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Sherwood's receiver performance table updated

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Tom McCulloch

Re: [Bulk] Re: Sherwood's receiver performance table updated

Heath DX-60= Model A

On 4/26/2016 8:48 PM, Chris Tate - N6WM wrote:

> Maybe apples and oranges is not the best comparison.. how about this
>
> Elecraft K3s = Porsche
> Flex 6000 = Tesla
> IC-7300 = Nissan Leaf
> Kenwood TS-590 =Toyota pickup
>
> ~C./WM
>
>
>
>
>
>
>
> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of Kevin Stover
> Sent: Tuesday, April 26, 2016 5:08 PM
> To: [hidden email]
> Subject: Re: [Elecraft] Sherwood's receiver performance table updated
>
> Ditto we still don't use them.
> Our users have a choice of laptop or iPad/Surface other than a desktop thin client on our VM Ware network.
> 90% choose the Win7 laptop. They're more expensive, slower, and break more often than the thin client but not as often as the iPads. The Surface's are new so no experience base with them yet. Our hardware group absolutely hate touch screens. I'm a Network Engineer...I have no use for them either.
>
> My brother does IT for a school district that equipped all of their middle school kids with cutting edge iPads. 700 of them. My brother had to get good at replacing the very expensive coated touch screens that the evil empire said mere mortals couldn't replace. He got no help from Apple other than expensive parts. That experiment lasted three years and they switched to Chrome books.
>
> I guarantee as sure as I'm sitting here *that touch screen will fail within a year...if not sooner*, and you've got no chance to fix it yourself. I can order parts from Elecraft for all my rigs and fix them.
> No sweat.
>
> I'm curious why is direct sampling SDR's like the 7300 are supposed to be the second coming why Icom stuck with the traditional superhet architecture on it's "flagship" 7851? Maybe they realize the technology is at least 5 years away from being competitive. Everybody is ignoring W4TV's 800lb Gorilla, ADC overload.
>
> On 4/26/2016 5:28 PM, Clay Autery wrote:
>> Coat it however you want... Doesn't stop dirt and grime being put on
>> the screen possibly scratching and/or gooping up the corners and edges...
>>
>> I've been in IS/IT for 25+ years... Screens are not for touching.
>>
>> Bottom Line... I'll stick with buttons, dials, and switches, thank
>> you. :)
>>
>> ______________________
>> Clay Autery, KG5LKV
>> MONTAC Enterprises
>> (318) 518-1389
>>
>
> --
> R. Kevin Stover
> AC0H
> ARRL
> FISTS #11993
> SKCC #215
> NAQCC #3441
>
>
>
> ---
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--

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Re: Sherwood's receiver performance table updated

In reply to this post by Gary Gregory-2

blockquote, div.yahoo_quoted { margin-left: 0 !important; border-left:1px #715FFA solid !important; padding-left:1ex !important; background-color:white !important; } Depends how many times you drop it.

Sent from Yahoo Mail for iPhone

On Tuesday, April 26, 2016, 5:32 PM, Gary <[hidden email]> wrote:

Hmm....how long is the life expectancy of a smart phone?

My k3 ain't goin anywhere....
Gary

-----Original Message-----
From: "Tony Estep" <[hidden email]>
Sent: ‎27/‎04/‎2016 10:21 AM
To: "Elecraft" <[hidden email]>
Subject: Re: [Elecraft] Sherwood's receiver performance table updated

> "25+ years.... Screens are not for touching..."

Hmmmm. By one estimate, there were more than 2.5 billion smartphones in use
last year (and more today, of course), all with touchscreens. If each
screen is used just for a few minutes a day, the total usage-years is in
the hundreds of millions.

Touchscreen-equipped devices, including phones and tablets, are among the
most widely-used consumer electronic devices of all time. If there is some
undiscovered flaw in the concept of a touchscreen, it hasn't shown up so
far.

Tony KT0NY
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Clay Autery

Re: Sherwood's receiver performance table updated

In reply to this post by Tony Estep

Are you trying to be obtuse, or is it an accident.

I carry a smart phone, too. For a manageable sized phone, the touch
screen is a necessity, and the crap on the screen STILL bugs the crap
out of me.

I do NOT however carry and HF-6M radio around in my pocket, so it does
NOT need a touch screen, and one isn't desired.

I never SAID there was a FLAW in the "concept". The concept is fine, I
just don't like them... and I have LOTS of company.

You want a touch screen... cool, buy one.... but I wouldn't be your
IS/IT support... I HIGHLY discourage the use of touch screens by my
clients... and charge a premium to those who INSIST on using them.

"That's why they have vanilla and chocolate ice cream." -- Mamaw Autery
in response to a discussion about preferences on one thing or another.

______________________
Clay Autery, KG5LKV
MONTAC Enterprises
(318) 518-1389

On 4/26/2016 7:20 PM, Tony Estep wrote:

>> "25+ years.... Screens are not for touching..."
>
> Hmmmm. By one estimate, there were more than 2.5 billion smartphones in use
> last year (and more today, of course), all with touchscreens. If each
> screen is used just for a few minutes a day, the total usage-years is in
> the hundreds of millions.
>
> Touchscreen-equipped devices, including phones and tablets, are among the
> most widely-used consumer electronic devices of all time. If there is some
> undiscovered flaw in the concept of a touchscreen, it hasn't shown up so
> far.
>
> Tony KT0NY

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Clay Autery

Re: Sherwood's receiver performance table updated

In reply to this post by Wes Stewart-2

Would not use an Apple product if it was given to me free... <whole
nuther discussion, and I do not want to have it.> ;-)

______________________
Clay Autery, KG5LKV
MONTAC Enterprises
(318) 518-1389

On 4/26/2016 7:43 PM, Wes wrote:

> My son is the IT Manager for a midsized nationwide corporation. He
> doesn't like touch screens either.
>
> But he uses iPhones and iPads. Go figure.
>
> On 4/26/2016 3:28 PM, Clay Autery wrote:
>> Coat it however you want... Doesn't stop dirt and grime being put on
>> the screen possibly scratching and/or gooping up the corners and
>> edges...
>>
>> I've been in IS/IT for 25+ years... Screens are not for touching.

