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K3 spurious radiation?

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John/K8AZT

K3 spurious radiation?

I have not been monitoring this mail list much recently so I apologize if this
subject has been discussed previously.

I like to monitor the reversebeacon.net website while calling cq or just
monitoring looking for a qso. Recently I have discovered a situation which has
me puzzled and I am hoping someone here might be able to give me some insight
what might be happening.

When calling cq (CW) on 7.0 MHz cw, I see several hits on the reverse beacon
website on 7.0 MHz, however I have also seen a couple stations allegedly hearing
me on 10.1 MHz (2 occurrences) and a station hearing me on 28 MHz bands (1
occurrence). I am hoping this is a problem with the skimmers, but want to check
out if there is anything which might not be right with my K3 and/or antenna
which might be generating unwanted radiations. At the moment I do not have
exact frequencies where I was being monitored. I just thought someone might
have a suggestion where do I proceed.

At the moment I do not have access to a frequency analyzer, but hope I can find
one to borrow locally.

Thank you for any suggestions/comments anyone in the reflector might have.

73,
John/K8AZT
K3/ SN 1693
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Thomas Horsten

Re: K3 spurious radiation?

Hi John,

I had this happen to me a few days ago where I was calling CQ on 7.015 and
was spotted on 14.0614 by Tim KQ8M's skimmer. I emailed KQ8M to ask him if
there was a problem with his skimmer. He replied that he wouldn't rule out
that the problem was in his Rx setup, but it was tuned to 20m.

Now I was running through the linear and an ATU, and I can't see any
logical relationship between the two frequencies, so I'm leaning to the
theory that his receiver was the culprit, although I did find it very
strange.

I think a lot of RBN skimmers use SoftRock receivers, and I'm guessing that
if his VFO was tuned to 14.050 using the 2nd harmonic of a 7.025
fundamental, it would kind of fit, but I'm still surprised that my 300W
signal to an inverted V was 6dB over the noise on the wrong band in Ohio,
3800 miles away on the other side of the Atlantic... I'm not sure exactly
because I don't know what receiver he was using, but it did have me puzzled
and when I saw John's post I thought I'd mention it.

Here's the spot in question:

de dx freq cq/dx snr speed time KQ8M<http://www.reversebeacon.net/qrz/KQ8M>
M0TRN <http://www.reversebeacon.net/qrz/M0TRN> 14061.4 CQ [LoTW] 6 dB 22
wpm 1952z 22 Jan S50ARX <http://www.reversebeacon.net/qrz/S50ARX>
M0TRN<http://www.reversebeacon.net/qrz/M0TRN>
7015.0 CQ [LoTW] 14 dB 21 wpm 1952z 22 Jan
W3LPL<http://www.reversebeacon.net/qrz/W3LPL>
M0TRN <http://www.reversebeacon.net/qrz/M0TRN> 7015.0 CQ [LoTW] 14 dB 19
wpm 1952z 22 Jan W3LPL <http://www.reversebeacon.net/qrz/W3LPL>
M0TRN<http://www.reversebeacon.net/qrz/M0TRN>
7015.0 CQ [LoTW] 14 dB 19 wpm 1952z 22 Jan

73, Thomas M0TRN

On 24 January 2012 13:08, John/K8AZT <[hidden email]> wrote:

> I have not been monitoring this mail list much recently so I apologize if
> this
> subject has been discussed previously.
>
> I like to monitor the reversebeacon.net website while calling cq or just
> monitoring looking for a qso. Recently I have discovered a situation
> which has
> me puzzled and I am hoping someone here might be able to give me some
> insight
> what might be happening.
>
> When calling cq (CW) on 7.0 MHz cw, I see several hits on the reverse
> beacon
> website on 7.0 MHz, however I have also seen a couple stations allegedly
> hearing
> me on 10.1 MHz (2 occurrences) and a station hearing me on 28 MHz bands (1
> occurrence). I am hoping this is a problem with the skimmers, but want to
> check
> out if there is anything which might not be right with my K3 and/or antenna
> which might be generating unwanted radiations. At the moment I do not have
> exact frequencies where I was being monitored. I just thought someone
> might
> have a suggestion where do I proceed.
>
> At the moment I do not have access to a frequency analyzer, but hope I can
> find
> one to borrow locally.
>
> Thank you for any suggestions/comments anyone in the reflector might have.
>
> 73,
> John/K8AZT
> K3/ SN 1693
> ______________________________________________________________
> 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
>

______________________________________________________________
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Gary K9GS

Re: K3 spurious radiation?

