Re: [Elecraft] I need a Sherlock Holmes (weird spurs on 40m) [resolution]
A bright "moon light" can keep solar panels generating solar power.
73, Lou KE1F
On 6/9/2022 20:09, Alan Bloom wrote:
Mystery solved! The spurs appear to be coming from a solar
installation on a house about 1/2 mile (3/4 km) from my house.
One interesting point is that the spurs do not go away at sundown, but
continue until fairly late in the evening. Apparently that solar
installation must have some kind of battery to store the energy.
Solar panels are DC devices and do not themselves generate
interference. Rather it is the inverter(s) and other electronics that
are the problem. There are two kinds of solar systems -- the ones
with all the panels in series feeding a single inverter and the kind
with a separate inverter for each panel. The latter is the kind I had
on my house in California before it was destroyed in a fire and I
never had a noise problem. I have heard that the single-inverter
systems are more troublesome from an RFI standpoint. There was an
article in April 2016 QST magazine about how to mitigate RFI from
solar systems. ("Can Solar Power and Ham Radio Coexist?" by Tony
Brock-Fisher K1KP)
--
The story: I finally go around to walking around the neighborhood
with my KX2. I only have the AX1 antenna for it, which is not
resonant on the 40 meter band, and I was not using a counterpoise so I
could barely hear the signal from in front of my house.
I started walking south down the street but the signal seemed to be
getting weaker. So I turned around and walked north. The signal was
getting slightly stronger the farther I went. I turned right at the
end of the street onto another street and it kept gradually getting a
little stronger. At one point I suspected it might be coming from a
Montessori school, but when I walked down the access street toward it
it didn't get any stronger. Plus with everything in the news these
days I didn't think it would be a good idea for a strange man holding
a strange contraption to be walking around the school grounds. :=)
So I kept walking down the main street and within a couple blocks the
signal started to rapidly increase in strength. It peaked in front of
a certain house, strongest at the right side of the house. Sure enough
there are solar panels on that side of the roof. The signal was
peaking about S4 or S5 on the KX2 S-meter. Again, this is with a
non-resonant antenna with no counterpoise.
As I mentioned, the spurs are about S6 on the ground-mounted trap
vertical at my house and they are almost buried in the noise when the
band opens up at night. So I'm not going to bug the neighbor about
it. But I bet they would have trouble trying to listen to AM radio at
their house.
Alan N1AL
On 6/7/22 17:21, Alan Bloom wrote:
As part of christening my new QTH/antenna/rig here at N1AL, today I
did the test where I recorded all off-the-air spurious signals on all
bands and then threw the main circuit breaker for the house and did
the measurement again, powering the K4 from a battery. This is to
identify any spurs that are coming from my house so I can do further
sleuthing to figure out what is causing them.
One spur (or set of spurs) has me mystified. It is a series of
harmonics, with very stable frequencies, spaced at precisely 24 kHz,
that extend from roughly 6.6 MHz to 7.4 MHz. Each spur consists of a
main carrier and a secondary carrier approximately 150 Hz lower in
frequency and approximately 8 dB lower in amplitude. The spurs are
all the same amplitude, around -90 dBm (S6), dropping off as you
approach 6.6 or 7.4 MHz. I don't see these spurs on any other band.
The spur amplitudes did not change when I turned off AC power, so it
can't be the rig's switching power supply or any other electronic
device in the house. It's nothing internal to the radio because if I
switch to a dummy antenna the spurs go away.
So it's coming in through the antenna. The antenna is a 6-band trap
vertical about 30 feet from the house, with the coax coming
underground to the shack. We're on a large lot, there is a canyon
(i.e. no houses) behind the property, and there is a vacant lot on
the side where the antenna is located so the nearest houses in the
neighborhood are about 150 feet away from the antenna.
The electric utility power lines switch from overhead to underground
at our property line, about 150 feet away from the antenna. Internet
is via cable, which is underground also. Both power and Internet
enter at the far end of the main house, which is over 100 feet from
the shack, located in a granny unit.
I believe the exact fundamental frequency is 7007.03 kHz / 292 =
23.9967 kHz, in case that's a clue.
Anyone have any ideas of what could be causing this?
Alan N1AL
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Re: [Elecraft] I need a Sherlock Holmes (weird spurs on 40m) [resolution]
Mystery solved! The spurs appear to be coming from a solar installation
on a house about 1/2 mile (3/4 km) from my house.
