[Elecraft] K3 to IC-7800 Comparison?

[Johnny Siu]

Yes, Adam did the test for both 2.7Khz 5 pole and 2.8Khz 8 pole.
73
Johnny Vr2XMC
  寄件人︰ Adam Farson <far...@shaw.ca>
 收件人︰ 'Jim Bolit' <jbol...@outlook.com> 
副本(CC)︰ 'Johnny Siu' <vr2...@yahoo.com.hk>; Elecraft List 
<elecraft@mailman.qth.net> 
 傳送日期︰ 2015年09月16日 (週三) 12:03 AM
 主題︰ RE: [Elecraft] K3 to IC-7800 Comparison?
   
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div.yiv3730855040WordSection1 {}#yiv3730855040 Hi Jim,  2.7 kHz 5-pole. I have 
added this information to my chart.  73, Adam VA7OJ/AB4OJ    

From: Jim Bolit [mailto:jbol...@outlook.com] 
Sent: 15-Sep-15 05:13
To: Adam Farson; 'Johnny Siu'
Cc: Elecraft List
Subject: RE: [Elecraft] K3 to IC-7800 Comparison?  Adam,      Please confirm 
what roofing filter was used for your test on the K3.  Tnx  JimW6AIM    .

 Original message 
From: Adam Farson <far...@shaw.ca> 
Date: 9/14/2015 3:14 AM (GMT-06:00) 
To: 'Johnny Siu' <vr2...@yahoo.com.hk> 
Cc: Elecraft List <elecraft@mailman.qth.net> 
Subject: Re: [Elecraft] K3 to IC-7800 Comparison? Hi Johnny,

 

The K3 with the KSYN3A is in a closely-packed cluster of radios which score 
highest in the NPR test. Its exact ranking depends on which test frequency is 
being compared. The differences are very slight, mostly within a couple of dB.

 

In practice, I regard an NPR value of 80 dB or higher as excellent.

 

73, Adam VA7OJ/AB4OJ

 

 

From: Johnny Siu [mailto:vr2...@yahoo.com.hk] 
Sent: 14-Sep-15 00:54
To: Adam Farson; Elecraft List
Subject: K3 to IC-7800 Comparison?

 

Hello Adam,

 

From reading of your NPR chart, could I understand that apart from IC7851, the 
K3 (with new KSYN3A installed) is the second best in terms of NPR test?

 

73

 

Johnny VR2XMC

 

  _  

寄件人︰ Adam Farson <far...@shaw.ca>
收件人︰ Elecraft List <elecraft@mailman.qth.net> 
傳送日期︰ 2015年09月14日 (週一) 2:51 PM
主題︰ Re: [Elecraft] K3 to IC-7800 Comparison?


For Jim K9YC:



Hi Jim,



Many thanks for the post on my presentations at the club meeting on Saturday
September 5.



To quote:

"There's an important caveat to his work. The NPR measurements require 

very sophisticated band-stop filters in his instrumentation setup, and 

based on the filters he has been able to source, that limits the 

frequency range where he can do his measurements. An example is in the 

footnote for the Flex-6700, which has no preselector for the range where 

he had to do his measurements, which may have caused that radio to 

measure worse than it would on the ham bands."



The instrumentation I use for NPR testing is re-purposed telecom test
equipment, as described in my Web article and also in my article in QEX for
March/April 2015. I rely on the surplus market for the test sets, and also
for the filter pairs (bandstop and bandpass). The bandstop filters typically
have 95 dB stopband attenuation and ~ 3 kHz stopband width.



A number of these filters are on (or near) amateur bands, e.g. 1940, 3886,
5340, 7600 and 11700 kHz. The first filter pair I acquired was on 5340 kHz,
so all the test data in my web article are on this frequency (which is in
the 60m band). The Flex-6700 does not have a preselector for this band, so
the noise loading will hit the front end and the ADC harder. This will
degrade the NPR reading by a few dB, but it will show how the receiver
behaves if heavily loaded on a band for which no preselector is fitted.



As I picked up additional filters, the number of frequencies on which I run
the test has steadily increased. Links to multi-frequency NPR data for
various radios (including the K3 with KSYN3A) are on my website:



http

Re: [Elecraft] K3 to IC-7800 Comparison?

[Wes (N7WS)]

I'll be.  "You are digging a deeper hole,"  is now a critique by a peer.

On 9/15/2015 1:31 PM, Jim Bolit wrote:
Yes, but many can be misled with "official looking" information that has cover 
statements buried in the content.


Anyone who publishes information of this nature should be prepared to have it 
critiqued by their peers.


Based on this mail string, it is clear there are numbers and methodologies 
that are in conflict, raising questions by peers.


Jim

W6AIM

.



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Re: [Elecraft] K3 to IC-7800 Comparison?

[Kevin Stover]

What???
Everybody doesn't get a trophy? ;-)


On 9/15/2015 1:31 PM, Guy Olinger K2AV wrote:
A test designed to make everyone feel good about what they bought is 
like T-ball for the tots. T-ball is really great for the little kids. 
Love to watch 'em. But the top of the Sherwood list is the major 
leagues. There are those that will make the "post-season" and those 
that will go home. In the playoffs you make the pitches, you make the 
plays, you get the hits, or you go home. No underhand pitches because 
the batter is hurt and can't swing hard. 73, Guy 



--
R. Kevin Stover
AC0H
ARRL
FISTS #11993
SKCC #215
NAQCC #3441

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Re: [Elecraft] K3 to IC-7800 Comparison?

[Jim Brown]

On Tue,9/15/2015 10:36 AM, Wes (N7WS) wrote:
I was responding to the comment that you "thoughtfully" deleted so you 
could go on with your critique.


I always try to trim what I'm replying to without losing meaning.

I know it's hard for some people to believe, but some of us in the 
unwashed masses 


You're hardly one of the unwashed masses, Wes. :)  As it happens, while 
looking for something else,  I just came across your excellent piece in 
ARRL Antenna Compendium #6 about loss in window line. I'd read and 
appreciated it years ago, but didn't remember that it was your work.


are actually capable of deciding what is "useful" to us in our own 
situations. 


Of course. I articulated my priorities so that readers might evaluate my 
concern with the strong signal handling issue and user interface. A more 
casual operator might place a far lower priority on those factors, and 
as a result be quite happy with an SDR.


When I take the time to write an explanation of concepts, it's directed 
at those who are less technical, with the intent of helping them develop 
a BS filter, or to generally expand their knowledge. Others have done 
that for me. A few who come to mind are you, Adam, W4TV, K2AV, N0AX, 
W8JI, and Wayne. Only last week, W8JI took the time to go through this 
same issue of front end overload in the context of a preamp. Don't 
recall whether it was on Tower Talk or Topband.


73, Jim K9YC
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Re: [Elecraft] K3 to IC-7800 Comparison?

[Wes (N7WS)]

I was responding to the comment that you "thoughtfully" deleted so you could go 
on with your critique.


I know it's hard for some people to believe, but some of us in the unwashed 
masses are actually capable of deciding what is "useful" to us in our own 
situations.

.

On 9/15/2015 9:50 AM, Jim Brown wrote:

On Tue,9/15/2015 7:10 AM, Wes (N7WS) wrote:
Seems to me that he's just trying to explain himself. 


Yes, but in doing so, he's making it clear that his work does not contribute 
useful information to a ham trying to evaluate the relative performance of 
radios in a strong signal environment, AND that's what the measurement is 
designed to show -- IF the same level of test signal is applied to all of the 
radios.


For me, primarily a contester, secondarily a DXer, the primary factors in 
choosing a radio are performance in a strong signal environment, a clean TX 
signal, and a very efficient user interface. After hearing Adam speak, I had 
hoped that his work would contribute to that process, but because the level of 
his excitation varies depending on the shortcomings of the radio, it fails to 
provide useful information.


To clarify -- the strong signal performance and dynamic range of SDRs is 
limited by the total voltage at the input to the digital system. If there is 
no input filtering (i.e., a preselector, bandpass filter, or hardware 
attenuator), the digital system sees the broadband spectrum from whatever 
antenna drives it. That's everything from DC to daylight -- AM broadcast, all 
the other ham bands, shortwave broadcast, all other users of the spectrum. It 
is the SUM of all of those signals that combine to overload the digital 
system. When that combined signal level hits digital clip (all bits are 
digital zero), the radio stops working.


