I don’t am still puzzled why the digital modes decided to use the 1837 to 1839
area with the size of the 160 M band. I know the SSB guys use a lot of the
1840-1900 area but 1900 to 2000 is usable isn’t it? I rarely hear much up
there and 3 or 4 khz up there would never be missed. Probably not an answer
but it has seemed strange to me since they started operating in that area.
Some of their signals are bone crushing and wide. 73 Mike K4PI
From: topband-request@contesting.com
Sent: Tuesday, December 31, 2013 12:00 PM
To: topband@contesting.com
Subject: Topband Digest, Vol 132, Issue 30
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than "Re: Contents of Topband digest..."
Today's Topics:
1. Digital mode spurious issues (Tom W8JI)
2. Re: Digital mode spurious issues (Mike Waters)
3. Re: Digital mode spurious issues (Jim Brown)
4. Re: Digital mode spurious issues (Richard (Rick) Karlquist)
5. Re: Digital mode spurious issues (Joe Subich, W4TV)
6. Re: Digital mode spurious issues (Charlie Cunningham)
7. Re: Digital mode spurious issues (Jim Brown)
8. Re: [CQ-Contest] Stew Perry Streaming Audio (Herb Schoenbohm)
9. Re: Digital mode spurious issues (Grant Saviers)
10. Re: Digital mode spurious issues (W2RU - Bud Hippisley)
11. Re: Digital mode spurious issues (Mike Waters)
12. Re: Digital mode spurious issues (Charlie Cunningham)
13. Re: Digital mode spurious issues (JC N4IS)
14. Re: Digital mode spurious issues (Mike Waters)
15. Re: Digital mode spurious issues (Tom W8JI)
16. Re: Digital mode spurious issues (Charlie Cunningham)
17. Re: Digital mode spurious issues (Steven Raas)
18. Re: Digital mode spurious issues (Mike Waters)
19. Re: Stew Perry Streaming Audio (Shoppa, Tim)
20. CA/OR/AZ activity during Stew Perry - anecdotal data (Barry N1EU)
21. Re: Digital mode spurious issues (Tom W8JI)
----------------------------------------------------------------------
Message: 1
Date: Mon, 30 Dec 2013 12:11:49 -0500
From: "Tom W8JI" <w8ji@w8ji.com>
To: "Topband" <topband@contesting.com>
Subject: Topband: Digital mode spurious issues
Message-ID: <AB0B5258E3B345428ADE0FAFD65179C0@MAIN>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=response
I have not been on the air for a year or so, but decided to get back on. I
was listening to a DX station around 1833 when a digimode station up roughly
around 1837 came on with a LSB "spurious" signal on 1833. His signal was a
series of slowly changing stepped tones. I don't know what mode that was.
His unwanted sideband suppression was about 40 dB, but that was not nearly
enough. He was 15 dB out of noise with his unwanted sideband.
Does anyone know of a universal software to decode signals? Since the FCC
does not require a CW ID, I think that is the only way to identify stations.
I assume:
1.) Operators are unlikely to accept they have a problem if they are getting
good reports on the intentional signal
2.) Some rigs just should not be used for digimodes (this was a sideband
suppression issue)
3.) Those who unwisely placed digimode subbands next to popular weak signal
areas, especially when sideband selection produces a supurious that falls in
weak signal areas, are unlikely to rethink the poor placement or poor advice
on selecting sidebands
4.) With a little work to convince them, most digital ops with radio
problems would avoid operating
73 Tom
------------------------------
Message: 2
Date: Mon, 30 Dec 2013 12:30:34 -0600
From: Mike Waters <mikewate@gmail.com>
To: Tom W8JI <w8ji@w8ji.com>
Cc: Topband <topband@contesting.com>
Subject: Re: Topband: Digital mode spurious issues
Message-ID:
<CA+FxYXj7jeqKdTtR1BWSWZU-ZjsC0h79YN8HhjDfJKs+xLzQPA@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Tom,
I believe the mode that operates at 1873-1838 is JT65, and WSJT is needed
to decode it. I never tried it. It was developed by K1JT for weak-signal
and EME work.
http://www.physics.princeton.edu/pulsar/K1JT/wsjt.html
A common scenario with digital modes is that the audio into the mic input
is too high, causing unwanted spurs.
73, Mike
www.w0btu.com
On Mon, Dec 30, 2013 at 11:11 AM, Tom W8JI <w8ji@w8ji.com> wrote:
> ... a digimode station up roughly around 1837 came on with a LSB
> "spurious" signal on 1833. His signal was a series of slowly changing
> stepped tones. I don't know what mode that was. His unwanted sideband
> suppression was about 40 dB, but that was not nearly enough. He was 15 dB
> out of noise with his unwanted sideband.