One interesting point is that the spurs do not go away at sundown, but
continue until fairly late in the evening. Apparently that solar
installation must have some kind of battery to store the energy.
Solar panels are DC devices and do not themselves generate
interference. Rather it is the inverter(s) and other electronics that
are the problem. There are two kinds of solar systems -- the ones with
all the panels in series feeding a single inverter and the kind with a
separate inverter for each panel. The latter is the kind I had on my
house in California before it was destroyed in a fire and I never had a
noise problem. I have heard that the single-inverter systems are more
troublesome from an RFI standpoint. There was an article in April 2016
QST magazine about how to mitigate RFI from solar systems. ("Can Solar
Power and Ham Radio Coexist?" by Tony Brock-Fisher K1KP)
--
The story: I finally go around to walking around the neighborhood with
my KX2. I only have the AX1 antenna for it, which is not resonant on
the 40 meter band, and I was not using a counterpoise so I could barely
hear the signal from in front of my house.
I started walking south down the street but the signal seemed to be
getting weaker. So I turned around and walked north. The signal was
getting slightly stronger the farther I went. I turned right at the end
of the street onto another street and it kept gradually getting a little
stronger. At one point I suspected it might be coming from a Montessori
school, but when I walked down the access street toward it it didn't get
any stronger. Plus with everything in the news these days I didn't
think it would be a good idea for a strange man holding a strange
contraption to be walking around the school grounds. :=)
So I kept walking down the main street and within a couple blocks the
signal started to rapidly increase in strength. It peaked in front of a
certain house, strongest at the right side of the house. Sure enough
there are solar panels on that side of the roof. The signal was peaking
about S4 or S5 on the KX2 S-meter. Again, this is with a non-resonant
antenna with no counterpoise.
As I mentioned, the spurs are about S6 on the ground-mounted trap
vertical at my house and they are almost buried in the noise when the
band opens up at night. So I'm not going to bug the neighbor about it.
But I bet they would have trouble trying to listen to AM radio at their
house.
Alan N1AL
On 6/7/22 17:21, Alan Bloom wrote:
As part of christening my new QTH/antenna/rig here at N1AL, today I
did the test where I recorded all off-the-air spurious signals on all
bands and then threw the main circuit breaker for the house and did
the measurement again, powering the K4 from a battery. This is to
identify any spurs that are coming from my house so I can do further
sleuthing to figure out what is causing them.
One spur (or set of spurs) has me mystified. It is a series of
harmonics, with very stable frequencies, spaced at precisely 24 kHz,
that extend from roughly 6.6 MHz to 7.4 MHz. Each spur consists of a
main carrier and a secondary carrier approximately 150 Hz lower in
frequency and approximately 8 dB lower in amplitude. The spurs are
all the same amplitude, around -90 dBm (S6), dropping off as you
approach 6.6 or 7.4 MHz. I don't see these spurs on any other band.
The spur amplitudes did not change when I turned off AC power, so it
can't be the rig's switching power supply or any other electronic
device in the house. It's nothing internal to the radio because if I
switch to a dummy antenna the spurs go away.
So it's coming in through the antenna. The antenna is a 6-band trap
vertical about 30 feet from the house, with the coax coming
underground to the shack. We're on a large lot, there is a canyon
(i.e. no houses) behind the property, and there is a vacant lot on the
side where the antenna is located so the nearest houses in the
neighborhood are about 150 feet away from the antenna.
The electric utility power lines switch from overhead to underground
at our property line, about 150 feet away from the antenna. Internet
is via cable, which is underground also. Both power and Internet
enter at the far end of the main house, which is over 100 feet from
the shack, located in a granny unit.
I believe the exact fundamental frequency is 7007.03 kHz / 292 =
23.9967 kHz, in case that's a clue.
Anyone have any ideas of what could be causing this?