It is, of course, possible for the user to add bandpass filters outboard to 
the radio, and many contesters with SO2R and multi-transmitter stations do so. 
This would, indeed, significantly reduce the input to the digital system to 
inband signals. BUT -- SO2R and multi-transmitter stations with closely spaced 
antennas could still overload the digital system even with that filtering.


And there's still in-band QRM to get you to digital clip -- a ham a block or 
two away running power amp, or a mile away with his antenna pointed at you, 
and the sum of all the in-band signals during a major contest. In EU and AS, 
there are big broadcast signals in parts of the 40M band that are going to 
sail right through the world's best preselector or bandpass filter without 
attenuation.


My neighbor W6DRX (0.3 miles from me and an active contester) and I both 
bought K3s as soon as the radio was announced because we realized that it was 
the only way we could coexist and remain friends. :)


73, Jim K9YC
__


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Re: [Elecraft] K3 to IC-7800 Comparison?

[Eric Swartz - WA6HHQ, Elecraft]

Guys - please keep it civil.

Eric
Moderator etc.
/elecraft.com/

On 9/15/2015 6:04 AM, Jim Bolit wrote:

Adam,
You are digging a deeper hole...
JimW6AIM

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Re: [Elecraft] K3 to IC-7800 Comparison?

[Jim Brown]

On Tue,9/15/2015 7:10 AM, Wes (N7WS) wrote:
Seems to me that he's just trying to explain himself. 


Yes, but in doing so, he's making it clear that his work does not 
contribute useful information to a ham trying to evaluate the relative 
performance of radios in a strong signal environment, AND that's what 
the measurement is designed to show -- IF the same level of test signal 
is applied to all of the radios.


For me, primarily a contester, secondarily a DXer, the primary factors 
in choosing a radio are performance in a strong signal environment, a 
clean TX signal, and a very efficient user interface. After hearing Adam 
speak, I had hoped that his work would contribute to that process, but 
because the level of his excitation varies depending on the shortcomings 
of the radio, it fails to provide useful information.


To clarify -- the strong signal performance and dynamic range of SDRs is 
limited by the total voltage at the input to the digital system. If 
there is no input filtering (i.e., a preselector, bandpass filter, or 
hardware attenuator), the digital system sees the broadband spectrum 
from whatever antenna drives it. That's everything from DC to daylight 
-- AM broadcast, all the other ham bands, shortwave broadcast, all other 
users of the spectrum. It is the SUM of all of those signals that 
combine to overload the digital system. When that combined signal level 
hits digital clip (all bits are digital zero), the radio stops working.


It is, of course, possible for the user to add bandpass filters outboard 
to the radio, and many contesters with SO2R and multi-transmitter 
stations do so. This would, indeed, significantly reduce the input to 
the digital system to inband signals. BUT -- SO2R and multi-transmitter 
stations with closely spaced antennas could still overload the digital 
system even with that filtering.


And there's still in-band QRM to get you to digital clip -- a ham a 
block or two away running power amp, or a mile away with his antenna 
pointed at you, and the sum of all the in-band signals during a major 
contest. In EU and AS, there are big broadcast signals in parts of the 
40M band that are going to sail right through the world's best 
preselector or bandpass filter without attenuation.


My neighbor W6DRX (0.3 miles from me and an active contester) and I both 
bought K3s as soon as the radio was announced because we realized that 
it was the only way we could coexist and remain friends. :)


73, Jim K9YC
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Re: [Elecraft] K3 to IC-7800 Comparison?

[Adam Farson]

Hi Jim,

 

2.7 kHz 5-pole. I have added this information to my chart.

 

73, Adam VA7OJ/AB4OJ

 

 

From: Jim Bolit [mailto:jbol...@outlook.com] 
Sent: 15-Sep-15 05:13
To: Adam Farson; 'Johnny Siu'
Cc: Elecraft List
Subject: RE: [Elecraft] K3 to IC-7800 Comparison?

 

Adam,  

 

 

Please confirm what roofing filter was used for your test on the K3.

 

Tnx

 

Jim

W6AIM

 

 

.



 Original message 
From: Adam Farson <far...@shaw.ca> 
Date: 9/14/2015 3:14 AM (GMT-06:00) 
To: 'Johnny Siu' <vr2...@yahoo.com.hk> 
Cc: Elecraft List <elecraft@mailman.qth.net> 
Subject: Re: [Elecraft] K3 to IC-7800 Comparison? 

Hi Johnny,

 

The K3 with the KSYN3A is in a closely-packed cluster of radios which score 
highest in the NPR test. Its exact ranking depends on which test frequency is 
being compared. The differences are very slight, mostly within a couple of dB.

 

In practice, I regard an NPR value of 80 dB or higher as excellent.

 

73, Adam VA7OJ/AB4OJ

 

 

From: Johnny Siu [mailto:vr2...@yahoo.com.hk] 
Sent: 14-Sep-15 00:54
To: Adam Farson; Elecraft List
Subject: K3 to IC-7800 Comparison?

 

Hello Adam,

 

From reading of your NPR chart, could I understand that apart from IC7851, the 
K3 (with new KSYN3A installed) is the second best in terms of NPR test?

 

73

 

Johnny VR2XMC

 

  _  

寄件人︰ Adam Farson <far...@shaw.ca>
收件人︰ Elecraft List <elecraft@mailman.qth.net> 
傳送日期︰ 2015年09月14日 (週一) 2:51 PM
主題︰ Re: [Elecraft] K3 to IC-7800 Comparison?


For Jim K9YC:



Hi Jim,



Many thanks for the post on my presentations at the club meeting on Saturday
September 5.



To quote:

"There's an important caveat to his work. The NPR measurements require 

very sophisticated band-stop filters in his instrumentation setup, and 

based on the filters he has been able to source, that limits the 

frequency range where he can do his measurements. An example is in the 

footnote for the Flex-6700, which has no preselector for the range where 

he had to do his measurements, which may have caused that radio to 

measure worse than it would on the ham bands."



The instrumentation I use for NPR testing is re-purposed telecom test
equipment, as described in my Web article and also in my article in QEX for
March/April 2015. I rely on the surplus market for the test sets, and also
for the filter pairs (bandstop and bandpass). The bandstop filters typically
have 95 dB stopband attenuation and ~ 3 kHz stopband width.



A number of these filters are on (or near) amateur bands, e.g. 1940, 3886,
5340, 7600 and 11700 kHz. The first filter pair I acquired was on 5340 kHz,
so all the test data in my web article are on this frequency (which is in
the 60m band). The Flex-6700 does not have a preselector for this band, so
the noise loading will hit the front end and the ADC harder. This will
degrade the NPR reading by a few dB, but it will show how the receiver
behaves if heavily loaded on a band for which no preselector is fitted.



As I picked up additional filters, the number of frequencies on which I run
the test has steadily increased. Links to multi-frequency NPR data for
various radios (including the K3 with KSYN3A) are on my website:



http://www.ab4oj.com/test/main.html#NPR  
<http://www.ab4oj.com/test/main.html#NPR> 



It was a pleasure meeting you guys over the Labour Day weekend.



73, Adam VA7OJ/AB4OJ



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Re: [Elecraft] K3 to IC-7800 Comparison?

[Jim Bolit]

Tnx

Jim
W6AIM

 Original message 
From: Adam Farson <far...@shaw.ca>
Date: 9/15/2015  11:03 AM  (GMT-06:00)
To: 'Jim Bolit' <jbol...@outlook.com>
Cc: 'Johnny Siu' <vr2...@yahoo.com.hk>, Elecraft List <elecraft@mailman.qth.net>
Subject: RE: [Elecraft] K3 to IC-7800 Comparison?

Hi Jim,



2.7 kHz 5-pole. I have added this information to my chart.



73, Adam VA7OJ/AB4OJ





From: Jim Bolit [mailto:jbol...@outlook.com]
Sent: 15-Sep-15 05:13
To: Adam Farson; 'Johnny Siu'
Cc: Elecraft List
Subject: RE: [Elecraft] K3 to IC-7800 Comparison?



