dBm of the transmitted signal. If the spurs go down by more than 10 dBm they are most likely being generated inside the SDR receiver by simply too much signal overload. You may be chasing a ghost. If the screen shot is really the third harmonic at 14 MHz why are you transmitting on 14/3 or 4.67 MHz?
    Any way lower the signal into the SDR and find out if the problem spurs go away. I think you are simply overloading the SDR with way too much signal.
  Lee   K7TJR   OR 

-----Original Message-----
From: RFI <rfi-bounces at contesting.com> On Behalf Of Matt NQ6N
Sent: Sunday, September 29, 2019 7:00 PM
To: rfi at contesting.com
Subject: [RFI] tips for finding the source of broadband mixing products

Hello,

I'm noticing that the second harmonic of my transmitted signal is accompanied by all sorts of broadband noise.

I am in the process of ruling out the equipment inside the shack as a cause of this noise.

But I want to be prepared to begin the search outside the shack for things (wall warts, etc.) that might be generating the broadband noise when exposed to RF.

What are some techniques for localizing the causes of this kind of broadband noise?

A screen shot of the pan adapter and a recording of the audio of the third harmonic + noise is attached via the below link:

https://www.dropbox.com/sh/2639h09dhr8qxkf/AADr4-Nl4GS7e-Cl3TKSuq5aa?dl=0

Any advice would be much appreciated.

73,
Matt NQ6N
_______________________________________________
RFI mailing list
RFI at contesting.com
http://lists.contesting.com/mailman/listinfo/rfi

From jim at audiosystemsgroup.com  Mon Sep 30 02:10:42 2019
From: jim at audiosystemsgroup.com (Jim Brown)
Date: Sun, 29 Sep 2019 23:10:42 -0700
Subject: [RFI] tips for finding the source of broadband mixing products
In-Reply-To: <MWHPR05MB2816C035AFEC94C6EEBF2686F5820@MWHPR05MB2816.namprd05.prod.outlook.com>
References: <CANth69isB9oyvEgW3dNzCMhL_9dPb=aAiznxZF+8UPzEKYWCrw@mail.gmail.com>
	<MWHPR05MB2816C035AFEC94C6EEBF2686F5820@MWHPR05MB2816.namprd05.prod.outlook.com>
Message-ID: <82c2184c-06c6-f76f-9a71-19c6f7731b67@audiosystemsgroup.com>

On 9/29/2019 10:24 PM, Lee STRAHAN wrote:
>   It looks and sounds to me like you are simply overloading the SDR receiver

If it's an SDR, this makes lots of sense!

73, Jim K9YC

From hs0zed at gmail.com  Mon Sep 30 05:17:19 2019
From: hs0zed at gmail.com (Martin Sole)
Date: Mon, 30 Sep 2019 16:17:19 +0700
Subject: [RFI] tips for finding the source of broadband mixing products
In-Reply-To: <MWHPR05MB2816C035AFEC94C6EEBF2686F5820@MWHPR05MB2816.namprd05.prod.outlook.com>
References: <CANth69isB9oyvEgW3dNzCMhL_9dPb=aAiznxZF+8UPzEKYWCrw@mail.gmail.com>
	<MWHPR05MB2816C035AFEC94C6EEBF2686F5820@MWHPR05MB2816.namprd05.prod.outlook.com>
Message-ID: <f82f2a65-f2b6-3ba9-b109-39f040a1f02d@gmail.com>

Definitely a possibility the SDR is in overload. A 10dB attenuator on 
the front will soon show if that is the case or not. If its an SDR 
amateur radio transceiver hopefully that's built in. If you use one of 
the lower end simple direct sampling boxes like an SDR play, investment 
in a stepped attenuator and perhaps a tunable preselector are both very 
worthwhile if not vital additions.