Elecraft mailing list

Re: Sherwood's receiver performance table updated

In reply to this post by Kevin Stover

> I'm curious why is direct sampling SDR's like the 7300 are supposed to be the second coming why Icom stuck with the traditional superhet architecture on it's "flagship" 7851? Maybe they realize the technology is at least 5 years away from being competitive. Everybody is ignoring W4TV's 800lb Gorilla, ADC overload

What suggests you that direct-sampling SDRs are 5 years away from being competitive? Elecraft will likely have moved to this architecture in less time than that to remain competitive. I suspect that one of the reason Icom stuck with the superheat on the IC-7851 is because this product was already in production by the time they made the decision to design a direct-sampling SDR. Now this is all speculation. What matters is that many of us who have high-end direct-sampling SDRs haven't experienced the overload issues. I don't doubt some operators have (maybe W4TV one of them), but these are probably isolated case. BTW, all receivers have weakness (every design has trade-offs), including the ones designed by Elecraft (I can hear images on KX3 sometimes). Just that you know, K9CT has one of the finest contesting station in the US. He has switched to direct-sampling SDRs (Flex-6700). Just ask him if this architecture is 5 years away from being competitive.

73,
Robert-KP4Y/W4

Sent from my iPhone

> On Apr 26, 2016, at 8:08 PM, Kevin Stover <[hidden email]> wrote:
>
> Ditto we still don't use them.
> Our users have a choice of laptop or iPad/Surface other than a desktop thin client on our VM Ware network.
> 90% choose the Win7 laptop. They're more expensive, slower, and break more often than the thin client but not as often as the iPads. The Surface's are new so no experience base with them yet. Our hardware group absolutely hate touch screens. I'm a Network Engineer...I have no use for them either.
>
> My brother does IT for a school district that equipped all of their middle school kids with cutting edge iPads. 700 of them. My brother had to get good at replacing the very expensive coated touch screens that the evil empire said mere mortals couldn't replace. He got no help from Apple other than expensive parts. That experiment lasted three years and they switched to Chrome books.
>
> I guarantee as sure as I'm sitting here *that touch screen will fail within a year...if not sooner*, and you've got no chance to fix it yourself. I can order parts from Elecraft for all my rigs and fix them. No sweat.
>
> I'm curious why is direct sampling SDR's like the 7300 are supposed to be the second coming why Icom stuck with the traditional superhet architecture on it's "flagship" 7851? Maybe they realize the technology is at least 5 years away from being competitive. Everybody is ignoring W4TV's 800lb Gorilla, ADC overload.
>
>> On 4/26/2016 5:28 PM, Clay Autery wrote:
>> Coat it however you want... Doesn't stop dirt and grime being put on
>> the screen possibly scratching and/or gooping up the corners and edges...
>>
>> I've been in IS/IT for 25+ years... Screens are not for touching.
>>
>> Bottom Line... I'll stick with buttons, dials, and switches, thank you. :)
>>
>> ______________________
>> Clay Autery, KG5LKV
>> MONTAC Enterprises
>> (318) 518-1389
>
>
> --
> R. Kevin Stover
> AC0H
> ARRL
> FISTS #11993
> SKCC #215
> NAQCC #3441
>
>
>
> ---
> This email has been checked for viruses by Avast antivirus software.
> https://www.avast.com/antivirus
> ______________________________________________________________
> 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]

Joe Subich, W4TV-4

Re: Sherwood's receiver performance table updated

In reply to this post by Kevin Stover

On 4/26/2016 8:08 PM, Kevin Stover wrote:
> Everybody is ignoring W4TV's 800lb Gorilla, ADC overload.

I can't take credit for that ... the warning comes from some of the
best RF designers in the world. Direct sampling receivers are very
good in controlled situations. Unfortunately, those who are used to
analog superhetrodyne receivers do not recognize the symptoms of ADC
overload/overflow in many cases.

The overflow can show up as an occasional click or pop if the number
and strength of signals continues to increase conditions go down hill
very rapidly. The best 16 bit ADC based SDRs can and do show very
significant overload issues when run without effective front end
bandpass filtering in high RF environments (160 meters near AM BC
stations, 40 meters in Europe, 160 meters in New England during a
contest, etc.).

One can apply filtering (which Icom seems to have done in the 7300),
apply attenuation (which Flex seems to have done in the 6000 series)
or both. Filtering limits the number and width of "slice receivers"
while attenuation kills weak signal performance.

I find Icom's implementation interesting in that they are using the
technology as a single band, single channel receiver (they could have
added Dual RX within the same band at practically no hardware cost) - an
application where, with tight bandpass filtering, direct sampling
may be ready to compete as indicated by the fact that Sherwood's tests
place the 7300's above some "good" conventional rigs like the Ten-Tec
Eagle, Kenwood TS-590SG and TS-990 in MDS, LO Phase noise and IMD DR.

However, for the ultimate multi-channel receiver, ADC technology is
still 4 to 6 bits short as witnessed by the need for 12 to 20 dB of
attenuation in the Flex 6000 or the 0 to 30 dB electronically stepped
attenuators in some of the other products like the Anan, Hermes, etc.
Sherwood's results hint at this when comparing the MDS with the
preamp on and preamp off ... even with its preamp on the Flex 6700
MDS is the same as the K3S with *no preamp*!

73,

... Joe, W4TV

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Re: Sherwood's receiver performance table updated

In reply to this post by Kevin Stover

> On Apr 26, 2016, at 8:08 PM, Kevin Stover <[hidden email]> wrote:

> I'm curious why is direct sampling SDR's like the 7300 are supposed to be the second coming why Icom stuck with the traditional superhet architecture on it's "flagship" 7851? Maybe they realize the technology is at least 5 years away from being competitive. Everybody is ignoring W4TV's 800lb Gorilla, ADC overload.