Adam,





Please confirm what roofing filter was used for your test on the K3.



Tnx



Jim

W6AIM





.



 Original message 
From: Adam Farson <far...@shaw.ca>
Date: 9/14/2015 3:14 AM (GMT-06:00)
To: 'Johnny Siu' <vr2...@yahoo.com.hk>
Cc: Elecraft List <elecraft@mailman.qth.net>
Subject: Re: [Elecraft] K3 to IC-7800 Comparison?

Hi Johnny,



The K3 with the KSYN3A is in a closely-packed cluster of radios which score 
highest in the NPR test. Its exact ranking depends on which test frequency is 
being compared. The differences are very slight, mostly within a couple of dB.



In practice, I regard an NPR value of 80 dB or higher as excellent.



73, Adam VA7OJ/AB4OJ





From: Johnny Siu [mailto:vr2...@yahoo.com.hk]
Sent: 14-Sep-15 00:54
To: Adam Farson; Elecraft List
Subject: K3 to IC-7800 Comparison?



Hello Adam,



From reading of your NPR chart, could I understand that apart from IC7851, the 
K3 (with new KSYN3A installed) is the second best in terms of NPR test?



73



Johnny VR2XMC



  _

寄件人︰ Adam Farson <far...@shaw.ca>
收件人︰ Elecraft List <elecraft@mailman.qth.net>
傳送日期︰ 2015年09月14日 (週一) 2:51 PM
主題︰ Re: [Elecraft] K3 to IC-7800 Comparison?


For Jim K9YC:



Hi Jim,



Many thanks for the post on my presentations at the club meeting on Saturday
September 5.



To quote:

"There's an important caveat to his work. The NPR measurements require

very sophisticated band-stop filters in his instrumentation setup, and

based on the filters he has been able to source, that limits the

frequency range where he can do his measurements. An example is in the

footnote for the Flex-6700, which has no preselector for the range where

he had to do his measurements, which may have caused that radio to

measure worse than it would on the ham bands."



The instrumentation I use for NPR testing is re-purposed telecom test
equipment, as described in my Web article and also in my article in QEX for
March/April 2015. I rely on the surplus market for the test sets, and also
for the filter pairs (bandstop and bandpass). The bandstop filters typically
have 95 dB stopband attenuation and ~ 3 kHz stopband width.



A number of these filters are on (or near) amateur bands, e.g. 1940, 3886,
5340, 7600 and 11700 kHz. The first filter pair I acquired was on 5340 kHz,
so all the test data in my web article are on this frequency (which is in
the 60m band). The Flex-6700 does not have a preselector for this band, so
the noise loading will hit the front end and the ADC harder. This will
degrade the NPR reading by a few dB, but it will show how the receiver
behaves if heavily loaded on a band for which no preselector is fitted.



As I picked up additional filters, the number of frequencies on which I run
the test has steadily increased. Links to multi-frequency NPR data for
various radios (including the K3 with KSYN3A) are on my website:



http://www.ab4oj.com/test/main.html#NPR  
<http://www.ab4oj.com/test/main.html#NPR>



It was a pleasure meeting you guys over the Labour Day weekend.



73, Adam VA7OJ/AB4OJ



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Re: [Elecraft] K3 to IC-7800 Comparison?

[Jim Bolit]

Adam,

Please confirm what roofing filter was used for your test on the K3.
Tnx
JimW6AIM

.

 Original message 
From: Adam Farson <far...@shaw.ca>
Date: 9/14/2015  3:14 AM  (GMT-06:00)
To: 'Johnny Siu' <vr2...@yahoo.com.hk>
Cc: Elecraft List <elecraft@mailman.qth.net>
Subject: Re: [Elecraft] K3 to IC-7800 Comparison?

Hi Johnny,



The K3 with the KSYN3A is in a closely-packed cluster of radios which score 
highest in the NPR test. Its exact ranking depends on which test frequency is 
being compared. The differences are very slight, mostly within a couple of dB.



In practice, I regard an NPR value of 80 dB or higher as excellent.



73, Adam VA7OJ/AB4OJ





From: Johnny Siu [mailto:vr2...@yahoo.com.hk]
Sent: 14-Sep-15 00:54
To: Adam Farson; Elecraft List
Subject: K3 to IC-7800 Comparison?



Hello Adam,



From reading of your NPR chart, could I understand that apart from IC7851, the 
K3 (with new KSYN3A installed) is the second best in terms of NPR test?



73



Johnny VR2XMC



  _

寄件人︰ Adam Farson <far...@shaw.ca>
收件人︰ Elecraft List <elecraft@mailman.qth.net>
傳送日期︰ 2015年09月14日 (週一) 2:51 PM
主題︰ Re: [Elecraft] K3 to IC-7800 Comparison?


For Jim K9YC:



Hi Jim,



Many thanks for the post on my presentations at the club meeting on Saturday
September 5.



To quote:

"There's an important caveat to his work. The NPR measurements require

very sophisticated band-stop filters in his instrumentation setup, and

based on the filters he has been able to source, that limits the

frequency range where he can do his measurements. An example is in the

footnote for the Flex-6700, which has no preselector for the range where

he had to do his measurements, which may have caused that radio to

measure worse than it would on the ham bands."



The instrumentation I use for NPR testing is re-purposed telecom test
equipment, as described in my Web article and also in my article in QEX for
March/April 2015. I rely on the surplus market for the test sets, and also
for the filter pairs (bandstop and bandpass). The bandstop filters typically
have 95 dB stopband attenuation and ~ 3 kHz stopband width.



A number of these filters are on (or near) amateur bands, e.g. 1940, 3886,
5340, 7600 and 11700 kHz. The first filter pair I acquired was on 5340 kHz,
so all the test data in my web article are on this frequency (which is in
the 60m band). The Flex-6700 does not have a preselector for this band, so
the noise loading will hit the front end and the ADC harder. This will
degrade the NPR reading by a few dB, but it will show how the receiver
behaves if heavily loaded on a band for which no preselector is fitted.



As I picked up additional filters, the number of frequencies on which I run
the test has steadily increased. Links to multi-frequency NPR data for
various radios (including the K3 with KSYN3A) are on my website:



http://www.ab4oj.com/test/main.html#NPR  
<http://www.ab4oj.com/test/main.html#NPR>



It was a pleasure meeting you guys over the Labour Day weekend.



73, Adam VA7OJ/AB4OJ



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Re: [Elecraft] K3 to IC-7800 Comparison?

[Bert Craig]

Wayne and/or Eric, 

Please do NOT shut this thread down. There is so much useful and interesting 
information being shared. Please let the censorship curmudgeons utilize the Del 
key. Thank you. Take care es... 

Vy 73 de Bert 
WA2SI 

Sent from my android device.
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Re: [Elecraft] K3 to IC-7800 Comparison?

[Jim Bolit]

Yes, but many can be misled with "official looking" information that has cover 
statements buried in the content.
Anyone who publishes information of this nature should be prepared to have it 
critiqued by their peers.
Based on this mail string, it is clear there are numbers and methodologies that 
are in conflict, raising questions by peers.
Jim
W6AIM
.

 Original message 
From: "Wes (N7WS)" <w...@triconet.org>
Date: 9/15/2015  12:37 PM  (GMT-06:00)
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3 to IC-7800 Comparison?

I was responding to the comment that you "thoughtfully" deleted so you could go
on with your critique.

I know it's hard for some people to believe, but some of us in the unwashed
masses are actually capable of deciding what is "useful" to us in our own
situations.
.

