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K3S QST Article

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Yngvi (TF3Y)

Re: K3S QST Article

Many thanks for sharing this Jim.

Very ambitious and informative.

73, Yngvi TF3Y

On Tue, Oct 18, 2016 at 5:51 PM, Jim Brown <[hidden email]>
wrote:

> On Tue,10/18/2016 3:43 AM, Yngvi (TF3Y) wrote:
>
>> How fast does IMD deteriorate with increased power from the K3S or K3?
>>
>> What are the IMD figures when running 20-25W driving a linear amp. such as
>> the KPA500?
>>
>
> I've looked carefully at this, and so has my neighbor Bob Wolbert, K6XX,
> who is an engineer at Elecraft and a serious contester. The first link
> shows my measurements, the second is a pdf of the slides for a talk that
> K6XX gave to NCCC three years ago. It includes measured data showing how TX
> power out and DC voltage affect IMD. In my measurements, increased IMD
> causes CW bandwidth to increase. You can see that difference by comparing
> measurements at 30W, 50W, and 100W.
>
> http://k9yc.com/P3_Spectrum_Measurements.pdf
>
> http://k9yc.com/K6XXAmpTalk.pdf
>
> 73, Jim K9YC
>
>
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--
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James Rogers

Re: K3S QST Article

In reply to this post by john@kk9a.com

I have received a response to my posts from Eric and understand that the
17M harmonic problem I was concerned about was limited to the test unit
supplied to ARRL.

I am a happy camper!

Jim, W4ATK

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Wes Stewart-2

Re: K3S QST Article

In reply to this post by Jim Brown-10

What method(s) did you use to verify the accuracy of your dB(c) numbers? I get
a little queasy when I see "-48.5 dBc."

On 10/18/2016 10:51 AM, Jim Brown wrote:

> On Tue,10/18/2016 3:43 AM, Yngvi (TF3Y) wrote:
>> How fast does IMD deteriorate with increased power from the K3S or K3?
>>
>> What are the IMD figures when running 20-25W driving a linear amp. such as
>> the KPA500?
>
> I've looked carefully at this, and so has my neighbor Bob Wolbert, K6XX, who
> is an engineer at Elecraft and a serious contester. The first link shows my
> measurements, the second is a pdf of the slides for a talk that K6XX gave to
> NCCC three years ago. It includes measured data showing how TX power out and
> DC voltage affect IMD. In my measurements, increased IMD causes CW bandwidth
> to increase. You can see that difference by comparing measurements at 30W,
> 50W, and 100W.
>
> http://k9yc.com/P3_Spectrum_Measurements.pdf
>
> http://k9yc.com/K6XXAmpTalk.pdf
>
> 73, Jim K9YC

EUGENE GABRY

Re: K3S QST Article

In reply to this post by Eric Swartz - WA6HHQ

Hi Eric,
Just curious/devils advocate question. Was this unit that was reviewed, picked at random from stock at Elecraft? If so, or not, wouldn't it's performance be reflective of a population of other units manufactured? Just curious how you can say all others shipped were/are OK on 17, when the review unit was not?

Just asking.

Also curious, when radios are factory built and aligned, does Elecraft keep some kind of history data base of performance measurements of hose radios. kind od like a Certificate of Analysis/Performance, of specifications?

Thanks and 73, Gene N9TF
K3S 10057

----- Original Message -----

From: "Eric Swartz - WA6HHQ, Elecraft" <[hidden email]>
To: "Jim Rogers" <[hidden email]>, "elecraft" <[hidden email]>
Sent: Tuesday, October 18, 2016 2:10:17 PM
Subject: Re: [Elecraft] K3S QST Article

Hi Jim - The 17 m harmonic problem was limited to the single review unit, which
we corrected. All others shipped were/are OK on 17M.

