#elad #fdm-duo#sherwood #elad


dpallis@...
 

Dear friends Today I read in the receiver test data at sherwood engineering:
http://www.sherweng.com/table.html
the measurements about dynamic range is very low (70db) insteed of QST review @ May 2016
do you have any idea or opinion about it?
thank you
73 de SV1JGW


Simon
 

If it was that low..then do you not think you would have noticed this in use??
I have not..

Simon g0zen


dpallis@...
 

I know, the rig seems perfect. i dont know what happpens with Sherwood Eng.

i found a german paper with sherwood mesaruments since 2015. and i dont know why they publish it now.
and of course the QST review says different thinks. personaly always trust the qst.


Simon
 

This has been covered on here before..

Search for more info..


Vianney Colombat
 


Hello,

the reason is due to different testing procedures, both Sherwood and ARRL provide documents available online explaining their choices. ARRL use a third tone to simulate a random noise while Sherwood not.

The ADC adopted is without dithering function that in presence of pure signals can cause spurious intermodulations that in real word do not exist due to random noise captured from antenna.

Vianney


Il 08/01/2021 19:11, dpallis@... ha scritto:
Dear friends Today I read in the receiver test data at sherwood engineering:
http://www.sherweng.com/table.html
the measurements about dynamic range is very low (70db) insteed of QST review @ May 2016
do you have any idea or opinion about it?
thank you
73 de SV1JGW



Le informazioni contenute in questo messaggio di posta elettronica sono riservate e confidenziali e ne è vietata la diffusione in qualunque modo eseguita (DL 196/2003). Qualora Lei non fosse la persona a cui il presente messaggio è destinato, La invitiamo ad eliminarlo e a non leggerlo, dandone gentilmente comunicazione al mittente.

The information contained in this e-mail and any attachments is confidential and may well also be legally privileged (DL 196/2003). If you are not among the named recipients, please notify the sender immediately by reply e-mail and then delete this message from your system, do not use the contents for any purpose whatsoever nor disclose them to anyone else.


Clint Chron
 

For those that might be interested, Rob has posted updated test data for the Elad Duo on his receiver test site.

 

http://www.sherweng.com/table.html

 

Rob shows the dynamic range for the Duo to be about 70 db.  That is pretty close to what I measured.  However, to get the full picture on overload, one needs to run an IFSS curve to see what happens with stronger signal levels.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Vianney Colombat
Sent: Tuesday, January 12, 2021 8:57 AM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 


Hello,

the reason is due to different testing procedures, both Sherwood and ARRL provide documents available online explaining their choices. ARRL use a third tone to simulate a random noise while Sherwood not.

The ADC adopted is without dithering function that in presence of pure signals can cause spurious intermodulations that in real word do not exist due to random noise captured from antenna.

Vianney

Il 08/01/2021 19:11, dpallis@... ha scritto:

Dear friends Today I read in the receiver test data at sherwood engineering:
http://www.sherweng.com/table.html
the measurements about dynamic range is very low (70db) insteed of QST review @ May 2016
do you have any idea or opinion about it?
thank you
73 de SV1JGW



Le informazioni contenute in questo messaggio di posta elettronica sono riservate e confidenziali e ne è vietata la diffusione in qualunque modo eseguita (DL 196/2003). Qualora Lei non fosse la persona a cui il presente messaggio è destinato, La invitiamo ad eliminarlo e a non leggerlo, dandone gentilmente comunicazione al mittente.

The information contained in this e-mail and any attachments is confidential and may well also be legally privileged (DL 196/2003). If you are not among the named recipients, please notify the sender immediately by reply e-mail and then delete this message from your system, do not use the contents for any purpose whatsoever nor disclose them to anyone else.


Klaus Brosche, DK3QN
 

What's right, what's wrong?

QST tested the ELAD FDM-DUO in issue May 2016 @ an IMD DR at 2KHz with 99 dB (shortwave bands)
with a remark.

Sherwood tested the ELAD-DUO (issued on his website 06-Jan-2021) @ 70 dB (DR narrow spaced
@ 2KHz).

This is an almost 30 (!) dB discrepancy between both test results.

Which is true? Who measured what? Looks pretty 'insane' to me.

Klaus, DK3QN



Am 12.01.2021 um 17:33 schrieb Clint Chron:

For those that might be interested, Rob has posted updated test data for the Elad Duo on his receiver test site.

 

http://www.sherweng.com/table.html

 

Rob shows the dynamic range for the Duo to be about 70 db.  That is pretty close to what I measured.  However, to get the full picture on overload, one needs to run an IFSS curve to see what happens with stronger signal levels.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Vianney Colombat
Sent: Tuesday, January 12, 2021 8:57 AM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 


Hello,

the reason is due to different testing procedures, both Sherwood and ARRL provide documents available online explaining their choices. ARRL use a third tone to simulate a random noise while Sherwood not.

The ADC adopted is without dithering function that in presence of pure signals can cause spurious intermodulations that in real word do not exist due to random noise captured from antenna.

Vianney

Il 08/01/2021 19:11, dpallis@... ha scritto:

Dear friends Today I read in the receiver test data at sherwood engineering:
http://www.sherweng.com/table.html
the measurements about dynamic range is very low (70db) insteed of QST review @ May 2016
do you have any idea or opinion about it?
thank you
73 de SV1JGW



Le informazioni contenute in questo messaggio di posta elettronica sono riservate e confidenziali e ne è vietata la diffusione in qualunque modo eseguita (DL 196/2003). Qualora Lei non fosse la persona a cui il presente messaggio è destinato, La invitiamo ad eliminarlo e a non leggerlo, dandone gentilmente comunicazione al mittente.

