K3 RX spurs

[Ramiro Aceves]

Hello K3 fans

I am a bit stranged and frustrated cause nobody has answered a single
word to my email "K3 RX spurs" posted on november the 20th. No comments,
no ideas....
After some tests I have concluded that the spurs are 3rd order
intermodulation products. They only occur in DATA or CW.
¿Can anyone please, try to reproduce those products in your K3/P3 or
K3/computer combination?.

"DATA A" mode: Cristal filter= 2.7KHz, SHIFT=1.5 KHz, WIDTH= 2.7 kHz
Tune some steady carrier in shortwave. Tune the signal to place a
beautiful 1000 Hz on the waterfall
Tune your signal generator 10 Hz more than the broadcast carrier
frequency to get an audio  signal 10 Hz over the 1000 Hz signal. Adjust
generator strenght to be similar to the broadcast carrier.

You will see strong beautiful 3rd order products on 1020 and 990 Hz.
Swith to USB--> much more weaker 3rd order products or inexistent.

http://ea1abz.ure.es/3erd-order.jpeg

That is my K3 behaviour. Just want to know if my K3 is ok or not.

Many thanks. I appreciate your effort in doing this test for me.

73, Ramiro, EA4NZ.

PD: Volume at the speaker is zero to avoid vibrations inside the K3
case.
______________________________________________________________
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

[Julian, G4ILO]

What output are you taking the audio from to plot these results? The line output signal goes through an isolating transformer. I think this saturates at quite a low audio level introducing non-linearity. You need to turn LIN OUT down to 2 or as low as you can get.

I haven't done the test you did, but if I look at a CW signal with a narrow filter selected I can see a ghost image of the signal on the waterfall at twice the audio frequency, well outside the IF passband. So I think the problem (if indeed it is a problem - nothing is perfect) is within the audio stages and particularly the line output.

Ramiro Aceves wrote

Hello K3 fans

I am a bit stranged and frustrated cause nobody has answered a single
word to my email "K3 RX spurs" posted on november the 20th. No comments,
no ideas....
After some tests I have concluded that the spurs are 3rd order
intermodulation products. They only occur in DATA or CW.
¿Can anyone please, try to reproduce those products in your K3/P3 or
K3/computer combination?.

"DATA A" mode: Cristal filter= 2.7KHz, SHIFT=1.5 KHz, WIDTH= 2.7 kHz
Tune some steady carrier in shortwave. Tune the signal to place a
beautiful 1000 Hz on the waterfall
Tune your signal generator 10 Hz more than the broadcast carrier
frequency to get an audio  signal 10 Hz over the 1000 Hz signal. Adjust
generator strenght to be similar to the broadcast carrier.

You will see strong beautiful 3rd order products on 1020 and 990 Hz.
Swith to USB--> much more weaker 3rd order products or inexistent.

http://ea1abz.ure.es/3erd-order.jpeg

That is my K3 behaviour. Just want to know if my K3 is ok or not.

Many thanks. I appreciate your effort in doing this test for me.

73, Ramiro, EA4NZ.

PD: Volume at the speaker is zero to avoid vibrations inside the K3
case.

[Ramiro Aceves]

Hi Julian

I am very glad to see that someone has replyied to my email.

I have LINE_OUT= "nor 019"

If I go down to 002 I need to rise gain at the sound card, and the
intermods are the same.

http://ea1abz.ure.es/spurs.jpeg

This spurs seem to produce only if both test signals are close, closer
than 50 Hz and in DATA/CW mode, not USB/LSB.

Do not think that this spurs will cause a problem in real life
operation. Just curious about the DATA/CW vs LSB/USB diferences found.
Perhaps a "pile up blur" will occur when many CW stations are very
close, who knows ( do not know how to say it in english)

Thanks for your suggestions!

73, Ramiro, EA1ABZ.



Julian, G4ILO escribió:

> What output are you taking the audio from to plot these results? The line
> output signal goes through an isolating transformer. I think this saturates
> at quite a low audio level introducing non-linearity. You need to turn LIN
> OUT down to 2 or as low as you can get.
>
> I haven't done the test you did, but if I look at a CW signal with a narrow
> filter selected I can see a ghost image of the signal on the waterfall at
> twice the audio frequency, well outside the IF passband. So I think the
> problem (if indeed it is a problem - nothing is perfect) is within the audio
> stages and particularly the line output.
>
>
> Ramiro Aceves wrote:
>> Hello K3 fans
>>
>> I am a bit stranged and frustrated cause nobody has answered a single
>> word to my email "K3 RX spurs" posted on november the 20th. No comments,
>> no ideas....
>> After some tests I have concluded that the spurs are 3rd order
>> intermodulation products. They only occur in DATA or CW.
>> ¿Can anyone please, try to reproduce those products in your K3/P3 or
>> K3/computer combination?.
>>
>> "DATA A" mode: Cristal filter= 2.7KHz, SHIFT=1.5 KHz, WIDTH= 2.7 kHz
>> Tune some steady carrier in shortwave. Tune the signal to place a
>> beautiful 1000 Hz on the waterfall
>> Tune your signal generator 10 Hz more than the broadcast carrier
>> frequency to get an audio  signal 10 Hz over the 1000 Hz signal. Adjust
>> generator strenght to be similar to the broadcast carrier.
>>
>> You will see strong beautiful 3rd order products on 1020 and 990 Hz.
>> Swith to USB--> much more weaker 3rd order products or inexistent.
>>
>> http://ea1abz.ure.es/3erd-order.jpeg
>>
>> That is my K3 behaviour. Just want to know if my K3 is ok or not.
>>
>> Many thanks. I appreciate your effort in doing this test for me.
>>
>> 73, Ramiro, EA4NZ.
>>
>> PD: Volume at the speaker is zero to avoid vibrations inside the K3
>> case.
>>
>>
>
>
> -----
> Julian, G4ILO. K2 #392  K3 #222.
> * G4ILO's Shack - http://www.g4ilo.com
> * KComm - http://www.g4ilo.com/kcomm.html
> * KTune - http://www.g4ilo.com/ktune.html
>

______________________________________________________________
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

[Igor Sokolov-2]

Is this about 3rd order inband IMD? The subject was widely discussed some
time ago. Just try to search the archaive.

73, Igor UA9DC
----- Original Message -----
From: "Ramiro Aceves" <[hidden email]>
To: <[hidden email]>
Sent: Tuesday, November 23, 2010 3:20 PM
Subject: [Elecraft] K3 RX spurs


Hello K3 fans

I am a bit stranged and frustrated cause nobody has answered a single
word to my email "K3 RX spurs" posted on november the 20th. No comments,
no ideas....
After some tests I have concluded that the spurs are 3rd order
intermodulation products. They only occur in DATA or CW.
¿Can anyone please, try to reproduce those products in your K3/P3 or
K3/computer combination?.

"DATA A" mode: Cristal filter= 2.7KHz, SHIFT=1.5 KHz, WIDTH= 2.7 kHz
Tune some steady carrier in shortwave. Tune the signal to place a
beautiful 1000 Hz on the waterfall
Tune your signal generator 10 Hz more than the broadcast carrier
frequency to get an audio  signal 10 Hz over the 1000 Hz signal. Adjust
generator strenght to be similar to the broadcast carrier.

You will see strong beautiful 3rd order products on 1020 and 990 Hz.
Swith to USB--> much more weaker 3rd order products or inexistent.

http://ea1abz.ure.es/3erd-order.jpeg

That is my K3 behaviour. Just want to know if my K3 is ok or not.

Many thanks. I appreciate your effort in doing this test for me.

73, Ramiro, EA4NZ.

PD: Volume at the speaker is zero to avoid vibrations inside the K3
case.
______________________________________________________________
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 

______________________________________________________________
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

[Ramiro Aceves]

Igor Sokolov escribió:
> Is this about 3rd order inband IMD? The subject was widely discussed
> some time ago. Just try to search the archaive.


Many information there, thanks

http://www.cliftonlaboratories.com/elecraft_k3_receive_audio.htm#Introduction_and_Test_Setup_

This is very interesting, but I have not found IMD measurements made
with very closed test sigs.