>
> Does anyone know of a universal software to decode signals? Since the FCC
> does not require a CW ID, I think that is the only way to identify
> stations. ...
>
------------------------------
Message: 3
Date: Mon, 30 Dec 2013 14:17:57 -0800
From: Jim Brown <jim@audiosystemsgroup.com>
To: topband@contesting.com
Subject: Re: Topband: Digital mode spurious issues
Message-ID: <52C1F115.6050304@audiosystemsgroup.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
You're both right -- it is either JT65 or JT9. WSJT software, based on
protocols developed by K1JT, will decode both modes. Another software
package called JT65-HF will decode only JT65.
And yes, the trash Tom was hearing was either overdriven audio or a
crummy radio or both. Some of the newer hams using these modes are also
using pretty crummy radios -- all-banders in the $900 price range. OTOH,
most are running flea power -- 20W is QRO for this crowd.
I've done a fair amount of JT65, mostly on 6M and 160M, using my K3.
I've also used other K1JT modes designed for meteor scatter (FSK441) and
ionospheric scatter (SCAT). JT9 is Joe's latest and greatest protocol,
requiring a fraction of the bandwidth of JT65.
73, Jim K9YC
On 12/30/2013 10:30 AM, Mike Waters wrote:
> I believe the mode that operates at 1873-1838 is JT65, and WSJT is needed
> to decode it. I never tried it. It was developed by K1JT for weak-signal
> and EME work.
> http://www.physics.princeton.edu/pulsar/K1JT/wsjt.html
>
> A common scenario with digital modes is that the audio into the mic input
> is too high, causing unwanted spurs.
------------------------------
Message: 4
Date: Mon, 30 Dec 2013 14:59:13 -0800
From: "Richard (Rick) Karlquist" <richard@karlquist.com>
To: topband@contesting.com
Subject: Re: Topband: Digital mode spurious issues
Message-ID: <52C1FAC1.2000809@karlquist.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
The simplest technical solution would be for the
digital mode users to put the radio in LSB mode.
This puts unwanted sideband QRM away from the
DX CW window. Does the Joe Taylor software have
a provision for this?
Rick N6RK
------------------------------
Message: 5
Date: Mon, 30 Dec 2013 18:05:12 -0500
From: "Joe Subich, W4TV" <lists@subich.com>
To: topband@contesting.com
Subject: Re: Topband: Digital mode spurious issues
Message-ID: <52C1FC28.60806@subich.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> Does the Joe Taylor software have a provision for this?
No, Joe Taylor's protocols are not capable of operating in LSB.
73,
... Joe, W4TV
On 12/30/2013 5:59 PM, Richard (Rick) Karlquist wrote:
> The simplest technical solution would be for the
> digital mode users to put the radio in LSB mode.
> This puts unwanted sideband QRM away from the
> DX CW window. Does the Joe Taylor software have
> a provision for this?
>
> Rick N6RK
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
>
------------------------------
Message: 6
Date: Mon, 30 Dec 2013 18:13:47 -0500
From: "Charlie Cunningham" <charlie-cunningham@nc.rr.com>
To: "'Joe Subich, W4TV'" <lists@subich.com>, <topband@contesting.com>
Subject: Re: Topband: Digital mode spurious issues
Message-ID:
<!&!AAAAAAAAAAAYAAAAAAAAAF0xXac1rOhFkn7GlcEWNIjCgAAAEAAAABg31XzAMKNCvuYjy/t7uksBAAAAAA==@nc.rr.com>
Content-Type: text/plain; charset="us-ascii"
I would think that IMD products in a high-level PA that is over-driven
beyond good linearity limits could add some junk in the "undesired
sideband"? FWIW
Charlie, K4OTV
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Joe
Subich, W4TV
Sent: Monday, December 30, 2013 6:05 PM
To: topband@contesting.com
Subject: Re: Topband: Digital mode spurious issues
> Does the Joe Taylor software have a provision for this?
No, Joe Taylor's protocols are not capable of operating in LSB.
73,
... Joe, W4TV
On 12/30/2013 5:59 PM, Richard (Rick) Karlquist wrote:
> The simplest technical solution would be for the digital mode users to
> put the radio in LSB mode.
> This puts unwanted sideband QRM away from the DX CW window. Does the
> Joe Taylor software have a provision for this?