What suggests you that direct-sampling SDRs are 5 years away from being competitive? Elecraft will likely have moved to this architecture in less time than that to remain competitive. I suspect that one of the reason Icom stuck with the superheat on the IC-7851 is because this product was already in production by the time they made the decision to design a direct-sampling SDR. Now this is all speculation. What matters is that many of us who have high-end direct-sampling SDRs haven't experienced the overload issues. I don't doubt some operators have (maybe W4TV one of them), but these are probably isolated case. BTW, all receivers have weakness (every design has trade-offs), including the ones designed by Elecraft (I can hear images on KX3 sometimes). Just that you know, K9CT has one of the finest contesting station in the US. He has switched to direct-sampling SDRs (Flex-6700). Just ask him if this architecture is 5 years away from being competitive.

73,
Robert-KP4Y/W4
Sent from my iPhone

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Joe Subich, W4TV-4

Re: Sherwood's receiver performance table updated

On 4/26/2016 10:15 PM, Robert Vargas-KP4Y via Elecraft wrote:
> Just that you know, K9CT has one of the finest contesting station in
> the US. He has switched to direct-sampling SDRs (Flex-6700). Just ask
> him if this architecture is 5 years away from being competitive.

While I do not know for sure, I suspect K9CT is using bandpass filters
and stubs to prevent inter-station interference in his multi-multi
operation just as he did when he used conventional transceivers. With
properly designed bandpass filters, stubs and the preselectors in his
6700s he's not likely to have a severe overload issue unless he happens
to be close to some high power AM stations (on 160 meters) and even
then indications are that a good highpass filter and 10 to 15 dB of
attenuation will resolve the problems with a 16 bit ADC.

I have not heard any reports of large multi-multi stations switching to
direct sampling transceivers in areas of Europe where the 40 meter SW
broadcast was a problem for many decades.

The point is that direct conversion receivers need either good filters
*ahead of the ADC*, attenuation or both to prevent problems. When one
uses a Flex 6300 *which has no preselector*, Flex 6500 on multiple
bands (which bypasses the preselector), an ELAD DUO which has no
preselector, etc. one must make a choice between sensitivity and
dynamic range. The ARRL lab tests show that, Sherwood's tests show
that, Adam Farson's noise power ratio testing shows that, and other
reviewers hint at the problem but they simply don't understand direct
sampling well enough to recognize its limits when they see them.

One needs to understand the nature of direct sampling receivers and the
way they react to overload to recognize the behavior but the test data
is unequivocal. 16 bit ADCs are probably 4 to 6 bits "short" of being
able to handle worst case signal levels while simultaneously providing
maximum sensitivity (MDS of -135 to -140 dBm in 500 Hz) and fully broad
band performance (multiple slice receivers on multiple amateur bands).

73,

... Joe, W4TV

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Barry K3NDM

Re: Sherwood's receiver performance table updated

In reply to this post by Joe Subich, W4TV-4

Joe,
I agree with you basically. I think it's just the manor in which you
state the problem.

You touch on the real problem 14-16 bits of sampling vice having
more bits in the sample. It's not specifically the direct sampling
architecture. I think the radio companies just can't get 24 bit ADCs
fast enough to do direct sampling at commodity pricing which would allow
direct sampling with out the baggage. If I can do 24 bit sampling and
high and low pass filtering, I can simplify receiver design AND have a
an acceptable dynamic range. Multiple instances of DSP processing of the
24 bit samples will allow as many virtual receivers, slices, as
processor power will allow. My guess is we are on the verge of getting
to where we would like to be.

Flex is using a 16 bit ADC and I'm not sure what the 7300 is using,
but I infer it, too, is 16 bit. I do believe that the Elecraft
architectures are all based on 24 bit sampling. The Elecraft designs
should be tolerant to serious environmental abuse short of a local
thunderstorm.

Our comments reflect a rigorous tech discussion. But, there is
another issue that has not been discussed in anything I've read so far,
ultimate filter rejection. Flex, Kenwood, and Elecraft have filtering
that runs in the 100 db region, or a little better. I saw that the
IC-7300 is about 20 db worse. What that means if you are a CW operator,
serious or otherwise, and there is a pile up on a DX station, a contest,
or just a really busy weekend, you may have problems from strong
stations not too far away while you are trying to work an S1-3 station.
SSB operators have other problems like splatter and no amount of superb
design will fix that.

I'm pleased there is a vigorous discussion on the new radios. It
helps push the designers and the technology.

73,
Barry
K3NDM

------ Original Message ------
From: "Joe Subich, W4TV" <[hidden email]>
To: [hidden email]
Sent: 4/26/2016 10:10:32 PM an
Subject: Re: [Elecraft] Sherwood's receiver performance table updated

>On 4/26/2016 8:08 PM, Kevin Stover wrote:
>>Everybody is ignoring W4TV's 800lb Gorilla, ADC overload.
>
>I can't take credit for that ... the warning comes from some of the
>best RF designers in the world. Direct sampling receivers are very
>good in controlled situations. Unfortunately, those who are used to
>analog superhetrodyne receivers do not recognize the symptoms of ADC
>overload/overflow in many cases.
>
>The overflow can show up as an occasional click or pop if the number
>and strength of signals continues to increase conditions go down hill
>very rapidly. The best 16 bit ADC based SDRs can and do show very
>significant overload issues when run without effective front end
>bandpass filtering in high RF environments (160 meters near AM BC
>stations, 40 meters in Europe, 160 meters in New England during a
>contest, etc.).
>
>One can apply filtering (which Icom seems to have done in the 7300),
>apply attenuation (which Flex seems to have done in the 6000 series)
>or both. Filtering limits the number and width of "slice receivers"
>while attenuation kills weak signal performance.
>
>I find Icom's implementation interesting in that they are using the
>technology as a single band, single channel receiver (they could have
>added Dual RX within the same band at practically no hardware cost) -
>an application where, with tight bandpass filtering, direct sampling
>may be ready to compete as indicated by the fact that Sherwood's tests
>place the 7300's above some "good" conventional rigs like the Ten-Tec
>Eagle, Kenwood TS-590SG and TS-990 in MDS, LO Phase noise and IMD DR.
>
>However, for the ultimate multi-channel receiver, ADC technology is
>still 4 to 6 bits short as witnessed by the need for 12 to 20 dB of
>attenuation in the Flex 6000 or the 0 to 30 dB electronically stepped
>attenuators in some of the other products like the Anan, Hermes, etc.
>Sherwood's results hint at this when comparing the MDS with the
>preamp on and preamp off ... even with its preamp on the Flex 6700
>MDS is the same as the K3S with *no preamp*!
>
>73,
>
> ... Joe, W4TV
>
>______________________________________________________________
>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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Chris Tate - N6WM