On 9/15/2015 9:50 AM, Jim Brown wrote:
> On Tue,9/15/2015 7:10 AM, Wes (N7WS) wrote:
>> Seems to me that he's just trying to explain himself.
>
> Yes, but in doing so, he's making it clear that his work does not contribute
> useful information to a ham trying to evaluate the relative performance of
> radios in a strong signal environment, AND that's what the measurement is
> designed to show -- IF the same level of test signal is applied to all of the
> radios.
>
> For me, primarily a contester, secondarily a DXer, the primary factors in
> choosing a radio are performance in a strong signal environment, a clean TX
> signal, and a very efficient user interface. After hearing Adam speak, I had
> hoped that his work would contribute to that process, but because the level of
> his excitation varies depending on the shortcomings of the radio, it fails to
> provide useful information.
>
> To clarify -- the strong signal performance and dynamic range of SDRs is
> limited by the total voltage at the input to the digital system. If there is
> no input filtering (i.e., a preselector, bandpass filter, or hardware
> attenuator), the digital system sees the broadband spectrum from whatever
> antenna drives it. That's everything from DC to daylight -- AM broadcast, all
> the other ham bands, shortwave broadcast, all other users of the spectrum. It
> is the SUM of all of those signals that combine to overload the digital
> system. When that combined signal level hits digital clip (all bits are
> digital zero), the radio stops working.
>
> It is, of course, possible for the user to add bandpass filters outboard to
> the radio, and many contesters with SO2R and multi-transmitter stations do so.
> This would, indeed, significantly reduce the input to the digital system to
> inband signals. BUT -- SO2R and multi-transmitter stations with closely spaced
> antennas could still overload the digital system even with that filtering.
>
> And there's still in-band QRM to get you to digital clip -- a ham a block or
> two away running power amp, or a mile away with his antenna pointed at you,
> and the sum of all the in-band signals during a major contest. In EU and AS,
> there are big broadcast signals in parts of the 40M band that are going to
> sail right through the world's best preselector or bandpass filter without
> attenuation.
>
> My neighbor W6DRX (0.3 miles from me and an active contester) and I both
> bought K3s as soon as the radio was announced because we realized that it was
> the only way we could coexist and remain friends. :)
>
> 73, Jim K9YC
> __

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Re: [Elecraft] K3 to IC-7800 Comparison?

[Wes (N7WS)]

Seems to me that he's just trying to explain himself.

On 9/15/2015 6:04 AM, Jim Bolit wrote:

Adam,
You are digging a deeper hole...
JimW6AIM

.

 Original message 
From: Adam Farson <far...@shaw.ca>
Date: 9/14/2015  6:48 PM  (GMT-06:00)
To: j...@audiosystemsgroup.com
Cc: Elecraft List <elecraft@mailman.qth.net>
Subject: [Elecraft] K3 to IC-7800 Comparison?

Hi Jim,



To quote:



"If the test is designed to show response of the receiver to a lot of strong
signals such as are present in a contesting or DX pileup environment, or as
are present in a multi-transmitter site, the signal level should be
consistent with that environment, NOT with the design of the receiver."



My explanation of the optimum noise loading point was intended to clarify
the test procedure. As it happens, the optimum noise loading point for an
ADC is also the clipping point, which is the limiting case for a
direct-sampling receiver with an ADC at RF.



I state clearly in my test reports for direct-sampling SDR's that I am
testing NPR just below the clip point. This hard limit dictates the maximum
aggregate signal power at which the receiver can still be expected to
demodulate signals correctly (assuming no attenuation is inserted ahead of
the ADC). I cannot perform the test above ADC clipping, as it will then
yield no usable results. In practice, some attenuation can often be inserted
to extend the upper power limit of the ADC, especially on the lower HF bands
where the band noise level is usually several dB above the receiver's noise
floor.



I have applied noise loading levels as high as -1 to 0 dBm when testing some
direct-sampling SDR receivers. This is equivalent to approx. 1000 contiguous
SSB voice channels, all transmitting simultaneously at S9 + 40 dB each.



In the final analysis, it is up to the radio buyer to decide whether or not
a direct-sampling SDR can handle his chosen operating environment.



73, Adam VA7OJ/AB4OJ





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Re: [Elecraft] K3 to IC-7800 Comparison?

[Jim Bolit]

Adam,
You are digging a deeper hole...
JimW6AIM

.

 Original message 
From: Adam Farson <far...@shaw.ca>
Date: 9/14/2015  6:48 PM  (GMT-06:00)
To: j...@audiosystemsgroup.com
Cc: Elecraft List <elecraft@mailman.qth.net>
Subject: [Elecraft] K3 to IC-7800 Comparison?

Hi Jim,



To quote:



"If the test is designed to show response of the receiver to a lot of strong
signals such as are present in a contesting or DX pileup environment, or as
are present in a multi-transmitter site, the signal level should be
consistent with that environment, NOT with the design of the receiver."



My explanation of the optimum noise loading point was intended to clarify
the test procedure. As it happens, the optimum noise loading point for an
ADC is also the clipping point, which is the limiting case for a
direct-sampling receiver with an ADC at RF.



I state clearly in my test reports for direct-sampling SDR's that I am
testing NPR just below the clip point. This hard limit dictates the maximum
aggregate signal power at which the receiver can still be expected to
demodulate signals correctly (assuming no attenuation is inserted ahead of
the ADC). I cannot perform the test above ADC clipping, as it will then
yield no usable results. In practice, some attenuation can often be inserted
to extend the upper power limit of the ADC, especially on the lower HF bands
where the band noise level is usually several dB above the receiver's noise
floor.



I have applied noise loading levels as high as -1 to 0 dBm when testing some
direct-sampling SDR receivers. This is equivalent to approx. 1000 contiguous
SSB voice channels, all transmitting simultaneously at S9 + 40 dB each.



In the final analysis, it is up to the radio buyer to decide whether or not
a direct-sampling SDR can handle his chosen operating environment.



73, Adam VA7OJ/AB4OJ



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Re: [Elecraft] K3 to IC-7800 Comparison?

[Jim Brown]

On Sun,9/13/2015 11:51 PM, Adam Farson wrote:

For Jim K9YC:


Hi Adam,

Thanks for the description of your work. Could you take the time to 
respond to recent posts by W4TV and W4BQF in this thread?


73, Jim

=   =   =   =   =

Adam is an out an out Icom evangelist - not exactly unbiased.


An example is in the footnote for the Flex-6700, which has no
preselector for the range where he had to do his measurements, which
may have caused that radio to measure worse than it would on the ham
bands.


On the other hand Adam limits noise power for direct sampling SDR
designs to a lower level than used with traditional up/down conversion
transceivers.  The lower noise power input gives the direct sampling
designs an unfair advantage be ignoring strong signal environments.

73,

  ... Joe, W4TV

I certainly agree with Joe about Adam! I've never heard such prejudicial
explanations trying to justify Icom's innocence for final transistor
failures in the IC-7700's. He took all reports of final failures and said he
was going to forward them to Icom, but very few of us ever believed he
actually forwarded any information to Icom from IC-7700 users about the
failures. And IF did, there was never any response from Japan.
I sold my IC-7700, not because the finals failed, but because the threat of
failure was there every time I turned that radio ON.

73,
Tom - W4BQF




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Re: [Elecraft] K3 to IC-7800 Comparison?

[Adam Farson]

For Joe, W4TV:

To quote: "On the other hand Adam limits noise power for direct sampling SDR
designs to a lower level than used with traditional up/down conversion
transceivers.  The lower noise power input gives the direct sampling
designs an unfair advantage be ignoring strong signal environments."

As explained in my web article (and also in my QEX article), the optimum
noise loading points for an ADC and a conventional receiver are different.
In the conventional receiver, optimum noise loading is reached when the
noise power induced in the IF passband within the notch (idle-channel noise)
is equal to the DUT's intrinsic thermal noise power in the same bandwidth.
At this point, the DUT's audio output rises by 3 dB. 

Walt Kester of ADI states in ADI Tutorial MT-005 that the optimum noise
loading point for an ADC is where the device's quantisation noise equals the
noise generated by clipping, i.e. the noise loading is run right up to clip
level or 0 dBFS. I use -1 dBFS as my optimum noise loading point, to ensure
that no clipping takes place during the test. In fact, when an ADC is driven
to clip level, it crashes, thus invalidating any tests attempted above clip
level. 

I do not compare NPR test data for direct-sampling receivers directly with
data for conventional receivers. The benchmark I use for direct-sampling
receivers is the theoretical value of NPR for the ADC in use; this can be
calculated using the procedure presented in MT-005 and described in my
articles. The closer the measured NPR value is to the theoretical one, the
better the front end will perform under heavy loading. A large drop in NPR
(10 dB or more) as compared to the theoretical value indicates an anomaly
such as passive IMD in the preselector or IMD in an active stage ahead of
the ADC.

