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Re: Topband: Digial mode spurious issues

To: topband@contesting.com
Subject: Re: Topband: Digial mode spurious issues
From: Jim <wa3mej@comcast.net>
Date: Thu, 2 Jan 2014 02:39:53 +0000 (UTC)
List-post: <topband@contesting.com">mailto:topband@contesting.com>
Tom and all, 
T he signal you describe is indeed a JT65 signal and you can either use JT65HF 
OR WSJT-X to decode it but might I submit that the problem was with: 


1 } Improperly adjusted sound card interface i.e. over driven and drawing ALC 
(remember it is a digital signal) 


2} A poorly operating SSB transceiver where the opposite sideband has poor 
suppression. This type of transceiver will most likely QRM someone even if on 
CW or SSB. 


3.) He was running way way too much power. I never operate with more than 30 
watts {its a low power mode.. I worked VK5BC with 30w on TB ........try that 
with CW) 


As a general rule all stations operating digital use USB now on all bands but 
the program does not care which sideband you use the transceiver sets that 


Remember that the signal that enters the transceiver is digital and as such 
will splatter if the signal input draws any appreciable ALC 


I agree that if a particular signal was being heard on 33 he had a problem of 
some type. If you find him again I would be willing to make first contact ... I 
understand what signals should sound like and look like on the display. I only 
suggest this because this mode is kinda unique and uses (for the most part) 
canned messages. 


Now to why digital is where it is in the band.. although we have been here 
before....it is not by chance that digital is at that spot in the band. They 
want to have QSOs with DX stations too and there are a lot of countries that 
don't allow operation down the bottom of the band but they do allow operation 
1930-1950. Besides IF someone misses these few KHz we have a major problem with 
the way we are operating. Next I can and have operated CW directly among a 
whole wack of JT65 they didn,t know the difference and neither did I and if I 
can do it with the TINITUS others can do it. 




By the way operating digital is not about being an elite operator as someone 
suggested in one of the local chat rooms, its about doing something different 
and forging new ground.. or as James T. Kirk called it .. "Going where no one 
has gone before" 


Jim 

Long Live Seal Team VI 

http://www.qsl.net/wa3mej/index.htm 
----- Original Message -----
From: topband-request@contesting.com 
To: topband@contesting.com 
Sent: Wednesday, January 1, 2014 12:00:12 PM 
Subject: Topband Digest, Vol 133, Issue 1 

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Today's Topics: 

1. Re: Digial mode spurious issues (Mike Greenway) 
2. Re: Digial mode spurious issues (Joe Subich, W4TV) 
3. Re: Digial mode spurious issues (Mike Waters) 
4. Re: Digital mode spurious issues (Tom W8JI) 


---------------------------------------------------------------------- 

Message: 1 
Date: Tue, 31 Dec 2013 17:10:27 -0500 
From: "Mike Greenway" <K4PI@BELLSOUTH.NET> 
To: <topband@contesting.com> 
Subject: Re: Topband: Digial mode spurious issues 
Message-ID: <52A7C61BC0414D61A4DD6EB286A01A81@SHACK> 
Content-Type: text/plain; charset="utf-8" 

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 

Send Topband mailing list submissions to 
topband@contesting.com 

To subscribe or unsubscribe via the World Wide Web, visit 
http://lists.contesting.com/mailman/listinfo/topband 
or, via email, send a message with subject or body 'help' to 
topband-request@contesting.com 

You can reach the person managing the list at 
topband-owner@contesting.com 

When replying, please edit your Subject line so it is more specific 
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: 
<!&!AAAAAAAAAAAYAAAAAAAAAF0xXac1rOhFkn7GlcEWNIjCgAAAEAAAABORbRe1dtFDk174Pca2TsABAAAAAA==@nc.rr.com>
 

Content-Type: text/plain; charset="us-ascii" 

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: 
<CABOEzZoFoWUPJ9zD3b4t1yDjwjLaBKui8dnU1L+1eYB=0woMYw@mail.gmail.com> 
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 
> 
_________________ 
Topband Reflector Archives - http://www.contesting.com/_topband 


------------------------------ 

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. 



------------------------------ 

Subject: Digest Footer 

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Topband mailing list 
Topband@contesting.com 
http://lists.contesting.com/mailman/listinfo/topband 


------------------------------ 

End of Topband Digest, Vol 132, Issue 30 
**************************************** 

------------------------------ 

Message: 2 
Date: Tue, 31 Dec 2013 17:51:52 -0500 
From: "Joe Subich, W4TV" <lists@subich.com> 
To: topband@contesting.com 
Subject: Re: Topband: Digial mode spurious issues 
Message-ID: <52C34A88.3010206@subich.com> 
Content-Type: text/plain; charset=windows-1252; format=flowed 


On 12/31/2013 5:10 PM, Mike Greenway wrote: 
> I don?t am still puzzled why the digital modes decided to use the 
> 1837to 1839 area with the size of the 160 M band. 