Re: Sherwood's receiver performance table updated

In reply to this post by Joe Subich, W4TV-4

Joet, interesting comments but perhaps misses a few conditions of the higher end Direct conversion systems. And thanks to Eric for allowing a relatively architecturally agnostic discussion on the reflector.

My responses below. I will stick to my guns that both platforms have different advantages and disadvantages.. and its probably most accurate to leave it at that.

While I do not know for sure, I suspect K9CT is using bandpass filters and stubs to prevent inter-station interference in his multi-multi operation just as he did when he used conventional transceivers. With properly designed bandpass filters, stubs and the preselectors in his 6700s he's not likely to have a severe overload issue unless he happens to be close to some high power AM stations (on 160 meters) and even then indications are that a good highpass filter and 10 to 15 dB of attenuation will resolve the problems with a 16 bit ADC.

N6WM- Most certainly. I have operated a flex 6500 in one major multi-op contest at N6RO and a 6700 in another one. In both cases external filtering was used. It was unbothered by near field interstation interference any more or less than a K3, and I did operate 40m for WPX SSB (and nearly broke the station record for that band).

I have not heard any reports of large multi-multi stations switching to direct sampling transceivers in areas of Europe where the 40 meter SW broadcast was a problem for many decades.

N6WM- This is a good point I would be interested in hearing data or testing on this.

The point is that direct conversion receivers need either good filters *ahead of the ADC*, attenuation or both to prevent problems. When one uses a Flex 6300 *which has no preselector*, Flex 6500 on multiple bands (which bypasses the preselector), an ELAD DUO which has no preselector, etc. one must make a choice between sensitivity and dynamic range. The ARRL lab tests show that, Sherwood's tests show that, Adam Farson's noise power ratio testing shows that, and other reviewers hint at the problem but they simply don't understand direct sampling well enough to recognize its limits when they see them.

N6WM- ah a good point. These options are available in one form or another (external filtering) and of course we use this with our K3's or any radio in a multi. Also, many of the high end ones have 2 scu (6700) allowing dual band operation simultaneously without disengaging the band preselectors.

One needs to understand the nature of direct sampling receivers and the way they react to overload to recognize the behavior but the test data is unequivocal. 16 bit ADCs are probably 4 to 6 bits "short" of being able to handle worst case signal levels while simultaneously providing maximum sensitivity (MDS of -135 to -140 dBm in 500 Hz) and fully broad band performance (multiple slice receivers on multiple amateur bands).

N6WM- This does create some limits, but In the case of the 6700 you can have multiple slices on 2 simultaneous bands and avoid disengaging the preselectors.... how many does one need to operate at a time? 2 needed for SO2R.

N6WM- these are different architectures with different challenges. The Direct conversion architecture is the new kid on the block and many of the features to enhance them are not there yet or are in an infant state. That does not say that the technology is unusable or if one or the other is better.. they are just different.

Make no mistake.. I love my Elecraft K line. It has won me many contests and has served me well for (omg!) 8 years. I remember all the different mods we needed to add to the K3 in the beginning.. and the numerous software updates that fixed bugs and added features.... I also find the higher end Direct conversion systems fascinating as they solve a number of challenges I have run into over the years and they are on the fast track to coming of age.

Also make no mistake.. despite the differences in architecture, challenges and advantages, both the systems in this email are competition grade transceivers. Check 3830.

Ineresting stuff!

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Chris Tate - N6WM

Re: Sherwood's receiver performance table updated

Sorry Freudian slip near the end corrected.. direct conversion changed to direct sampling ;-).

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Chris Tate - N6WM
Sent: Tuesday, April 26, 2016 9:08 PM
To: Joe Subich, W4TV <[hidden email]>; [hidden email]
Subject: Re: [Elecraft] Sherwood's receiver performance table updated

Joet, interesting comments but perhaps misses a few conditions of the higher end Direct conversion systems. And thanks to Eric for allowing a relatively architecturally agnostic discussion on the reflector.

My responses below. I will stick to my guns that both platforms have different advantages and disadvantages.. and its probably most accurate to leave it at that.

While I do not know for sure, I suspect K9CT is using bandpass filters and stubs to prevent inter-station interference in his multi-multi operation just as he did when he used conventional transceivers. With properly designed bandpass filters, stubs and the preselectors in his 6700s he's not likely to have a severe overload issue unless he happens to be close to some high power AM stations (on 160 meters) and even then indications are that a good highpass filter and 10 to 15 dB of attenuation will resolve the problems with a 16 bit ADC.

N6WM- Most certainly. I have operated a flex 6500 in one major multi-op contest at N6RO and a 6700 in another one. In both cases external filtering was used. It was unbothered by near field interstation interference any more or less than a K3, and I did operate 40m for WPX SSB (and nearly broke the station record for that band).

I have not heard any reports of large multi-multi stations switching to direct sampling transceivers in areas of Europe where the 40 meter SW broadcast was a problem for many decades.

N6WM- This is a good point I would be interested in hearing data or testing on this.