The information contained in this e-mail and any attachments is confidential and may well also be legally privileged (DL 196/2003). If you are not among the named recipients, please notify the sender immediately by reply e-mail and then delete this message from your system, do not use the contents for any purpose whatsoever nor disclose them to anyone else.



Clint Chron
 

I just ran the same tests several times on my Duo.  The results came out the same each time.

The challenge in testing the Dynamic Range of SDR receivers is that the DR bounces all over the board, depending upon the level of your two primary test tones (separated by 2 kHz).

So while the DR of the Duo may be low at the MDS measuring point, that does not mean that it is low for all measuring points.

 

Here is the IFSS graph for my Duo, the IC-7300, and the Perseus.

To get the dynamic range for a given primary signal level, subtract the IMD product signal level from the primary signal level.

Example:

The MDS on my Duo is -132 dbm.  A -64 dbm primary signal produces an IMD product of -132 dbm.  So the dynamic range is 68 db.

Now look at a primary signal of -40 dbm.  This produces an IMD product of -126 dbm.  So the dynamic range is 86 db.

Now look at  a primary signal at -30 dbm.  This produces an IMD product of -125 dbm.  So the dynamic range is 95 db.

 

For a given primary signal level, the radio that has the lowest IMD product signal level has the best dynamic range for that particular measuring point.

Of the three radios that I tested, the Perseus receiver has the best overall dynamic range.

 

73

Clint

W7KEC

 

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Klaus Brosche
Sent: Tuesday, January 12, 2021 12:22 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

What's right, what's wrong?

 

QST tested the ELAD FDM-DUO in issue May 2016 @ an IMD DR at 2KHz with 99 dB (shortwave bands)
with a remark.

 

Sherwood tested the ELAD-DUO (issued on his website 06-Jan-2021) @ 70 dB (DR narrow spaced
@ 2KHz).

 

This is an almost 30 (!) dB discrepancy between both test results.

 

Which is true? Who measured what? Looks pretty 'insane' to me.

 

Klaus, DK3QN

 

 

 

Am 12.01.2021 um 17:33 schrieb Clint Chron:

For those that might be interested, Rob has posted updated test data for the Elad Duo on his receiver test site.

 

http://www.sherweng.com/table.html

 

Rob shows the dynamic range for the Duo to be about 70 db.  That is pretty close to what I measured.  However, to get the full picture on overload, one needs to run an IFSS curve to see what happens with stronger signal levels.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Vianney Colombat
Sent: Tuesday, January 12, 2021 8:57 AM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 


Hello,

the reason is due to different testing procedures, both Sherwood and ARRL provide documents available online explaining their choices. ARRL use a third tone to simulate a random noise while Sherwood not.

The ADC adopted is without dithering function that in presence of pure signals can cause spurious intermodulations that in real word do not exist due to random noise captured from antenna.

Vianney


Il 08/01/2021 19:11, dpallis@... ha scritto:

Dear friends Today I read in the receiver test data at sherwood engineering:
http://www.sherweng.com/table.html
the measurements about dynamic range is very low (70db) insteed of QST review @ May 2016
do you have any idea or opinion about it?
thank you
73 de SV1JGW



Le informazioni contenute in questo messaggio di posta elettronica sono riservate e confidenziali e ne è vietata la diffusione in qualunque modo eseguita (DL 196/2003). Qualora Lei non fosse la persona a cui il presente messaggio è destinato, La invitiamo ad eliminarlo e a non leggerlo, dandone gentilmente comunicazione al mittente.

The information contained in this e-mail and any attachments is confidential and may well also be legally privileged (DL 196/2003). If you are not among the named recipients, please notify the sender immediately by reply e-mail and then delete this message from your system, do not use the contents for any purpose whatsoever nor disclose them to anyone else.

 


Neil Smith G4DBN
 

Hi Clint, does injecting a realistic level of wideband noise (or some additional non-harmonically-related signals to provide dithering) change the results at all?

Neil G4DBN

On 12/01/2021 19:54, Clint Chron wrote:

I just ran the same tests several times on my Duo.  The results came out the same each time.

The challenge in testing the Dynamic Range of SDR receivers is that the DR bounces all over the board, depending upon the level of your two primary test tones (separated by 2 kHz).

So while the DR of the Duo may be low at the MDS measuring point, that does not mean that it is low for all measuring points.

 

Here is the IFSS graph for my Duo, the IC-7300, and the Perseus.

To get the dynamic range for a given primary signal level, subtract the IMD product signal level from the primary signal level.

Example:

The MDS on my Duo is -132 dbm.  A -64 dbm primary signal produces an IMD product of -132 dbm.  So the dynamic range is 68 db.

Now look at a primary signal of -40 dbm.  This produces an IMD product of -126 dbm.  So the dynamic range is 86 db.

Now look at  a primary signal at -30 dbm.  This produces an IMD product of -125 dbm.  So the dynamic range is 95 db.

 

For a given primary signal level, the radio that has the lowest IMD product signal level has the best dynamic range for that particular measuring point.

Of the three radios that I tested, the Perseus receiver has the best overall dynamic range.

 

73

Clint

W7KEC



Clint Chron
 

I am not sure.  I don’t have the ability to inject a signal from a 3rd signal generator.

 

A couple of things to keep in mind.

Putting a HF pre-selector on the front end of the Duo should improve the DR, but I have not made that test.

The NPR measurements on the DUO come out very good, when compared with other high end radios.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Neil Smith G4DBN
Sent: Tuesday, January 12, 2021 1:17 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

Hi Clint, does injecting a realistic level of wideband noise (or some additional non-harmonically-related signals to provide dithering) change the results at all?