Martin, HS0ZED



On 30/09/2019 12:24, Lee STRAHAN wrote:
>    Hi Matt,
>     It looks and sounds to me like you are simply overloading the SDR receiver and generating the spurs and noise inside it. What level of the fundamental signal is actually being applied to the SDR? I am guessing the largest pip shown is the third harmonic you refer to.
>     One way to find out is to lower the transmitter power by 10 dBm of the transmitted signal. If the spurs go down by more than 10 dBm they are most likely being generated inside the SDR receiver by simply too much signal overload. You may be chasing a ghost. If the screen shot is really the third harmonic at 14 MHz why are you transmitting on 14/3 or 4.67 MHz?
>      Any way lower the signal into the SDR and find out if the problem spurs go away. I think you are simply overloading the SDR with way too much signal.
>    Lee   K7TJR   OR
>
> -----Original Message-----
> From: RFI <rfi-bounces at contesting.com> On Behalf Of Matt NQ6N
> Sent: Sunday, September 29, 2019 7:00 PM
> To: rfi at contesting.com
> Subject: [RFI] tips for finding the source of broadband mixing products
>
> Hello,
>
> I'm noticing that the second harmonic of my transmitted signal is accompanied by all sorts of broadband noise.
>
> I am in the process of ruling out the equipment inside the shack as a cause of this noise.
>
> But I want to be prepared to begin the search outside the shack for things (wall warts, etc.) that might be generating the broadband noise when exposed to RF.
>
> What are some techniques for localizing the causes of this kind of broadband noise?
>
> A screen shot of the pan adapter and a recording of the audio of the third harmonic + noise is attached via the below link:
>
> https://www.dropbox.com/sh/2639h09dhr8qxkf/AADr4-Nl4GS7e-Cl3TKSuq5aa?dl=0
>
> Any advice would be much appreciated.
>
> 73,
> Matt NQ6N
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi


From jwin95 at yahoo.com  Mon Sep 30 07:35:36 2019
From: jwin95 at yahoo.com (JW)
Date: Mon, 30 Sep 2019 11:35:36 +0000 (UTC)
Subject: [RFI] tips for finding the source of broadband mixing products
In-Reply-To: <7f7d7ad8-c602-19f0-17a0-2e187e15dafb@audiosystemsgroup.com>
References: <CANth69isB9oyvEgW3dNzCMhL_9dPb=aAiznxZF+8UPzEKYWCrw@mail.gmail.com>
	<1087360026.746283.1569811727104@mail.yahoo.com>
	<7f7d7ad8-c602-19f0-17a0-2e187e15dafb@audiosystemsgroup.com>
Message-ID: <597978595.840422.1569843336033@mail.yahoo.com>

 re: "If that happens, there are errors in design and/or construction."

50 or 60 dB down?

Pshaw.

de AA5CT

PS 50 dB down can STILL be quite receivable WHEN the rig is operated into a 
dummy load. It's WHY operators often think their equipment is faulty IF they 
don't sample the RF coming out the antenna port but rather just 'listen' with
another rig nearby connected to an antenna or just a piece of wire.

One of the rigs we demonstrated this on was an old Collins tube-type radio too ...

These 'things' are easily demonstrable, Jim Brown. Surprised you have _not_ 
encountered it.
     On Sunday, September 29, 2019, 10:28:53 PM GMT-5, Jim Brown <jim at audiosystemsgroup.com> wrote:  
 
 On 9/29/2019 7:48 PM, JW via RFI wrote:
> How are you determining all this - you do realize, in close proximity to
> a transmitting rig, much (albeit low-level) RF comes straight out the
> power leads 

If that happens, there are errors in design and/or construction.

and can 'modulate'/be modulated by the power supply
> energy that also escapes, including simple rectifier supplies using only
> diodes?

Ingress/egress is a linear function, and depends strongly on details of 
both design and construction. Nearly all modern equipment fails to 
terminate cable shields and power green wires properly. They SHOULD go 
the the shielding enclosure (chassis), but they nearly always go first 
to the circuit board, THEN eventually find the chassis after wandering 
around return circuitry for a while. This equipment flaw, first 
discovered by a ham working in pro audio, is called "The Pin One 
Problem," because the designated shield contact of the connector 
commonly used for balanced audio circuits is Pin 1.

The method in which equipment is built usually makes it impractical to 
correct these design errors, so the best fix is a serious common mode 
choke on the cable(s) involved. And because the ingress/egress is via 
the green wire or the cable shield, conventional line filters are 
useless UNLESS they are internal, and with their shielding enclosure 
bonding the green wire to the equipment shielding enclosure! They treat 
only the differential voltage and current between phase and neutral, 
phase and ground, and neutral and ground.

The only effect of signal strength is on the strength of the mixing 
products.
> 
> We demonstrated this at Heathkit several different ways, including using
> a spectrum analyzer to 'sniff' the stray RF coming back out via the radio's
> power cable WHICH in turn was modulated and showed 120 Hz sidebands ...

So you added an AC line filter with its shielded enclosure bonded to the 
chassis, right? THAT would work.