Alan N1AL
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Re: [Elecraft] I need a Sherlock Holmes (weird spurs on 40m)
Alan, If you have central air-condx/heating with variable speed compressor and / or fans(s), shut it down and check for the spurs. What you are describing is the same I see at my QTh when my unit is cooling/heating. I see spurs only wihen the compressor and/or fans are running. My unit is a “dual fuel” unit, used as a heatpump above 43F, swithching to a gas fired furnace below 43F. It has no electric powered “heat strips.” For summer cooling it is configured as a “normal” AC unit. 73 de Ben W4SC Sent from Mail for Windows __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] I need a Sherlock Holmes (weird spurs on 40m)
Check out the RFI reflector r...@contesting.com W0MU On 6/7/2022 7:36 PM, Alan Bloom wrote: Hi John, In this case the Internet is not via DSL, it's via cable. The coax comes out of the ground and then to the modem/router and from there via a 150-foot Ethernet LAN cable to the granny unit, where there is an additional router with its own Wi-Fi. Anyway, that entire system was turned off when I threw the main breaker to the house. I assume it could be caused by Internet from some neighbor, but as I said, the nearest neighbor's house is about 150 feet away and all services are underground. It's a puzzlement... Alan N1AL On 6/7/22 19:23, John Oppenheimer wrote: Hi Alan, I've had issues with the service from street to modem. As I understand, there's a VDSL band which overlaps 7MHz band. In my case, it was reversed, any transmission on 7MHz would disable TV and Internet service. John KN5L On 6/7/22 7:54 PM, Alan Bloom wrote: The ISP is TDS. They offer up to 1 Gbps internet (I only pay for 200 Mbps) via cable. Just as a sanity check, I just walked down to the main house and unplugged the 150-foot LAN cable from the modem/router that feeds the router in the granny unit here where the shack is. As expected, the spurs are still there. There is no wired connection from the K4 or the desktop computer to the LAN (Wi-Fi only). Alan N1AL On 6/7/22 18:29, John Oppenheimer wrote: Hi Alan, What is your TV/Internet provider? John KN5L On 6/7/22 6:59 PM, Alan Bloom wrote: The weird thing about these spurs is how clean and stable they are. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to a...@elecraft.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to w...@w0mu.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] I need a Sherlock Holmes (weird spurs on 40m)
OFDM is also what is used for [A]DSL, and, but at UHF, or SHF, digital TV (terrestrial and satellite). It's also, at least in Europe, for digital radio, at VHF. I think it is also used for 4/5G mobile. phones. It is not intrinsically secure. It's main advantage is that it gets close to the theoretical (Shannon) limits on error free bit rates in the presence of purely Gaussian noise, and has good multipath tolerance (not useful for ADSL, though). Encryption isn't required. Scrambling may be done to avoid spectral peaks, but actually encryption, if used, is done at a higher level. -- David Woolley On 08/06/2022 09:22, Dynolab wrote: Your 24kHz spaced spurs from 6.6 MHz to 7.4MHz sounds very much like Orthogonal Frequency Division Multiplexing (OFDM). A secure type of modulation encryption that is often used on the HF bands for High Frequency securities trading. If it is a foreign source, they may not respect our 40 meter ham band frequencies. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] I need a Sherlock Holmes (weird spurs on 40m)
Your 24kHz spaced spurs from 6.6 MHz to 7.4MHz sounds very much like Orthogonal Frequency Division Multiplexing (OFDM). A secure type of modulation encryption that is often used on the HF bands for High Frequency securities trading. If it is a foreign source, they may not respect our 40 meter ham band frequencies. 73, Hal W7YNC -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Victor Rosenthal 4X6GP Sent: Tuesday, June 07, 2022 10:30 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] I need a Sherlock Holmes (weird spurs on 40m) I don't have a guess as to the cause, but it might be worth trying a common mode choke at the base of the vertical. I know that some of these antennas (like the Cushcraft/MFJ versions) do have such chokes built in, but I found that an additional one helped isolate the line from the antenna. Indeed, you can't even say for sure that the signal doesn't come from the K4 if it goes away when you switch to a dummy load, because if the antenna coax is not entirely isolated from the antenna, the signal could be flowing from the radio back to the antenna via the outside of the coax. The dummy load is probably shielded, so there's no way for this to happen. 