The point is that direct conversion receivers need either good filters *ahead of the ADC*, attenuation or both to prevent problems. When one uses a Flex 6300 *which has no preselector*, Flex 6500 on multiple bands (which bypasses the preselector), an ELAD DUO which has no preselector, etc. one must make a choice between sensitivity and dynamic range. The ARRL lab tests show that, Sherwood's tests show that, Adam Farson's noise power ratio testing shows that, and other reviewers hint at the problem but they simply don't understand direct sampling well enough to recognize its limits when they see them.

N6WM- ah a good point. These options are available in one form or another (external filtering) and of course we use this with our K3's or any radio in a multi. Also, many of the high end ones have 2 scu (6700) allowing dual band operation simultaneously without disengaging the band preselectors.

One needs to understand the nature of direct sampling receivers and the way they react to overload to recognize the behavior but the test data is unequivocal. 16 bit ADCs are probably 4 to 6 bits "short" of being able to handle worst case signal levels while simultaneously providing maximum sensitivity (MDS of -135 to -140 dBm in 500 Hz) and fully broad band performance (multiple slice receivers on multiple amateur bands).

N6WM- This does create some limits, but In the case of the 6700 you can have multiple slices on 2 simultaneous bands and avoid disengaging the preselectors.... how many does one need to operate at a time? 2 needed for SO2R.

N6WM- these are different architectures with different challenges. The Direct conversion architecture is the new kid on the block and many of the features to enhance them are not there yet or are in an infant state. That does not say that the technology is unusable or if one or the other is better.. they are just different.

Make no mistake.. I love my Elecraft K line. It has won me many contests and has served me well for (omg!) 8 years. I remember all the different mods we needed to add to the K3 in the beginning.. and the numerous software updates that fixed bugs and added features.... I also find the higher end Direct sampling systems fascinating as they solve a number of challenges I have run into over the years and they are on the fast track to coming of age.

Also make no mistake.. despite the differences in architecture, challenges and advantages, both the systems in this email are competition grade transceivers. Check 3830.

Ineresting stuff!

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Re: Sherwood's receiver performance table updated

In reply to this post by Joe Subich, W4TV-4

Joe, I have an MSEE, so I perfectly understand the design aspects and math behind a direct-sampling SDR. That's why I stated previously that this architecture has some wrinkles that will eventually be ironed out as more capable and affordable ( this is a key factor to be competitive in the amateur radio market) ADC and DSP chips become available in the future. Also, just that we are clear, I'm familiar with the way how the ADC overload issue that you are describing would manifest in a direct-sampling SDR. However, I'm yet to experience this issue during actual operating conditions.

BTW, I don't see the need for preselector filter as a deficiency in a direct-sampling architecture. That would be sort of equivalent to seeing the need for roofing filters in the K3 to put out impressive blocking dynamic range numbers as a deficiency.

Finally, I have seen great reviews about the Flex-6300, and I'm actually impressed by the fact that it has not preselector filters. However, as satisfied Elecraft customer, I'm confident they will be able to produce a much better implementation of direct-sampling radio in the no so distant future.

73,
Robert-KP4Y/W4

Sent from my iPhone

> On Apr 26, 2016, at 11:35 PM, Joe Subich, W4TV <[hidden email]> wrote:
>
>
>> On 4/26/2016 10:15 PM, Robert Vargas-KP4Y via Elecraft wrote:
>> Just that you know, K9CT has one of the finest contesting station in
> > the US. He has switched to direct-sampling SDRs (Flex-6700). Just ask
> > him if this architecture is 5 years away from being competitive.
>
> While I do not know for sure, I suspect K9CT is using bandpass filters
> and stubs to prevent inter-station interference in his multi-multi
> operation just as he did when he used conventional transceivers. With
> properly designed bandpass filters, stubs and the preselectors in his
> 6700s he's not likely to have a severe overload issue unless he happens
> to be close to some high power AM stations (on 160 meters) and even
> then indications are that a good highpass filter and 10 to 15 dB of
> attenuation will resolve the problems with a 16 bit ADC.
>
> I have not heard any reports of large multi-multi stations switching to
> direct sampling transceivers in areas of Europe where the 40 meter SW
> broadcast was a problem for many decades.
>
> The point is that direct conversion receivers need either good filters
> *ahead of the ADC*, attenuation or both to prevent problems. When one
> uses a Flex 6300 *which has no preselector*, Flex 6500 on multiple
> bands (which bypasses the preselector), an ELAD DUO which has no
> preselector, etc. one must make a choice between sensitivity and
> dynamic range. The ARRL lab tests show that, Sherwood's tests show
> that, Adam Farson's noise power ratio testing shows that, and other
> reviewers hint at the problem but they simply don't understand direct
> sampling well enough to recognize its limits when they see them.
>
> One needs to understand the nature of direct sampling receivers and the
> way they react to overload to recognize the behavior but the test data
> is unequivocal. 16 bit ADCs are probably 4 to 6 bits "short" of being
> able to handle worst case signal levels while simultaneously providing
> maximum sensitivity (MDS of -135 to -140 dBm in 500 Hz) and fully broad
> band performance (multiple slice receivers on multiple amateur bands).
>
> 73,
>
> ... Joe, W4TV
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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N1EU

Re: Sherwood's receiver performance table updated

In reply to this post by Barry K3NDM

The IC-7300 uses a 14-bit ADC.

My ANAN-100D uses 16-bit ADC and overload of ADC occurs at a signal level
of -10dBm, which I never see in my single transmitter environment. I do
prefer the K3s for contesting, but not for lack of front-end robustness on
the part of the ANAN.