>
> Rick N6RK
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
>
_________________
Topband Reflector Archives - http://www.contesting.com/_topband
------------------------------
Message: 7
Date: Mon, 30 Dec 2013 15:51:38 -0800
From: Jim Brown <jim@audiosystemsgroup.com>
To: topband@contesting.com
Subject: Re: Topband: Digital mode spurious issues
Message-ID: <52C2070A.40705@audiosystemsgroup.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
On 12/30/2013 3:13 PM, Charlie Cunningham wrote:
> I would think that IMD products in a high-level PA that is over-driven
> beyond good linearity limits could add some junk in the "undesired
> sideband"? FWIW
Yes. Indeed, any IMD would do that. K6XX is an Elecraft engineer who
worked on their KPA500, among other things, and looked at a lot of
competing power amps in preparation for doing so. Bob recently did an
excellent tutorial presentation to a meeting of the Northern California
Contest Club about the root causes of sideband trash, the general
properties of various amplifier types, and how to minimize the trash.
In general:
Distortion products increase when the antenna is poorly matched to the
amplifier That's true whether it's a tuned tube amp or a fixed tuned
solid state amp -- in other words, the tube amp must be carefully tuned,
and the solid state amp should be used with a tuner if the antenna is
not an ideal match.
Distortion products increase as power supply voltage decreases. In other
words, a rig designed to run on 13.8 volts will be much cleaner at 13.8
volts than at 12V.
Most solid state output stages are cleaner at half power than at full
power. That means that a rig will be cleaner driving a power amp at 50W
than at 100 W.
Using AGC between the power amp and the rig to set output level is a
recipe for sideband trash.
A properly tuned hollow state power amp is typically 8-10 dB cleaner
than the best solid state amps.
Fast rise time of the keying waveform is the major cause of clicks W8JI
and others long ago identified this as the cause of the FT1000-series
rigs awful clicks, and fixed them. The rise time of some rigs (notably
the IC7600) is adjustable, and only the slowest rise time is acceptable.
The K3 uses an optimally shaped keying waveform (which designer N6KR
calls "sigmoidal") to minimize clicks, and it is not user adjustable.
Most ICOM rigs have overshoot that also causes clicks.
Something I learned from N6KR a few days ago is that the very low level
of sideband trash from a K3 is the result of two design elements. First,
the synthesizer is very clean.. Second, they run it through the TX
crystal filter, which gets rid of trash more distant from the carrier.
73, Jim K9YC
------------------------------
Message: 8
Date: Mon, 30 Dec 2013 20:39:45 -0400
From: Herb Schoenbohm <herbs@vitelcom.net>
To: topband@contesting.com
Subject: Re: Topband: [CQ-Contest] Stew Perry Streaming Audio
Message-ID: <52C21251.6010200@vitelcom.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
This is just not possible anymore and there are so many situations like
Greg experiences where the only hope to hear anything is by employing
new technology. Also the 100KM rule, if there is such a rule, is
intriguing because a remote RX in the BVI (a different DXCC country)
would really be nice now that I have a new ham a few blocks away running
a CQ machine during the contest in the DX window for the duration of the
contest. Problems such as this along with high urban QRN are much more
common and solution will be found. To arbitrarily block new innovations
and technology to solve some of these issues is to me not going in the
right direction. I think a better approach would be to allow for
different categories creating incentives for inovations, rather than
just outright ban them.
Herb Schoenbohm, KV4FZ
On 12/28/2013 4:19 PM, Greg - ZL3IX wrote:
> "enjoy the contest the way we did back when Stew Perry was around"
------------------------------
Message: 9
Date: Mon, 30 Dec 2013 17:12:10 -0800
From: Grant Saviers <grants2@pacbell.net>
To: Tom W8JI <w8ji@w8ji.com>, Topband <topband@contesting.com>
Subject: Re: Topband: Digital mode spurious issues
Message-ID: <52C219EA.6040106@pacbell.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
The SignaLink supported software page has a nice summary of software
decoders see http://www.tigertronics.com/sl_soft.htm
If "universal" means automatic selection of the correct decoding mode,
that would be a challenge!
Grant KZ1W
On 12/30/2013 9:11 AM, Tom W8JI wrote:
> I have not been on the air for a year or so, but decided to get back
> on. I was listening to a DX station around 1833 when a digimode
> station up roughly around 1837 came on with a LSB "spurious" signal on
> 1833. His signal was a series of slowly changing stepped tones. I
> don't know what mode that was. His unwanted sideband suppression was
> about 40 dB, but that was not nearly enough. He was 15 dB out of noise
> with his unwanted sideband.
>
> Does anyone know of a universal software to decode signals? Since the
> FCC does not require a CW ID, I think that is the only way to identify
> stations.