73, Jim K9YC

_______________________________________________
RFI mailing list
RFI at contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
  

From matt at nq6n.com  Mon Sep 30 12:26:46 2019
From: matt at nq6n.com (Matt NQ6N)
Date: Mon, 30 Sep 2019 11:26:46 -0500
Subject: [RFI] tips for finding the source of broadband mixing products
In-Reply-To: <597978595.840422.1569843336033@mail.yahoo.com>
References: <CANth69isB9oyvEgW3dNzCMhL_9dPb=aAiznxZF+8UPzEKYWCrw@mail.gmail.com>
	<1087360026.746283.1569811727104@mail.yahoo.com>
	<7f7d7ad8-c602-19f0-17a0-2e187e15dafb@audiosystemsgroup.com>
	<597978595.840422.1569843336033@mail.yahoo.com>
Message-ID: <CANth69hXxdVSmipeUNqgQeeyU4rW3g8wKXazyzkkrw2A3KqyOQ@mail.gmail.com>

I'll add a bit more information.  Thanks much for the suggestions so far:


- The rig is a Flex 6600 SDR transmitting 1 Watt.  There is a Morgan
Manufacturing 40m bandpass filter (I measured it as having 28 db of
attenuation at 14 MHz) between the rig and amp (which is in standby) and
also a VA6AM high power 40m bandpass filter (air coil version with claimed
performance of -70 db at 14 MHz) after the amplifier.

- The TX antenna is an inverted vee in the back yard, and the RX antenna is
an inverted L in the front yard.  So only about 50' of physical separation
of omnidirectional antennas, but lots of BPF filtering and low TX power.

- Completely disconnecting the RX antenna weakens the second harmonic
signal quite a lot and makes the note sound like a pure sine wave, but it
could be that I am not hearing the IMD products when the signal is so much
weaker.

- I had a typo in my original message. It was the second harmonic. I'd just
been listening to the third harmonic when I hastily typed my message, and
didn't notice before hitting send.

- I'll be onsite today with a spectrum analyzer, so any tips on things to
measure would be helpful.  Just wanted to update the thread with the above
info.

73,
Matt NQ6N




On Mon, Sep 30, 2019 at 6:35 AM JW via RFI <rfi at contesting.com> wrote:

>  re: "If that happens, there are errors in design and/or construction."
>
> 50 or 60 dB down?
>
> Pshaw.
>
> de AA5CT
>
> PS 50 dB down can STILL be quite receivable WHEN the rig is operated into
> a
> dummy load. It's WHY operators often think their equipment is faulty IF
> they
> don't sample the RF coming out the antenna port but rather just 'listen'
> with
> another rig nearby connected to an antenna or just a piece of wire.
>
> One of the rigs we demonstrated this on was an old Collins tube-type radio
> too ...
>
> These 'things' are easily demonstrable, Jim Brown. Surprised you have
> _not_
> encountered it.
>      On Sunday, September 29, 2019, 10:28:53 PM GMT-5, Jim Brown <
> jim at audiosystemsgroup.com> wrote:
>
>  On 9/29/2019 7:48 PM, JW via RFI wrote:
> > How are you determining all this - you do realize, in close proximity to
> > a transmitting rig, much (albeit low-level) RF comes straight out the
> > power leads
>
> If that happens, there are errors in design and/or construction.
>
> and can 'modulate'/be modulated by the power supply
> > energy that also escapes, including simple rectifier supplies using only
> > diodes?
>
> Ingress/egress is a linear function, and depends strongly on details of
> both design and construction. Nearly all modern equipment fails to
> terminate cable shields and power green wires properly. They SHOULD go
> the the shielding enclosure (chassis), but they nearly always go first
> to the circuit board, THEN eventually find the chassis after wandering
> around return circuitry for a while. This equipment flaw, first
> discovered by a ham working in pro audio, is called "The Pin One
> Problem," because the designated shield contact of the connector
> commonly used for balanced audio circuits is Pin 1.
>
> The method in which equipment is built usually makes it impractical to
> correct these design errors, so the best fix is a serious common mode
> choke on the cable(s) involved. And because the ingress/egress is via
> the green wire or the cable shield, conventional line filters are
> useless UNLESS they are internal, and with their shielding enclosure
> bonding the green wire to the equipment shielding enclosure! They treat
> only the differential voltage and current between phase and neutral,
> phase and ground, and neutral and ground.
>
> The only effect of signal strength is on the strength of the mixing
> products.
> >
> > We demonstrated this at Heathkit several different ways, including using
> > a spectrum analyzer to 'sniff' the stray RF coming back out via the
> radio's
> > power cable WHICH in turn was modulated and showed 120 Hz sidebands ...
>
> So you added an AC line filter with its shielded enclosure bonded to the
> chassis, right? THAT would work.
>
> 73, Jim K9YC
>
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>