73, Ramiro.
EA4NZ

>
> 73, Igor UA9DC
> ----- Original Message ----- From: "Ramiro Aceves" <[hidden email]>
> To: <[hidden email]>
> Sent: Tuesday, November 23, 2010 3:20 PM
> Subject: [Elecraft] K3 RX spurs
>
>
> Hello K3 fans
>
> I am a bit stranged and frustrated cause nobody has answered a single
> word to my email "K3 RX spurs" posted on november the 20th. No comments,
> no ideas....
> After some tests I have concluded that the spurs are 3rd order
> intermodulation products. They only occur in DATA or CW.
> ¿Can anyone please, try to reproduce those products in your K3/P3 or
> K3/computer combination?.
>
> "DATA A" mode: Cristal filter= 2.7KHz, SHIFT=1.5 KHz, WIDTH= 2.7 kHz
> Tune some steady carrier in shortwave. Tune the signal to place a
> beautiful 1000 Hz on the waterfall
> Tune your signal generator 10 Hz more than the broadcast carrier
> frequency to get an audio  signal 10 Hz over the 1000 Hz signal. Adjust
> generator strenght to be similar to the broadcast carrier.
>
> You will see strong beautiful 3rd order products on 1020 and 990 Hz.
> Swith to USB--> much more weaker 3rd order products or inexistent.
>
> http://ea1abz.ure.es/3erd-order.jpeg
>
> That is my K3 behaviour. Just want to know if my K3 is ok or not.
>
> Many thanks. I appreciate your effort in doing this test for me.
>
> 73, Ramiro, EA4NZ.
>
> PD: Volume at the speaker is zero to avoid vibrations inside the K3
> case.
> ______________________________________________________________
> 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
>

______________________________________________________________
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

[Geoffrey Mackenzie-Kennedy]

Ramiro,

Are you using a hybrid to combine the SW carrier and the signal generator's
output before sending them to the K3, and how strong are these two signals
(dbm)?

If you are not using some type of hybrid, could you please let me know how
you are "adding" these signals.

It is possible that these products are not generated by the K3, but by the
test equipment.

73,
Geoff
GM4ESD


Ramiro Aceves wrote on Tuesday, November 23, 2010, at 10:20 AM:



Hello K3 fans

I am a bit stranged and frustrated cause nobody has answered a single
word to my email "K3 RX spurs" posted on november the 20th. No comments,
no ideas....
After some tests I have concluded that the spurs are 3rd order
intermodulation products. They only occur in DATA or CW.
¿Can anyone please, try to reproduce those products in your K3/P3 or
K3/computer combination?.

<snip>



______________________________________________________________
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

[Ramiro Aceves]

For comparison, sigs of FT-897 and K3. Notice the increase in IMD on
DATA mode. FT-897 and K3 on USB have got similar IMD.

http://ea1abz.ure.es/k3_vs_ft897.jpeg

I have seen worst IMDs but I have not registered them

73, Ramiro.


______________________________________________________________
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

[Ramiro Aceves]

A more evident difference in IMD between DATA and USB modes.

http://ea1abz.ure.es/cw_vs_data.jpeg


Thanks,

Ramiro, EA4NZ
______________________________________________________________
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

[Ramiro Aceves]

Lyle Johnson escribió:
> Hello Ramiro!


Ohhhh, Yesssssssss, yessssssssssssssssssssssssssssss, yessssssssssssss
Lyle, you are a genius!!!!! I must go out home now, I will tell you later!!

>
> It may be AGC pumping due to the close spaced signals having a beat note
> that is slower than the AGC decay time.  This causes the AGC to modulate
> the incoming signals at the rate of the beat note, resulting in sidebands.
>
> Please try your test with AGC OFF, and with AGC SLOW.  There is also a
> special AGC command
>
> CONFIG:AGC DCY
>
> Setting it to SOFT helps with extreme QRM conditions from strong, very
> closely spaced signals.
>
> I suspect that you have AGC FAST in CW and DATA modes, and AGC SLOW in
> SSB mode, and that this may be the cause for the IMD you are seeing.
>
> 73,
>
> Lyle KK7P
>

______________________________________________________________
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

[Geoffrey Mackenzie-Kennedy]

Thank you. My suspicion is that the IMD is being generated outside of the
radios, but I need to take a closer look at your data.

I see that there are many more IMD products below 990 Hz than above 1000 Hz
in the top half of the waterfall in your CW vs DATA comparison, which could
suggest that the roofer is blocking some products.

Will return as soon as possible.

73,
Geoff
GM4ESD


Ramiro Aceves wrote:

 > For comparison, sigs of FT-897 and K3. Notice the increase in IMD on
> DATA mode. FT-897 and K3 on USB have got similar IMD.
>
> http://ea1abz.ure.es/k3_vs_ft897.jpeg
>
> I have seen worst IMDs but I have not registered them
>
> 73, Ramiro.


______________________________________________________________
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

[G3TCT]

Ramiro
I don't see any difference here between USB, CW and Data.  Third order
products are about 45-50dB down here, whereas yours seem to be about
20dB down (difficult to see on the spectrum though).  Maybe your sound
card input is being over-driven?