For a conventional receiver, the closer the NPR figure is to the bandstop
filter's stopband attenuation, the better the receiver (at least from the
NPR standpoint). I do not use NPR as the sole criterion for receiver
selection; my intent in adapting this test method to HF receivers is to
provide the test engineer with an additional test tool for evaluating a
receiver's behaviour on a band packed with extremely strong signals.

Along these same lines, it is virtually impossible to correlate certain
narrow-band test results for a direct-sampling receiver with those for a
conventional receiver, as the familiar traditional test metrics (DR3, IP3,
blocking gain compression) are completely meaningless in the context of an
ADC. Phase noise (RMDR) is still very much a valid parameter, but RMDR in a
direct-sampling receiver is usually very high as the ADC clock is the only
major source of phase noise. (ADC aperture jitter is a minor phase noise
source.) Of course MDS is valid for both receiver types. I have proposed,
and myself use a front-end IMD test method in which I measure the absolute
power of the IMD3 products at 2 kHz spacing over a range of input power
levels, and draw a chart. I then draw lines across the chart at the typical
ITU-R urban and rural band noise levels. If the IMD product is below the
site band noise level, it is inaudible and can thus be disregarded. I term
this test IFSS (interference-free signal strength) and use it exclusively in
my direct-sampling SDR test suite.

Ultimately, the decision as to whether to acquire a direct-sampling SDR or a
conventional transceiver comes down to the operator's personal operating
preferences.

73, Adam VA7OJ/AB4OJ

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[Elecraft] K3 to IC-7800 Comparison?

[Adam Farson]

Hi Jim,

 

To quote:

 

"If the test is designed to show response of the receiver to a lot of strong
signals such as are present in a contesting or DX pileup environment, or as
are present in a multi-transmitter site, the signal level should be
consistent with that environment, NOT with the design of the receiver."

 

My explanation of the optimum noise loading point was intended to clarify
the test procedure. As it happens, the optimum noise loading point for an
ADC is also the clipping point, which is the limiting case for a
direct-sampling receiver with an ADC at RF.

 

I state clearly in my test reports for direct-sampling SDR's that I am
testing NPR just below the clip point. This hard limit dictates the maximum
aggregate signal power at which the receiver can still be expected to
demodulate signals correctly (assuming no attenuation is inserted ahead of
the ADC). I cannot perform the test above ADC clipping, as it will then
yield no usable results. In practice, some attenuation can often be inserted
to extend the upper power limit of the ADC, especially on the lower HF bands
where the band noise level is usually several dB above the receiver's noise
floor. 

 

I have applied noise loading levels as high as -1 to 0 dBm when testing some
direct-sampling SDR receivers. This is equivalent to approx. 1000 contiguous
SSB voice channels, all transmitting simultaneously at S9 + 40 dB each.

 

In the final analysis, it is up to the radio buyer to decide whether or not
a direct-sampling SDR can handle his chosen operating environment. 

 

73, Adam VA7OJ/AB4OJ

 

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Re: [Elecraft] K3 to IC-7800 Comparison?

[Vic Rosenthal]

I bought a K2 the year it came out and I have one of the first K3s. I still 
hate the tap/hold interface. I paid what I feel was an obscene amount of money 
for a set of heavy, machined VFO knobs to replace the stock ones. I wish the K3 
had more room for controls, so there would be less overloading of functions.

But all this pales into insignificance when I dial down the selectivity and 
pick out the weak one in the midst of the pounding 20-over signals from nearby 
EU stations. And then there is the improvement in copy from diversity reception!

Everyone has different interests. Mine is to work DX on CW. Satisfaction 
doesn't come from a comfortable interface, but rather from achieving one's 
goals. The K3 is simply the best tool available to do that.

Vic 4X6GP/K2VCO 

> On Sep 14, 2015, at 10:51 PM, Luis V. Romero  wrote:
> 
> All:
> 
> 
> 
> OK, I will jump in on this one.  It's close to my heart.
> 
> 
> 
> My closest local ham friends are IC-7800 owners.  All 5 of them.  All of
> them have larger and taller antennas than I do.  I can hear everything they
> hear and, though I'm at a 500w transmitter disadvantage viz their kilowatt
> amplifiers, I can and do work everything they work with my K3.
> 
> 
> 
> My local club (Tampa Amateur Radio Club) is a 100% Icom facility with a
> 7700, two 7600'ds, one 746Pro and a 7100 in their HF "studios"  (more like
> "cubicles": there are 6 of them - one is reserved for "classic" AM rigs)  
> 
> 
> 
> I operated SS SSB two years in succession (2010 and 2011) at our clubhouse
> SOABLP using identical antennas (a C31XR at 108 feet, a EF240 at 118 feet, a
> C19X at 70 feet and a 80m Dipole at 90 ft).  In 2010 I used the club 7700.
> The receiver sounded really crunchy, much like my former TS850.  Lots or
> crackly splatter, lots of adjacent desense.  I use that rig often, so I know
> how to drive it.  It is never pleasant to use that rig in heavy QRM contest
> conditions.  The same can be said for the 7600'ds.  The 746 and the 7100 are
> worse by a long shot to the 7700.
> 
> 
> 
> The following year, I brought my K3 to the club and operated SS using the
> club's identical antenna complement.  Not once did I hear any crunching in
> the receiver, no splatter mess and no desense.  The contest was much more
> pleasant on the ears and all signals were much easier to copy on the K3 than
> on the 7700 receiver.
> 
> 
> 
> I love using the 7700, but not in a serious contesting environment. It
> reminds me of my  old TS850.  But I still love to use it!  The reason is the
> tactile feel of the 7700 and, a bit less by the same token, the 7600'ds
> feels like that too.  While the K3 layout is fine and very workable, the
> controls on the Icoms are just so incredibly smooth!  The "feeling of
> Luxury" is exuded by the 7700'ds tactile feedback from its controls.  As a
> NY friend says "It feels like buttah!". It's a hard concept to explain, but
> the feel of the Icom controls is really special. My K3 feels OK, just not as
> "silky" as the 7700'd. 
> 
> 
> 
> Kind of like cars. Drive a Lexus SC430 for show, and a Lotus Elise for go.
> Two sports cars for different priorities.
> 
> 
> 
> If you are into luxury feel, "free" logo'd leather jackets, and 70lb
> transceivers that "feel like buttah", the 78/7700'ds are a great choice.  If
> you are into well behaved receivers, high operational performance in a
> compact, under 10lb lightweight package, the choice is obvious.
> 
> 
> 
> Takes all kinds to make a world!  I have my priorities, you have yours. 
> 
> 
> 
> Lu - W4LT
> 
> K-Line
> 
> 
> 
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Re: [Elecraft] K3 to IC-7800 Comparison?

[Jim Brown]

On Mon,9/14/2015 10:10 AM, Adam Farson wrote:

As explained in my web article (and also in my QEX article), the optimum
noise loading points for an ADC and a conventional receiver are different.
In the conventional receiver, optimum noise loading is reached when the
noise power induced in the IF passband within the notch (idle-channel noise)
is equal to the DUT's intrinsic thermal noise power in the same bandwidth.
At this point, the DUT's audio output rises by 3 dB.


I strongly disagree, Adam. If the test is designed to show response of 
the receiver to a lot of strong signals such as are present in a 
contesting or DX pileup environment, or as are present in a 
multi-transmitter site, the signal level should be consistent with that 
environment, NOT with the design of the receiver. In other words, if the 
input of the RX would be overloaded by those strong signals, the test 
should show it. This does (at least) two things -- it lets buyers know 
which radios perform best in this environment, and it also puts the 
manufacturer's feet to the fire to make the RX better. And this matters 
no matter what the architecture of the RX. It would also, for example, 
clearly show the difference between an RX with a preselector (or other 
selectivity) in front of the input and one without.


And finally, if you choose to test at a reduced signal level to stay 
below overload, the report should clearly state by how many dB the test 
signal had to be reduced.


I do appreciate your work and your dedication, but to be of value, it 
must be consistent with real world conditions, and it must expose the 
real differences between radios.


73, Jim K9YC


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[Elecraft] K3 to IC-7800 Comparison?