>
> I assume:
>
> 1.) Operators are unlikely to accept they have a problem if they are
> getting good reports on the intentional signal
>
> 2.) Some rigs just should not be used for digimodes (this was a
> sideband suppression issue)
>
> 3.) Those who unwisely placed digimode subbands next to popular weak
> signal areas, especially when sideband selection produces a supurious
> that falls in weak signal areas, are unlikely to rethink the poor
> placement or poor advice on selecting sidebands
>
> 4.) With a little work to convince them, most digital ops with radio
> problems would avoid operating
>
> 73 Tom
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
>
------------------------------
Message: 10
Date: Mon, 30 Dec 2013 20:32:37 -0500
From: W2RU - Bud Hippisley <W2RU@frontiernet.net>
To: jim@audiosystemsgroup.com
Cc: topband@contesting.com
Subject: Re: Topband: Digital mode spurious issues
Message-ID: <656317B8-1858-42F1-9FFD-23DDE17534A6@frontiernet.net>
Content-Type: text/plain; charset=us-ascii
This is a little off-topic relative to the Subject line, but extremely relevant
to enjoyable Topband operating:
On Dec 30, 2013, at 6:51 38PM, Jim Brown <jim@audiosystemsgroup.com> wrote:
> Fast rise time of the keying waveform is the major cause of clicks. W8JI and
> others long ago identified this as the cause of the FT1000-series rigs awful
> clicks, and fixed them. The rise time of some rigs (notably the IC7600) is
> adjustable, and only the slowest rise time is acceptable.
Add the venerable Kenwood TS-950SDX to the list of rigs with user-adjustable
rise/fall times. And -- as Jim notes -- only the slowest rise time is fully
acceptable, despite the pains Kenwood took to carefully "shape" those RF
waveforms during their "on" and "off" transition periods.
In the case of the 950SDX, the user can select nominal rise/fall times labeled
2, 4, 6, or 8 milliseconds (ms) from one of the configuration menus accessible
via the front panel MENU options. A few years back, in extensive tests on a
daytime 80-m band with an equally fanatical friend listening critically, we
determined that -only- the 8-ms setting was "clean" with respect to click
generation. Probably the 6-ms setting would be marginally "OK" if the
transmitted signal were not loud anywhere, but since my usual objective when
chasing DX on 160 is to be as loud as I can, 6 ms is not really an acceptable
solution for maintaining good relations with my close-in Topband "neighbors"
here on the east coast of North America. Once we ran those tests, I set the
TS-950SDX menu choice to 8 ms, and I've not changed it since.
Bud, W2RU
------------------------------
Message: 11
Date: Mon, 30 Dec 2013 20:12:33 -0600
From: Mike Waters <mikewate@gmail.com>
To: topband <topband@contesting.com>
Subject: Re: Topband: Digital mode spurious issues
Message-ID:
<CA+FxYXiRKZnGLMKGdN1aTsFzBFkrGdY03znWG59EtadKSmF+jQ@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
You are right. There is no universal software that can do that. But I used
to code software, and I'm convinced that the status quo in amateur digital
software can be greatly improved. See
http://www.eham.net/ehamforum/smf/index.php?topic=80740.0 .
If anyone wants to take up where we left off on that eHam thread, then
let's take the discussion there.
73, Mike
www.w0btu.com
On Mon, Dec 30, 2013 at 7:12 PM, Grant Saviers <grants2@pacbell.net> wrote:
>
> If "universal" means automatic selection of the correct decoding mode,
> that would be a challenge!
>
------------------------------
Message: 12
Date: Mon, 30 Dec 2013 21:34:26 -0500
From: "Charlie Cunningham" <charlie-cunningham@nc.rr.com>
To: <jim@audiosystemsgroup.com>, <topband@contesting.com>
Subject: Re: Topband: Digital mode spurious issues
Message-ID:
<!&!AAAAAAAAAAAYAAAAAAAAAF0xXac1rOhFkn7GlcEWNIjCgAAAEAAAAJjC6JAJz/RMjAuEvO+ytjsBAAAAAA==@nc.rr.com>
Content-Type: text/plain; charset="us-ascii"
Hi, Jim
Well as one who has been an RF and radio engineer and designer for 40+
years, I have to agree with most all of your points. Great deal of truth in
there, but so many guys don't appreciate all those things and their
inclination is "crank it to the right" and "the "louder you shout, the
further you get"! And they are looking for large meter excursions. To
appreciate the tendency to overdrive transmitters and amplifiers. One need
only listen to the the prevalence of awful key clicks and SSB splatter in
contests!
(And "real men" use vacuum tubes to develop "real power"! :-) )
73,
Charie, K4OTV
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Jim Brown
Sent: Monday, December 30, 2013 6:52 PM
To: topband@contesting.com
Subject: Re: Topband: Digital mode spurious issues
On 12/30/2013 3:13 PM, Charlie Cunningham wrote:
> I would think that IMD products in a high-level PA that is over-driven
> beyond good linearity limits could add some junk in the "undesired
> sideband"? FWIW
Yes. Indeed, any IMD would do that. K6XX is an Elecraft engineer who
worked on their KPA500, among other things, and looked at a lot of
competing power amps in preparation for doing so. Bob recently did an
excellent tutorial presentation to a meeting of the Northern California
Contest Club about the root causes of sideband trash, the general
properties of various amplifier types, and how to minimize the trash.