In reply to this post by John/K8AZT

I've seen this happen before and it has also happened to me. Once I was
on the low end of 40M and the W3LPL skimmer spotted me just below 7100.
go figure.....

If you watch skimmer spots you'll often notice weird things showing up.
One of the JA skimmers regularly spots T2DE on 40M. There is not, to
the best of my knowledge, a station from Tuvalu licensed at T2DE. I've
seen other skimmers spot the same callsign when there was no way there
was a propagation path.

On 1/24/2012 7:08 AM, John/K8AZT wrote:

> I have not been monitoring this mail list much recently so I apologize if this
> subject has been discussed previously.
>
> I like to monitor the reversebeacon.net website while calling cq or just
> monitoring looking for a qso. Recently I have discovered a situation which has
> me puzzled and I am hoping someone here might be able to give me some insight
> what might be happening.
>
> When calling cq (CW) on 7.0 MHz cw, I see several hits on the reverse beacon
> website on 7.0 MHz, however I have also seen a couple stations allegedly hearing
> me on 10.1 MHz (2 occurrences) and a station hearing me on 28 MHz bands (1
> occurrence). I am hoping this is a problem with the skimmers, but want to check
> out if there is anything which might not be right with my K3 and/or antenna
> which might be generating unwanted radiations. At the moment I do not have
> exact frequencies where I was being monitored. I just thought someone might
> have a suggestion where do I proceed.
>
> At the moment I do not have access to a frequency analyzer, but hope I can find
> one to borrow locally.
>
> Thank you for any suggestions/comments anyone in the reflector might have.
>
> 73,
> John/K8AZT
> K3/ SN 1693
> ______________________________________________________________
> 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
>

Matt Murphy

Re: K3 spurious radiation?

I have noticed that pskreporter.info often spots me on the wrong band as
well. I think there must be some glitch in the software. I've never been
spotted on the wrong band by the cw skimmer network (that I'm aware of).

-Matt NQ6N

On Tue, Jan 24, 2012 at 8:49 PM, Gary K9GS <[hidden email]> wrote:

> I've seen this happen before and it has also happened to me. Once I was
> on the low end of 40M and the W3LPL skimmer spotted me just below 7100.
> go figure.....
>
> If you watch skimmer spots you'll often notice weird things showing up.
> One of the JA skimmers regularly spots T2DE on 40M. There is not, to
> the best of my knowledge, a station from Tuvalu licensed at T2DE. I've
> seen other skimmers spot the same callsign when there was no way there
> was a propagation path.
>
>
>
> On 1/24/2012 7:08 AM, John/K8AZT wrote:
> > I have not been monitoring this mail list much recently so I apologize
> if this
> > subject has been discussed previously.
> >
> > I like to monitor the reversebeacon.net website while calling cq or just
> > monitoring looking for a qso. Recently I have discovered a situation
> which has
> > me puzzled and I am hoping someone here might be able to give me some
> insight
> > what might be happening.
> >
> > When calling cq (CW) on 7.0 MHz cw, I see several hits on the reverse
> beacon
> > website on 7.0 MHz, however I have also seen a couple stations allegedly
> hearing
> > me on 10.1 MHz (2 occurrences) and a station hearing me on 28 MHz bands
> (1
> > occurrence). I am hoping this is a problem with the skimmers, but want
> to check
> > out if there is anything which might not be right with my K3 and/or
> antenna
> > which might be generating unwanted radiations. At the moment I do not
> have
> > exact frequencies where I was being monitored. I just thought someone
> might
> > have a suggestion where do I proceed.
> >
> > At the moment I do not have access to a frequency analyzer, but hope I
> can find
> > one to borrow locally.
> >
> > Thank you for any suggestions/comments anyone in the reflector might
> have.
> >
> > 73,
> > John/K8AZT
> > K3/ SN 1693
> > ______________________________________________________________
> > 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
> >
>
> --
>
>
> 73,
>
> Gary K9GS
>
> Check out K9NS on the web: http://www.k9ns.com
> Greater Milwaukee DX Association: http://www.gmdxa.org
> Society of Midwest Contesters: http://www.w9smc.com
>
> ************************************************
>
> ______________________________________________________________
> 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
>

Pete Smith N4ZR

Re: K3 spurious radiation?