[Johnny Siu]

Hello Adam,
From reading of your NPR chart, could I understand that apart from IC7851, the 
K3 (with new KSYN3A installed) is the second best in terms of NPR test?
73
Johnny VR2XMC
  寄件人︰ Adam Farson <far...@shaw.ca>
 收件人︰ Elecraft List <elecraft@mailman.qth.net> 
 傳送日期︰ 2015年09月14日 (週一) 2:51 PM
 主題︰ Re: [Elecraft] K3 to IC-7800 Comparison?
   
For Jim K9YC:

 

Hi Jim,

 

Many thanks for the post on my presentations at the club meeting on Saturday
September 5.

 

To quote:

"There's an important caveat to his work. The NPR measurements require 

very sophisticated band-stop filters in his instrumentation setup, and 

based on the filters he has been able to source, that limits the 

frequency range where he can do his measurements. An example is in the 

footnote for the Flex-6700, which has no preselector for the range where 

he had to do his measurements, which may have caused that radio to 

measure worse than it would on the ham bands."

 

The instrumentation I use for NPR testing is re-purposed telecom test
equipment, as described in my Web article and also in my article in QEX for
March/April 2015. I rely on the surplus market for the test sets, and also
for the filter pairs (bandstop and bandpass). The bandstop filters typically
have 95 dB stopband attenuation and ~ 3 kHz stopband width.

 

A number of these filters are on (or near) amateur bands, e.g. 1940, 3886,
5340, 7600 and 11700 kHz. The first filter pair I acquired was on 5340 kHz,
so all the test data in my web article are on this frequency (which is in
the 60m band). The Flex-6700 does not have a preselector for this band, so
the noise loading will hit the front end and the ADC harder. This will
degrade the NPR reading by a few dB, but it will show how the receiver
behaves if heavily loaded on a band for which no preselector is fitted.

 

As I picked up additional filters, the number of frequencies on which I run
the test has steadily increased. Links to multi-frequency NPR data for
various radios (including the K3 with KSYN3A) are on my website:

 

http://www.ab4oj.com/test/main.html#NPR 

 

It was a pleasure meeting you guys over the Labour Day weekend.

 

73, Adam VA7OJ/AB4OJ


  
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Re: [Elecraft] K3 to IC-7800 Comparison?

[Adam Farson]

For Jim K9YC:

 

Hi Jim,

 

Many thanks for the post on my presentations at the club meeting on Saturday
September 5.

 

To quote:

"There's an important caveat to his work. The NPR measurements require 

very sophisticated band-stop filters in his instrumentation setup, and 

based on the filters he has been able to source, that limits the 

frequency range where he can do his measurements. An example is in the 

footnote for the Flex-6700, which has no preselector for the range where 

he had to do his measurements, which may have caused that radio to 

measure worse than it would on the ham bands."

 

The instrumentation I use for NPR testing is re-purposed telecom test
equipment, as described in my Web article and also in my article in QEX for
March/April 2015. I rely on the surplus market for the test sets, and also
for the filter pairs (bandstop and bandpass). The bandstop filters typically
have 95 dB stopband attenuation and ~ 3 kHz stopband width.

 

A number of these filters are on (or near) amateur bands, e.g. 1940, 3886,
5340, 7600 and 11700 kHz. The first filter pair I acquired was on 5340 kHz,
so all the test data in my web article are on this frequency (which is in
the 60m band). The Flex-6700 does not have a preselector for this band, so
the noise loading will hit the front end and the ADC harder. This will
degrade the NPR reading by a few dB, but it will show how the receiver
behaves if heavily loaded on a band for which no preselector is fitted.

 

As I picked up additional filters, the number of frequencies on which I run
the test has steadily increased. Links to multi-frequency NPR data for
various radios (including the K3 with KSYN3A) are on my website:

 

http://www.ab4oj.com/test/main.html#NPR 

 

It was a pleasure meeting you guys over the Labour Day weekend.

 

73, Adam VA7OJ/AB4OJ

 

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Re: [Elecraft] K3 to IC-7800 Comparison?

[Luis V. Romero]

All:

 

OK, I will jump in on this one.  It's close to my heart.

 

My closest local ham friends are IC-7800 owners.  All 5 of them.  All of
them have larger and taller antennas than I do.  I can hear everything they
hear and, though I'm at a 500w transmitter disadvantage viz their kilowatt
amplifiers, I can and do work everything they work with my K3.

 

My local club (Tampa Amateur Radio Club) is a 100% Icom facility with a
7700, two 7600'ds, one 746Pro and a 7100 in their HF "studios"  (more like
"cubicles": there are 6 of them - one is reserved for "classic" AM rigs)  

 

I operated SS SSB two years in succession (2010 and 2011) at our clubhouse
SOABLP using identical antennas (a C31XR at 108 feet, a EF240 at 118 feet, a
C19X at 70 feet and a 80m Dipole at 90 ft).  In 2010 I used the club 7700.
The receiver sounded really crunchy, much like my former TS850.  Lots or
crackly splatter, lots of adjacent desense.  I use that rig often, so I know
how to drive it.  It is never pleasant to use that rig in heavy QRM contest
conditions.  The same can be said for the 7600'ds.  The 746 and the 7100 are
worse by a long shot to the 7700.

 

The following year, I brought my K3 to the club and operated SS using the
club's identical antenna complement.  Not once did I hear any crunching in
the receiver, no splatter mess and no desense.  The contest was much more
pleasant on the ears and all signals were much easier to copy on the K3 than
on the 7700 receiver.

 

I love using the 7700, but not in a serious contesting environment. It
reminds me of my  old TS850.  But I still love to use it!  The reason is the
tactile feel of the 7700 and, a bit less by the same token, the 7600'ds
feels like that too.  While the K3 layout is fine and very workable, the
controls on the Icoms are just so incredibly smooth!  The "feeling of
Luxury" is exuded by the 7700'ds tactile feedback from its controls.  As a
NY friend says "It feels like buttah!". It's a hard concept to explain, but
the feel of the Icom controls is really special. My K3 feels OK, just not as
"silky" as the 7700'd. 

 

Kind of like cars. Drive a Lexus SC430 for show, and a Lotus Elise for go.
Two sports cars for different priorities.

 

If you are into luxury feel, "free" logo'd leather jackets, and 70lb
transceivers that "feel like buttah", the 78/7700'ds are a great choice.  If
you are into well behaved receivers, high operational performance in a
compact, under 10lb lightweight package, the choice is obvious.

 

Takes all kinds to make a world!  I have my priorities, you have yours. 

 

Lu - W4LT

K-Line

 

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Re: [Elecraft] K3 to IC-7800 Comparison?

[Adam Farson]

Hi Johnny,

 

The K3 with the KSYN3A is in a closely-packed cluster of radios which score 
highest in the NPR test. Its exact ranking depends on which test frequency is 
being compared. The differences are very slight, mostly within a couple of dB.

 

In practice, I regard an NPR value of 80 dB or higher as excellent.

 

73, Adam VA7OJ/AB4OJ

 

 

From: Johnny Siu [mailto:vr2...@yahoo.com.hk] 
Sent: 14-Sep-15 00:54
To: Adam Farson; Elecraft List
Subject: K3 to IC-7800 Comparison?

 

Hello Adam,

 

From reading of your NPR chart, could I understand that apart from IC7851, the 
K3 (with new KSYN3A installed) is the second best in terms of NPR test?

 

73

 

Johnny VR2XMC

 

  _  

寄件人︰ Adam Farson <far...@shaw.ca>
收件人︰ Elecraft List <elecraft@mailman.qth.net> 
傳送日期︰ 2015年09月14日 (週一) 2:51 PM
主題︰ Re: [Elecraft] K3 to IC-7800 Comparison?


For Jim K9YC:



Hi Jim,



Many thanks for the post on my presentations at the club meeting on Saturday
September 5.



To quote:

"There's an important caveat to his work. The NPR measurements require 

very sophisticated band-stop filters in his instrumentation setup, and 

based on the filters he has been able to source, that limits the 

frequency range where he can do his measurements. An example is in the 

footnote for the Flex-6700, which has no preselector for the range where 

he had to do his measurements, which may have caused that radio to 

measure worse than it would on the ham bands."



The instrumentation I use for NPR testing is re-purposed telecom test
equipment, as described in my Web article and also in my article in QEX for
March/April 2015. I rely on the surplus market for the test sets, and also
for the filter pairs (bandstop and bandpass). The bandstop filters typically
have 95 dB stopband attenuation and ~ 3 kHz stopband width.