73, Victor, 4X6GP Rehovot, Israel CWops #5 Formerly K2VCO https://www.qsl.net/k2vco/ On 08/06/2022 2:21, Alan Bloom wrote: > As part of christening my new QTH/antenna/rig here at N1AL, today I > did the test where I recorded all off-the-air spurious signals on all > bands and then threw the main circuit breaker for the house and did > the measurement again, powering the K4 from a battery. This is to > identify any spurs that are coming from my house so I can do further > sleuthing to figure out what is causing them. > > One spur (or set of spurs) has me mystified. It is a series of > harmonics, with very stable frequencies, spaced at precisely 24 kHz, > that extend from roughly 6.6 MHz to 7.4 MHz. Each spur consists of a > main carrier and a secondary carrier approximately 150 Hz lower in > frequency and approximately 8 dB lower in amplitude. The spurs are > all the same amplitude, around -90 dBm (S6), dropping off as you > approach > 6.6 or 7.4 MHz. I don't see these spurs on any other band. > > The spur amplitudes did not change when I turned off AC power, so it > can't be the rig's switching power supply or any other electronic > device in the house. It's nothing internal to the radio because if I > switch to a dummy antenna the spurs go away. > > So it's coming in through the antenna. The antenna is a 6-band trap > vertical about 30 feet from the house, with the coax coming > underground to the shack. We're on a large lot, there is a canyon > (i.e. no houses) behind the property, and there is a vacant lot on the > side where the antenna is located so the nearest houses in the > neighborhood are about > 150 feet away from the antenna. > > The electric utility power lines switch from overhead to underground > at our property line, about 150 feet away from the antenna. Internet > is via cable, which is underground also. Both power and Internet > enter at the far end of the main house, which is over 100 feet from > the shack, located in a granny unit. > > I believe the exact fundamental frequency is 7007.03 kHz / 292 = > 23.9967 kHz, in case that's a clue. > > Anyone have any ideas of what could be causing this? > > Alan N1AL > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net Please help support this email > list: http://www.qsl.net/donate.html Message delivered to > k2vco@gmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to dyno...@comcast.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] I need a Sherlock Holmes (weird spurs on 40m)
I don't have a guess as to the cause, but it might be worth trying a common mode choke at the base of the vertical. I know that some of these antennas (like the Cushcraft/MFJ versions) do have such chokes built in, but I found that an additional one helped isolate the line from the antenna. Indeed, you can't even say for sure that the signal doesn't come from the K4 if it goes away when you switch to a dummy load, because if the antenna coax is not entirely isolated from the antenna, the signal could be flowing from the radio back to the antenna via the outside of the coax. The dummy load is probably shielded, so there's no way for this to happen. 73, Victor, 4X6GP Rehovot, Israel CWops #5 Formerly K2VCO https://www.qsl.net/k2vco/ On 08/06/2022 2:21, Alan Bloom wrote: As part of christening my new QTH/antenna/rig here at N1AL, today I did the test where I recorded all off-the-air spurious signals on all bands and then threw the main circuit breaker for the house and did the measurement again, powering the K4 from a battery. This is to identify any spurs that are coming from my house so I can do further sleuthing to figure out what is causing them. One spur (or set of spurs) has me mystified. It is a series of harmonics, with very stable frequencies, spaced at precisely 24 kHz, that extend from roughly 6.6 MHz to 7.4 MHz. Each spur consists of a main carrier and a secondary carrier approximately 150 Hz lower in frequency and approximately 8 dB lower in amplitude. The spurs are all the same amplitude, around -90 dBm (S6), dropping off as you approach 6.6 or 7.4 MHz. I don't see these spurs on any other band. The spur amplitudes did not change when I turned off AC power, so it can't be the rig's switching power supply or any other electronic device in the house. It's nothing internal to the radio because if I switch to a dummy antenna the spurs go away. So it's coming in through the antenna. The antenna is a 6-band trap vertical about 30 feet from the house, with the coax coming underground to the shack. We're on a large lot, there is a canyon (i.e. no houses) behind the property, and there is a vacant lot on the side where the antenna is located so the nearest houses in the neighborhood are about 150 feet away from the antenna. The electric utility power lines switch from overhead to underground at our property line, about 150 feet away from the antenna. Internet is via cable, which is underground also. Both power and Internet enter at the far end of the main house, which is over 100 feet from the shack, located in a granny unit. I believe the exact fundamental frequency is 7007.03 kHz / 292 = 23.9967 kHz, in case that's a clue. Anyone have any ideas of what could be causing this? Alan N1AL __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to k2vco@gmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] I need a Sherlock Holmes (weird spurs on 40m)