In reply to this post by Gary K9GS

This is way OT, but false decodes like T2DE are quite common when a
Skimmer is listening in the RTTY area of the band.

73, Pete N4ZR
The World Contest Station Database, updated daily at www.conteststations.com
The Reverse Beacon Network at http://reversebeacon.net, blog at reversebeacon.blogspot.com,
spots at telnet.reversebeacon.net, port 7000 and
arcluster.reversebeacon.net, port 7000

On 1/24/2012 11:49 PM, Gary K9GS wrote:

> I've seen this happen before and it has also happened to me. Once I was
> on the low end of 40M and the W3LPL skimmer spotted me just below 7100.
> go figure.....
>
> If you watch skimmer spots you'll often notice weird things showing up.
> One of the JA skimmers regularly spots T2DE on 40M. There is not, to
> the best of my knowledge, a station from Tuvalu licensed at T2DE. I've
> seen other skimmers spot the same callsign when there was no way there
> was a propagation path.
>
>
>
> On 1/24/2012 7:08 AM, John/K8AZT wrote:
>> I have not been monitoring this mail list much recently so I apologize if this
>> subject has been discussed previously.
>>
>> I like to monitor the reversebeacon.net website while calling cq or just
>> monitoring looking for a qso. Recently I have discovered a situation which has
>> me puzzled and I am hoping someone here might be able to give me some insight
>> what might be happening.
>>
>> When calling cq (CW) on 7.0 MHz cw, I see several hits on the reverse beacon
>> website on 7.0 MHz, however I have also seen a couple stations allegedly hearing
>> me on 10.1 MHz (2 occurrences) and a station hearing me on 28 MHz bands (1
>> occurrence). I am hoping this is a problem with the skimmers, but want to check
>> out if there is anything which might not be right with my K3 and/or antenna
>> which might be generating unwanted radiations. At the moment I do not have
>> exact frequencies where I was being monitored. I just thought someone might
>> have a suggestion where do I proceed.
>>
>> At the moment I do not have access to a frequency analyzer, but hope I can find
>> one to borrow locally.
>>
>> Thank you for any suggestions/comments anyone in the reflector might have.
>>
>> 73,
>> John/K8AZT
>> K3/ SN 1693
>> ______________________________________________________________
>> 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
>>

Tim Herrick

Re: K3 spurious radiation?

In reply to this post by Gary K9GS

Just an FYI, the W3LPL spots are not his skimmer. He has special code that
re-spots skimmers that are sent to the Reverse Beacon Network. He has a
skimmer system but the ones you see on the clusters is not that network. The
skimmer operators only dump their decodes to the RBN. Well the ones that
know what is going on do. During contests, the big gun stations have a local
network of skimmers that they connect to to help with locating DX. These are
also not seen by the general public.

Some of us cluster operators also have a local skimmer or are connected to a
skimmer but these spots are only seen on our nodes. Mine only has my local
skimmers. These can also be filtered out. I am running the beta code of V6
ARCluster which allows connecting to a skimmer and only allowing the spots
locally.

Tim Herrick, KQ8M
North Coast Contesters
[hidden email]

K3 Serial #5934

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Gary K9GS
Sent: Tuesday, January 24, 2012 11:49 PM
To: [hidden email]
Subject: Re: [Elecraft] K3 spurious radiation?

I've seen this happen before and it has also happened to me. Once I was
on the low end of 40M and the W3LPL skimmer spotted me just below 7100.
go figure.....

If you watch skimmer spots you'll often notice weird things showing up.
One of the JA skimmers regularly spots T2DE on 40M. There is not, to
the best of my knowledge, a station from Tuvalu licensed at T2DE. I've
seen other skimmers spot the same callsign when there was no way there
was a propagation path.