Neil G4DBN

On 12/01/2021 19:54, Clint Chron wrote:

I just ran the same tests several times on my Duo.  The results came out the same each time.

The challenge in testing the Dynamic Range of SDR receivers is that the DR bounces all over the board, depending upon the level of your two primary test tones (separated by 2 kHz).

So while the DR of the Duo may be low at the MDS measuring point, that does not mean that it is low for all measuring points.

 

Here is the IFSS graph for my Duo, the IC-7300, and the Perseus.

To get the dynamic range for a given primary signal level, subtract the IMD product signal level from the primary signal level.

Example:

The MDS on my Duo is -132 dbm.  A -64 dbm primary signal produces an IMD product of -132 dbm.  So the dynamic range is 68 db.

Now look at a primary signal of -40 dbm.  This produces an IMD product of -126 dbm.  So the dynamic range is 86 db.

Now look at  a primary signal at -30 dbm.  This produces an IMD product of -125 dbm.  So the dynamic range is 95 db.

 

For a given primary signal level, the radio that has the lowest IMD product signal level has the best dynamic range for that particular measuring point.

Of the three radios that I tested, the Perseus receiver has the best overall dynamic range.

 

73

Clint

W7KEC

 


Andy G4JNT
 

Single / two tones tests on a wideband SDR are meaningless as they tell you nothing about the quality of the A/D process.  
The proper way to test such a receiver is with broadband notched noise, or a comb of many carriers, tens or hundreds.



Virus-free. www.avg.com

On Tue, 12 Jan 2021 at 20:31, Clint Chron <c.kiheiman@...> wrote:

I am not sure.  I don’t have the ability to inject a signal from a 3rd signal generator.

 

A couple of things to keep in mind.

Putting a HF pre-selector on the front end of the Duo should improve the DR, but I have not made that test.

The NPR measurements on the DUO come out very good, when compared with other high end radios.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Neil Smith G4DBN
Sent: Tuesday, January 12, 2021 1:17 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

Hi Clint, does injecting a realistic level of wideband noise (or some additional non-harmonically-related signals to provide dithering) change the results at all?

Neil G4DBN

On 12/01/2021 19:54, Clint Chron wrote:

I just ran the same tests several times on my Duo.  The results came out the same each time.

The challenge in testing the Dynamic Range of SDR receivers is that the DR bounces all over the board, depending upon the level of your two primary test tones (separated by 2 kHz).

So while the DR of the Duo may be low at the MDS measuring point, that does not mean that it is low for all measuring points.

 

Here is the IFSS graph for my Duo, the IC-7300, and the Perseus.

To get the dynamic range for a given primary signal level, subtract the IMD product signal level from the primary signal level.

Example:

The MDS on my Duo is -132 dbm.  A -64 dbm primary signal produces an IMD product of -132 dbm.  So the dynamic range is 68 db.

Now look at a primary signal of -40 dbm.  This produces an IMD product of -126 dbm.  So the dynamic range is 86 db.

Now look at  a primary signal at -30 dbm.  This produces an IMD product of -125 dbm.  So the dynamic range is 95 db.

 

For a given primary signal level, the radio that has the lowest IMD product signal level has the best dynamic range for that particular measuring point.

Of the three radios that I tested, the Perseus receiver has the best overall dynamic range.

 

73

Clint

W7KEC

 


Virus-free. www.avg.com


Neil Smith G4DBN
 

If the two source signals are pure tones, then you'll get pretty terrible results as there is no dither signal injected into a DUO as far as I know. A proper test of a radio with a straightforward ADC at the front end needs a reasonably large unrelated signal or random noise to smother the artefacts.  In any normal usage with an antenna, there will be enough wideband noise and signals to add sufficient random dither.

At very low levels, the receiver noise floor is probably sufficient to dither the signal, hence perhaps the better results measured close to MDS.

The Sherwood results are correct, but if I understand his methods, the results don't provide any useful information, he is just mapping out what a 16 bit ADC does with two pure signals.

I might be wildly wrong about this of course!

Neil G4DBN


On 12/01/2021 20:31, Clint Chron wrote:

I am not sure.  I don’t have the ability to inject a signal from a 3rd signal generator.

 

A couple of things to keep in mind.

Putting a HF pre-selector on the front end of the Duo should improve the DR, but I have not made that test.

The NPR measurements on the DUO come out very good, when compared with other high end radios.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Neil Smith G4DBN
Sent: Tuesday, January 12, 2021 1:17 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

Hi Clint, does injecting a realistic level of wideband noise (or some additional non-harmonically-related signals to provide dithering) change the results at all?

Neil G4DBN

On 12/01/2021 19:54, Clint Chron wrote:

I just ran the same tests several times on my Duo.  The results came out the same each time.

The challenge in testing the Dynamic Range of SDR receivers is that the DR bounces all over the board, depending upon the level of your two primary test tones (separated by 2 kHz).

So while the DR of the Duo may be low at the MDS measuring point, that does not mean that it is low for all measuring points.

 

Here is the IFSS graph for my Duo, the IC-7300, and the Perseus.

To get the dynamic range for a given primary signal level, subtract the IMD product signal level from the primary signal level.

Example:

The MDS on my Duo is -132 dbm.  A -64 dbm primary signal produces an IMD product of -132 dbm.  So the dynamic range is 68 db.

Now look at a primary signal of -40 dbm.  This produces an IMD product of -126 dbm.  So the dynamic range is 86 db.

Now look at  a primary signal at -30 dbm.  This produces an IMD product of -125 dbm.  So the dynamic range is 95 db.

 

For a given primary signal level, the radio that has the lowest IMD product signal level has the best dynamic range for that particular measuring point.

Of the three radios that I tested, the Perseus receiver has the best overall dynamic range.

 

73

Clint

W7KEC

 



Klaus Brosche, DK3QN
 

I had the belief (from tech articles) that NPR measurements are the way to go for -at least -
SDRs.

Analog and SDR transceivers and receivers behave different re. 'old school' tests.
That's also been written in many publications since a number of years.

If there is such a different behaviour, it needs to be explained in understandable language
to the average user, including the consequences that come with such a system behaviour.

It's then not very helpful to just throw out 'numbers'. They need to be explained in the
context of a 'real life' experience.

Else: just "numbers".

Klaus, DK3QN


Am 12.01.2021 um 20:54 schrieb Clint Chron:

I just ran the same tests several times on my Duo.  The results came out the same each time.

The challenge in testing the Dynamic Range of SDR receivers is that the DR bounces all over the board, depending upon the level of your two primary test tones (separated by 2 kHz).

So while the DR of the Duo may be low at the MDS measuring point, that does not mean that it is low for all measuring points.

 

Here is the IFSS graph for my Duo, the IC-7300, and the Perseus.

To get the dynamic range for a given primary signal level, subtract the IMD product signal level from the primary signal level.

Example:

The MDS on my Duo is -132 dbm.  A -64 dbm primary signal produces an IMD product of -132 dbm.  So the dynamic range is 68 db.

Now look at a primary signal of -40 dbm.  This produces an IMD product of -126 dbm.  So the dynamic range is 86 db.

Now look at  a primary signal at -30 dbm.  This produces an IMD product of -125 dbm.  So the dynamic range is 95 db.

 

For a given primary signal level, the radio that has the lowest IMD product signal level has the best dynamic range for that particular measuring point.

Of the three radios that I tested, the Perseus receiver has the best overall dynamic range.

 

73

Clint

W7KEC

 

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Klaus Brosche
Sent: Tuesday, January 12, 2021 12:22 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

What's right, what's wrong?

 

QST tested the ELAD FDM-DUO in issue May 2016 @ an IMD DR at 2KHz with 99 dB (shortwave bands)
with a remark.

 

Sherwood tested the ELAD-DUO (issued on his website 06-Jan-2021) @ 70 dB (DR narrow spaced
@ 2KHz).

 

This is an almost 30 (!) dB discrepancy between both test results.

 

Which is true? Who measured what? Looks pretty 'insane' to me.

 

Klaus, DK3QN

 

 

 

Am 12.01.2021 um 17:33 schrieb Clint Chron:

For those that might be interested, Rob has posted updated test data for the Elad Duo on his receiver test site.

 

http://www.sherweng.com/table.html

 

Rob shows the dynamic range for the Duo to be about 70 db.  That is pretty close to what I measured.  However, to get the full picture on overload, one needs to run an IFSS curve to see what happens with stronger signal levels.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Vianney Colombat
Sent: Tuesday, January 12, 2021 8:57 AM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 


Hello,

the reason is due to different testing procedures, both Sherwood and ARRL provide documents available online explaining their choices. ARRL use a third tone to simulate a random noise while Sherwood not.

The ADC adopted is without dithering function that in presence of pure signals can cause spurious intermodulations that in real word do not exist due to random noise captured from antenna.

Vianney


Il 08/01/2021 19:11, dpallis@... ha scritto:

Dear friends Today I read in the receiver test data at sherwood engineering:
http://www.sherweng.com/table.html
the measurements about dynamic range is very low (70db) insteed of QST review @ May 2016
do you have any idea or opinion about it?
thank you
73 de SV1JGW



Le informazioni contenute in questo messaggio di posta elettronica sono riservate e confidenziali e ne è vietata la diffusione in qualunque modo eseguita (DL 196/2003). Qualora Lei non fosse la persona a cui il presente messaggio è destinato, La invitiamo ad eliminarlo e a non leggerlo, dandone gentilmente comunicazione al mittente.

The information contained in this e-mail and any attachments is confidential and may well also be legally privileged (DL 196/2003). If you are not among the named recipients, please notify the sender immediately by reply e-mail and then delete this message from your system, do not use the contents for any purpose whatsoever nor disclose them to anyone else.

 



Clint Chron
 

For Rob’s receiver tests, he turns on Dither is the radio supports that option.  The IC-7300, the Perseus, and other models support dither.  However, there are radios that have a very high DR without dither.  Look at Rob’s recent test on the Yaesu FTDX10.

 

It is my understand that the QST Product reviews use a 3rd signal to simulate noise.  They measured a DR of about 70 for the Duo in their 2016 review.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Neil Smith G4DBN
Sent: Tuesday, January 12, 2021 1:56 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

If the two source signals are pure tones, then you'll get pretty terrible results as there is no dither signal injected into a DUO as far as I know. A proper test of a radio with a straightforward ADC at the front end needs a reasonably large unrelated signal or random noise to smother the artefacts.  In any normal usage with an antenna, there will be enough wideband noise and signals to add sufficient random dither.

At very low levels, the receiver noise floor is probably sufficient to dither the signal, hence perhaps the better results measured close to MDS.

The Sherwood results are correct, but if I understand his methods, the results don't provide any useful information, he is just mapping out what a 16 bit ADC does with two pure signals.

I might be wildly wrong about this of course!

Neil G4DBN

 

On 12/01/2021 20:31, Clint Chron wrote:

I am not sure.  I don’t have the ability to inject a signal from a 3rd signal generator.

 

A couple of things to keep in mind.

Putting a HF pre-selector on the front end of the Duo should improve the DR, but I have not made that test.

The NPR measurements on the DUO come out very good, when compared with other high end radios.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Neil Smith G4DBN
Sent: Tuesday, January 12, 2021 1:17 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

Hi Clint, does injecting a realistic level of wideband noise (or some additional non-harmonically-related signals to provide dithering) change the results at all?

Neil G4DBN

On 12/01/2021 19:54, Clint Chron wrote:

I just ran the same tests several times on my Duo.  The results came out the same each time.

The challenge in testing the Dynamic Range of SDR receivers is that the DR bounces all over the board, depending upon the level of your two primary test tones (separated by 2 kHz).

So while the DR of the Duo may be low at the MDS measuring point, that does not mean that it is low for all measuring points.

 

Here is the IFSS graph for my Duo, the IC-7300, and the Perseus.

To get the dynamic range for a given primary signal level, subtract the IMD product signal level from the primary signal level.

Example:

The MDS on my Duo is -132 dbm.  A -64 dbm primary signal produces an IMD product of -132 dbm.  So the dynamic range is 68 db.

Now look at a primary signal of -40 dbm.  This produces an IMD product of -126 dbm.  So the dynamic range is 86 db.

Now look at  a primary signal at -30 dbm.  This produces an IMD product of -125 dbm.  So the dynamic range is 95 db.

 

For a given primary signal level, the radio that has the lowest IMD product signal level has the best dynamic range for that particular measuring point.

Of the three radios that I tested, the Perseus receiver has the best overall dynamic range.

 

73

Clint

W7KEC

 

 


Clint Chron
 

Some like the NPR tests and some do not.  The NPR test equipment is very hard to find – most of it is 30 to 40 years old.  However, a complete set of equipment can be purchased for about $300.  On Adam Farson’s web site, you can find reviews on a lot of different radios and the NPR tests results.

 

https://www.ab4oj.com/test/reports.html

 

If anyone is interested in NPR tests, please send to my personal email.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Klaus Brosche
Sent: Tuesday, January 12, 2021 2:06 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

I had the belief (from tech articles) that NPR measurements are the way to go for -at least -
SDRs.

 

Analog and SDR transceivers and receivers behave different re. 'old school' tests.
That's also been written in many publications since a number of years.

 

If there is such a different behaviour, it needs to be explained in understandable language
to the average user, including the consequences that come with such a system behaviour.

 

It's then not very helpful to just throw out 'numbers'. They need to be explained in the
context of a 'real life' experience.

 

Else: just "numbers".

 

Klaus, DK3QN

 

 

Am 12.01.2021 um 20:54 schrieb Clint Chron:

I just ran the same tests several times on my Duo.  The results came out the same each time.

The challenge in testing the Dynamic Range of SDR receivers is that the DR bounces all over the board, depending upon the level of your two primary test tones (separated by 2 kHz).

So while the DR of the Duo may be low at the MDS measuring point, that does not mean that it is low for all measuring points.

 

Here is the IFSS graph for my Duo, the IC-7300, and the Perseus.

To get the dynamic range for a given primary signal level, subtract the IMD product signal level from the primary signal level.

Example:

The MDS on my Duo is -132 dbm.  A -64 dbm primary signal produces an IMD product of -132 dbm.  So the dynamic range is 68 db.

Now look at a primary signal of -40 dbm.  This produces an IMD product of -126 dbm.  So the dynamic range is 86 db.

Now look at  a primary signal at -30 dbm.  This produces an IMD product of -125 dbm.  So the dynamic range is 95 db.

 

For a given primary signal level, the radio that has the lowest IMD product signal level has the best dynamic range for that particular measuring point.

Of the three radios that I tested, the Perseus receiver has the best overall dynamic range.

 

73

Clint

W7KEC

 

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Klaus Brosche
Sent: Tuesday, January 12, 2021 12:22 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

What's right, what's wrong?

 

QST tested the ELAD FDM-DUO in issue May 2016 @ an IMD DR at 2KHz with 99 dB (shortwave bands)
with a remark.

 

Sherwood tested the ELAD-DUO (issued on his website 06-Jan-2021) @ 70 dB (DR narrow spaced
@ 2KHz).

 

This is an almost 30 (!) dB discrepancy between both test results.

 

Which is true? Who measured what? Looks pretty 'insane' to me.

 

Klaus, DK3QN

 

 

 

Am 12.01.2021 um 17:33 schrieb Clint Chron:

For those that might be interested, Rob has posted updated test data for the Elad Duo on his receiver test site.

 

http://www.sherweng.com/table.html

 

Rob shows the dynamic range for the Duo to be about 70 db.  That is pretty close to what I measured.  However, to get the full picture on overload, one needs to run an IFSS curve to see what happens with stronger signal levels.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Vianney Colombat
Sent: Tuesday, January 12, 2021 8:57 AM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 


Hello,

the reason is due to different testing procedures, both Sherwood and ARRL provide documents available online explaining their choices. ARRL use a third tone to simulate a random noise while Sherwood not.

The ADC adopted is without dithering function that in presence of pure signals can cause spurious intermodulations that in real word do not exist due to random noise captured from antenna.

Vianney



Il 08/01/2021 19:11, dpallis@... ha scritto:

Dear friends Today I read in the receiver test data at sherwood engineering:
http://www.sherweng.com/table.html
the measurements about dynamic range is very low (70db) insteed of QST review @ May 2016
do you have any idea or opinion about it?
thank you
73 de SV1JGW



Le informazioni contenute in questo messaggio di posta elettronica sono riservate e confidenziali e ne è vietata la diffusione in qualunque modo eseguita (DL 196/2003). Qualora Lei non fosse la persona a cui il presente messaggio è destinato, La invitiamo ad eliminarlo e a non leggerlo, dandone gentilmente comunicazione al mittente.