73, Barry N1EU

On Wed, Apr 27, 2016 at 3:48 AM, Barry LaZar <[hidden email]> wrote:

> Joe,
> I agree with you basically. I think it's just the manor in which you
> state the problem.
>
> You touch on the real problem 14-16 bits of sampling vice having more
> bits in the sample. It's not specifically the direct sampling architecture.
> I think the radio companies just can't get 24 bit ADCs fast enough to do
> direct sampling at commodity pricing which would allow direct sampling with
> out the baggage. If I can do 24 bit sampling and high and low pass
> filtering, I can simplify receiver design AND have a an acceptable dynamic
> range. Multiple instances of DSP processing of the 24 bit samples will
> allow as many virtual receivers, slices, as processor power will allow. My
> guess is we are on the verge of getting to where we would like to be.
>
> Flex is using a 16 bit ADC and I'm not sure what the 7300 is using,
> but I infer it, too, is 16 bit. I do believe that the Elecraft
> architectures are all based on 24 bit sampling. The Elecraft designs should
> be tolerant to serious environmental abuse short of a local thunderstorm.
>
> Our comments reflect a rigorous tech discussion. But, there is another
> issue that has not been discussed in anything I've read so far, ultimate
> filter rejection. Flex, Kenwood, and Elecraft have filtering that runs in
> the 100 db region, or a little better. I saw that the IC-7300 is about 20
> db worse. What that means if you are a CW operator, serious or otherwise,
> and there is a pile up on a DX station, a contest, or just a really busy
> weekend, you may have problems from strong stations not too far away while
> you are trying to work an S1-3 station. SSB operators have other problems
> like splatter and no amount of superb design will fix that.
>
> I'm pleased there is a vigorous discussion on the new radios. It helps
> push the designers and the technology.
>
> 73,
> Barry
> K3NDM
>
>
> ------ Original Message ------
> From: "Joe Subich, W4TV" <[hidden email]>
> To: [hidden email]
> Sent: 4/26/2016 10:10:32 PM an
> Subject: Re: [Elecraft] Sherwood's receiver performance table updated
>
> On 4/26/2016 8:08 PM, Kevin Stover wrote:
>>
>>> Everybody is ignoring W4TV's 800lb Gorilla, ADC overload.
>>>
>>
>> I can't take credit for that ... the warning comes from some of the
>> best RF designers in the world. Direct sampling receivers are very
>> good in controlled situations. Unfortunately, those who are used to
>> analog superhetrodyne receivers do not recognize the symptoms of ADC
>> overload/overflow in many cases.
>>
>> The overflow can show up as an occasional click or pop if the number
>> and strength of signals continues to increase conditions go down hill
>> very rapidly. The best 16 bit ADC based SDRs can and do show very
>> significant overload issues when run without effective front end
>> bandpass filtering in high RF environments (160 meters near AM BC
>> stations, 40 meters in Europe, 160 meters in New England during a
>> contest, etc.).
>>
>> One can apply filtering (which Icom seems to have done in the 7300),
>> apply attenuation (which Flex seems to have done in the 6000 series)
>> or both. Filtering limits the number and width of "slice receivers"
>> while attenuation kills weak signal performance.
>>
>> I find Icom's implementation interesting in that they are using the
>> technology as a single band, single channel receiver (they could have
>> added Dual RX within the same band at practically no hardware cost) - an
>> application where, with tight bandpass filtering, direct sampling
>> may be ready to compete as indicated by the fact that Sherwood's tests
>> place the 7300's above some "good" conventional rigs like the Ten-Tec
>> Eagle, Kenwood TS-590SG and TS-990 in MDS, LO Phase noise and IMD DR.
>>
>> However, for the ultimate multi-channel receiver, ADC technology is
>> still 4 to 6 bits short as witnessed by the need for 12 to 20 dB of
>> attenuation in the Flex 6000 or the 0 to 30 dB electronically stepped
>> attenuators in some of the other products like the Anan, Hermes, etc.
>> Sherwood's results hint at this when comparing the MDS with the
>> preamp on and preamp off ... even with its preamp on the Flex 6700
>> MDS is the same as the K3S with *no preamp*!
>>
>> 73,
>>
>> ... Joe, W4TV
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
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>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
>>
>
> ______________________________________________________________
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>

EUGENE GABRY

Re: Sherwood's receiver performance table updated

In reply to this post by Joe Subich, W4TV-4

On 4/26/2016 10:15 PM, Robert Vargas-KP4Y via Elecraft wrote:
> Just that you know, K9CT has one of the finest contesting station in
> the US. He has switched to direct-sampling SDRs (Flex-6700). Just ask >
him if this architecture is 5 years away from being competitive.

>While I do not know for sure, I suspect K9CT is using bandpass filters and
stubs to prevent inter-station interference in his multi-multi operation
just >as he did when he used conventional transceivers. With properly
designed bandpass filters, stubs and the preselectors in his 6700s he's not
likely to >have a severe overload issue unless he happens to be close to
some high power AM stations (on 160 meters) and even then indications are
that a good >highpass filter and 10 to 15 dB of attenuation will resolve the
problems with a 16 bit ADC.

Yes, I can confirm K9CT uses BP filters on his 6700's. His main reason for
switching to mostly 6700's at his contest station was for the "simplicity"
of being able to operate SO2R or multi -2 without the need for all the
access cables and extras required with the K3 set up. The WiFi ability that
comes with the Maestro made networking wireless as well. I believe he still
uses a K3S or two at his home station and uses K3S's on DXpeditions.

There are conditions and reasons where each platform can win, with proper
configurations, tools and expectations.

Gene, N9TF
Society of Midwest Contesters

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Joe Subich, W4TV-4

Re: Sherwood's receiver performance table updated

In reply to this post by Barry K3NDM

On 4/26/2016 11:48 PM, Barry LaZar wrote:
> You touch on the real problem 14-16 bits of sampling vice having
> more bits in the sample. It's not specifically the direct sampling
> architecture.

The real problem is not enough bits. DSR proponents continue to ignore
the sensitivity vs. overload trade-off. They tout their "top of the
list" IMD performance and "multiple slice receiver" capabilities while
completely hiding the fact that those items can only be accomplished by
reducing sensitivity some 30 dB compared to a conventional superhet
receiver in the presence of strong signals.

