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[K3] Attenuator and soundcard digital modes

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Don Putnick

[K3] Attenuator and soundcard digital modes

After having a less than successful time with PSK31 during the 13 Colonies Special Event, I think I need to learn more about noise reduction. I've read the section in KE7X's manual, but I'm looking for guidance specific to the soundcard digital modes.

1) It appears the K3's attenuator is fixed at -10 dB. Is that the case or is it reprogrammable?

2) What is the collective wisdom on noise reduction for soundcard digital modes: K3 attenuator, K3 noise reduction, PSK31 software noise reduction, some combination of the three, or none at all?

Thanks and 73,
Don NA6Z K3 #5495
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Don Wilhelm-4

Re: [K3] Attenuator and soundcard digital modes

Don,

What is your specific problem? If it is strong signals within the
passband, then more narrow roofing filters are the answer. Instead of
using the entire 2.7 kHz bandwidth and depending on the software
application to resolve any one signal, use the K3 filtering to zero in
on a specific signal, and you will find the decoding much better, with
or without the presence of noise.

Yes, what I am suggesting is that you first reduce the bandwidth of the
K3, and then the PSK31 software has fewer signals to deal with, and can
decode them better.

I know that most PSK31 operators just use the full SSB bandwidth and let
the software resolve the signals. While that works when all those
transmitting PSK31 keep their power down to a reasonable level, there
are those few who insist on being "band hogs", and transmit at 100 watts
plus. PSK31 can be very effective when used at 15 to 25 watts, and many
do keep it at that - but Special Events and contests, I find that some
crank up the power, and decoding for everyone else on the band suffers.

The K3 with its roofing filter selection and DSP filtering can help
greatly, but to take advantage of that, one must reduce the bandwidth of
the K3, and that means not using the full spectrum waterfall display --
use the K3 VFO to move from signal to signal, and your decoding will be
greatly improved.

73,
Don W3FPR

On 7/5/2011 7:39 PM, Don Putnick wrote:

> After having a less than successful time with PSK31 during the 13 Colonies Special Event, I think I need to learn more about noise reduction. I've read the section in KE7X's manual, but I'm looking for guidance specific to the soundcard digital modes.
>
> 1) It appears the K3's attenuator is fixed at -10 dB. Is that the case or is it reprogrammable?
>
> 2) What is the collective wisdom on noise reduction for soundcard digital modes: K3 attenuator, K3 noise reduction, PSK31 software noise reduction, some combination of the three, or none at all?
>
> Thanks and 73,
> Don NA6Z K3 #5495
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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KD8NNU

Re: [K3] Attenuator and soundcard digital modes

In reply to this post by Don Putnick

Hi Don,

I concurr with Don on his analysis.

I have a 700hz and 200 hz filter and I use them quite a bit for PSK31.
If you try to use just the DSP to narrow down the bandwith it does not
work as well. I used to only have a 2.7 and 2.1 k hz filters and used
the DSP only. However after using the narrow filters my receive on weak
signals has improved a lot.

Now on the transmitt side of things there are many times that even
thought I can hear them I am not able to work them. Part of this is
probally due to my receive being more efficient than my TX with my
dipole.

Also are you using Data A mode and not SSB. Plus you need to turn off
much of the noise reduction to make PSK work.

I find that I have to go to between 30 and 40 watts to make contacts
with my K3 and dipole.

I tried to work some of the special events but only got one on PSK and
one SSB, but I did not try very hard. Plus they had a lot of traffic.

Hope this helps

Now its Don Cubed!

Don
KD8NNU

On Tue, Jul 5, 2011 at 8:02 PM, Don Wilhelm wrote:

> Don,
>
> What is your specific problem? If it is strong signals within the
> passband, then more narrow roofing filters are the answer. Instead of
> using the entire 2.7 kHz bandwidth and depending on the software
> application to resolve any one signal, use the K3 filtering to zero in
> on a specific signal, and you will find the decoding much better, with
> or without the presence of noise.
>
> Yes, what I am suggesting is that you first reduce the bandwidth of
> the K3, and then the PSK31 software has fewer signals to deal with,
> and can decode them better.
>
> I know that most PSK31 operators just use the full SSB bandwidth and
> let the software resolve the signals. While that works when all those
> transmitting PSK31 keep their power down to a reasonable level, there
> are those few who insist on being "band hogs", and transmit at 100
> watts plus. PSK31 can be very effective when used at 15 to 25 watts,
> and many do keep it at that - but Special Events and contests, I find
> that some crank up the power, and decoding for everyone else on the
> band suffers.
>
> The K3 with its roofing filter selection and DSP filtering can help
> greatly, but to take advantage of that, one must reduce the bandwidth
> of the K3, and that means not using the full spectrum waterfall
> display -- use the K3 VFO to move from signal to signal, and your
> decoding will be greatly improved.
>
> 73,
> Don W3FPR
>
> On 7/5/2011 7:39 PM, Don Putnick wrote:
>> After having a less than successful time with PSK31 during the 13
>> Colonies Special Event, I think I need to learn more about noise
>> reduction. I've read the section in KE7X's manual, but I'm looking
>> for guidance specific to the soundcard digital modes.
>>
>> 1) It appears the K3's attenuator is fixed at -10 dB. Is that the
>> case or is it reprogrammable?
>>
>> 2) What is the collective wisdom on noise reduction for soundcard
>> digital modes: K3 attenuator, K3 noise reduction, PSK31 software
>> noise reduction, some combination of the three, or none at all?
>>
>> Thanks and 73,
>> Don NA6Z K3 #5495
>> ______________________________________________________________
>> 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

ik1bxn

Re: [K3] Attenuator and soundcard digital modes

Even if my name is not Don...HI I'm posting the way I use to work psk31. normally I keep 2700 Hz bandwith in order to have the waterfall at a glance. Then if ther's a track that I want insulate from the rest of the world (for example because it's a weak trace or there's a very close strong track) I move the filter center to the frequency of the track I want to follow (inside the 50 Hz granularity of course) and then I reduce the filter bandwidth to 100-150 Hz (the k3 automatically switches to my 400 Hz 8 pole filter).Sometimes at that point I switch on the Pre. I use normally 40w power in DATA-A mode.73 to everybody-Giorgio

alsopb

Re: [K3] Attenuator and soundcard digital modes

In reply to this post by Don Putnick

Don,

Noise reduction is unavailable for K3 digital modes. You get a N/A when
trying to use it. (If you really want to try it you'd have to use USB.
A high potential exists for poor copy with NR on.)

Oddly enough NB is selectable. I can imagine some of the higher
settings of NB can likewise scramble copy, though I haven't any data to
support that.

Attenuator on is a good idea if you (and your sound card) can live with
the signal strength it produces.

73 de Brian/K3KO

On 7/5/2011 23:39, Don Putnick wrote:
> After having a less than successful time with PSK31 during the 13 Colonies Special Event, I think I need to learn more about noise reduction. I've read the section in KE7X's manual, but I'm looking for guidance specific to the soundcard digital modes.
>
> 1) It appears the K3's attenuator is fixed at -10 dB. Is that the case or is it reprogrammable?
>
> 2) What is the collective wisdom on noise reduction for soundcard digital modes: K3 attenuator, K3 noise reduction, PSK31 software noise reduction, some combination of the three, or none at all?
>
> Thanks and 73,
> Don NA6Z K3 #5495
>

-----
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Checked by AVG - www.avg.com
Version: 10.0.1388 / Virus Database: 1516/3745 - Release Date: 07/05/11

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Guy, K2AV

Re: [K3] Attenuator and soundcard digital modes

If NR was available on data, it would be expected to work by the
newbies with endless complaints, even if there were mounds of reports
out there saying why it shouldn't be used. Then the vagaries of
digital operation would be blamed on Elecraft. Each digital mode has
a specific collection of clean detection tricks that belong in the PC
software, not the K3. My gut lurch is that NB probably needs to be
X'd out as well.

73, Guy.

On Wed, Jul 6, 2011 at 7:46 AM, Brian Alsop <[hidden email]> wrote:

> Don,
>
> Noise reduction is unavailable for K3 digital modes. You get a N/A when
> trying to use it. (If you really want to try it you'd have to use USB.
> A high potential exists for poor copy with NR on.)
>
> Oddly enough NB is selectable. I can imagine some of the higher
> settings of NB can likewise scramble copy, though I haven't any data to
> support that.
>
> Attenuator on is a good idea if you (and your sound card) can live with
> the signal strength it produces.
>
> 73 de Brian/K3KO
>
>
> On 7/5/2011 23:39, Don Putnick wrote:
>> After having a less than successful time with PSK31 during the 13 Colonies Special Event, I think I need to learn more about noise reduction. I've read the section in KE7X's manual, but I'm looking for guidance specific to the soundcard digital modes.
>>
>> 1) It appears the K3's attenuator is fixed at -10 dB. Is that the case or is it reprogrammable?
>>
>> 2) What is the collective wisdom on noise reduction for soundcard digital modes: K3 attenuator, K3 noise reduction, PSK31 software noise reduction, some combination of the three, or none at all?
>>
>> Thanks and 73,
>> Don NA6Z K3 #5495
>>
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1388 / Virus Database: 1516/3745 - Release Date: 07/05/11
>
> ______________________________________________________________
> 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
>