From k7tjr at msn.com  Mon Sep 30 13:08:15 2019
From: k7tjr at msn.com (Lee STRAHAN)
Date: Mon, 30 Sep 2019 17:08:15 +0000
Subject: [RFI] tips for finding the source of broadband mixing products
Message-ID: <MWHPR05MB2816D9C0496A936A09C5686BF5820@MWHPR05MB2816.namprd05.prod.outlook.com>




Hi Matt,
   Thanks for the additional information. Even though you are filtering the harmonics from the source transmitter the SDR if overloaded will generate its own level of harmonics. Please be very careful if you use a spectrum analyzer and do NOT connect it to your antenna. There will possibly be enough energy on the RX antenna to burn out the front end of the spectrum analyzer. No need to ask me how I know this suffice to say building high level signal generators put out enough signal level to burn out the old HP spectrum analyzers. At the most a 4 inch piece of wire (maybe more length if needed) feeding into the analyzer with a close transmitter will yield plenty of signal for display. The best advice I can offer is to use a 20 dB pad on the input of the analyzer and leave it there. Unless of course the analyzer you use is rated for high levels of RF. Start with small signals and work your way up slowly paying close attention to the fundamental frequency level and not the harmonics for the maximum to connect to the analyzer.
Good luck and be careful.
Lee  K7TJR  OR

-----Original Message-----
From: RFI <rfi-bounces at contesting.com> On Behalf Of Matt NQ6N
Sent: Monday, September 30, 2019 9:27 AM
To: JW <jwin95 at yahoo.com>
Cc: rfi at contesting.com
Subject: Re: [RFI] tips for finding the source of broadband mixing products

I'll add a bit more information.  Thanks much for the suggestions so far:


- The rig is a Flex 6600 SDR transmitting 1 Watt.  There is a Morgan Manufacturing 40m bandpass filter (I measured it as having 28 db of attenuation at 14 MHz) between the rig and amp (which is in standby) and also a VA6AM high power 40m bandpass filter (air coil version with claimed performance of -70 db at 14 MHz) after the amplifier.

- The TX antenna is an inverted vee in the back yard, and the RX antenna is an inverted L in the front yard.  So only about 50' of physical separation of omnidirectional antennas, but lots of BPF filtering and low TX power.

- Completely disconnecting the RX antenna weakens the second harmonic signal quite a lot and makes the note sound like a pure sine wave, but it could be that I am not hearing the IMD products when the signal is so much weaker.

- I had a typo in my original message. It was the second harmonic. I'd just been listening to the third harmonic when I hastily typed my message, and didn't notice before hitting send.

- I'll be onsite today with a spectrum analyzer, so any tips on things to measure would be helpful.  Just wanted to update the thread with the above info.

73,
Matt NQ6N




On Mon, Sep 30, 2019 at 6:35 AM JW via RFI <rfi at contesting.com> wrote:

>  re: "If that happens, there are errors in design and/or construction."
>
> 50 or 60 dB down?
>
> Pshaw.
>
> de AA5CT
>
> PS 50 dB down can STILL be quite receivable WHEN the rig is operated 
> into a dummy load. It's WHY operators often think their equipment is 
> faulty IF they don't sample the RF coming out the antenna port but 
> rather just 'listen'
> with
> another rig nearby connected to an antenna or just a piece of wire.
>
> One of the rigs we demonstrated this on was an old Collins tube-type 
> radio too ...
>
> These 'things' are easily demonstrable, Jim Brown. Surprised you have 
> _not_ encountered it.
>      On Sunday, September 29, 2019, 10:28:53 PM GMT-5, Jim Brown < 
> jim at audiosystemsgroup.com> wrote:
>
>  On 9/29/2019 7:48 PM, JW via RFI wrote:
> > How are you determining all this - you do realize, in close 
> > proximity to a transmitting rig, much (albeit low-level) RF comes 
> > straight out the power leads
>
> If that happens, there are errors in design and/or construction.
>
> and can 'modulate'/be modulated by the power supply
> > energy that also escapes, including simple rectifier supplies using 
> > only diodes?
>
> Ingress/egress is a linear function, and depends strongly on details 
> of both design and construction. Nearly all modern equipment fails to 
> terminate cable shields and power green wires properly. They SHOULD go 
> the the shielding enclosure (chassis), but they nearly always go first 
> to the circuit board, THEN eventually find the chassis after wandering 
> around return circuitry for a while. This equipment flaw, first 
> discovered by a ham working in pro audio, is called "The Pin One 
> Problem," because the designated shield contact of the connector 
> commonly used for balanced audio circuits is Pin 1.
>
> The method in which equipment is built usually makes it impractical to 
> correct these design errors, so the best fix is a serious common mode 
> choke on the cable(s) involved. And because the ingress/egress is via 
> the green wire or the cable shield, conventional line filters are 
> useless UNLESS they are internal, and with their shielding enclosure 
> bonding the green wire to the equipment shielding enclosure! They 
> treat only the differential voltage and current between phase and 
> neutral, phase and ground, and neutral and ground.
>
> The only effect of signal strength is on the strength of the mixing 
> products.
> >
> > We demonstrated this at Heathkit several different ways, including 
> > using a spectrum analyzer to 'sniff' the stray RF coming back out 
> > via the
> radio's
> > power cable WHICH in turn was modulated and showed 120 Hz sidebands ...
>
> So you added an AC line filter with its shielded enclosure bonded to 
> the chassis, right? THAT would work.
>
> 73, Jim K9YC
>
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>
_______________________________________________
RFI mailing list
RFI at contesting.com
http://lists.contesting.com/mailman/listinfo/rfi