A number of these filters are on (or near) amateur bands, e.g. 1940, 3886,
5340, 7600 and 11700 kHz. The first filter pair I acquired was on 5340 kHz,
so all the test data in my web article are on this frequency (which is in
the 60m band). The Flex-6700 does not have a preselector for this band, so
the noise loading will hit the front end and the ADC harder. This will
degrade the NPR reading by a few dB, but it will show how the receiver
behaves if heavily loaded on a band for which no preselector is fitted.



As I picked up additional filters, the number of frequencies on which I run
the test has steadily increased. Links to multi-frequency NPR data for
various radios (including the K3 with KSYN3A) are on my website:



http://www.ab4oj.com/test/main.html#NPR  
<http://www.ab4oj.com/test/main.html#NPR> 



It was a pleasure meeting you guys over the Labour Day weekend.



73, Adam VA7OJ/AB4OJ



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Re: [Elecraft] K3 to IC-7800 Comparison?

[Jim Brown]

On Sat,9/12/2015 2:12 PM, Skip Cameron wrote:

If anyone has done a K3 to IC-7800 comparison,


Here's another VERY interesting set of RX measurements. The Noise Power 
Ratio (NPR), is essentially a measure of how broadband noise and QRM 
outside the passband show up inside the passband. It combines the 
effects of phase noise and various forms of non-linearity in the RX 
system. First study the methodology, then the data. Big numbers are 
better. :)


http://www.ab4oj.com/test/docs/npr_test.pdf

The guy who did this work is Adam Farson, VA7OJ, AB4OJ, an EE retired 
from a career in telecom, now living in Vancouver, BC. He spoke to our 
local ham club last weekend, and his presentation was quite interesting. 
Several of us had dinner with him. He seems quite genuine, no horses in 
the race, his objectives seem to be the same as Rob Sherwood and my own 
-- to put mfrs feet to the fire to improve the receive performance and 
signal quality of the stuff they sell us. :)


There's an important caveat to his work. The NPR measurements require 
very sophisticated band-stop filters in his instrumentation setup, and 
based on the filters he has been able to source, that limits the 
frequency range where he can do his measurements. An example is in the 
footnote for the Flex-6700, which has no preselector for the range where 
he had to do his measurements, which may have caused that radio to 
measure worse than it would on the ham bands.


73, Jim K9YC
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Re: [Elecraft] K3 to IC-7800 Comparison?

[Joe Subich, W4TV]

On 9/13/2015 2:10 AM, Jim Brown wrote:

He seems quite genuine, no horses in the race, his objectives seem to
be the same as Rob Sherwood and my own -- to put mfrs feet to the
fire to improve the receive performance and signal quality of the
stuff they sell us. :)


Adam is an out an out Icom evangelist - not exactly unbiased.


An example is in the footnote for the Flex-6700, which has no
preselector for the range where he had to do his measurements, which
may have caused that radio to measure worse than it would on the ham
bands.


On the other hand Adam limits noise power for direct sampling SDR
designs to a lower level than used with traditional up/down conversion
transceivers.  The lower noise power input gives the direct sampling
designs an unfair advantage be ignoring strong signal environments.

73,

  ... Joe, W4TV


On 9/13/2015 2:10 AM, Jim Brown wrote:

On Sat,9/12/2015 2:12 PM, Skip Cameron wrote:

If anyone has done a K3 to IC-7800 comparison,


Here's another VERY interesting set of RX measurements. The Noise Power
Ratio (NPR), is essentially a measure of how broadband noise and QRM
outside the passband show up inside the passband. It combines the
effects of phase noise and various forms of non-linearity in the RX
system. First study the methodology, then the data. Big numbers are
better. :)

http://www.ab4oj.com/test/docs/npr_test.pdf

The guy who did this work is Adam Farson, VA7OJ, AB4OJ, an EE retired
from a career in telecom, now living in Vancouver, BC. He spoke to our
local ham club last weekend, and his presentation was quite interesting.
Several of us had dinner with him. He seems quite genuine, no horses in
the race, his objectives seem to be the same as Rob Sherwood and my own
-- to put mfrs feet to the fire to improve the receive performance and
signal quality of the stuff they sell us. :)

There's an important caveat to his work. The NPR measurements require
very sophisticated band-stop filters in his instrumentation setup, and
based on the filters he has been able to source, that limits the
frequency range where he can do his measurements. An example is in the
footnote for the Flex-6700, which has no preselector for the range where
he had to do his measurements, which may have caused that radio to
measure worse than it would on the ham bands.

73, Jim K9YC
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Re: [Elecraft] K3 to IC-7800 Comparison?

[Chester Alderman]

I certainly agree with Joe about Adam! I've never heard such prejudicial
explanations trying to justify Icom's innocence for final transistor
failures in the IC-7700's. He took all reports of final failures and said he
was going to forward them to Icom, but very few of us ever believed he
actually forwarded any information to Icom from IC-7700 users about the
failures. And IF did, there was never any response from Japan.
I sold my IC-7700, not because the finals failed, but because the threat of
failure was there every time I turned that radio ON.

73,
Tom - W4BQF


-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Joe
Subich, W4TV
Sent: Sunday, September 13, 2015 8:09 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3 to IC-7800 Comparison?

On 9/13/2015 2:10 AM, Jim Brown wrote:
> He seems quite genuine, no horses in the race, his objectives seem to 
> be the same as Rob Sherwood and my own -- to put mfrs feet to the fire 
> to improve the receive performance and signal quality of the stuff 
> they sell us. :)

Adam is an out an out Icom evangelist - not exactly unbiased.

> An example is in the footnote for the Flex-6700, which has no 
> preselector for the range where he had to do his measurements, which 
> may have caused that radio to measure worse than it would on the ham 
> bands.

On the other hand Adam limits noise power for direct sampling SDR designs to
a lower level than used with traditional up/down conversion transceivers.
The lower noise power input gives the direct sampling designs an unfair
advantage be ignoring strong signal environments.

73,

   ... Joe, W4TV


On 9/13/2015 2:10 AM, Jim Brown wrote:
> On Sat,9/12/2015 2:12 PM, Skip Cameron wrote:
>> If anyone has done a K3 to IC-7800 comparison,
>
> Here's another VERY interesting set of RX measurements. The Noise 
> Power Ratio (NPR), is essentially a measure of how broadband noise and 
> QRM outside the passband show up inside the passband. It combines the 
> effects of phase noise and various forms of non-linearity in the RX 
> system. First study the methodology, then the data. Big numbers are 
> better. :)
>
> http://www.ab4oj.com/test/docs/npr_test.pdf
>
> The guy who did this work is Adam Farson, VA7OJ, AB4OJ, an EE retired 
> from a career in telecom, now living in Vancouver, BC. He spoke to our 
> local ham club last weekend, and his presentation was quite interesting.
> Several of us had dinner with him. He seems quite genuine, no horses 
> in the race, his objectives seem to be the same as Rob Sherwood and my 
> own
> -- to put mfrs feet to the fire to improve the receive performance and 
> signal quality of the stuff they sell us. :)
>
> There's an important caveat to his work. The NPR measurements require 
> very sophisticated band-stop filters in his instrumentation setup, and 
> based on the filters he has been able to source, that limits the 
> frequency range where he can do his measurements. An example is in the 
> footnote for the Flex-6700, which has no preselector for the range 
> where he had to do his measurements, which may have caused that radio 
> to measure worse than it would on the ham bands.
>
> 73, Jim K9YC
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> li...@subich.com
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Re: [Elecraft] K3 to IC-7800 Comparison?

[Phil Wheeler]

Tom,

This is pretty off-topic, but not all 
vendors/manufacturers operate like that. I had a 
Canon camera which had known problems so that I 
didn't use it much due to "the threat of failure 
was there every time I turned that radio[camera] 
ON". So I bought a new camera, a later Canon 
model, to replace it. Well I turned on the old one 
to compare the image quality (IQ), and it failed!  
Sent it to Canon and they fixed it (may have 
replaced) and I had it back in a week -- at no 
cost, even though it was out of warranty. Turns 
out it was a known manufacturing defect -- which 
the IC-7700 sounds like. End of story is that I 
preferred the old camera's IQ so returned the new 
one :-)


I wish more manufacturers operated that way. In 
ham radio, Elecraft is the one I am most confident 
would (but none of my Elecraft gear has ever 
failed, even better!).