Don Putnick

[K3] Soundcard digital mode follow-up

In reply to this post by Don Putnick

2nd try - don't know why my last e-mail was blank

Thanks to all of you for the suggestions. I didn't make it clear what the circumstances were, so here goes.
I was using the K3 in DATA A mode with the stock 2700 roofing filter. No attenuation, preamp, or noise reduction. I connect the LINE IN and OUT to my MacBook's External Speaker and Mic. I use cocoaModem software for PSK31. I was going after weak traces in the presence of 1-3 band hogs. My first reaction was to do exactly what Don Wilhelm suggested. I reduced the DSP filter to 400 Hz, but when I did that, the waterfall saturated. Knowing from a propagation analysis that it was very unlikely I'd be successful anyway, I gave up.

Here are the suggestions I received, the last three in combination with the first two.

1. Decrease the DSP filter bandwidth
2. Buy a narrow roofing filter for digital modes
3. Reduce LIN OUT level
4. Turn Attenuator on
5. Turn AGC off

I'll give these a try over the weekend. Thanks again to all of you

Don NA6Z K3 #5495

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K5DNL

Re: [K3] Soundcard digital mode follow-up

Don,
20 Meters is a good place to start.
Make sure your not overdriving your sound card.
Turn ATT on , signal are so strong on 20M you dont need
a preamp.

GL 73 Ken K5DNL
---------------------------------------------------------

--- On Wed, 7/6/11, Don Putnick <[hidden email]> wrote:

> From: Don Putnick <[hidden email]>
> Subject: [Elecraft] [K3] Soundcard digital mode follow-up
> To: "Elecraft Mailing List" <[hidden email]>
> Date: Wednesday, July 6, 2011, 2:45 PM
> 2nd try - don't know why my last
> e-mail was blank
>
> Thanks to all of you for the suggestions. I didn't make it
> clear what the circumstances were, so here goes.
> I was using the K3 in DATA A mode with the stock 2700
> roofing filter. No attenuation, preamp, or noise reduction.
> I connect the LINE IN and OUT to my MacBook's External
> Speaker and Mic. I use cocoaModem software for PSK31. I was
> going after weak traces in the presence of 1-3 band hogs. My
> first reaction was to do exactly what Don Wilhelm suggested.
> I reduced the DSP filter to 400 Hz, but when I did that, the
> waterfall saturated. Knowing from a propagation analysis
> that it was very unlikely I'd be successful anyway, I gave
> up.
>
> Here are the suggestions I received, the last three in
> combination with the first two.
>
> 1. Decrease the DSP filter bandwidth
> 2. Buy a narrow roofing filter for digital modes
> 3. Reduce LIN OUT level
> 4. Turn Attenuator on
> 5. Turn AGC off
>
> I'll give these a try over the weekend. Thanks again to all
> of you
>
> Don NA6Z K3 #5495
>
>
> ______________________________________________________________
> 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
>

Jim Brown-10

Re: [K3] Soundcard digital mode follow-up

In reply to this post by Don Putnick

On 7/6/2011 12:45 PM, Don Putnick wrote:
> I was using the K3 in DATA A mode with the stock 2700 roofing filter. No attenuation, preamp, or noise reduction. I connect the LINE IN and OUT to my MacBook's External Speaker and Mic. I use cocoaModem software for PSK31. I was going after weak traces in the presence of 1-3 band hogs. My first reaction was to do exactly what Don Wilhelm suggested. I reduced the DSP filter to 400 Hz, but when I did that, the waterfall saturated.

What do you mean saturated? What SHOULD happen when you narrow the
bandwidth is that you should see fewer signals.

> Knowing from a propagation analysis that it was very unlikely I'd be successful anyway, I gave up.
>
> Here are the suggestions I received, the last three in combination with the first two.
>
> 1. Decrease the DSP filter bandwidth

Yes, but also tune the IF up or down so that the IF filter favors the
signal you're trying to work. .(Or retune the main dial -- there's
nothing "magic" about setting to 14070, or whatever.

> 2. Buy a narrow roofing filter for digital modes

Yes, but probably necessary only in heavy contesting or DX pileup
conditions.

> 3. Reduce LIN OUT level

YES.
> 4. Turn Attenuator on

Maybe, but certainly turn off the preamp.
> 5. Turn AGC off

Try turning down the RF gain a bit.

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