On 1/24/2012 7:08 AM, John/K8AZT wrote:
> I have not been monitoring this mail list much recently so I apologize if
this
> subject has been discussed previously.
>
> I like to monitor the reversebeacon.net website while calling cq or just
> monitoring looking for a qso. Recently I have discovered a situation
which has
> me puzzled and I am hoping someone here might be able to give me some
insight
> what might be happening.
>
> When calling cq (CW) on 7.0 MHz cw, I see several hits on the reverse
beacon
> website on 7.0 MHz, however I have also seen a couple stations allegedly
hearing
> me on 10.1 MHz (2 occurrences) and a station hearing me on 28 MHz bands (1
> occurrence). I am hoping this is a problem with the skimmers, but want to
check
> out if there is anything which might not be right with my K3 and/or
antenna
> which might be generating unwanted radiations. At the moment I do not
have
> exact frequencies where I was being monitored. I just thought someone
might
> have a suggestion where do I proceed.
>
> At the moment I do not have access to a frequency analyzer, but hope I can
find

> one to borrow locally.
>
> Thank you for any suggestions/comments anyone in the reflector might have.
>
> 73,
> John/K8AZT
> K3/ SN 1693
> ______________________________________________________________
> 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
>

--

73,

Gary K9GS

Check out K9NS on the web: http://www.k9ns.com
Greater Milwaukee DX Association: http://www.gmdxa.org
Society of Midwest Contesters: http://www.w9smc.com

************************************************

______________________________________________________________
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

______________________________________________________________
Elecraft mailing list
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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

VR2BrettGraham

Re: K3 spurious radiation?

In reply to this post by John/K8AZT

M0TRN replied to K8AZT:

> I had this happen to me a few days ago where I was calling CQ on 7.015 and
> was spotted on 14.0614 by Tim KQ8M's skimmer. I emailed KQ8M to ask him if
> there was a problem with his skimmer. He replied that he wouldn't rule out
> that the problem was in his Rx setup, but it was tuned to 20m.
>
> Now I was running through the linear and an ATU, and I can't see any
> logical relationship between the two frequencies, so I'm leaning to the
> theory that his receiver was the culprit, although I did find it very
> strange.
>
> I think a lot of RBN skimmers use SoftRock receivers, and I'm guessing
> that
> if his VFO was tuned to 14.050 using the 2nd harmonic of a 7.025
> fundamental, it would kind of fit, but I'm still surprised that my 300W
> signal to an inverted V was 6dB over the noise on the wrong band in Ohio,
> 3800 miles away on the other side of the Atlantic... I'm not sure exactly
> because I don't know what receiver he was using, but it did have me
> puzzled
> and when I saw John's post I thought I'd mention it.
>
> Here's the spot in question:
>
> de dx freq cq/dx snr speed time
> M0TRN 14061.4 CQ [LoTW] 6 dB 22 wpm 1952z 22 Jan KQ8M
> M0TRN 7015.0 CQ [LoTW] 14 dB 21 wpm 1952z 22 Jan S50ARX
> M0TRN 7015.0 CQ [LoTW] 14 dB 19 wpm 1952z 22 Jan W3LPL
> M0TRN 7015.0 CQ [LoTW] 14 dB 19 wpm 1952z 22 Jan W3LPL

This from only a very quick look at RBN spots from the day I believe
K8AZT's wrong-band RBN spot happened on - but all of the 14 wrong-band
RBN spots from that skimmer had a relationship between the wrong-band
spotted & the actual frequencies the stations were on (based on where
all the other skimmers were spotting those 14 stations at the time).

In the course of looking those up, I noticed another wrong-band RBN spot
from KQ8M's skimmer that wrong-band spotted M0TRN above.

Also found in the course of looking at not quite all of the 13 calls
spotted on 10m by the skimmer that wrong-band spotted K8AZT
(coincidentally another K3 owner), were three wrong-band RBN spots from
yet another skimmer.

Not sure, but I think all three skimmers concerned use Softrock SDRs
(standalone, not IF).

Well spotted, gentlemen. No worries about your K3s, but anyone into RBN
might bear in mind I see about at least 3% of what was RBN spotted on
one day by one of these three skimmers (together roughly 2.5% of
skimmers QRV in the past 7 days) was spotted on 10, 15 or 20 when the
station was actually on 40m. I even found two of these skimmers saying
one station's CQ was on both 28031 & 14043 at the same time (not a
multi-multi contest station & it was a GMT Monday). A more thorough
look into all the possible Softrock spurious response RBN spots might be
interesting, but beyond me. I'm rather surprised at how many of these
apparently LO harmonic related ones I found in such short order.

73/HLNY, ex-VR2BG/p.