73,

Eric
/elecraft.com/

On 10/18/2016 11:38 AM, Jim Rogers wrote:

> To all who responded, certainly my friend Don and others....
>
> "During initial testing, we found that the second harmonic on 17 meters
> measured 42 dB below the fundamental, well below the specified >50 dB we
> measured on the other bands. We returned the transceiver to Elecraft for
> repair and they brought it into spec." Bob Allison, WB1GCM Assistant ARRL
> Laboratory Manager, QST (Nov 2016) p.50 sidebar.
>
> Elecraft K3s Operators manual pg. 9 "Harmonic Spurious Outputs >50 dB below
> carrier @ 100W (>60 dB on 6 meters).
>
> Just sayin' if that is the case with my K3s s/n 10271, send me the necessary
> board/module(s) to correct the situation and I will be more than happy to make
> the replacement in my K3s and return the defective units to Elecraft for
> rework. Just don't ask me to send the whole radio back for something I can
> accomplish in the field.
>
> I am not angry, perhaps a bit dissappointed. I love my K-Line, which
> originated with a K3 and when the K3s came out, I elected to buy a K3s rather
> than upgrade my K3. Tell me my radio meets the spec and does not need repair
> to meet the spec and I am a happy camper.
>
> Jim, W4ATK
>
>
>
>
> ______________________________________________________________
> 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]
>

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kstover

Re: K3S QST Article

In reply to this post by Wes Stewart-2

That's harmonics which the FCC regulates to -43 dBc or better, better
being a bigger number, on 160-10m, and -60dBc for 6 meters and up. That
number IS regulated.

That is not the same as two tone TX IMD which is specified by Elecraft
as around -30dB, and NOT regulated by the FCC, because most hams can't
measure it accurately.

On 10/18/2016 2:53 PM, Wes Stewart wrote:

> What method(s) did you use to verify the accuracy of your dB(c)
> numbers? I get a little queasy when I see "-48.5 dBc."
>
> On 10/18/2016 10:51 AM, Jim Brown wrote:
>> On Tue,10/18/2016 3:43 AM, Yngvi (TF3Y) wrote:
>>> How fast does IMD deteriorate with increased power from the K3S or K3?
>>>
>>> What are the IMD figures when running 20-25W driving a linear amp.
>>> such as
>>> the KPA500?
>>
>> I've looked carefully at this, and so has my neighbor Bob Wolbert,
>> K6XX, who is an engineer at Elecraft and a serious contester. The
>> first link shows my measurements, the second is a pdf of the slides
>> for a talk that K6XX gave to NCCC three years ago. It includes
>> measured data showing how TX power out and DC voltage affect IMD. In
>> my measurements, increased IMD causes CW bandwidth to increase. You
>> can see that difference by comparing measurements at 30W, 50W, and 100W.
>>
>> http://k9yc.com/P3_Spectrum_Measurements.pdf
>>
>> http://k9yc.com/K6XXAmpTalk.pdf
>>
>> 73, Jim K9YC
>
> ______________________________________________________________
> 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]
>

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

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Jim Brown-10

Re: K3S QST Article

In reply to this post by Wes Stewart-2

The data is accumulated peaks for 30-40 seconds. Reference for dBC is
the peak of the waveform. That terminology is not appropriate, of
course, for the SSB data.

73, Jim

On Tue,10/18/2016 12:53 PM, Wes Stewart wrote:
> What method(s) did you use to verify the accuracy of your dB(c)
> numbers? I get a little queasy when I see "-48.5 dBc."

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wayne burdick

Re: K3S QST Article

Administrator

In reply to this post by EUGENE GABRY

It certainly left the factory working on 17 meters, because we do a 100% test on all bands for TX harmonic suppression. My working theory is that the unit was damaged in shipping. We may never know.