In general:
Distortion products increase when the antenna is poorly matched to the
amplifier That's true whether it's a tuned tube amp or a fixed tuned
solid state amp -- in other words, the tube amp must be carefully tuned,
and the solid state amp should be used with a tuner if the antenna is
not an ideal match.
Distortion products increase as power supply voltage decreases. In other
words, a rig designed to run on 13.8 volts will be much cleaner at 13.8
volts than at 12V.
Most solid state output stages are cleaner at half power than at full
power. That means that a rig will be cleaner driving a power amp at 50W
than at 100 W.
Using AGC between the power amp and the rig to set output level is a
recipe for sideband trash.
A properly tuned hollow state power amp is typically 8-10 dB cleaner
than the best solid state amps.
Fast rise time of the keying waveform is the major cause of clicks W8JI
and others long ago identified this as the cause of the FT1000-series
rigs awful clicks, and fixed them. The rise time of some rigs (notably
the IC7600) is adjustable, and only the slowest rise time is acceptable.
The K3 uses an optimally shaped keying waveform (which designer N6KR
calls "sigmoidal") to minimize clicks, and it is not user adjustable.
Most ICOM rigs have overshoot that also causes clicks.
Something I learned from N6KR a few days ago is that the very low level
of sideband trash from a K3 is the result of two design elements. First,
the synthesizer is very clean.. Second, they run it through the TX
crystal filter, which gets rid of trash more distant from the carrier.
73, Jim K9YC
_________________
Topband Reflector Archives - http://www.contesting.com/_topband
------------------------------
Message: 13
Date: Mon, 30 Dec 2013 21:50:47 -0500
From: "JC N4IS" <n4is@comcast.net>
To: "'Mike Waters'" <mikewate@gmail.com>, "'Tom W8JI'" <w8ji@w8ji.com>
Cc: 'Topband' <topband@contesting.com>
Subject: Re: Topband: Digital mode spurious issues
Message-ID: <005801cf05d3$1bd5f9c0$5381ed40$@comcast.net>
Content-Type: text/plain; charset="us-ascii"
Tom, Mike is right, the issue with audio overload is complex for most of
new radios, most of them have A/D just at the MIC input, if the A/D
overloads the RF chain is compromised. These radios have no actual filters,
everything is digital, like the IC7600. An analog radio is BW limited by the
SSB crystal filter but SDR don't, when the A/D overloads, there are spoors
everywhere several KHz far from the carrier; enough to trash the entire
band.
Using a SDR water fall it is easy to see the signal transitions and
associate the trash with the main signal. I've seen several spoors every 10
KHz almost 100KHz up and down 1838. This is a growing problem.
73, JC
N4IS
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Mike
Waters
Sent: Monday, December 30, 2013 1:31 PM
To: Tom W8JI
Cc: Topband
Subject: Re: Topband: Digital mode spurious issues
Tom,
I believe the mode that operates at 1873-1838 is JT65, and WSJT is needed to
decode it. I never tried it. It was developed by K1JT for weak-signal and
EME work.
http://www.physics.princeton.edu/pulsar/K1JT/wsjt.html
A common scenario with digital modes is that the audio into the mic input is
too high, causing unwanted spurs.
73, Mike
www.w0btu.com
On Mon, Dec 30, 2013 at 11:11 AM, Tom W8JI <w8ji@w8ji.com> wrote:
> ... a digimode station up roughly around 1837 came on with a LSB
> "spurious" signal on 1833. His signal was a series of slowly changing
> stepped tones. I don't know what mode that was. His unwanted sideband
> suppression was about 40 dB, but that was not nearly enough. He was 15
> dB out of noise with his unwanted sideband.
>
> Does anyone know of a universal software to decode signals? Since the
> FCC does not require a CW ID, I think that is the only way to identify
> stations. ...
>
_________________
Topband Reflector Archives - http://www.contesting.com/_topband
------------------------------
Message: 14
Date: Mon, 30 Dec 2013 21:17:28 -0600
From: Mike Waters <mikewate@gmail.com>
To: topband <topband@contesting.com>
Subject: Re: Topband: Digital mode spurious issues
Message-ID:
<CA+FxYXikYNQqzEAf+rHdJkNG1ztop1_V3UbBiTauLsRzpMqQ_g@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Bingo! The waterfall display was a wonderful invention, wasn't it? And I
don't even use SDR. (Yet.)
When I used to operate PSK31, I adjusted the audio levels with my own
signal displayed on the waterfall, and so it was easy to see when the input
from the sound card was too high. The spurs from AF overload are very easy
to see on the waterfall.