> On 24 January 2012 13:08, John/K8AZT <[hidden email]> wrote:
>
>> > I have not been monitoring this mail list much recently so I
>> apologize if
>> > this
>> > subject has been discussed previously.
>> >
>> > I like to monitor the reversebeacon.net website while calling cq or just
>> > monitoring looking for a qso. Recently I have discovered a situation
>> > which has
>> > me puzzled and I am hoping someone here might be able to give me some
>> > insight
>> > what might be happening.
>> >
>> > When calling cq (CW) on 7.0 MHz cw, I see several hits on the reverse
>> > beacon
>> > website on 7.0 MHz, however I have also seen a couple stations allegedly
>> > hearing
>> > me on 10.1 MHz (2 occurrences) and a station hearing me on 28 MHz
>> bands (1
>> > occurrence). I am hoping this is a problem with the skimmers, but
>> want to
>> > check
>> > out if there is anything which might not be right with my K3 and/or
>> antenna
>> > which might be generating unwanted radiations. At the moment I do
>> not have
>> > exact frequencies where I was being monitored. I just thought someone
>> > might
>> > have a suggestion where do I proceed.
>> >
>> > At the moment I do not have access to a frequency analyzer, but hope
>> I can
>> > find
>> > one to borrow locally.
>> >
>> > Thank you for any suggestions/comments anyone in the reflector might
>> have.
>> >
>> > 73,
>> > John/K8AZT

John/K8AZT

Re: K3 spurious radiation?

In reply to this post by John/K8AZT

Thank you to all who have taken the time to respond to my question regarding
possible false spots by the skimmer receivers used for reporting on
reversebeacon web site. I appreciate all the responses.

73,
John/K8AZT
______________________________________________________________
Elecraft mailing list
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

Pete Smith N4ZR

Re: K3 spurious radiation?

We're actively chasing a few cases where this has happened on the RBN.
Obviously we'd prefer it didn't. One hypothesis for phantom spots on
the low bands is strong AM broadcast stations causing clipping and
resulting in intermod. Another appears to have been caused by
interaction between recording software sharing the USB data stream with
SkimSrv. As far as I know, though, all of these issues are in-band
phantoms, which would not explain those spots on another band altogether.

73, Pete N4ZR
The World Contest Station Database, updated daily at www.conteststations.com
The Reverse Beacon Network at http://reversebeacon.net, blog at reversebeacon.blogspot.com,
spots at telnet.reversebeacon.net, port 7000 and
arcluster.reversebeacon.net, port 7000

On 1/26/2012 6:27 PM, John/K8AZT wrote:

> Thank you to all who have taken the time to respond to my question regarding
> possible false spots by the skimmer receivers used for reporting on
> reversebeacon web site. I appreciate all the responses.
>
> 73,
> John/K8AZT
> ______________________________________________________________
> 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
>
>

Thomas Horsten

Re: K3 spurious radiation?

In reply to this post by John/K8AZT

>From the SoftRock Lite build
guide<http://www.wb5rvz.com/sdr/sr_lite_ii/02_lo.htm> -
I guess this could explain what we're seeing:

Sub-harmonic Sampling

Alan, G4ZFQ points out that on the 30m, 20m, 15m receivers, the Local
Oscillator produces a signal that is 4/3 times the desired center frequency
as opposed to the 4x the center frequency output for the lower band models.

"Subharmonic" works like this:- The LO outputs a 13.5MHz signl that goes to
the dividers /4, resulting in 1 3.375MHz square wave ( rich in odd
harmonics) being fed to the mixer. At the mixer, a strong 3rd harmonic is
present on the clock inputs, along with the fundamental of 3.375 MHz. The
3.375 fundamental multiplied by 3 yields the third harmonic of 10.125MHZ.
The Bandpass filter (BPF) performs the essential function of severely
attenuating any signals centered around the 3.375MHz fundamental frequency
and first harmonmic, but allows 30m signals centering around the third
harmonic of the 3.375MHz LO output. The result is that the mixer is dealing
with signals in the passband, centering on 10.125MHz, as though the
dividers were passing a fundamental frequency of 10.125 to the mixer. BPFs
are all that stop Softrocks from working on unwanted frequencies

73, Thomas M0TRN

On 24 January 2012 13:08, John/K8AZT <[hidden email]> wrote: