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Update to KSYN3A FAQ (some measured dynamic range numbers)

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wayne burdick

Update to KSYN3A FAQ (some measured dynamic range numbers)

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Hi all,

I've updated the KSYN3A FAQ with the following information regarding testing of a K3 with the new synthesizer performed by Rob Sherwood, NC0B.

* * *

Q: What is the approximate 2-kHz dynamic range (IMDDR3) of the K3 when using the new synthesizer?

A: Our tests show in excess of 105 dB with the narrowest filters, though there are many factors, and this should be considered approximate. (A very robust test setup is required to make these measurements.) Rob Sherwood tested a K3 with a KSYN3A and obtained the following results:

2-kHz IMDDR3 with 200-Hz roofing and DSP filter = 106 dB
2-kHz IMDDR3 with 400-Hz roofing and DSP filter = 103 dB

Rob will be posting this information in his receiver performance chart (http://www.sherweng.com/table.html) after he completes his full suite of tests.

* * *

The above numbers were used with Rob's permission.

73,
Wayne
N6KR

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Johnny Siu

Update to KSYN3A FAQ (some measured dynamic range numbers)

I must admit that understanding those figures are beyond my knowledge. In practical terms, if I can now hear a below S1 cw weak signal 10KHz away from a S9+60db station before upgrade, what will be the improvement after the installation of KSYN3A assuming operating under the same condition?
Such a demonstation was given to me when I visited Icom HQ in Osaka last year in the announcement of the IC7850/IC7851. Again, IC7850 is known foir extremely low phase noise.
Can any elecrafters interpret the improvements in an understandable layman terms?
73
Johnny VR2XMCK-Line + KX3 + HR50
寄件人︰ Wayne Burdick <[hidden email]>
收件人︰ Elecraft Reflector <[hidden email]>
副本(CC)︰ "[hidden email]" <[hidden email]>
傳送日期︰ 2015年02月14日 (週六) 7:34 AM
主題︰ [Elecraft] Update to KSYN3A FAQ (some measured dynamic range numbers)

Hi all,

I've updated the KSYN3A FAQ with the following information regarding testing of a K3 with the new synthesizer performed by Rob Sherwood, NC0B.

* * *

Q: What is the approximate 2-kHz dynamic range (IMDDR3) of the K3 when using the new synthesizer?

A: Our tests show in excess of 105 dB with the narrowest filters, though there are many factors, and this should be considered approximate. (A very robust test setup is required to make these measurements.) Rob Sherwood tested a K3 with a KSYN3A and obtained the following results:

2-kHz IMDDR3 with 200-Hz roofing and DSP filter = 106 dB
2-kHz IMDDR3 with 400-Hz roofing and DSP filter = 103 dB

Rob will be posting this information in his receiver performance chart (http://www.sherweng.com/table.html) after he completes his full suite of tests.

* * *

The above numbers were used with Rob's permission.

73,
Wayne
N6KR

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Don Wilhelm-4

Re: Update to KSYN3A FAQ (some measured dynamic range numbers)

Johnny,

Hopefully I can simplify it a bit given your example.
That S9+60dB signal will have a weaker response in your receiver *if*
your receiver was the limiting factor. If the transmitter phase noise
(splatter and other 'bad stuff' was the original problem, then you may
or may not have any improvement for that example.

In other words, you will notice an improvement if other signals on the
band are relatively clean. The improvement when other signals on the
band are not clean will not be as obvious.

Actually if an S9+60dB signal 10 kHz away is going to give you problems,
then that signal is coming from a 'dirty transmitter'. I think a better
example would be -- If you can operate within 2 kHz of a strong signal
with the current KSYN3, then the KSYN3A may be able to allow you to
operate within 1.5 to 1.8 kHz of that same signal. In other words, you
will be able to "saddle up closer" to any signal unless the transmitter
is creating trash.

Note: All numbers are for relative comparison only. I pulled those
numbers out of my head for illustration purposes only and do not
represent any test data. I have not seen nor used the KSYN3A.

73,
Don W3FPR

On 2/13/2015 7:19 PM, Johnny Siu wrote:

> I must admit that understanding those figures are beyond my knowledge. In practical terms, if I can now hear a below S1 cw weak signal 10KHz away from a S9+60db station before upgrade, what will be the improvement after the installation of KSYN3A assuming operating under the same condition?
> Such a demonstation was given to me when I visited Icom HQ in Osaka last year in the announcement of the IC7850/IC7851. Again, IC7850 is known foir extremely low phase noise.
> Can any elecrafters interpret the improvements in an understandable layman terms?
> 73
> Johnny VR2XMCK-Line + KX3 + HR50
> 寄件人︰ Wayne Burdick <[hidden email]>
> 收件人︰ Elecraft Reflector <[hidden email]>
> 副本(CC)︰ "[hidden email]" <[hidden email]>
> 傳送日期︰ 2015年02月14日 (週六) 7:34 AM
> 主題︰ [Elecraft] Update to KSYN3A FAQ (some measured dynamic range numbers)
>
> Hi all,
>
> I've updated the KSYN3A FAQ with the following information regarding testing of a K3 with the new synthesizer performed by Rob Sherwood, NC0B.
>
> * * *
>
> Q: What is the approximate 2-kHz dynamic range (IMDDR3) of the K3 when using the new synthesizer?
>
> A: Our tests show in excess of 105 dB with the narrowest filters, though there are many factors, and this should be considered approximate. (A very robust test setup is required to make these measurements.) Rob Sherwood tested a K3 with a KSYN3A and obtained the following results:
>
> 2-kHz IMDDR3 with 200-Hz roofing and DSP filter = 106 dB
> 2-kHz IMDDR3 with 400-Hz roofing and DSP filter = 103 dB
>
> Rob will be posting this information in his receiver performance chart (http://www.sherweng.com/table.html) after he completes his full suite of tests.
>
> * * *
>
> The above numbers were used with Rob's permission.
>
> 73,
> Wayne
> N6KR
>
> ______________________________________________________________
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>
>
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Jim Brown-10

Re: Update to KSYN3A FAQ (some measured dynamic range numbers)

In reply to this post by Johnny Siu

On Fri,2/13/2015 4:19 PM, Johnny Siu wrote:
> Again, IC7850 is known foir extremely low phase noise.

Is it known for it's low phase noise on TX?

73, Jim K9YC
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Elecraft mailing list

Re: Update to KSYN3A FAQ (some measured dynamic range numbers)

In reply to this post by wayne burdick

Thanks for the figures. I am trying to understand the amount of improvement we can expect.
According to the ARRL Review in January 2009 the IMDDR was 106/103 dbm at 2 KHZ but the Reciprocal Mixing was -86dbc at 2KHZ offset with 500 HZ bandwidth.
The new synthesizer has essential the SAME IMDDR 106 or 103 depending on the filter bandwidth.
So, my question: is the real import of all this that the new synthesizer will give the K3 an IMDDR which is NOT limited to 86 dbs by Reciprocal Mixing so we will now get the FULL benefit of a IMDDR of 106/103?If so, that 20 db improvement is huge.
I may be mixing apples and oranges, but I am just trying to understand this.
Thanks for any clarification the group can provide.
73,
Bob/AA6VB

From: Wayne Burdick <[hidden email]>
To: Elecraft Reflector <[hidden email]>
Cc: "[hidden email]" <[hidden email]>
Sent: Friday, February 13, 2015 3:34 PM
Subject: [Elecraft] Update to KSYN3A FAQ (some measured dynamic range numbers)

Hi all,

I've updated the KSYN3A FAQ with the following information regarding testing of a K3 with the new synthesizer performed by Rob Sherwood, NC0B.

* * *

Q: What is the approximate 2-kHz dynamic range (IMDDR3) of the K3 when using the new synthesizer?

A: Our tests show in excess of 105 dB with the narrowest filters, though there are many factors, and this should be considered approximate. (A very robust test setup is required to make these measurements.) Rob Sherwood tested a K3 with a KSYN3A and obtained the following results:

2-kHz IMDDR3 with 200-Hz roofing and DSP filter = 106 dB
2-kHz IMDDR3 with 400-Hz roofing and DSP filter = 103 dB

Rob will be posting this information in his receiver performance chart (http://www.sherweng.com/table.html) after he completes his full suite of tests.

* * *

The above numbers were used with Rob's permission.

73,
Wayne
N6KR

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Joe Subich, W4TV-4

Re: Update to KSYN3A FAQ (some measured dynamic range numbers)

In reply to this post by wayne burdick

Argh! That will make the K3 second to the Flex 6700 in Sherwood's
table <G> although the 100 KHz blocking will be better than the "A/D
Limited" for the 6700.

73,

... Joe, W4TV

On 2015-02-13 6:34 PM, Wayne Burdick wrote:

> Hi all,
>
> I've updated the KSYN3A FAQ with the following information regarding testing of a K3 with the new synthesizer performed by Rob Sherwood, NC0B.
>
> * * *
>
> Q: What is the approximate 2-kHz dynamic range (IMDDR3) of the K3 when using the new synthesizer?
>
> A: Our tests show in excess of 105 dB with the narrowest filters, though there are many factors, and this should be considered approximate. (A very robust test setup is required to make these measurements.) Rob Sherwood tested a K3 with a KSYN3A and obtained the following results:
>
> 2-kHz IMDDR3 with 200-Hz roofing and DSP filter = 106 dB
> 2-kHz IMDDR3 with 400-Hz roofing and DSP filter = 103 dB
>
> Rob will be posting this information in his receiver performance chart (http://www.sherweng.com/table.html) after he completes his full suite of tests.
>
> * * *
>
> The above numbers were used with Rob's permission.
>
> 73,
> Wayne
> N6KR
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
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>

Joe Subich, W4TV-4

Re: Update to KSYN3A FAQ (some measured dynamic range numbers)

In reply to this post by Elecraft mailing list

On 2015-02-13 10:08 PM, Chortek Bob via Elecraft wrote:
> The new synthesizer has essential the SAME IMDDR 106 or 103
> depending on the filter bandwidth.

Incorrect! You are comparing measurements by different labs with
different test equipment and procedures.

Sherwood measured 104 dB w/200 Hz filter and 96 dB w/400 Hz filter
for the old Synth vs. 106 and 103 for new synth. That's 2 to 7 dB
improvement depending on filter bandwidth. Since the synthesizer
is about 6dBc/Hz better than the old synthesizer, the first order
estimation is that the improvement in narrow spaced IMDDR3 is due
to the decrease in phase noise.

> So, my question: is the real import of all this that the new
> synthesizer will give the K3 an IMDDR which is NOT limited to 86
> dbs by Reciprocal Mixing so we will now get the FULL benefit of a
> IMDDR of 106/103?If so, that 20 db improvement is huge.

One would need to look into the way in which ARRL measures Reciprocal
Mixing to understand exactly what that "Spec" is telling you and what
improvement one might find. It is safe to expect the reduction in
phase noise to directly impact both narrow spaced IMDDR3 and Reciprocal
Mixing.

BTW, I just reviewed the original ARRL review of the K3 (April 2008) and
their Reciprocal Mixing numbers were -116 dBc @20 KHz, -106 dBc
@ 5 KHz and -95dBc at 2 KHz. That's a far ways from -89 dB that you
quote. Assuming a 6 dBc/Hz noise improvement in the new synthesizer,
you can make the numbers -122, -112, -101 which would be a significant
improvement.

73,

... Joe, W4TV

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Dave-7

Re: Update to KSYN3A FAQ (some measured dynamic range numbers)

> That's a far ways from -89 dB that you
> quote.

The ARRL review in the April 2008 issue of the K3/10 showed reciprocal
mixing as -95 dBc at 2 kHz spacing.

The ARRL review in the Jan 2009 issue of the K3/100 showed reciprocal
mixing as -86 dBc at 2 kHz spacing.

This is the same lab. Dunno about same test equipment.