That's the strange thing about this. It doesn't have a grinding sound or anything other than a clean carrier. Actually two carriers, the weaker one about 150 Hz lower than the main one. That pretty much rules out any kind of switching power supply, for example. Maybe tomorrow I'll take my KX2 pedestrian mobile and walk around the neighborhood to see if the signal level changes. Alan N1AL On 6/7/22 19:36, jerry wrote: On 40M I see noise every 15 kHz. It's constant. Sometimes stronger, sometimes weaker, but it's always there. The pattern is obvious on the waterfall display. When I tune in one of the peaks, it sounds like a rhythmic grinding. - Jerry KF6VB On 2022-06-07 16:59, Alan Bloom wrote: The weird thing about these spurs is how clean and stable they are. Switching power supply noise is generally not frequency-stable and it is not a clean CW carrier. This one is actually TWO clean carriers, separated by about 150 Hz. Alan N1AL On 6/7/22 17:43, Fred Jensen wrote: I did the "Main Breaker 2-Step" and nothing went away. My noise on 80 and 40 on the K3/P3 is highly varied ... 1. Narrow discrete carriers [that appear linked, 25-35 kHz apart] come and go, sometimes within seconds 2. Broad [5-10 kHz] bands of noise, often without any harmonic brethren [that I can find] that come in pulses that look like wide-band AMTOR 3. "Rope-like" noise on the WF, with and without harmonic brethren that often changes in character but mainly a primary signal oscillating back and forth in frequency over maybe 5 kHz. Underground utilities, but we do have a 345 kV transmission line about two miles away that runs from a large power plant 5 or 6 miles east to somewhere up in OR near the Columbia. Sources are a mystery, but I've suspected harmonics of transmission line carrier-current signaling ... they really look like sometimes it's just idling, and then a burst of information. 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County Alan Bloom wrote on 6/7/2022 4:21 PM: As part of christening my new QTH/antenna/rig here at N1AL, today I did the test where I recorded all off-the-air spurious signals on all bands and then threw the main circuit breaker for the house and did the measurement again, powering the K4 from a battery. This is to identify any spurs that are coming from my house so I can do further sleuthing to figure out what is causing them. One spur (or set of spurs) has me mystified. It is a series of harmonics, with very stable frequencies, spaced at precisely 24 kHz, that extend from roughly 6.6 MHz to 7.4 MHz. Each spur consists of a main carrier and a secondary carrier approximately 150 Hz lower in frequency and approximately 8 dB lower in amplitude. The spurs are all the same amplitude, around -90 dBm (S6), dropping off as you approach 6.6 or 7.4 MHz. I don't see these spurs on any other band. The spur amplitudes did not change when I turned off AC power, so it can't be the rig's switching power supply or any other electronic device in the house. It's nothing internal to the radio because if I switch to a dummy antenna the spurs go away. So it's coming in through the antenna. The antenna is a 6-band trap vertical about 30 feet from the house, with the coax coming underground to the shack. We're on a large lot, there is a canyon (i.e. no houses) behind the property, and there is a vacant lot on the side where the antenna is located so the nearest houses in the neighborhood are about 150 feet away from the antenna. The electric utility power lines switch from overhead to underground at our property line, about 150 feet away from the antenna. Internet is via cable, which is underground also. Both power and Internet enter at the far end of the main house, which is over 100 feet from the shack, located in a granny unit. I believe the exact fundamental frequency is 7007.03 kHz / 292 = 23.9967 kHz, in case that's a clue. Anyone have any ideas of what could be causing this? Alan N1AL __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to je...@tr2.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] I need a Sherlock Holmes (weird spurs on 40m)
I also had power line interference on 7MHz. Made a shielded loop using a Hula hoop as support, BL2 for balanced loop to coax, and KX3 receiver. Didn't take long to DF it out. John KN5L On 6/7/22 8:36 PM, Alan Bloom wrote: > Hi John, > > In this case the Internet is not via DSL, it's via cable. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] I need a Sherlock Holmes (weird spurs on 40m)