Graham

On 19:59, Ramiro Aceves wrote:

> Hello K3 fans
>
> I am a bit stranged and frustrated cause nobody has answered a single
> word to my email "K3 RX spurs" posted on november the 20th. No
> comments, no ideas....
> After some tests I have concluded that the spurs are 3rd order
> intermodulation products. They only occur in DATA or CW.
> ¿Can anyone please, try to reproduce those products in your K3/P3 or
> K3/computer combination?.
>
> "DATA A" mode: Cristal filter= 2.7KHz, SHIFT=1.5 KHz, WIDTH= 2.7 kHz
> Tune some steady carrier in shortwave. Tune the signal to place a
> beautiful 1000 Hz on the waterfall
> Tune your signal generator 10 Hz more than the broadcast carrier
> frequency to get an audio  signal 10 Hz over the 1000 Hz signal.
> Adjust generator strenght to be similar to the broadcast carrier.
>
> You will see strong beautiful 3rd order products on 1020 and 990 Hz.
> Swith to USB--> much more weaker 3rd order products or inexistent.
>
> http://ea1abz.ure.es/3erd-order.jpeg
>
> That is my K3 behaviour. Just want to know if my K3 is ok or not.
>
> Many thanks. I appreciate your effort in doing this test for me.
>
> 73, Ramiro, EA4NZ.
>
> PD: Volume at the speaker is zero to avoid vibrations inside the K3 case.
>

______________________________________________________________
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

[Igor Sokolov-2]

Ramiro, the in band IMD subject was discussed here on this reflector as
well.
Here is the link
http://mailman.qth.net/pipermail/elecraft/2008-November/099616.html

73, Igor UA9CDC

----- Original Message -----
From: "Ramiro Aceves" <[hidden email]>
To: "Igor Sokolov" <[hidden email]>
Cc: <[hidden email]>
Sent: Tuesday, November 23, 2010 5:55 PM
Subject: Re: [Elecraft] K3 RX spurs

> Igor Sokolov escribió:
>> Is this about 3rd order inband IMD? The subject was widely discussed some
>> time ago. Just try to search the archaive.
>
>
> Many information there, thanks
>
> http://www.cliftonlaboratories.com/elecraft_k3_receive_audio.htm#Introduction_and_Test_Setup_
>
> This is very interesting, but I have not found IMD measurements made with
> very closed test sigs.
>
> 73, Ramiro.
> EA4NZ
>
>
>
>>
>> 73, Igor UA9DC
>> ----- Original Message ----- From: "Ramiro Aceves" <[hidden email]>
>> To: <[hidden email]>
>> Sent: Tuesday, November 23, 2010 3:20 PM
>> Subject: [Elecraft] K3 RX spurs
>>
>>
>> Hello K3 fans
>>
>> I am a bit stranged and frustrated cause nobody has answered a single
>> word to my email "K3 RX spurs" posted on november the 20th. No comments,
>> no ideas....
>> After some tests I have concluded that the spurs are 3rd order
>> intermodulation products. They only occur in DATA or CW.
>> ¿Can anyone please, try to reproduce those products in your K3/P3 or
>> K3/computer combination?.
>>
>> "DATA A" mode: Cristal filter= 2.7KHz, SHIFT=1.5 KHz, WIDTH= 2.7 kHz
>> Tune some steady carrier in shortwave. Tune the signal to place a
>> beautiful 1000 Hz on the waterfall
>> Tune your signal generator 10 Hz more than the broadcast carrier
>> frequency to get an audio  signal 10 Hz over the 1000 Hz signal. Adjust
>> generator strenght to be similar to the broadcast carrier.
>>
>> You will see strong beautiful 3rd order products on 1020 and 990 Hz.
>> Swith to USB--> much more weaker 3rd order products or inexistent.
>>
>> http://ea1abz.ure.es/3erd-order.jpeg
>>
>> That is my K3 behaviour. Just want to know if my K3 is ok or not.
>>
>> Many thanks. I appreciate your effort in doing this test for me.
>>
>> 73, Ramiro, EA4NZ.
>>
>> PD: Volume at the speaker is zero to avoid vibrations inside the K3
>> case.
>> ______________________________________________________________
>> 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
>>
>

______________________________________________________________
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

[Ramiro Aceves]

Thank you very much for all who reply to may problem and gave ideas and
suggestions.

http://ea1abz.ure.es/agcF-agcS.jpeg

Notice the 3rd order spur suppression after changing from AGC-F to AGS-S
settings  in DATA A mode.

Igor, very interesting article, what a pitty that is in  russian language.

This one supperb article:

http://www.cliftonlaboratories.com/elecraft_k3_receive_audio.htm

73, Ramiro. EA4NZ




______________________________________________________________
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