73, Mike
www.w0btu.com
On Mon, Dec 30, 2013 at 8:50 PM, JC N4IS <n4is@comcast.net> wrote:
>
> Using a SDR water fall it is easy to see the signal transitions and
> associate the trash with the main signal. I've seen several spoors every 10
> KHz almost 100KHz up and down 1838. This is a growing problem.
>
------------------------------
Message: 15
Date: Mon, 30 Dec 2013 22:55:46 -0500
From: "Tom W8JI" <w8ji@w8ji.com>
To: <topband@contesting.com>
Subject: Re: Topband: Digital mode spurious issues
Message-ID: <11A6F15D3D9F452F83930E7A3EBDA10F@MAIN>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Thanks everyone for the suggestions. I'm going to have to install some
software to identify some of the signals.
>I would think that IMD products in a high-level PA that is over-driven
> beyond good linearity limits could add some junk in the "undesired
> sideband"? FWIW
>
IMD **requires** two or more signals at once, and does not appear anything
like sideband leakage. This was a single shifting tone, and the lower
frequency signal went the opposite way but the same amount as the main
signal with shifts. That is classic for inadequate sideband suppression.
There are multiple problems with using SSB to transmit audio tones and
"thinking" it is a pure digi mode.
1.) things like this do not show on almost all digi waterfalls because they
are out of passband of the other fellows receiver.
2.) SSB carrier, noise, and opposite sideband suppression is limited by the
radio quality
3.) output purity is also limited by audio input purity, which includes
audio line issues
4.) most digi operators do not have the low noise antennas most DXers have,
and cannot hear some fairly strong signals. They are often on digimodes
because of that!
5.) radios have terrible SSB transmitter performance compared to even fair
receivers, so the transmitters often set the adjacent channel interference
levels
Placing digimodes near weak signal areas is not very wise frequency
planning, but there is nothing anyone can do about it.
------------------------------
Message: 16
Date: Mon, 30 Dec 2013 23:28:41 -0500
From: "Charlie Cunningham" <charlie-cunningham@nc.rr.com>
To: "'Tom W8JI'" <w8ji@w8ji.com>, <topband@contesting.com>
Subject: Re: Topband: Digital mode spurious issues
Message-ID:
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Well, I certainly have to agree, Tom, if the signal on the desired sideband
is just a single shifting tone. Might get messier if an sudio stage or A/D
is driven into limiting and producing harmonic distortion at audio, I guess.
73,
Charlie, K4OTV
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Tom W8JI
Sent: Monday, December 30, 2013 10:56 PM
To: topband@contesting.com
Subject: Re: Topband: Digital mode spurious issues
Thanks everyone for the suggestions. I'm going to have to install some
software to identify some of the signals.
>I would think that IMD products in a high-level PA that is over-driven
> beyond good linearity limits could add some junk in the "undesired
> sideband"? FWIW
>
IMD **requires** two or more signals at once, and does not appear anything
like sideband leakage. This was a single shifting tone, and the lower
frequency signal went the opposite way but the same amount as the main
signal with shifts. That is classic for inadequate sideband suppression.
There are multiple problems with using SSB to transmit audio tones and
"thinking" it is a pure digi mode.
1.) things like this do not show on almost all digi waterfalls because they
are out of passband of the other fellows receiver.
2.) SSB carrier, noise, and opposite sideband suppression is limited by the
radio quality
3.) output purity is also limited by audio input purity, which includes
audio line issues
4.) most digi operators do not have the low noise antennas most DXers have,
and cannot hear some fairly strong signals. They are often on digimodes
because of that!
5.) radios have terrible SSB transmitter performance compared to even fair
receivers, so the transmitters often set the adjacent channel interference
levels
Placing digimodes near weak signal areas is not very wise frequency
planning, but there is nothing anyone can do about it.