Hi John, In this case the Internet is not via DSL, it's via cable. The coax comes out of the ground and then to the modem/router and from there via a 150-foot Ethernet LAN cable to the granny unit, where there is an additional router with its own Wi-Fi. Anyway, that entire system was turned off when I threw the main breaker to the house. I assume it could be caused by Internet from some neighbor, but as I said, the nearest neighbor's house is about 150 feet away and all services are underground. It's a puzzlement... Alan N1AL On 6/7/22 19:23, John Oppenheimer wrote: Hi Alan, I've had issues with the service from street to modem. As I understand, there's a VDSL band which overlaps 7MHz band. In my case, it was reversed, any transmission on 7MHz would disable TV and Internet service. John KN5L On 6/7/22 7:54 PM, Alan Bloom wrote: The ISP is TDS. They offer up to 1 Gbps internet (I only pay for 200 Mbps) via cable. Just as a sanity check, I just walked down to the main house and unplugged the 150-foot LAN cable from the modem/router that feeds the router in the granny unit here where the shack is. As expected, the spurs are still there. There is no wired connection from the K4 or the desktop computer to the LAN (Wi-Fi only). Alan N1AL On 6/7/22 18:29, John Oppenheimer wrote: Hi Alan, What is your TV/Internet provider? John KN5L On 6/7/22 6:59 PM, Alan Bloom wrote: The weird thing about these spurs is how clean and stable they are. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to a...@elecraft.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] I need a Sherlock Holmes (weird spurs on 40m)
On 40M I see noise every 15 kHz. It's constant. Sometimes stronger, sometimes weaker, but it's always there. The pattern is obvious on the waterfall display. When I tune in one of the peaks, it sounds like a rhythmic grinding. - Jerry KF6VB On 2022-06-07 16:59, Alan Bloom wrote: The weird thing about these spurs is how clean and stable they are. Switching power supply noise is generally not frequency-stable and it is not a clean CW carrier. This one is actually TWO clean carriers, separated by about 150 Hz. Alan N1AL On 6/7/22 17:43, Fred Jensen wrote: I did the "Main Breaker 2-Step" and nothing went away. My noise on 80 and 40 on the K3/P3 is highly varied ... 1. Narrow discrete carriers [that appear linked, 25-35 kHz apart] come and go, sometimes within seconds 2. Broad [5-10 kHz] bands of noise, often without any harmonic brethren [that I can find] that come in pulses that look like wide-band AMTOR 3. "Rope-like" noise on the WF, with and without harmonic brethren that often changes in character but mainly a primary signal oscillating back and forth in frequency over maybe 5 kHz. Underground utilities, but we do have a 345 kV transmission line about two miles away that runs from a large power plant 5 or 6 miles east to somewhere up in OR near the Columbia. Sources are a mystery, but I've suspected harmonics of transmission line carrier-current signaling ... they really look like sometimes it's just idling, and then a burst of information. 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County Alan Bloom wrote on 6/7/2022 4:21 PM: As part of christening my new QTH/antenna/rig here at N1AL, today I did the test where I recorded all off-the-air spurious signals on all bands and then threw the main circuit breaker for the house and did the measurement again, powering the K4 from a battery. This is to identify any spurs that are coming from my house so I can do further sleuthing to figure out what is causing them. One spur (or set of spurs) has me mystified. It is a series of harmonics, with very stable frequencies, spaced at precisely 24 kHz, that extend from roughly 6.6 MHz to 7.4 MHz. Each spur consists of a main carrier and a secondary carrier approximately 150 Hz lower in frequency and approximately 8 dB lower in amplitude. The spurs are all the same amplitude, around -90 dBm (S6), dropping off as you approach 6.6 or 7.4 MHz. I don't see these spurs on any other band. The spur amplitudes did not change when I turned off AC power, so it can't be the rig's switching power supply or any other electronic device in the house. It's nothing internal to the radio because if I switch to a dummy antenna the spurs go away. So it's coming in through the antenna. The antenna is a 6-band trap vertical about 30 feet from the house, with the coax coming underground to the shack. We're on a large lot, there is a canyon (i.e. no houses) behind the property, and there is a vacant lot on the side where the antenna is located so the nearest houses in the neighborhood are about 150 feet away from the antenna. The electric utility power lines switch from overhead to underground at our property line, about 150 feet away from the antenna. Internet is via cable, which is underground also. Both power and Internet enter at the far end of the main house, which is over 100 feet from the shack, located in a granny unit. I believe the exact fundamental frequency is 7007.03 kHz / 292 = 23.9967 kHz, in case that's a clue. Anyone have any ideas of what could be causing this? Alan N1AL __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to je...@tr2.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] I need a Sherlock Holmes (weird spurs on 40m)