73 de dave
ab9ca/4

On 2/13/15 10:29 PM, Joe Subich, W4TV wrote:

>
> On 2015-02-13 10:08 PM, Chortek Bob via Elecraft wrote:
>> The new synthesizer has essential the SAME IMDDR 106 or 103
>> depending on the filter bandwidth.
>
> Incorrect! You are comparing measurements by different labs with
> different test equipment and procedures.
>
> Sherwood measured 104 dB w/200 Hz filter and 96 dB w/400 Hz filter
> for the old Synth vs. 106 and 103 for new synth. That's 2 to 7 dB
> improvement depending on filter bandwidth. Since the synthesizer
> is about 6dBc/Hz better than the old synthesizer, the first order
> estimation is that the improvement in narrow spaced IMDDR3 is due
> to the decrease in phase noise.
>
>> So, my question: is the real import of all this that the new
>> synthesizer will give the K3 an IMDDR which is NOT limited to 86
>> dbs by Reciprocal Mixing so we will now get the FULL benefit of a
>> IMDDR of 106/103?If so, that 20 db improvement is huge.
>
> One would need to look into the way in which ARRL measures Reciprocal
> Mixing to understand exactly what that "Spec" is telling you and what
> improvement one might find. It is safe to expect the reduction in
> phase noise to directly impact both narrow spaced IMDDR3 and Reciprocal
> Mixing.
>
> BTW, I just reviewed the original ARRL review of the K3 (April 2008)
> and their Reciprocal Mixing numbers were -116 dBc @20 KHz, -106 dBc
> @ 5 KHz and -95dBc at 2 KHz. That's a far ways from -89 dB that you
> quote. Assuming a 6 dBc/Hz noise improvement in the new synthesizer,
> you can make the numbers -122, -112, -101 which would be a significant
> improvement.
>
> 73,
>
> ... Joe, W4TV
>
> ______________________________________________________________
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>
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>

Johnny Siu

Update to KSYN3A FAQ (some measured dynamic range numbers)

In reply to this post by Don Wilhelm-4

Thanks, Don, you are great in explaining the figures in layman terms. While I cannot control the other's transmitters' IMD / phase noise, I now at least know what I will expect to be better off by using the KSYN3A especially under very difficult RX conditions (assuming everything under the same conditions as the current KSYN3).
TNX,
Johnny VR2XMC
寄件人︰ Don Wilhelm <[hidden email]>
收件人︰ Johnny Siu <[hidden email]>; Elecraft Reflector <[hidden email]>
傳送日期︰ 2015年02月14日 (週六) 8:44 AM
主題︰ Re: [Elecraft] Update to KSYN3A FAQ (some measured dynamic range numbers)

Johnny,

Hopefully I can simplify it a bit given your example.
That S9+60dB signal will have a weaker response in your receiver *if*
your receiver was the limiting factor. If the transmitter phase noise
(splatter and other 'bad stuff' was the original problem, then you may
or may not have any improvement for that example.

In other words, you will notice an improvement if other signals on the
band are relatively clean. The improvement when other signals on the
band are not clean will not be as obvious.

Actually if an S9+60dB signal 10 kHz away is going to give you problems,
then that signal is coming from a 'dirty transmitter'. I think a better
example would be -- If you can operate within 2 kHz of a strong signal
with the current KSYN3, then the KSYN3A may be able to allow you to
operate within 1.5 to 1.8 kHz of that same signal. In other words, you
will be able to "saddle up closer" to any signal unless the transmitter
is creating trash.

Note: All numbers are for relative comparison only. I pulled those
numbers out of my head for illustration purposes only and do not
represent any test data. I have not seen nor used the KSYN3A.

73,
Don W3FPR

On 2/13/2015 7:19 PM, Johnny Siu wrote:

Johnny Siu

Update to KSYN3A FAQ (some measured dynamic range numbers)

In reply to this post by Jim Brown-10

If both RX and TX are using the same synthesizer, TX phase noise should be lowered.
However, I am no expert on Icom IC7850 but more information will be given in the link below:
The Icom IC-7850 at APDXC 2014

| |
| | | | | | | |
| The Icom IC-7850 at APDXC 2014The IC-7850 at APDXC 2014, Osaka, Japan by Adam Farson VA7OJ/AB4OJ Hot News! The IC-7850 and IC-7851 received FCC and IC certification on 15 January 201... |
| |
| 查看於 www.ab4oj.com | Yahoo 預覽 |
| |
| |

The idea of reciprocal mixing dynamic range RMDR now becomes a more realistic measure of RX.
73
Johnny VR2XMC 寄件人︰ Jim Brown <[hidden email]>
收件人︰ [hidden email]
傳送日期︰ 2015年02月14日 (週六) 11:00 AM
主題︰ Re: [Elecraft] Update to KSYN3A FAQ (some measured dynamic range numbers)

On Fri,2/13/2015 4:19 PM, Johnny Siu wrote:
> Again, IC7850 is known foir extremely low phase noise.

Is it known for it's low phase noise on TX?

73, Jim K9YC

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Jim Brown-10

Re: Update to KSYN3A FAQ (some measured dynamic range numbers)

On Fri,2/13/2015 9:42 PM, Johnny Siu wrote:
> If both RX and TX are using the same synthesizer, TX phase noise
> should be lowered.

Not necessarily -- it depends on the design. Some rigs have low phase
noise on RX but not on TX.

73, Jim K9YC
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gm3sek

Re: Update to KSYN3A FAQ (some measured dynamic range numbers)

>> If both RX and TX are using the same synthesizer, TX phase noise
>> should be lowered.
>
>Not necessarily -- it depends on the design. Some rigs have low phase
>noise on RX but not on TX.
>

The noise that we hear on transmitted signals, or through reciprocal
mixing in our receivers, is always the COMPOSITE noise - the vector sum
of both the Phase Noise and the Amplitude-Modulated noise.

Most modern test equipment measures exclusively phase noise, so that's
what the equipment reviews quote as well. Then the advertisers jumped on
the bandwagon so now it's "Phase noise, phase noise, everybody's talkin'
'bout phase noise!" We are carelessly sliding towards labeling every
kind of noise as "phase noise" when very often it isn't.

Don't ever forget that AM noise component. At some frequencies AM noise
can be even more important than the phase noise.

If the transmit and receive paths use the same frequency-determining
signals (oscillators) then the phase noise - true phase noise, that is -
in the TX and RX paths should be very similar. Generically they should
be the same, so you'd need to identify some quite specific reasons for
PN to be different between TX and RX in any particular transceiver.

But a transceiver also contains many, many sources of AM noise - not so
much in the oscillators but in the TX and RX signal pathways. Because
those pathways are different, the levels of AM noise generically *do*
differ between TX and RX.

Therefore we should always expect the *composite* noise to be different
between TX and RX - and that will probably be mostly because of
different AM noise levels.

Problems with AM noise on transmit are often made worse by designers
forgetting that the problem even exists. In older analog rigs, for
example, there may be significant AM noise on transmit because the TX
chain starts out at too low a signal level, and the designer forgot to
use low-noise techniques in that weak spot.

In modern digital rigs, the analog TX signal comes from a DAC (Digital
to Analog Converter) which is heavily laden with AM digital noise that
needs careful filtering. There is an awful example in SM5BSZ's 2013
article on 'Band Pollution by Amateur Transmitters'
<http://sm5bsz.com/dynrange/dubus313.pdf>. Figure 8 shows a very high
noise level at the output of the DAC (enough to make the sine-wave look
like a fuzzy caterpillar). Then that noise is insufficiently filtered,
leaving serious TX noise sidebands of only -75dBc at +/- 300kHz. Because
this is almost entirely AM noise, any test that focuses exclusively on
phase noise will miss it... and that particular manufacturer did miss
it.

In contrast, the K3 came top of the table for suppression of wideband TX
noise (Table 1, which pre-dates the KX3).

73 from Ian GM3SEK

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Elecraft mailing list

Re: Update to KSYN3A FAQ (some measured dynamic range numbers)

In reply to this post by Johnny Siu

Hi Johhny,
I'll probably get flamed for saying this, or someone more knowledgeable that I will point out how ignorant I am, but here is my layperson's understanding of this issue:
Assuming a MDS of -128 dbm, and an S9 signal equivalent to -73 dbm, IMD will begin to be a problem when two out of passband signals combine as follows:
IMDDR Signal causing IMD = Noise Floor
55 db S960 db S9 plus 5 db65 db S9 plus 10 db70 db S9 plus 15 db75 db S9 plus 20 db80 db S9 plus 25 db85 db S9 plus 30 db90 db S9 plus 35 db95 db S9 plus 40 db100 db S9 plus 45 db105 db S9 plus 50 db
You can see that if your rig has an IMDDR of 90 db, it would take a signal S9 + 35 db before you would likely notice any adverse affects from IMD caused by two out of passband signals (at the required spacing).
So, a person who has a rig with an IMDDR of say 95 db would only notice an improvement in the IMDDR when they are exposed to two out of band signals causing an IMD product when those signals are more than S9 plus 40 db. The question you need to ask yourself is, how often are you faced with that situation? The constant pursuit for improved IMD performance, it seems to me, is a worthy goal, but whether it benefits a particlar amature operator depends on whether he or she is faced with two out of passband signals that combine with the spacing required to cause an IMD product in his or her rig, AND the number of times those signals are sufficiently strong to exceed the IMDDR of their rig. For some contestants, this is a BIG factor, but for other folks it rarely matters. It all depends on your operating environment....

I'm am sure this is not 100 correct, as I am not an engineer, but you should get the general idea
73,

Bob/AA6VB

From: Johnny Siu <[hidden email]>
To: Wayne Burdick <[hidden email]>; Elecraft Reflector <[hidden email]>
Cc: "[hidden email]" <[hidden email]>
Sent: Friday, February 13, 2015 4:19 PM
Subject: [Elecraft] Update to KSYN3A FAQ (some measured dynamic range numbers)

I must admit that understanding those figures are beyond my knowledge. In practical terms, if I can now hear a below S1 cw weak signal 10KHz away from a S9+60db station before upgrade, what will be the improvement after the installation of KSYN3A assuming operating under the same condition?
Such a demonstation was given to me when I visited Icom HQ in Osaka last year in the announcement of the IC7850/IC7851. Again, IC7850 is known foir extremely low phase noise.
Can any elecrafters interpret the improvements in an understandable layman terms?
73
Johnny VR2XMCK-Line + KX3 + HR50
寄件人︰ Wayne Burdick <[hidden email]>
收件人︰ Elecraft Reflector <[hidden email]>
副本(CC)︰ "[hidden email]" <[hidden email]>
傳送日期︰ 2015年02月14日 (週六) 7:34 AM
主題︰ [Elecraft] Update to KSYN3A FAQ (some measured dynamic range numbers)

Hi all,

I've updated the KSYN3A FAQ with the following information regarding testing of a K3 with the new synthesizer performed by Rob Sherwood, NC0B.

* * *

Q: What is the approximate 2-kHz dynamic range (IMDDR3) of the K3 when using the new synthesizer?

A: Our tests show in excess of 105 dB with the narrowest filters, though there are many factors, and this should be considered approximate. (A very robust test setup is required to make these measurements.) Rob Sherwood tested a K3 with a KSYN3A and obtained the following results:

2-kHz IMDDR3 with 200-Hz roofing and DSP filter = 106 dB
2-kHz IMDDR3 with 400-Hz roofing and DSP filter = 103 dB

Rob will be posting this information in his receiver performance chart (http://www.sherweng.com/table.html) after he completes his full suite of tests.

* * *

The above numbers were used with Rob's permission.

73,
Wayne
N6KR

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Re: Update to KSYN3A FAQ (some measured dynamic range numbers)

The table got compressed. Let me try again -
IMDDR Signal causing IMD = Noise Floor

55 db      S9
60 db      S9 plus 5 db
65 db      S9 plus 10 db
70 db      S9 plus 15 db
75 db      S9 plus 20 db
80 db      S9 plus 25 db
85 db      S9 plus 30 db
90 db      S9 plus 35 db
95 db      S9 plus 40 db
100 db      S9 plus 45 db
105 db      S9 plus 50 db
From: Chortek Bob via Elecraft <[hidden email]>
To: Johnny Siu <[hidden email]>; Wayne Burdick <[hidden email]>; Elecraft Reflector <[hidden email]>
Cc: "[hidden email]" <[hidden email]>
Sent: Saturday, February 14, 2015 12:57 PM
Subject: Re: [Elecraft] Update to KSYN3A FAQ (some measured dynamic range numbers)

Hi Johhny,
I'll probably get flamed for saying this, or someone more knowledgeable that I will point out how ignorant I am, but here is my layperson's understanding of this issue:
Assuming a MDS of -128 dbm, and an S9 signal equivalent to -73 dbm, IMD will begin to be a problem when two out of passband signals combine as follows:
IMDDR Signal causing IMD = Noise Floor
55 db S960 db S9 plus 5 db65 db S9 plus 10 db70 db S9 plus 15 db75 db S9 plus 20 db80 db S9 plus 25 db85 db S9 plus 30 db90 db S9 plus 35 db95 db S9 plus 40 db100 db S9 plus 45 db105 db S9 plus 50 db
You can see that if your rig has an IMDDR of 90 db, it would take a signal S9 + 35 db before you would likely notice any adverse affects from IMD caused by two out of passband signals (at the required spacing).
So, a person who has a rig with an IMDDR of say 95 db would only notice an improvement in the IMDDR when they are exposed to two out of band signals causing an IMD product when those signals are more than S9 plus 40 db. The question you need to ask yourself is, how often are you faced with that situation? The constant pursuit for improved IMD performance, it seems to me, is a worthy goal, but whether it benefits a particlar amature operator depends on whether he or she is faced with two out of passband signals that combine with the spacing required to cause an IMD product in his or her rig, AND the number of times those signals are sufficiently strong to exceed the IMDDR of their rig. For some contestants, this is a BIG factor, but for other folks it rarely matters. It all depends on your operating environment....

I'm am sure this is not 100 correct, as I am not an engineer, but you should get the general idea
73,

Bob/AA6VB

From: Johnny Siu <[hidden email]>
To: Wayne Burdick <[hidden email]>; Elecraft Reflector <[hidden email]>
Cc: "[hidden email]" <[hidden email]>
Sent: Friday, February 13, 2015 4:19 PM
Subject: [Elecraft] Update to KSYN3A FAQ (some measured dynamic range numbers)

I must admit that understanding those figures are beyond my knowledge. In practical terms, if I can now hear a below S1 cw weak signal 10KHz away from a S9+60db station before upgrade, what will be the improvement after the installation of KSYN3A assuming operating under the same condition?
Such a demonstation was given to me when I visited Icom HQ in Osaka last year in the announcement of the IC7850/IC7851. Again, IC7850 is known foir extremely low phase noise.
Can any elecrafters interpret the improvements in an understandable layman terms?
73
Johnny VR2XMCK-Line + KX3 + HR50
   寄件人︰ Wayne Burdick <[hidden email]>
收件人︰ Elecraft Reflector <[hidden email]>
副本(CC)︰ "[hidden email]" <[hidden email]>
傳送日期︰ 2015年02月14日 (週六) 7:34 AM
主題︰ [Elecraft] Update to KSYN3A FAQ (some measured dynamic range numbers)

Hi all,

I've updated the KSYN3A FAQ with the following information regarding testing of a K3 with the new synthesizer performed by Rob Sherwood, NC0B.

* * *

Q: What is the approximate 2-kHz dynamic range (IMDDR3) of the K3 when using the new synthesizer?

A: Our tests show in excess of 105 dB with the narrowest filters, though there are many factors, and this should be considered approximate. (A very robust test setup is required to make these measurements.) Rob Sherwood tested a K3 with a KSYN3A and obtained the following results:

2-kHz IMDDR3 with 200-Hz roofing and DSP filter = 106 dB
2-kHz IMDDR3 with 400-Hz roofing and DSP filter = 103 dB

Rob will be posting this information in his receiver performance chart (http://www.sherweng.com/table.html) after he completes his full suite of tests.

* * *

The above numbers were used with Rob's permission.

73,
Wayne
N6KR

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Oliver Dröse

Re: Update to KSYN3A FAQ (some measured dynamic range numbers)

In reply to this post by Don Wilhelm-4

Problem is that (at least in SSB) I feel the K3 receiver (with the "old"
synth board) is never the limiting factor, it's always all those dirty
other signals (splatter, key-clicks, a.s.o. ... the new synth board will
*not* help anything if they splatter into your passband). I will not
upgrade for exactly that reason! In every contest I feel I already have
too good an RX and TX while other people gain advantages from their
dirty rigs ... :-(

73, Olli - DH8BQA

Contest, DX & radio projects: http://www.dh8bqa.de

Am 14.02.2015 um 01:44 schrieb Don Wilhelm:

> Johnny,
>
> Hopefully I can simplify it a bit given your example.
> That S9+60dB signal will have a weaker response in your receiver *if*
> your receiver was the limiting factor. If the transmitter phase noise
> (splatter and other 'bad stuff' was the original problem, then you may
> or may not have any improvement for that example.
>
> In other words, you will notice an improvement if other signals on the
> band are relatively clean. The improvement when other signals on the
> band are not clean will not be as obvious.
>
> Actually if an S9+60dB signal 10 kHz away is going to give you
> problems, then that signal is coming from a 'dirty transmitter'. I
> think a better example would be -- If you can operate within 2 kHz of
> a strong signal with the current KSYN3, then the KSYN3A may be able to
> allow you to operate within 1.5 to 1.8 kHz of that same signal. In
> other words, you will be able to "saddle up closer" to any signal
> unless the transmitter is creating trash.
>
> Note: All numbers are for relative comparison only. I pulled those
> numbers out of my head for illustration purposes only and do not
> represent any test data. I have not seen nor used the KSYN3A.
>
> 73,
> Don W3FPR
>
> On 2/13/2015 7:19 PM, Johnny Siu wrote:
>> I must admit that understanding those figures are beyond my
>> knowledge. In practical terms, if I can now hear a below S1 cw weak
>> signal 10KHz away from a S9+60db station before upgrade, what will be
>> the improvement after the installation of KSYN3A assuming operating
>> under the same condition?
>> Such a demonstation was given to me when I visited Icom HQ in Osaka
>> last year in the announcement of the IC7850/IC7851. Again, IC7850 is
>> known foir extremely low phase noise.
>> Can any elecrafters interpret the improvements in an understandable
>> layman terms?
>> 73
>> Johnny VR2XMCK-Line + KX3 + HR50
>> 寄件人︰ Wayne Burdick <[hidden email]>
>> 收件人︰ Elecraft Reflector <[hidden email]>
>> 副本(CC)︰ "[hidden email]" <[hidden email]>
>> 傳送日期︰ 2015年02月14日 (週六) 7:34 AM
>> 主題︰ [Elecraft] Update to KSYN3A FAQ (some measured dynamic range
>> numbers)
>> Hi all,
>>
>> I've updated the KSYN3A FAQ with the following information regarding
>> testing of a K3 with the new synthesizer performed by Rob Sherwood,
>> NC0B.
>>
>> * * *
>>
>> Q: What is the approximate 2-kHz dynamic range (IMDDR3) of the K3
>> when using the new synthesizer?
>>
>> A: Our tests show in excess of 105 dB with the narrowest filters,
>> though there are many factors, and this should be considered
>> approximate. (A very robust test setup is required to make these
>> measurements.) Rob Sherwood tested a K3 with a KSYN3A and obtained
>> the following results:
>>
>> 2-kHz IMDDR3 with 200-Hz roofing and DSP filter = 106 dB
>> 2-kHz IMDDR3 with 400-Hz roofing and DSP filter = 103 dB
>>
>> Rob will be posting this information in his receiver performance
>> chart (http://www.sherweng.com/table.html) after he completes his
>> full suite of tests.
>>
>> * * *
>>
>> The above numbers were used with Rob's permission.
>>
>> 73,
>> Wayne
>> N6KR
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
>
> ______________________________________________________________
> Elecraft mailing list
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>
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