The information contained in this e-mail and any attachments is confidential and may well also be legally privileged (DL 196/2003). If you are not among the named recipients, please notify the sender immediately by reply e-mail and then delete this message from your system, do not use the contents for any purpose whatsoever nor disclose them to anyone else.

 

 


Klaus Brosche, DK3QN
 

<quote W7KEC> It is my understand that the QST Product reviews use a 3rd signal to simulate noise.  They measured a DR of about 70 for the Duo in their 2016 review. <unquote>

Clint,

Where in that QST review can I find that number?

Klaus, DK3QN


Am 12.01.2021 um 22:40 schrieb Clint Chron:

For Rob’s receiver tests, he turns on Dither is the radio supports that option.  The IC-7300, the Perseus, and other models support dither.  However, there are radios that have a very high DR without dither.  Look at Rob’s recent test on the Yaesu FTDX10.

 

It is my understand that the QST Product reviews use a 3rd signal to simulate noise.  They measured a DR of about 70 for the Duo in their 2016 review.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Neil Smith G4DBN
Sent: Tuesday, January 12, 2021 1:56 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

If the two source signals are pure tones, then you'll get pretty terrible results as there is no dither signal injected into a DUO as far as I know. A proper test of a radio with a straightforward ADC at the front end needs a reasonably large unrelated signal or random noise to smother the artefacts.  In any normal usage with an antenna, there will be enough wideband noise and signals to add sufficient random dither.

At very low levels, the receiver noise floor is probably sufficient to dither the signal, hence perhaps the better results measured close to MDS.

The Sherwood results are correct, but if I understand his methods, the results don't provide any useful information, he is just mapping out what a 16 bit ADC does with two pure signals.

I might be wildly wrong about this of course!

Neil G4DBN

 

On 12/01/2021 20:31, Clint Chron wrote:

I am not sure.  I don’t have the ability to inject a signal from a 3rd signal generator.

 

A couple of things to keep in mind.

Putting a HF pre-selector on the front end of the Duo should improve the DR, but I have not made that test.

The NPR measurements on the DUO come out very good, when compared with other high end radios.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Neil Smith G4DBN
Sent: Tuesday, January 12, 2021 1:17 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

Hi Clint, does injecting a realistic level of wideband noise (or some additional non-harmonically-related signals to provide dithering) change the results at all?

Neil G4DBN

On 12/01/2021 19:54, Clint Chron wrote:

I just ran the same tests several times on my Duo.  The results came out the same each time.

The challenge in testing the Dynamic Range of SDR receivers is that the DR bounces all over the board, depending upon the level of your two primary test tones (separated by 2 kHz).

So while the DR of the Duo may be low at the MDS measuring point, that does not mean that it is low for all measuring points.

 

Here is the IFSS graph for my Duo, the IC-7300, and the Perseus.

To get the dynamic range for a given primary signal level, subtract the IMD product signal level from the primary signal level.

Example:

The MDS on my Duo is -132 dbm.  A -64 dbm primary signal produces an IMD product of -132 dbm.  So the dynamic range is 68 db.

Now look at a primary signal of -40 dbm.  This produces an IMD product of -126 dbm.  So the dynamic range is 86 db.

Now look at  a primary signal at -30 dbm.  This produces an IMD product of -125 dbm.  So the dynamic range is 95 db.

 

For a given primary signal level, the radio that has the lowest IMD product signal level has the best dynamic range for that particular measuring point.

Of the three radios that I tested, the Perseus receiver has the best overall dynamic range.

 

73

Clint

W7KEC

 

 



Clint Chron
 

Hi Klaus,

 

I was wrong on the QST Review.  I got my numbers mixed up.  Looks like the value was 99 db at 14 MHz for a 2 Khz spacing. 

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Klaus Brosche
Sent: Tuesday, January 12, 2021 4:18 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

<quote W7KEC> It is my understand that the QST Product reviews use a 3rd signal to simulate noise.  They measured a DR of about 70 for the Duo in their 2016 review. <unquote>

 

Clint,

 

Where in that QST review can I find that number?

 

Klaus, DK3QN

 

 

Am 12.01.2021 um 22:40 schrieb Clint Chron:

For Rob’s receiver tests, he turns on Dither is the radio supports that option.  The IC-7300, the Perseus, and other models support dither.  However, there are radios that have a very high DR without dither.  Look at Rob’s recent test on the Yaesu FTDX10.

 

It is my understand that the QST Product reviews use a 3rd signal to simulate noise.  They measured a DR of about 70 for the Duo in their 2016 review.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Neil Smith G4DBN
Sent: Tuesday, January 12, 2021 1:56 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

If the two source signals are pure tones, then you'll get pretty terrible results as there is no dither signal injected into a DUO as far as I know. A proper test of a radio with a straightforward ADC at the front end needs a reasonably large unrelated signal or random noise to smother the artefacts.  In any normal usage with an antenna, there will be enough wideband noise and signals to add sufficient random dither.

At very low levels, the receiver noise floor is probably sufficient to dither the signal, hence perhaps the better results measured close to MDS.

The Sherwood results are correct, but if I understand his methods, the results don't provide any useful information, he is just mapping out what a 16 bit ADC does with two pure signals.

I might be wildly wrong about this of course!

Neil G4DBN

 

On 12/01/2021 20:31, Clint Chron wrote:

I am not sure.  I don’t have the ability to inject a signal from a 3rd signal generator.