Hi Alan, I've had issues with the service from street to modem. As I understand, there's a VDSL band which overlaps 7MHz band. In my case, it was reversed, any transmission on 7MHz would disable TV and Internet service. John KN5L On 6/7/22 7:54 PM, Alan Bloom wrote: > The ISP is TDS. They offer up to 1 Gbps internet (I only pay for 200 > Mbps) via cable. > > Just as a sanity check, I just walked down to the main house and > unplugged the 150-foot LAN cable from the modem/router that feeds the > router in the granny unit here where the shack is. As expected, the > spurs are still there. There is no wired connection from the K4 or the > desktop computer to the LAN (Wi-Fi only). > > Alan N1AL > > > On 6/7/22 18:29, John Oppenheimer wrote: >> Hi Alan, >> >> What is your TV/Internet provider? >> >> John KN5L >> >> On 6/7/22 6:59 PM, Alan Bloom wrote: >>> The weird thing about these spurs is how clean and stable they are. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] I need a Sherlock Holmes (weird spurs on 40m)
The ISP is TDS. They offer up to 1 Gbps internet (I only pay for 200 Mbps) via cable. Just as a sanity check, I just walked down to the main house and unplugged the 150-foot LAN cable from the modem/router that feeds the router in the granny unit here where the shack is. As expected, the spurs are still there. There is no wired connection from the K4 or the desktop computer to the LAN (Wi-Fi only). Alan N1AL On 6/7/22 18:29, John Oppenheimer wrote: Hi Alan, What is your TV/Internet provider? John KN5L On 6/7/22 6:59 PM, Alan Bloom wrote: The weird thing about these spurs is how clean and stable they are. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to a...@elecraft.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] I need a Sherlock Holmes (weird spurs on 40m)
Hi Alan, What is your TV/Internet provider? John KN5L On 6/7/22 6:59 PM, Alan Bloom wrote: > The weird thing about these spurs is how clean and stable they are. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] I need a Sherlock Holmes (weird spurs on 40m)
The weird thing about these spurs is how clean and stable they are. Switching power supply noise is generally not frequency-stable and it is not a clean CW carrier. This one is actually TWO clean carriers, separated by about 150 Hz. Alan N1AL On 6/7/22 17:43, Fred Jensen wrote: I did the "Main Breaker 2-Step" and nothing went away. My noise on 80 and 40 on the K3/P3 is highly varied ... 1. Narrow discrete carriers [that appear linked, 25-35 kHz apart] come and go, sometimes within seconds 2. Broad [5-10 kHz] bands of noise, often without any harmonic brethren [that I can find] that come in pulses that look like wide-band AMTOR 3. "Rope-like" noise on the WF, with and without harmonic brethren that often changes in character but mainly a primary signal oscillating back and forth in frequency over maybe 5 kHz. Underground utilities, but we do have a 345 kV transmission line about two miles away that runs from a large power plant 5 or 6 miles east to somewhere up in OR near the Columbia. Sources are a mystery, but I've suspected harmonics of transmission line carrier-current signaling ... they really look like sometimes it's just idling, and then a burst of information. 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County Alan Bloom wrote on 6/7/2022 4:21 PM: As part of christening my new QTH/antenna/rig here at N1AL, today I did the test where I recorded all off-the-air spurious signals on all bands and then threw the main circuit breaker for the house and did the measurement again, powering the K4 from a battery. This is to identify any spurs that are coming from my house so I can do further sleuthing to figure out what is causing them. One spur (or set of spurs) has me mystified. It is a series of harmonics, with very stable frequencies, spaced at precisely 24 kHz, that extend from roughly 6.6 MHz to 7.4 MHz. Each spur consists of a main carrier and a secondary carrier approximately 150 Hz lower in frequency and approximately 8 dB lower in amplitude. The spurs are all the same amplitude, around -90 dBm (S6), dropping off as you approach 6.6 or 7.4 MHz. I don't see these spurs on any other band. The spur amplitudes did not change when I turned off AC power, so it can't be the rig's switching power supply or any other electronic device in the house. It's nothing internal to the radio because if I switch to a dummy antenna the spurs go away. So it's coming in through the antenna. The antenna is a 6-band trap vertical about 30 feet from the house, with the coax coming underground to the shack. We're on a large lot, there is a canyon (i.e. no houses) behind the property, and there is a vacant lot on the side where the antenna is located so the nearest houses in the neighborhood are about 150 feet away from the antenna. The electric utility power lines switch from overhead to underground at our property line, about 150 feet away from the antenna. Internet is via cable, which is underground also. Both power and Internet enter at the far end of the main house, which is over 100 feet from the shack, located in a granny unit. I believe the exact fundamental frequency is 7007.03 kHz / 292 = 23.9967 kHz, in case that's a clue. Anyone have any ideas of what could be causing this? Alan N1AL __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] I need a Sherlock Holmes (weird spurs on 40m)