From matt at nq6n.com  Mon Sep 30 16:14:19 2019
From: matt at nq6n.com (Matt NQ6N)
Date: Mon, 30 Sep 2019 15:14:19 -0500
Subject: [RFI] tips for finding the source of broadband mixing products
In-Reply-To: <MWHPR05MB2816D9C0496A936A09C5686BF5820@MWHPR05MB2816.namprd05.prod.outlook.com>
References: <MWHPR05MB2816D9C0496A936A09C5686BF5820@MWHPR05MB2816.namprd05.prod.outlook.com>
Message-ID: <CANth69gTf_1UFTRrT=ftJvsehvjOchFwNyQrFwn0GB8sbb+hhA@mail.gmail.com>

Thanks for the tips on not destroying the spectrum analyzer, Lee!  And
thanks to everyone. I will be putting together an RDF setup for localizing
noise but I wanted to share the spectrum plot of the TX signal (the antenna
is connected directly to the rig with no additional BPFs inline):

The link below shows the peak fundamental and harmonics. The second
harmonic is down less than 20 dB from the fundamental. I'm not sure if this
is within spec or not and wlil contact Flex to verify.  The antenna SWR is
about 1.5:1 and using the built-in ATU does not seem to change the result
all that much.

Question: Is there any benefit to running the same test transmitting into a
dummy load and sampling the RF via a directional coupler rather than the
short piece of wire "antenna"?

https://www.dropbox.com/s/ixde7dou0uga5mj/100w_peaks_no_atu.jpg?dl=0

(and with the ATU)

https://www.dropbox.com/s/2bgip59493qa6og/100w_peaks_with_atu.jpg?dl=0

Interpretation and advice is much appreciated.

73,
Matt NQ6N


On Mon, Sep 30, 2019 at 12:08 PM Lee STRAHAN <k7tjr at msn.com> wrote:

>
>
>
> Hi Matt,
>    Thanks for the additional information. Even though you are filtering
> the harmonics from the source transmitter the SDR if overloaded will
> generate its own level of harmonics. Please be very careful if you use a
> spectrum analyzer and do NOT connect it to your antenna. There will
> possibly be enough energy on the RX antenna to burn out the front end of
> the spectrum analyzer. No need to ask me how I know this suffice to say
> building high level signal generators put out enough signal level to burn
> out the old HP spectrum analyzers. At the most a 4 inch piece of wire
> (maybe more length if needed) feeding into the analyzer with a close
> transmitter will yield plenty of signal for display. The best advice I can
> offer is to use a 20 dB pad on the input of the analyzer and leave it
> there. Unless of course the analyzer you use is rated for high levels of
> RF. Start with small signals and work your way up slowly paying close
> attention to the fundamental frequency level and not the harmonics for
>   the maximum to connect to the analyzer.
> Good luck and be careful.
> Lee  K7TJR  OR
>
> -----Original Message-----
> From: RFI <rfi-bounces at contesting.com> On Behalf Of Matt NQ6N
> Sent: Monday, September 30, 2019 9:27 AM
> To: JW <jwin95 at yahoo.com>
> Cc: rfi at contesting.com
> Subject: Re: [RFI] tips for finding the source of broadband mixing products
>
> I'll add a bit more information.  Thanks much for the suggestions so far:
>
>
> - The rig is a Flex 6600 SDR transmitting 1 Watt.  There is a Morgan
> Manufacturing 40m bandpass filter (I measured it as having 28 db of
> attenuation at 14 MHz) between the rig and amp (which is in standby) and
> also a VA6AM high power 40m bandpass filter (air coil version with claimed
> performance of -70 db at 14 MHz) after the amplifier.
>
> - The TX antenna is an inverted vee in the back yard, and the RX antenna
> is an inverted L in the front yard.  So only about 50' of physical
> separation of omnidirectional antennas, but lots of BPF filtering and low
> TX power.
>
> - Completely disconnecting the RX antenna weakens the second harmonic
> signal quite a lot and makes the note sound like a pure sine wave, but it
> could be that I am not hearing the IMD products when the signal is so much
> weaker.
>
> - I had a typo in my original message. It was the second harmonic. I'd
> just been listening to the third harmonic when I hastily typed my message,
> and didn't notice before hitting send.
>
> - I'll be onsite today with a spectrum analyzer, so any tips on things to
> measure would be helpful.  Just wanted to update the thread with the above
> info.
>
> 73,
> Matt NQ6N
>
>
>
>
> On Mon, Sep 30, 2019 at 6:35 AM JW via RFI <rfi at contesting.com> wrote:
>
> >  re: "If that happens, there are errors in design and/or construction."
> >
> > 50 or 60 dB down?
> >
> > Pshaw.
> >
> > de AA5CT
> >
> > PS 50 dB down can STILL be quite receivable WHEN the rig is operated
> > into a dummy load. It's WHY operators often think their equipment is
> > faulty IF they don't sample the RF coming out the antenna port but
> > rather just 'listen'
> > with
> > another rig nearby connected to an antenna or just a piece of wire.
> >
> > One of the rigs we demonstrated this on was an old Collins tube-type
> > radio too ...
> >
> > These 'things' are easily demonstrable, Jim Brown. Surprised you have
> > _not_ encountered it.
> >      On Sunday, September 29, 2019, 10:28:53 PM GMT-5, Jim Brown <
> > jim at audiosystemsgroup.com> wrote:
> >
> >  On 9/29/2019 7:48 PM, JW via RFI wrote:
> > > How are you determining all this - you do realize, in close
> > > proximity to a transmitting rig, much (albeit low-level) RF comes
> > > straight out the power leads
> >
> > If that happens, there are errors in design and/or construction.
> >
> > and can 'modulate'/be modulated by the power supply
> > > energy that also escapes, including simple rectifier supplies using
> > > only diodes?
> >
> > Ingress/egress is a linear function, and depends strongly on details
> > of both design and construction. Nearly all modern equipment fails to
> > terminate cable shields and power green wires properly. They SHOULD go
> > the the shielding enclosure (chassis), but they nearly always go first
> > to the circuit board, THEN eventually find the chassis after wandering
> > around return circuitry for a while. This equipment flaw, first
> > discovered by a ham working in pro audio, is called "The Pin One
> > Problem," because the designated shield contact of the connector
> > commonly used for balanced audio circuits is Pin 1.
> >
> > The method in which equipment is built usually makes it impractical to
> > correct these design errors, so the best fix is a serious common mode
> > choke on the cable(s) involved. And because the ingress/egress is via
> > the green wire or the cable shield, conventional line filters are
> > useless UNLESS they are internal, and with their shielding enclosure
> > bonding the green wire to the equipment shielding enclosure! They
> > treat only the differential voltage and current between phase and
> > neutral, phase and ground, and neutral and ground.
> >
> > The only effect of signal strength is on the strength of the mixing
> > products.
> > >
> > > We demonstrated this at Heathkit several different ways, including
> > > using a spectrum analyzer to 'sniff' the stray RF coming back out
> > > via the
> > radio's
> > > power cable WHICH in turn was modulated and showed 120 Hz sidebands ...
> >
> > So you added an AC line filter with its shielded enclosure bonded to
> > the chassis, right? THAT would work.
> >
> > 73, Jim K9YC
> >
> > _______________________________________________
> > RFI mailing list
> > RFI at contesting.com
> > http://lists.contesting.com/mailman/listinfo/rfi
> >
> > _______________________________________________
> > RFI mailing list
> > RFI at contesting.com
> > http://lists.contesting.com/mailman/listinfo/rfi
> >
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>