 

A couple of things to keep in mind.

Putting a HF pre-selector on the front end of the Duo should improve the DR, but I have not made that test.

The NPR measurements on the DUO come out very good, when compared with other high end radios.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Neil Smith G4DBN
Sent: Tuesday, January 12, 2021 1:17 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

Hi Clint, does injecting a realistic level of wideband noise (or some additional non-harmonically-related signals to provide dithering) change the results at all?

Neil G4DBN

On 12/01/2021 19:54, Clint Chron wrote:

I just ran the same tests several times on my Duo.  The results came out the same each time.

The challenge in testing the Dynamic Range of SDR receivers is that the DR bounces all over the board, depending upon the level of your two primary test tones (separated by 2 kHz).

So while the DR of the Duo may be low at the MDS measuring point, that does not mean that it is low for all measuring points.

 

Here is the IFSS graph for my Duo, the IC-7300, and the Perseus.

To get the dynamic range for a given primary signal level, subtract the IMD product signal level from the primary signal level.

Example:

The MDS on my Duo is -132 dbm.  A -64 dbm primary signal produces an IMD product of -132 dbm.  So the dynamic range is 68 db.

Now look at a primary signal of -40 dbm.  This produces an IMD product of -126 dbm.  So the dynamic range is 86 db.

Now look at  a primary signal at -30 dbm.  This produces an IMD product of -125 dbm.  So the dynamic range is 95 db.

 

For a given primary signal level, the radio that has the lowest IMD product signal level has the best dynamic range for that particular measuring point.

Of the three radios that I tested, the Perseus receiver has the best overall dynamic range.

 

73

Clint

W7KEC

 

 

 


Clint Chron
 

On the IC-7300, enabling IP+ turns on dither and does improve the DR (less than 10 db improvement).  Here is a graph that shows the difference in DR with dither on and dither off.

 

DR at MDS – Dither Off:  75 db

DR at MDS – Dither On:   87 db

 

DR at -40 dbm – Dither Off:  84 db

DR at -40 dbm – Dither On:   90 db

 

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Neil Smith G4DBN
Sent: Tuesday, January 12, 2021 1:56 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

If the two source signals are pure tones, then you'll get pretty terrible results as there is no dither signal injected into a DUO as far as I know. A proper test of a radio with a straightforward ADC at the front end needs a reasonably large unrelated signal or random noise to smother the artefacts.  In any normal usage with an antenna, there will be enough wideband noise and signals to add sufficient random dither.

At very low levels, the receiver noise floor is probably sufficient to dither the signal, hence perhaps the better results measured close to MDS.

The Sherwood results are correct, but if I understand his methods, the results don't provide any useful information, he is just mapping out what a 16 bit ADC does with two pure signals.

I might be wildly wrong about this of course!

Neil G4DBN

 

On 12/01/2021 20:31, Clint Chron wrote:

I am not sure.  I don’t have the ability to inject a signal from a 3rd signal generator.

 

A couple of things to keep in mind.

Putting a HF pre-selector on the front end of the Duo should improve the DR, but I have not made that test.

The NPR measurements on the DUO come out very good, when compared with other high end radios.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Neil Smith G4DBN
Sent: Tuesday, January 12, 2021 1:17 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

Hi Clint, does injecting a realistic level of wideband noise (or some additional non-harmonically-related signals to provide dithering) change the results at all?

Neil G4DBN

On 12/01/2021 19:54, Clint Chron wrote:

I just ran the same tests several times on my Duo.  The results came out the same each time.

The challenge in testing the Dynamic Range of SDR receivers is that the DR bounces all over the board, depending upon the level of your two primary test tones (separated by 2 kHz).

So while the DR of the Duo may be low at the MDS measuring point, that does not mean that it is low for all measuring points.

 

Here is the IFSS graph for my Duo, the IC-7300, and the Perseus.

To get the dynamic range for a given primary signal level, subtract the IMD product signal level from the primary signal level.

Example:

The MDS on my Duo is -132 dbm.  A -64 dbm primary signal produces an IMD product of -132 dbm.  So the dynamic range is 68 db.

Now look at a primary signal of -40 dbm.  This produces an IMD product of -126 dbm.  So the dynamic range is 86 db.

Now look at  a primary signal at -30 dbm.  This produces an IMD product of -125 dbm.  So the dynamic range is 95 db.

 

For a given primary signal level, the radio that has the lowest IMD product signal level has the best dynamic range for that particular measuring point.

Of the three radios that I tested, the Perseus receiver has the best overall dynamic range.

 

73

Clint

W7KEC

 

 


Paul Jones
 

Sherwoods testing of the duo is flawed 


On Jan 13, 2021, at 00:05, Clint Chron <c.kiheiman@...> wrote:



On the IC-7300, enabling IP+ turns on dither and does improve the DR (less than 10 db improvement).  Here is a graph that shows the difference in DR with dither on and dither off.

 

DR at MDS – Dither Off:  75 db

DR at MDS – Dither On:   87 db

 

DR at -40 dbm – Dither Off:  84 db

DR at -40 dbm – Dither On:   90 db

 

<image001.png>

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Neil Smith G4DBN
Sent: Tuesday, January 12, 2021 1:56 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

If the two source signals are pure tones, then you'll get pretty terrible results as there is no dither signal injected into a DUO as far as I know. A proper test of a radio with a straightforward ADC at the front end needs a reasonably large unrelated signal or random noise to smother the artefacts.  In any normal usage with an antenna, there will be enough wideband noise and signals to add sufficient random dither.