_________________
Topband Reflector Archives - http://www.contesting.com/_topband
------------------------------
Message: 17
Date: Mon, 30 Dec 2013 23:29:09 -0500
From: Steven Raas <sjraas@gmail.com>
To: Tom W8JI <w8ji@w8ji.com>
Cc: "topband@contesting.com" <topband@contesting.com>
Subject: Re: Topband: Digital mode spurious issues
Message-ID:
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Content-Type: text/plain; charset=ISO-8859-1
Tom,
I would have to agree. Let me also add my personal experiences on 160m
JT65, were good, however, at the latter stages of me being QRV on the band,
I was very politely spoken to, and delightfully educated on such matters by
Les, KL7J , whom really gave me some great insight on a then and still new
band to me, for this I am ever grateful. We tried to contact on many
occasions a few years back on 160M JT-65, however the latter attempts were
lower in the band , 1807 ish or so if I recall. I was one of the many daily
160M ops for quite some time, but after learning, & progressing, if I was
QRV on 160 at the moment, I would take it ( digital ops ) down the band. I
will also admit, that I was lured with the possibility ( at those times )
of my 1st trans-oceanic 160m QSO using JT65 ( or any mode ) , with my
experiences now, I would say that waiting for prop, and running 4 or 5 cw
q's was much easier for those 1st trans-oceanic q's. Not to mention that
the long deep fades that I had ( with very very limited antennas which are
frequently common with 160 digi mode ops ) would not be very beneficial for
JT65 ' long haul / high qsb qso's, however this is not always the case. I
can even say that to this day, I had yet to work any DX on 160m JT-65, cw
now, is a different story thankfully :) There is also WSPR activity in
that area of the band if I recall ( that may have changed ) amongst a few
others. I think that progress could be made in getting the digi ops to qsy,
perhaps to the lower end of the band, I'll be honest tho, I think that the
hardest part would be getting the word out to the masses, however when
presented with facts, and honest concern with the forsight of keeping the
band active and everyone happy, my guess is that few would gripe.. but the
masses just want to make qso's like the rest of us, and would in time
oblige. I digress..have a great new year everyone & enjoy !
-Steve Raas
N2JDQ
On Mon, Dec 30, 2013 at 10:55 PM, Tom W8JI <w8ji@w8ji.com> wrote:
> Thanks everyone for the suggestions. I'm going to have to install some
> software to identify some of the signals.
>
>
>
> I would think that IMD products in a high-level PA that is over-driven
>> beyond good linearity limits could add some junk in the "undesired
>> sideband"? FWIW
>>
>>
> IMD **requires** two or more signals at once, and does not appear anything
> like sideband leakage. This was a single shifting tone, and the lower
> frequency signal went the opposite way but the same amount as the main
> signal with shifts. That is classic for inadequate sideband suppression.
>
> There are multiple problems with using SSB to transmit audio tones and
> "thinking" it is a pure digi mode.
>
> 1.) things like this do not show on almost all digi waterfalls because
> they are out of passband of the other fellows receiver.
>
> 2.) SSB carrier, noise, and opposite sideband suppression is limited by
> the radio quality
>
> 3.) output purity is also limited by audio input purity, which includes
> audio line issues
>
> 4.) most digi operators do not have the low noise antennas most DXers
> have, and cannot hear some fairly strong signals. They are often on
> digimodes because of that!
>
> 5.) radios have terrible SSB transmitter performance compared to even fair
> receivers, so the transmitters often set the adjacent channel interference
> levels
>
> Placing digimodes near weak signal areas is not very wise frequency
> planning, but there is nothing anyone can do about it.
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
>
------------------------------
Message: 18
Date: Mon, 30 Dec 2013 22:48:18 -0600
From: Mike Waters <mikewate@gmail.com>
To: topband <topband@contesting.com>
Subject: Re: Topband: Digital mode spurious issues
Message-ID:
<CA+FxYXjOemiJtEBo+HJsWjeeNBZvc8YVEwx8tgEQhoCJ-8Mfcg@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Maybe not.
I got a private e-mail earlier (which I haven't had time to respond to yet)
that stated "To see who is QRV on 160M WSPR at any given time, check at
http://wsprnet.org/drupal/wsprnet/activity
Scroll down to 160M and the stations are listed (those followed by an R are
just receiving)."
73, Mike
www.w0btu.com
On Mon, Dec 30, 2013 at 9:55 PM, Tom W8JI <w8ji@w8ji.com> wrote:
> Thanks everyone for the suggestions. I'm going to have to install some
> software to identify some of the signals.
>
------------------------------
Message: 19
Date: Tue, 31 Dec 2013 13:49:06 +0000
From: "Shoppa, Tim" <tshoppa@wmata.com>
Cc: "topband@contesting.com" <topband@contesting.com>
Subject: Re: Topband: Stew Perry Streaming Audio
Message-ID:
<303A17BD5F8FA34DA45EEC245271AC0B949D647F@JGEX2K10MBX2.wmata.local>
Content-Type: text/plain; charset="us-ascii"
I always set these software-based goals before the test, but funny how they get
delayed in the face of driving kids around to acitivities and stringing up
antennas in the trees, and then when the sun goes down and the contest starts
swinging, all those pie in the sky virtual dreams evaporate in the face of real
QSO's to be made :-)
I had a lot of fun in the Stew Perry and felt my new west-facing pennant was an
improvement for stations in the deeper west and on west coast. I'm sure I
didn't hear some low power California stations that tried to call me.
Tim N3QE
________________________________________
From: Shoppa, Tim
Sent: Saturday, December 28, 2013 9:58 AM
Cc: topband@contesting.com
Subject: RE: Topband: Stew Perry Streaming Audio
Streaming audio live during the contest doesn't seem particularly useful to me.