For the same reason the SSB guys insist on using 1840-1850 ... 
with their significantly smaller band (1810-1850 in some cases) 
Region 1 put digital between CW (1810-1830) and SSB (1840-1850). 
With what is left of the "DX Window" at 1830-1835 that left 
1835-1840 for digital. 

It's an unavoidable fact of life that new activity will go where 
the existing activity is. Look at digital on 40 meters - it is 
almost all between 7030/7035 and 7045 because that's where the EU 
and JA stations are. 160 is no different, digital activity in EU 
is 1835-1840 so that's where everyone else will be if they want a 
chance to work EU. As much as it pains me to say it - if you 
want to fix the situation get ITU to expand the 160 meter band 
in Region 1 and convince IARU Region 1 to relocate both digital 
and SSB activity higher/into the expanded band. 

73, 

... Joe, W4TV 


On 12/31/2013 5:10 PM, Mike Greenway wrote: 
> I don?t am still puzzled why the digital modes decided to use the 
> 1837to 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 



------------------------------ 

Message: 3 
Date: Tue, 31 Dec 2013 17:29:57 -0600 
From: Mike Waters <mikewate@gmail.com> 
To: Mike Greenway <K4PI@bellsouth.net>, topband 
<topband@contesting.com> 
Subject: Re: Topband: Digial mode spurious issues 
Message-ID: 
<CA+FxYXimxpes9qB+SafJF2JdnM1fAvtrFd0NuBKOOg3ohw9Nbg@mail.gmail.com> 
Content-Type: text/plain; charset=windows-1252 

Absolutely! From what I see from my QTH in SW MO, 1845 would be a good 
place for JT65 to move to. There is a ragchew group that meets on 1850, but 
seldom is there much activity below that. 

I seldom listen much above 1900. Maybe you're right, that would be a better 
place. But they definitely need to move up, as there's often DX just below 
them and we are just not going to get everyone to transmit a clean digital 
signal. 

By the way, Mike, it's easy to trim the large amount of text off the end of 
your messages with Shift-Ctrl-End and then Delete. :-) I've noticed others 
here forgetting to do that lately, too. 

73, Mike 
www.w0btu.com 


On Tue, Dec 31, 2013 at 4:10 PM, Mike Greenway <K4PI@bellsouth.net> wrote: 

> 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 
> 


------------------------------ 

Message: 4 
Date: Tue, 31 Dec 2013 19:14:13 -0500 
From: "Tom W8JI" <w8ji@w8ji.com> 
To: <topband@contesting.com> 
Subject: Re: Topband: Digital mode spurious issues 
Message-ID: <18EE60A52F2A4E9182529136341FE673@MAIN> 
Content-Type: text/plain; format=flowed; charset="iso-8859-1"; 
reply-type=response 

> AFAIK, all non-DSP rigs with synthesizers work this way. 
> Assuming you want the output frequency to be derived 
> from the master clock frequency, there is no easy 
> way to shift an RF carrier. You can't use a free 
> running oscillator, because it won't be derived 
> from the master clock frequency. You can't switch between 
> a mark synthesizer and a space synthesizer because of 
> transients. If you try to key the programmed frequency 
> of a BFO synthesizer, the PLL will probably go out 
> of lock momentarily, producing garbage. Also, it 
> may not be fast enough to keep up with RTTY. After 
> considering all this (as a very experienced synthesizer 
> designer) it is hard for me to blame the designers 
> for using AFSK. 

It is easy to do it much better, and it would only cost pennies extra at the 
most. The signal could be generated by the normal SSB system and then run 
through a narrow IF filter. Problem solved. They could have done CW the same 
way, or in a similar fashion, with an unshaped off-on carrier through a 
narrow filter. They just didn't think to use the parts they already had in 
the radio. 

But that isn't this issue. This issue is they run baseband audio from a 
computer into a SSB transmitter to generate TX signals. This means it is 
really a SSB transmitter processing the tones, and they don't even restrict 
bandwidth with a narrow filter. That is really the entire issue. Instead of 
a narrow filter cleaning up stuff, it all goes through a SSB filter. Anyone 
with a computer and a little skill can invent a "new mode". It's just bad 
engineering to stick that stuff near weak signals, because the problem can 
only be fixed at the transmitter. 

73 Tom 



------------------------------ 

Subject: Digest Footer 

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Topband mailing list 
Topband@contesting.com 
http://lists.contesting.com/mailman/listinfo/topband 


------------------------------ 

End of Topband Digest, Vol 133, Issue 1 
*************************************** 
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