At very low levels, the receiver noise floor is probably sufficient to dither the signal, hence perhaps the better results measured close to MDS.

The Sherwood results are correct, but if I understand his methods, the results don't provide any useful information, he is just mapping out what a 16 bit ADC does with two pure signals.

I might be wildly wrong about this of course!

Neil G4DBN

 

On 12/01/2021 20:31, Clint Chron wrote:

I am not sure.  I don’t have the ability to inject a signal from a 3rd signal generator.

 

A couple of things to keep in mind.

Putting a HF pre-selector on the front end of the Duo should improve the DR, but I have not made that test.

The NPR measurements on the DUO come out very good, when compared with other high end radios.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Neil Smith G4DBN
Sent: Tuesday, January 12, 2021 1:17 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

Hi Clint, does injecting a realistic level of wideband noise (or some additional non-harmonically-related signals to provide dithering) change the results at all?

Neil G4DBN

On 12/01/2021 19:54, Clint Chron wrote:

I just ran the same tests several times on my Duo.  The results came out the same each time.

The challenge in testing the Dynamic Range of SDR receivers is that the DR bounces all over the board, depending upon the level of your two primary test tones (separated by 2 kHz).

So while the DR of the Duo may be low at the MDS measuring point, that does not mean that it is low for all measuring points.

 

Here is the IFSS graph for my Duo, the IC-7300, and the Perseus.

To get the dynamic range for a given primary signal level, subtract the IMD product signal level from the primary signal level.

Example:

The MDS on my Duo is -132 dbm.  A -64 dbm primary signal produces an IMD product of -132 dbm.  So the dynamic range is 68 db.

Now look at a primary signal of -40 dbm.  This produces an IMD product of -126 dbm.  So the dynamic range is 86 db.

Now look at  a primary signal at -30 dbm.  This produces an IMD product of -125 dbm.  So the dynamic range is 95 db.

 

For a given primary signal level, the radio that has the lowest IMD product signal level has the best dynamic range for that particular measuring point.

Of the three radios that I tested, the Perseus receiver has the best overall dynamic range.

 

73

Clint

W7KEC

 

 


Clint Chron
 

It what way is his testing flawed?  Rob tests all of the receivers with the same process – two signal generators.  I use the same test process and almost identical test equipment and I get the same results, but I only have a limited number of receivers.

Here is my test setup:

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Paul Jones
Sent: Wednesday, January 13, 2021 12:18 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

Sherwoods testing of the duo is flawed 



On Jan 13, 2021, at 00:05, Clint Chron <c.kiheiman@...> wrote:



On the IC-7300, enabling IP+ turns on dither and does improve the DR (less than 10 db improvement).  Here is a graph that shows the difference in DR with dither on and dither off.

 

DR at MDS – Dither Off:  75 db

DR at MDS – Dither On:   87 db

 

DR at -40 dbm – Dither Off:  84 db

DR at -40 dbm – Dither On:   90 db

 

<image001.png>

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Neil Smith G4DBN
Sent: Tuesday, January 12, 2021 1:56 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

If the two source signals are pure tones, then you'll get pretty terrible results as there is no dither signal injected into a DUO as far as I know. A proper test of a radio with a straightforward ADC at the front end needs a reasonably large unrelated signal or random noise to smother the artefacts.  In any normal usage with an antenna, there will be enough wideband noise and signals to add sufficient random dither.

At very low levels, the receiver noise floor is probably sufficient to dither the signal, hence perhaps the better results measured close to MDS.

The Sherwood results are correct, but if I understand his methods, the results don't provide any useful information, he is just mapping out what a 16 bit ADC does with two pure signals.

I might be wildly wrong about this of course!

Neil G4DBN

 

On 12/01/2021 20:31, Clint Chron wrote:

I am not sure.  I don’t have the ability to inject a signal from a 3rd signal generator.

 

A couple of things to keep in mind.

Putting a HF pre-selector on the front end of the Duo should improve the DR, but I have not made that test.

The NPR measurements on the DUO come out very good, when compared with other high end radios.

 

73

Clint

W7KEC

 

From: EladSDR@groups.io [mailto:EladSDR@groups.io] On Behalf Of Neil Smith G4DBN
Sent: Tuesday, January 12, 2021 1:17 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] #elad #fdm-duo#sherwood

 

Hi Clint, does injecting a realistic level of wideband noise (or some additional non-harmonically-related signals to provide dithering) change the results at all?

Neil G4DBN

On 12/01/2021 19:54, Clint Chron wrote:

I just ran the same tests several times on my Duo.  The results came out the same each time.

The challenge in testing the Dynamic Range of SDR receivers is that the DR bounces all over the board, depending upon the level of your two primary test tones (separated by 2 kHz).

So while the DR of the Duo may be low at the MDS measuring point, that does not mean that it is low for all measuring points.

 

Here is the IFSS graph for my Duo, the IC-7300, and the Perseus.

To get the dynamic range for a given primary signal level, subtract the IMD product signal level from the primary signal level.

Example:

The MDS on my Duo is -132 dbm.  A -64 dbm primary signal produces an IMD product of -132 dbm.  So the dynamic range is 68 db.

Now look at a primary signal of -40 dbm.  This produces an IMD product of -126 dbm.  So the dynamic range is 86 db.

Now look at  a primary signal at -30 dbm.  This produces an IMD product of -125 dbm.  So the dynamic range is 95 db.

 

For a given primary signal level, the radio that has the lowest IMD product signal level has the best dynamic range for that particular measuring point.

Of the three radios that I tested, the Perseus receiver has the best overall dynamic range.

 

73

Clint

W7KEC