But recordings made available post-contest over the web, those might be
interesting to others. I'm going to see if I can set that up at my (much more
modest) shack. I would love to hear what my signal sounds like on West Coast or
in EU.
Tim N3QE
________________________________________
From: Topband [topband-bounces@contesting.com] on behalf of Tree [tree@kkn.net]
Sent: Saturday, December 28, 2013 9:39 AM
To: Eric NO3M
Cc: Stan Stockton; topband@contesting.com; cq-contest@contesting.com; Clive
GM3POI
Subject: Re: Topband: Stew Perry Streaming Audio
Perhaps a different approach is to make it available to people who are
interested in hearing it. There are probably some people who are not able
to operate the contest and would appreciate the opportunity to hear what it
sounds like. Also - Eric is a top notch operator and being able to listen
to how he uses two radios might be educational for some.
I really doubt there is going to be abuse of this - despite what our
imaginations come up with. I know K5ZD and others have done this for other
major contests.
Tree N6TR
On Sat, Dec 28, 2013 at 3:39 AM, Eric NO3M <no3m@no3m.net> wrote:
> Since there seems to be too much concern over this, though no ill intent
> was intended, audio will not be broadcast.
>
> GL / 73 Eric NO3M
>
> On 12/28/2013 06:23 AM, Stan Stockton wrote:
>
>> Eric,
>>
>> You made it clear what you were doing, and I am quite sure Clive
>> understood. I think the logic behind his question has to do with whether
>> it is within the spirit of the contest - especially this one. Let's say,
>> as a result of the announcement or advertisement , 15 DX stations and 25
>> USA stations who are not even going to send in their log called you, just
>> for fun and the novelty of it, so they could listen to their own signal at
>> your end via Internet.
>>
>> What if some have enough QRM or QRN that they could only copy whether you
>> came back to them by listening via internet? Fair to your competitors?
>>
>> It is cool, but I've always had a problem with this, regardless of what
>> contest.
>>
>> 73...Stan, K5GO
>>
>> Sent from my iPad
>>
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
>
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------------------------------
Message: 20
Date: Tue, 31 Dec 2013 09:21:38 -0500
From: Barry N1EU <barry.n1eu@gmail.com>
To: topBand List <topband@contesting.com>
Subject: Topband: CA/OR/AZ activity during Stew Perry - anecdotal data
Message-ID:
<CAFmfzDsZyK07vxthFnRs141HN_9Q6uo8HpGSOQfHAUaO86pGmw@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
I thought I'd share some data points from my Stew Perry log. Even though
propagation to the west coast seemed good from upstate NY, I had the
impression of less activity than expected from California so I looked
closer at my log. What I found was 13 q's from California and 14 q's each
from neighboring Oregon and Arizona (each with 1/7 of the ham population of
CA). Perhaps the ham population in California is disproportionately
urban/suburban with less topband activity, Californians disproportionately
go QRP in SP or ???
73 & Happy New Year,
Barry N1EU
------------------------------
Message: 21
Date: Tue, 31 Dec 2013 10:13:29 -0500
From: "Tom W8JI" <w8ji@w8ji.com>
To: "Charlie Cunningham" <charlie-cunningham@nc.rr.com>,
<topband@contesting.com>
Subject: Re: Topband: Digital mode spurious issues
Message-ID: <952FFD43F713459C9780E88B677DE50E@MAIN>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
> Well, I certainly have to agree, Tom, if the signal on the desired
> sideband
> is just a single shifting tone. Might get messier if an sudio stage or A/D
> is driven into limiting and producing harmonic distortion at audio, I
> guess.
>
The entire thing for digital modes was poorly planned. I'm surprised no one
objected to the frequency choices (of Europe), because they are technically
always going to be a long term problem. The frequency range really could not
have been more poorly planned for future long-term band use.
Any digital mode piped into the SSB transmitter system, like it or not, is
really SSB modulated. It has all the noise, carrier, and opposite sideband
suppression issues, as well as sensitivity to levels. If they transmit
1835-40 using USB on the radio, the opposite sideband falls in the 1832 and
upward range. IMD can be anywhere, if it is a multiple tone at the same time
mode. Harmonic distortion is upward from the carrier on USB.
Collins got burned by this. They tried running a pure audio tone into the
SSB transmitter of the early S line to generate CW. The FCC (back when they
did enforcement) starting handing out pink slips left and right to Collins
owners. Any carrier, noise, or harmonic distortion at all resulted in an FCC
citation, so Collins had to convert transmitters back to a keyed carrier.
Anything converted to RF in a SSB transmitter system really belongs off by
itself, well away from other operation. It's really a technical issue that
will always exist, because the basic RF generation system or idea is flawed.
------------------------------
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