I have nothing against direct sampling receivers and I'm intrigued by
the performance/features balance Icom made - to the extent that I'm
likely to replace the IC-706mkIIg I use as an Icom proxy in my CAT test
bench with a 7300 once the "new" price moderates.

> But, there is another issue that has not been discussed in anything
> I've read so far, ultimate filter rejection. Flex, Kenwood, and
> Elecraft have filtering that runs in the 100 db region, or a little
> better.

Top of the line rigs with dual (distributed) filtering may reach the
100 dB region. However, that is not the case in all rigs. The IC-7300
is competitive with rigs such as the Yaesu FTdx3000 (80 dB), Icom
IC-7600 (78 dB), Icom 706 mkIIg (78dB) or K2 (80 dB) and not all that
far from the TS-590 (92 dB) or TS-990 (90 dB). Remember, most of the
crystal filters flatten out around -80 to-90 dB (with tighter filters
having even less ultimate rejection and - see the K3/Inrad curves) -
circuit layout often causes leakage above those levels in many rigs.

73,

... Joe, W4TV

On 4/26/2016 11:48 PM, Barry LaZar wrote:

> Joe,
> I agree with you basically. I think it's just the manor in which you
> state the problem.
>
> You touch on the real problem 14-16 bits of sampling vice having
> more bits in the sample. It's not specifically the direct sampling
> architecture. I think the radio companies just can't get 24 bit ADCs
> fast enough to do direct sampling at commodity pricing which would allow
> direct sampling with out the baggage. If I can do 24 bit sampling and
> high and low pass filtering, I can simplify receiver design AND have a
> an acceptable dynamic range. Multiple instances of DSP processing of the
> 24 bit samples will allow as many virtual receivers, slices, as
> processor power will allow. My guess is we are on the verge of getting
> to where we would like to be.
>
> Flex is using a 16 bit ADC and I'm not sure what the 7300 is using,
> but I infer it, too, is 16 bit. I do believe that the Elecraft
> architectures are all based on 24 bit sampling. The Elecraft designs
> should be tolerant to serious environmental abuse short of a local
> thunderstorm.
>
> Our comments reflect a rigorous tech discussion. But, there is
> another issue that has not been discussed in anything I've read so far,
> ultimate filter rejection. Flex, Kenwood, and Elecraft have filtering
> that runs in the 100 db region, or a little better. I saw that the
> IC-7300 is about 20 db worse. What that means if you are a CW operator,
> serious or otherwise, and there is a pile up on a DX station, a contest,
> or just a really busy weekend, you may have problems from strong
> stations not too far away while you are trying to work an S1-3 station.
> SSB operators have other problems like splatter and no amount of superb
> design will fix that.
>
> I'm pleased there is a vigorous discussion on the new radios. It
> helps push the designers and the technology.
>
> 73,
> Barry
> K3NDM
>
>
> ------ Original Message ------
> From: "Joe Subich, W4TV" <[hidden email]>
> To: [hidden email]
> Sent: 4/26/2016 10:10:32 PM an
> Subject: Re: [Elecraft] Sherwood's receiver performance table updated
>
>> On 4/26/2016 8:08 PM, Kevin Stover wrote:
>>> Everybody is ignoring W4TV's 800lb Gorilla, ADC overload.
>>
>> I can't take credit for that ... the warning comes from some of the
>> best RF designers in the world. Direct sampling receivers are very
>> good in controlled situations. Unfortunately, those who are used to
>> analog superhetrodyne receivers do not recognize the symptoms of ADC
>> overload/overflow in many cases.
>>
>> The overflow can show up as an occasional click or pop if the number
>> and strength of signals continues to increase conditions go down hill
>> very rapidly. The best 16 bit ADC based SDRs can and do show very
>> significant overload issues when run without effective front end
>> bandpass filtering in high RF environments (160 meters near AM BC
>> stations, 40 meters in Europe, 160 meters in New England during a
>> contest, etc.).
>>
>> One can apply filtering (which Icom seems to have done in the 7300),
>> apply attenuation (which Flex seems to have done in the 6000 series)
>> or both. Filtering limits the number and width of "slice receivers"
>> while attenuation kills weak signal performance.
>>
>> I find Icom's implementation interesting in that they are using the
>> technology as a single band, single channel receiver (they could have
>> added Dual RX within the same band at practically no hardware cost) -
>> an application where, with tight bandpass filtering, direct sampling
>> may be ready to compete as indicated by the fact that Sherwood's tests
>> place the 7300's above some "good" conventional rigs like the Ten-Tec
>> Eagle, Kenwood TS-590SG and TS-990 in MDS, LO Phase noise and IMD DR.
>>
>> However, for the ultimate multi-channel receiver, ADC technology is
>> still 4 to 6 bits short as witnessed by the need for 12 to 20 dB of
>> attenuation in the Flex 6000 or the 0 to 30 dB electronically stepped
>> attenuators in some of the other products like the Anan, Hermes, etc.
>> Sherwood's results hint at this when comparing the MDS with the
>> preamp on and preamp off ... even with its preamp on the Flex 6700
>> MDS is the same as the K3S with *no preamp*!
>>
>> 73,
>>
>> ... Joe, W4TV
>>
>> ______________________________________________________________
>> 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

Re: Sherwood's receiver performance table updated

In reply to this post by EUGENE GABRY

Very comprehensive review of the 7300 explaining how it handles ADC
overload at

http://www.ab4oj.com/icom/ic7300/7300notes.pdf

K4ia
Buck
Honor Roll 335
8BDXCC

On 4/27/2016 8:17 AM, Gene Gabry wrote:

> On 4/26/2016 10:15 PM, Robert Vargas-KP4Y via Elecraft wrote:
>> Just that you know, K9CT has one of the finest contesting station in
> > the US. He has switched to direct-sampling SDRs (Flex-6700). Just ask >
> him if this architecture is 5 years away from being competitive.
>
>> While I do not know for sure, I suspect K9CT is using bandpass filters and
> stubs to prevent inter-station interference in his multi-multi operation
> just >as he did when he used conventional transceivers. With properly
> designed bandpass filters, stubs and the preselectors in his 6700s he's not
> likely to >have a severe overload issue unless he happens to be close to
> some high power AM stations (on 160 meters) and even then indications are
> that a good >highpass filter and 10 to 15 dB of attenuation will resolve the
> problems with a 16 bit ADC.
>
> Yes, I can confirm K9CT uses BP filters on his 6700's. His main reason for
> switching to mostly 6700's at his contest station was for the "simplicity"
> of being able to operate SO2R or multi -2 without the need for all the
> access cables and extras required with the K3 set up. The WiFi ability that
> comes with the Maestro made networking wireless as well. I believe he still
> uses a K3S or two at his home station and uses K3S's on DXpeditions.
>
> There are conditions and reasons where each platform can win, with proper
> configurations, tools and expectations.
>
> Gene, N9TF
> Society of Midwest Contesters
>
>
> ______________________________________________________________
> 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]

Jim Sheldon

Re: Sherwood's receiver performance table updated

In reply to this post by EUGENE GABRY

Geez guys, I thought this was the Elecraft List. Getting a tired
finger hitting the delete button on all the IC 7300 ICOM discussion
totally irrelevant to any Elecraft information. I'm sure Eric would
have stepped in and closed this thread long ago if they weren't all
extremely busy getting ready for Dayton.

I, and many others, have absolutely no interest in extolling the virtues
of the IC 7300.

Jim - W0EB

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Eric Swartz - WA6HHQ

Re: Sherwood's receiver performance table updated

Administrator

In reply to this post by Joe Subich, W4TV-4

Folks - In the interest of relieving our list readers from severe single topic
email overload, let's end this thread now.

While an interesting topic with lots of good comments, its had a -huge- number
of postings. It is time to give it a rest.

(I would have jumped in earlier yesterday, but I was extremely busy at my other
job - making the best all around radios in the world :-)

73,

Eric
Elecraft list moderator
/elecraft.com/

On 4/27/2016 5:26 AM, Joe Subich, W4TV wrote:

>
> On 4/26/2016 11:48 PM, Barry LaZar wrote:
> > You touch on the real problem 14-16 bits of sampling vice having
> > more bits in the sample. It's not specifically the direct sampling
> > architecture.
>
> The real problem is not enough bits. DSR proponents continue to ignore
> the sensitivity vs. overload trade-off. They tout their "top of the
> list" IMD performance and "multiple slice receiver" capabilities while
> completely hiding the fact that those items can only be accomplished by
> reducing sensitivity some 30 dB compared to a conventional superhet
> receiver in the presence of strong signals.
>

NK7Z

Re: Sherwood's receiver performance table updated

In reply to this post by Clay Autery

I'm with you Clay, the very last thing I want is a touch screen, which
is always dirty.

The concept of a touch screen rig is interesting though, perhaps a
touch screen that is separate from the rig would be good... Soft Keys
you can program, thin, wireless, now that I could get behind. Maybe
controlled via a smart device, like a phone or pad. Bluetooth
connected...
--
73's, and thanks,
Dave (NK7Z)

For software/hardware reviews see:
http://www.nk7z.net

For MixW support see:
https://groups.yahoo.com/neo/groups/mixw/info

For SSTV help see:
http://groups.yahoo.com/neo/groups/MM-SSTV/info

On Tue, 2016-04-26 at 17:01 -0500, Clay Autery wrote:

> Yep... Jim has it correct....
>
> I regularly use Marker A and B to set frequencies.  If I am doing it
> right, it sets to the exact frequency.... even though the P3 only
> shows
> to the 10 Hz resolution.
>
> And I don't have to put fingerprints on my screen/bezel...
>
> Why ANYONE wants to touch the screen they are VIEWING data on escapes
> me
> COMPLETELY.  I want my screen ABSOLUTELY clean...
>
> ______________________
> Clay Autery, KG5LKV
> MONTAC Enterprises
> (318) 518-1389
>
> On 4/26/2016 3:29 PM, Jim Brown wrote:
> >
> > On Tue,4/26/2016 1:12 PM, James D. (Jimmy) Walker, Jr. via Elecraft
> > wrote:
> > >
> > > What interests me most in the IC-7300 is the ability for direct
> > > entry
> > > of a frequency by touching the waterfall display.
> > To the accuracy of the width of your finger. :)   I looked at the
> > 7300
> > at Visalia. Nice LOOKING radio at an entry level price.
> >
> > >
> > > The P-3 does not offer that feature,
> > While it doesn't have a touch screen, direct frequency entry can be
> > done by moving the marker to the blip on the screen and pushing the
> > Menu button. And to FAR greater precision.
> >
> > 73, Jim K9YC
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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WA2SI

Re: Sherwood's receiver performance table updated

In reply to this post by Jim Sheldon

Why can't we let the folks who are engaged in the discussion, as well as those who find it not only interesting, but very relevant to Elecraft, enjoy the discussion. That's precisely what the delete key is for.

Imagine coming across a roundtable QSO and asking the participants to cease their discussion rather than just QSY. Strange times these are.

Vy 73 de Bert
WA2SI

Sent from my android device.

-----Original Message-----
From: Jim Sheldon <[hidden email]>
To: Gene Gabry <[hidden email]>, "'Joe Subich, W4TV'" <[hidden email]>, [hidden email]
Sent: Wed, 27 Apr 2016 8:42
Subject: Re: [Elecraft] Sherwood's receiver performance table updated

Geez guys, I thought this was the Elecraft List. Getting a tired
finger hitting the delete button on all the IC 7300 ICOM discussion
totally irrelevant to any Elecraft information. I'm sure Eric would
have stepped in and closed this thread long ago if they weren't all
extremely busy getting ready for Dayton.

I, and many others, have absolutely no interest in extolling the virtues
of the IC 7300.

Jim - W0EB

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