73,
Wayne
N6KR

On Oct 18, 2016, at 2:51 PM, [hidden email] wrote:

> Hi Eric,
> Just curious/devils advocate question. Was this unit that was reviewed, picked at random from stock at Elecraft? If so, or not, wouldn't it's performance be reflective of a population of other units manufactured? Just curious how you can say all others shipped were/are OK on 17, when the review unit was not?
>
> Just asking.
>
> Also curious, when radios are factory built and aligned, does Elecraft keep some kind of history data base of performance measurements of hose radios. kind od like a Certificate of Analysis/Performance, of specifications?
>
> Thanks and 73, Gene N9TF
> K3S 10057
>
> ----- Original Message -----
>
> From: "Eric Swartz - WA6HHQ, Elecraft" <[hidden email]>
> To: "Jim Rogers" <[hidden email]>, "elecraft" <[hidden email]>
> Sent: Tuesday, October 18, 2016 2:10:17 PM
> Subject: Re: [Elecraft] K3S QST Article
>
> Hi Jim - The 17 m harmonic problem was limited to the single review unit, which
> we corrected. All others shipped were/are OK on 17M.
>
> 73,
>
> Eric
> /elecraft.com/
>
> On 10/18/2016 11:38 AM, Jim Rogers wrote:
>> To all who responded, certainly my friend Don and others....
>>
>> "During initial testing, we found that the second harmonic on 17 meters
>> measured 42 dB below the fundamental, well below the specified >50 dB we
>> measured on the other bands. We returned the transceiver to Elecraft for
>> repair and they brought it into spec." Bob Allison, WB1GCM Assistant ARRL
>> Laboratory Manager, QST (Nov 2016) p.50 sidebar.
>>
>> Elecraft K3s Operators manual pg. 9 "Harmonic Spurious Outputs >50 dB below
>> carrier @ 100W (>60 dB on 6 meters).
>>
>> Just sayin' if that is the case with my K3s s/n 10271, send me the necessary
>> board/module(s) to correct the situation and I will be more than happy to make
>> the replacement in my K3s and return the defective units to Elecraft for
>> rework. Just don't ask me to send the whole radio back for something I can
>> accomplish in the field.
>>
>> I am not angry, perhaps a bit dissappointed. I love my K-Line, which
>> originated with a K3 and when the K3s came out, I elected to buy a K3s rather
>> than upgrade my K3. Tell me my radio meets the spec and does not need repair
>> to meet the spec and I am a happy camper.
>>
>> Jim, W4ATK
>>
>>
>>
>>
>> ______________________________________________________________
>> 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]
>>
>
> ______________________________________________________________
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> 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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> Post: mailto:[hidden email]
>
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wayne burdick

Re: K3S QST Article

Administrator

In reply to this post by EUGENE GABRY

And by the way, it *was* picked at random, in effect; we had no idea who purchased the unit, or when, until the ARRL gave us their first set of numbers.

73,
Wayne
N6KR

On Oct 18, 2016, at 2:51 PM, [hidden email] wrote:

Eric Swartz - WA6HHQ

Re: K3S QST Article

Administrator

In reply to this post by EUGENE GABRY

Hi Gene,

The K3S was definitely a random production unit. The failure was quite unusual
as it was an intermittent solder connection in that particular LPF. We rarely
see that in this area on our professionally assembled and inspected boards. It
must have been intermittent as it passed our automated board level and final K3S
tests.

As a double check we tightened our visual inspection of that area of the board
and reviewed our test procedures. So far no other failures like this one found.

73,
Eric
/elecraft.com/

On 10/18/2016 2:51 PM, [hidden email] wrote:

> Hi Eric,
> Just curious/devils advocate question. Was this unit that was reviewed, picked at random from stock at Elecraft? If so, or not, wouldn't it's performance be reflective of a population of other units manufactured? Just curious how you can say all others shipped were/are OK on 17, when the review unit was not?
>
> Just asking.
>
> Also curious, when radios are factory built and aligned, does Elecraft keep some kind of history data base of performance measurements of hose radios. kind od like a Certificate of Analysis/Performance, of specifications?
>
> Thanks and 73, Gene N9TF
> K3S 10057
>
> ----- Original Message -----
>
> From: "Eric Swartz - WA6HHQ, Elecraft" <[hidden email]>
> To: "Jim Rogers" <[hidden email]>, "elecraft" <[hidden email]>
> Sent: Tuesday, October 18, 2016 2:10:17 PM
> Subject: Re: [Elecraft] K3S QST Article
>
> Hi Jim - The 17 m harmonic problem was limited to the single review unit, which
> we corrected. All others shipped were/are OK on 17M.
>
> 73,
>
> Eric
> /elecraft.com/
>
> On 10/18/2016 11:38 AM, Jim Rogers wrote:
>> To all who responded, certainly my friend Don and others....
>>
>> "During initial testing, we found that the second harmonic on 17 meters
>> measured 42 dB below the fundamental, well below the specified >50 dB we
>> measured on the other bands. We returned the transceiver to Elecraft for
>> repair and they brought it into spec." Bob Allison, WB1GCM Assistant ARRL
>> Laboratory Manager, QST (Nov 2016) p.50 sidebar.
>>
>> Elecraft K3s Operators manual pg. 9 "Harmonic Spurious Outputs >50 dB below
>> carrier @ 100W (>60 dB on 6 meters).
>>
>> Just sayin' if that is the case with my K3s s/n 10271, send me the necessary
>> board/module(s) to correct the situation and I will be more than happy to make
>> the replacement in my K3s and return the defective units to Elecraft for
>> rework. Just don't ask me to send the whole radio back for something I can
>> accomplish in the field.
>>
>> I am not angry, perhaps a bit dissappointed. I love my K-Line, which
>> originated with a K3 and when the K3s came out, I elected to buy a K3s rather
>> than upgrade my K3. Tell me my radio meets the spec and does not need repair
>> to meet the spec and I am a happy camper.
>>
>> Jim, W4ATK
>>
>>
>>
>>
>> ______________________________________________________________
>> 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
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> Post: mailto:[hidden email]
>
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>
> ______________________________________________________________
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Bill Leonard N0CU

Re: K3S QST Article

In reply to this post by James Rogers

The official response I got from the factory is that to have any of the IMD mods done, the radio needs to be sent in to the factory.

Bill N0CU

Wes Stewart-2

Re: K3S QST Article

In reply to this post by Jim Brown-10

You didn't answer the question.

On 10/18/2016 4:47 PM, Jim Brown wrote:
> The data is accumulated peaks for 30-40 seconds. Reference for dBC is the peak
> of the waveform. That terminology is not appropriate, of course, for the SSB
> data.
>
> 73, Jim
>
> On Tue,10/18/2016 12:53 PM, Wes Stewart wrote:
>> What method(s) did you use to verify the accuracy of your dB(c) numbers? I
>> get a little queasy when I see "-48.5 dBc."

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Jim Brown-10

Re: K3S QST Article

Gee, I thought I did. I told you how I made the measurements. Every data
point was picked off of the curves with the cursor. The SSB data is
relative to the highest peak in the envelope, not to the carrier, of
course, which is suppressed. The "carrier" reference for other
modulation is the peak of the envelope.

73, Jim

On Tue,10/18/2016 7:38 PM, Wes Stewart wrote:
> You didn't answer the question.

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Joe Subich, W4TV-4

Re: K3S QST Article

On 10/19/2016 2:11 AM, Jim Brown wrote:
> The "carrier" reference for other modulation is the peak of the
> envelope.

Which means your dBc references should be labelled "dB PEP" for
the particular modulation. The reference to dBc is only strictly
accurate for the unmodulated carrier and possibly CW.

Unless you are using known modulation (e.g., 2 tone for SSB, "idle"
for PSK31) there is no simple PEP to carrier reference.

73,

... Joe, W4TV

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Eric Swartz - WA6HHQ

Re: K3S QST Article

Administrator

Guys, let's take the dBc discussion off list.

73,

Eric
Mooderator
/elecraft.com/

On 10/19/2016 6:35 AM, Joe Subich, W4TV wrote:

> On 10/19/2016 2:11 AM, Jim Brown wrote:
>> The "carrier" reference for other modulation is the peak of the
>> envelope.
>
> Which means your dBc references should be labelled "dB PEP" for
> the particular modulation. The reference to dBc is only strictly
> accurate for the unmodulated carrier and possibly CW.
>
> Unless you are using known modulation (e.g., 2 tone for SSB, "idle"
> for PSK31) there is no simple PEP to carrier reference.
>
> 73,
> ... Joe, W4TV
>
> ______________________________________________________________
> Elecraft mailing list