73, Phil W7OX

On 9/13/15 8:01 AM, Chester Alderman wrote:

I certainly agree with Joe about Adam! I've never heard such prejudicial
explanations trying to justify Icom's innocence for final transistor
failures in the IC-7700's. He took all reports of final failures and said he
was going to forward them to Icom, but very few of us ever believed he
actually forwarded any information to Icom from IC-7700 users about the
failures. And IF did, there was never any response from Japan.
I sold my IC-7700, not because the finals failed, but because the threat of
failure was there every time I turned that radio ON.

73,
Tom - W4BQF


-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Joe
Subich, W4TV
Sent: Sunday, September 13, 2015 8:09 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3 to IC-7800 Comparison?

On 9/13/2015 2:10 AM, Jim Brown wrote:

He seems quite genuine, no horses in the race, his objectives seem to
be the same as Rob Sherwood and my own -- to put mfrs feet to the fire
to improve the receive performance and signal quality of the stuff
they sell us. :)

Adam is an out an out Icom evangelist - not exactly unbiased.


An example is in the footnote for the Flex-6700, which has no
preselector for the range where he had to do his measurements, which
may have caused that radio to measure worse than it would on the ham
bands.

On the other hand Adam limits noise power for direct sampling SDR designs to
a lower level than used with traditional up/down conversion transceivers.
The lower noise power input gives the direct sampling designs an unfair
advantage be ignoring strong signal environments.

73,

... Joe, W4TV


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Re: [Elecraft] K3 to IC-7800 Comparison?

[Al Lorona]

Adam has always been very dismissive publicly of the K3 architecture. However, 
I would hope that his personal opinion does not in any way influence the 
results of his testing.
Al  W6LX

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Re: [Elecraft] K3 to IC-7800 Comparison?

[Dr. William J. Schmidt, II]

I have two of each.  What do you want to know?


Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ 

Owner - Operator
Big Signal Ranch - K9ZC
Staunton, Illinois

Owner - Operator
Villa Grand Piton - J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com

email:  b...@wjschmidt.com

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Skip
Cameron
Sent: Saturday, September 12, 2015 4:13 PM
To: elecraft@mailman.qth.net
Subject: [Elecraft] K3 to IC-7800 Comparison?

If anyone has done a K3 to IC-7800 comparison, please reply direct to me
with your assessment.
Thanks,
Skip W5GAI
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Re: [Elecraft] K3 to IC-7800 Comparison?

[Walter Underwood]

A couple of operators have posted comparisons between the IC-7800 and K3 
recently. Look at these e-mails.

http://mailman.qth.net/pipermail/elecraft/2015-August/220182.html 

http://mailman.qth.net/pipermail/elecraft/2015-August/220169.html 


wunder
K6WRU
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Sep 12, 2015, at 2:31 PM, Jim Brown  wrote:
> 
> On Sat,9/12/2015 2:12 PM, Skip Cameron wrote:
>> If anyone has done a K3 to IC-7800 comparison, please reply direct to me
>> with your assessment.
> 
> I've never seen a 7800, so no experience. However, ARRL and Rob Sherwood 
> have. Rob's data is on his webpage. It concentrates on receiver performance. 
> I've gathered ARRL Lab test data for a selected bunch of modern rigs and 
> published it in a form making it easier to compare the rigs as TRANSMITTERS.  
> My report is at http://k9yc.com/TXNoise.pdf
> 
> The original K3 is MUCH cleaner on CW than the 7800. Also, the original K3 
> has about 15 dB less phase noise than the 7800, which matters a lot on Field 
> Day and at a multi-TX contest station. The new synth board reduces both TX 
> and RX phase noise quite a bit (I've heard numbers in the range of 10 dB).
> 
> I haven't seen ARRL Lab tests of the new K3S or a K3 with the new synth 
> board, but I suspect both will turn out to be at the head of the pack for TX 
> cleanliness. Yes, I know about Pure Signal -- NR0V is my neighbor.
> 
> 73, Jim K9YC
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[Elecraft] K3 to IC-7800 Comparison?

[Skip Cameron]

If anyone has done a K3 to IC-7800 comparison, please reply direct to me
with your assessment.
Thanks,
Skip W5GAI
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Re: [Elecraft] K3 to IC-7800 Comparison?

[Jim Brown]

On Sat,9/12/2015 2:12 PM, Skip Cameron wrote:

If anyone has done a K3 to IC-7800 comparison, please reply direct to me
with your assessment.


I've never seen a 7800, so no experience. However, ARRL and Rob Sherwood 
have. Rob's data is on his webpage. It concentrates on receiver 
performance. I've gathered ARRL Lab test data for a selected bunch of 
modern rigs and published it in a form making it easier to compare the 
rigs as TRANSMITTERS.  My report is at http://k9yc.com/TXNoise.pdf


The original K3 is MUCH cleaner on CW than the 7800. Also, the original 
K3 has about 15 dB less phase noise than the 7800, which matters a lot 
on Field Day and at a multi-TX contest station. The new synth board 
reduces both TX and RX phase noise quite a bit (I've heard numbers in 
the range of 10 dB).


I haven't seen ARRL Lab tests of the new K3S or a K3 with the new synth 
board, but I suspect both will turn out to be at the head of the pack 
for TX cleanliness. Yes, I know about Pure Signal -- NR0V is my neighbor.


73, Jim K9YC
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Re: [Elecraft] K3 to IC-7800 Comparison?

[Bill]

Every now and then I will think of how many dollars I have tied up in my 
K-Line and how it is way overkill for what I do. Then I read some of 
this type of thread - and I am again convinced that I spent wisely.


Over 55 years on the air and the K-Line beats everything I have ever had 
- no contest.


But, these threads are sure interesting to read.

Bill W2BLC K3-Line

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Re: [Elecraft] K3 to IC-7800 Comparison?

[George Fritkin via Elecraft]

You guys are right, the Elecraft radio are great.  But I have lots of radios 
from many manufacturers, current stuff, and Elecraft will have to keep on there 
toes to stay up there.

Sent from my iPad

> On Sep 12, 2015, at 4:57 PM, Bill  wrote:
> 
> Every now and then I will think of how many dollars I have tied up in my 
> K-Line and how it is way overkill for what I do. Then I read some of this 
> type of thread - and I am again convinced that I spent wisely.
> 
> Over 55 years on the air and the K-Line beats everything I have ever had - no 
> contest.
> 
> But, these threads are sure interesting to read.
> 
> Bill W2BLC K3-Line
> 
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> 
> This list hosted by: http://www.qsl.net
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> Message delivered to georgefrit...@yahoo.com
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Re: [Elecraft] K3 to IC-7800 Comparison?

[Wes (N7WS)]

I'd like a comparison with the IC-7851.  
https://www.youtube.com/watch?v=-sVpoPJKgo8

On 9/12/2015 2:31 PM, Jim Brown wrote:

On Sat,9/12/2015 2:12 PM, Skip Cameron wrote:

If anyone has done a K3 to IC-7800 comparison, please reply direct to me
with your assessment.


I've never seen a 7800, so no experience. However, ARRL and Rob Sherwood have. 
Rob's data is on his webpage. It concentrates on receiver performance. I've 
gathered ARRL Lab test data for a selected bunch of modern rigs and published 
it in a form making it easier to compare the rigs as TRANSMITTERS.  My report 
is at http://k9yc.com/TXNoise.pdf


The original K3 is MUCH cleaner on CW than the 7800. Also, the original K3 has 
about 15 dB less phase noise than the 7800, which matters a lot on Field Day 
and at a multi-TX contest station. The new synth board reduces both TX and RX 
phase noise quite a bit (I've heard numbers in the range of 10 dB).


I haven't seen ARRL Lab tests of the new K3S or a K3 with the new synth board, 
but I suspect both will turn out to be at the head of the pack for TX 
cleanliness. Yes, I know about Pure Signal -- NR0V is my neighbor.


73, Jim K9YC
_


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