I did the "Main Breaker 2-Step" and nothing went away. My noise on 80 and 40 on the K3/P3 is highly varied ... 1. Narrow discrete carriers [that appear linked, 25-35 kHz apart] come and go, sometimes within seconds 2. Broad [5-10 kHz] bands of noise, often without any harmonic brethren [that I can find] that come in pulses that look like wide-band AMTOR 3. "Rope-like" noise on the WF, with and without harmonic brethren that often changes in character but mainly a primary signal oscillating back and forth in frequency over maybe 5 kHz. Underground utilities, but we do have a 345 kV transmission line about two miles away that runs from a large power plant 5 or 6 miles east to somewhere up in OR near the Columbia. Sources are a mystery, but I've suspected harmonics of transmission line carrier-current signaling ... they really look like sometimes it's just idling, and then a burst of information. 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County Alan Bloom wrote on 6/7/2022 4:21 PM: As part of christening my new QTH/antenna/rig here at N1AL, today I did the test where I recorded all off-the-air spurious signals on all bands and then threw the main circuit breaker for the house and did the measurement again, powering the K4 from a battery. This is to identify any spurs that are coming from my house so I can do further sleuthing to figure out what is causing them. One spur (or set of spurs) has me mystified. It is a series of harmonics, with very stable frequencies, spaced at precisely 24 kHz, that extend from roughly 6.6 MHz to 7.4 MHz. Each spur consists of a main carrier and a secondary carrier approximately 150 Hz lower in frequency and approximately 8 dB lower in amplitude. The spurs are all the same amplitude, around -90 dBm (S6), dropping off as you approach 6.6 or 7.4 MHz. I don't see these spurs on any other band. The spur amplitudes did not change when I turned off AC power, so it can't be the rig's switching power supply or any other electronic device in the house. It's nothing internal to the radio because if I switch to a dummy antenna the spurs go away. So it's coming in through the antenna. The antenna is a 6-band trap vertical about 30 feet from the house, with the coax coming underground to the shack. We're on a large lot, there is a canyon (i.e. no houses) behind the property, and there is a vacant lot on the side where the antenna is located so the nearest houses in the neighborhood are about 150 feet away from the antenna. The electric utility power lines switch from overhead to underground at our property line, about 150 feet away from the antenna. Internet is via cable, which is underground also. Both power and Internet enter at the far end of the main house, which is over 100 feet from the shack, located in a granny unit. I believe the exact fundamental frequency is 7007.03 kHz / 292 = 23.9967 kHz, in case that's a clue. Anyone have any ideas of what could be causing this? Alan N1AL -- This email has been checked for viruses by AVG. https://www.avg.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] I need a Sherlock Holmes (weird spurs on 40m)
As part of christening my new QTH/antenna/rig here at N1AL, today I did the test where I recorded all off-the-air spurious signals on all bands and then threw the main circuit breaker for the house and did the measurement again, powering the K4 from a battery. This is to identify any spurs that are coming from my house so I can do further sleuthing to figure out what is causing them. One spur (or set of spurs) has me mystified. It is a series of harmonics, with very stable frequencies, spaced at precisely 24 kHz, that extend from roughly 6.6 MHz to 7.4 MHz. Each spur consists of a main carrier and a secondary carrier approximately 150 Hz lower in frequency and approximately 8 dB lower in amplitude. The spurs are all the same amplitude, around -90 dBm (S6), dropping off as you approach 6.6 or 7.4 MHz. I don't see these spurs on any other band. The spur amplitudes did not change when I turned off AC power, so it can't be the rig's switching power supply or any other electronic device in the house. It's nothing internal to the radio because if I switch to a dummy antenna the spurs go away. So it's coming in through the antenna. The antenna is a 6-band trap vertical about 30 feet from the house, with the coax coming underground to the shack. We're on a large lot, there is a canyon (i.e. no houses) behind the property, and there is a vacant lot on the side where the antenna is located so the nearest houses in the neighborhood are about 150 feet away from the antenna. The electric utility power lines switch from overhead to underground at our property line, about 150 feet away from the antenna. Internet is via cable, which is underground also. Both power and Internet enter at the far end of the main house, which is over 100 feet from the shack, located in a granny unit. I believe the exact fundamental frequency is 7007.03 kHz / 292 = 23.9967 kHz, in case that's a clue. Anyone have any ideas of what could be causing this? Alan N1AL __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
