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Re: Suggestions for good 192kHz external sound card fordigital modes

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ve3dvy

Re: Suggestions for good 192kHz external sound card fordigital modes

Im just curious

I can see the bit depth making a difference 16 bit will have poor
dynamic range compared to 24 or 32 bit and this is important for some
modes like wspr or JTXX, but is there any advantage to high bit
rates in digital modes even a 44khz card has a bandwidth way beond
what any digital mode on HF needs. or is it that to get a 32bit
adapter just by default it will have high bit rates.

David Moes
VE3DVY

On Tuesday 11/11/2014 at 7:08 pm, David Orman wrote:

> Hi,
>
> Splitting off from the Signalink thread, since it's actually a
> different
> question, what are the current external sound cards that people
> suggest
> (that are supported in Linux if known - if not - that's ok)?
>
> I see the Tascam mentioned in the PDF in the other thread, so I'm
> looking
> into those (the ones that support 192kHz now, that is) - are there any
> other suggestions to look into? I operate on a lot of digital modes,
> but my
> Lenovo Thinkpad T400's built in sound card adds a lot of noise to the
> signal I'm receiving. I have a Native Instruments Audio Kontrol 1
> which
> works much better, but it is USB powered (it seemed to be indicated
> this
> was a no-no for best decoding in digital modes in the other thread).
>
> There are a lot of options out there now, so it's hard to sift through
> them
> all, and make a guess as to which are best for HF radio digital
> communication, so I thought a thread would be helpful in getting some
> ideas
> on what is tested/true. If Linux support is unknown, that's ok - I can
> do
> that research - but it would be great to have a list to start looking
> at
> that are known good performers with low noise.
>
> Thanks!
> David/K5DJO
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David Orman

Re: Suggestions for good 192kHz external sound card fordigital modes

KX3 == SDR == able to display large chunk of spectrum at a time. A 44kHz
card significantly limits this. My PX3 does 200kHz well. fldigi with some
source code edits can too.

Thank you for all of the responses, I'm reading up on every suggestion (and
site linked).

Thanks!
David

On Tue, Nov 11, 2014 at 7:51 PM, <[hidden email]> wrote:

>
> Im just curious
>
> I can see the bit depth making a difference 16 bit will have poor
> dynamic range compared to 24 or 32 bit and this is important for some
> modes like wspr or JTXX, but is there any advantage to high bit rates in
> digital modes even a 44khz card has a bandwidth way beond what any
> digital mode on HF needs. or is it that to get a 32bit adapter just
> by default it will have high bit rates.
>
> David Moes
> VE3DVY
>
>
> On Tuesday 11/11/2014 at 7:08 pm, David Orman wrote:
>
>> Hi,
>>
>> Splitting off from the Signalink thread, since it's actually a different
>> question, what are the current external sound cards that people suggest
>> (that are supported in Linux if known - if not - that's ok)?
>>
>> I see the Tascam mentioned in the PDF in the other thread, so I'm looking
>> into those (the ones that support 192kHz now, that is) - are there any
>> other suggestions to look into? I operate on a lot of digital modes, but
>> my
>> Lenovo Thinkpad T400's built in sound card adds a lot of noise to the
>> signal I'm receiving. I have a Native Instruments Audio Kontrol 1 which
>> works much better, but it is USB powered (it seemed to be indicated this
>> was a no-no for best decoding in digital modes in the other thread).
>>
>> There are a lot of options out there now, so it's hard to sift through
>> them
>> all, and make a guess as to which are best for HF radio digital
>> communication, so I thought a thread would be helpful in getting some
>> ideas
>> on what is tested/true. If Linux support is unknown, that's ok - I can do
>> that research - but it would be great to have a list to start looking at
>> that are known good performers with low noise.
>>
>> Thanks!
>> David/K5DJO
>> ______________________________________________________________
>> 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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>
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>

Don Wilhelm-4

Re: Suggestions for good 192kHz external sound card fordigital modes

In reply to this post by ve3dvy

David,

A regular 16 bit soundcard will do well when being used for digital
modes. Yes, the better soundcards have a lower noise floor which can
help, but great bandwidth and bit rates are not required for those
applications.
OTOH, if you are looking at panadapter applications, a good soundcard is
important to get 192 kHz span width with low noise, and you sill want to
use it at the higher bit rates unless you are satisfied with a 96 kHz span.

Select your needs and then select the soundcard that will fulfill those
needs. Even the lowly 16 bit cards are adequate for data mode applications.

73,
Don W3FPR

On 11/11/2014 8:51 PM, [hidden email] wrote:

Don Wilhelm-4

Re: Suggestions for good 192kHz external sound card fordigital modes

In reply to this post by David Orman

The limit in the KX3 I/Q outputs is due to the falloff of the output
response of the KX3 - no soundcard can compensate for that.
The PX3 however has circuits that do compensate for that falloff and can
display the full 200kHz spectrum.

73,
Don W3FPR

On 11/11/2014 9:01 PM, David Orman wrote:
> KX3 == SDR == able to display large chunk of spectrum at a time. A 44kHz
> card significantly limits this. My PX3 does 200kHz well. fldigi with some
> source code edits can too.
>
> Thank you for all of the responses, I'm reading up on every suggestion (and
> site linked).
>
>

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David Orman

Re: Suggestions for good 192kHz external sound card fordigital modes

In reply to this post by Don Wilhelm-4

I am using it for wide-frequency viewing, which is why I made my request as
such re: 192kHz. I definitely want a 24bit card for the reasons you
mentions. You also have mentioned the noise floor - this is very important
to me. I'm often operating in non-optimal conditions, so every little bit
helps.

I posted requesting feedback on 192kHz sound cards (I should have specified
24-bit or better) specifically for a reason. You've basically hit the
hammer on the head for the reasons. :)

As to the falloff, can you point me to a thread so I can understand it? If
it's something the PX3 (which I also own) compensates for, I can probably
write code to do the same in my favorite applications.

I very much appreciate the input,
David

On Tue, Nov 11, 2014 at 8:08 PM, Don Wilhelm <[hidden email]> wrote:

> David,
>
> A regular 16 bit soundcard will do well when being used for digital
> modes. Yes, the better soundcards have a lower noise floor which can help,
> but great bandwidth and bit rates are not required for those applications.
> OTOH, if you are looking at panadapter applications, a good soundcard is
> important to get 192 kHz span width with low noise, and you sill want to
> use it at the higher bit rates unless you are satisfied with a 96 kHz span.
>
> Select your needs and then select the soundcard that will fulfill those
> needs. Even the lowly 16 bit cards are adequate for data mode applications.
>
> 73,
> Don W3FPR
>
> On 11/11/2014 8:51 PM, [hidden email] wrote:
>
>>
>> Im just curious
>>
>> I can see the bit depth making a difference 16 bit will have poor
>> dynamic range compared to 24 or 32 bit and this is important for some
>> modes like wspr or JTXX, but is there any advantage to high bit rates in
>> digital modes even a 44khz card has a bandwidth way beond what any
>> digital mode on HF needs. or is it that to get a 32bit adapter just
>> by default it will have high bit rates.
>>
>>
> ______________________________________________________________
> 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]
>

Alan Bloom

Re: Suggestions for good 192kHz external sound card fordigital modes

In reply to this post by Don Wilhelm-4

I agree with Don. A high sample rate and large dynamic range are
important for a panadapter but not for digital modes via the audio
in/out of a transceiver.

Even a 16-bit sound card theoretically has 96 dB dynamic range. True, it
is probably not that good in practice, but it's hard to imagine the
noise would be high enough to affect decoding the digital signal. For
example, if the signal is S9 and the noise is S2, that's only (9-2) * 6
= 42 dB signal to noise ratio (assuming 6 dB per S-unit).

Another factor is that 192 ksamples/sec sound cards need custom drivers
that you have to install. The standard USB audio device driver that is
built into Windows is only good to 48 ksamples/sec (stereo) as I recall.

Alan N1AL

On 11/11/2014 06:08 PM, Don Wilhelm wrote:

> David,
>
> A regular 16 bit soundcard will do well when being used for digital
> modes. Yes, the better soundcards have a lower noise floor which can
> help, but great bandwidth and bit rates are not required for those
> applications.
> OTOH, if you are looking at panadapter applications, a good soundcard
> is important to get 192 kHz span width with low noise, and you sill
> want to use it at the higher bit rates unless you are satisfied with a
> 96 kHz span.
>
> Select your needs and then select the soundcard that will fulfill
> those needs. Even the lowly 16 bit cards are adequate for data mode
> applications.
>
> 73,
> Don W3FPR
>
> On 11/11/2014 8:51 PM, [hidden email] wrote:
>>
>> Im just curious
>>
>> I can see the bit depth making a difference 16 bit will have poor
>> dynamic range compared to 24 or 32 bit and this is important for
>> some modes like wspr or JTXX, but is there any advantage to high
>> bit rates in digital modes even a 44khz card has a bandwidth way
>> beond what any digital mode on HF needs. or is it that to get
>> a 32bit adapter just by default it will have high bit rates.
>>
>
> ______________________________________________________________
> 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]
>
>

Don Wilhelm-4

Re: Suggestions for good 192kHz external sound card fordigital modes

In reply to this post by David Orman

David,

Some time ago, Wayne posted the expected falloff of the RX I/Q levels in
dB as the width of the display increased. That info should be available
in the archives if you do a search.

If you have a Panadapter application loaded on your computer and a good
quality wideband soundcard, you will be able to see the falloff on the
display. When receiving no signals, but only band noise, the panadapter
passband will take on an upside down "U" shape if your soundcard is
capable of 192 kHz.
That shape will indicate the actual falloff for your particular KX3.

The PX3 does compensate for this loss of gain as the spectrum width is
increased. Most of us do not have the capability to build special
soundcard software, but if you do have that capability, perhaps you can
make a KX3 panadapter application available to KX3 users which does the
same "boost at the edges" as the PX3 does.

73,
Don W3FPR

On 11/11/2014 9:27 PM, David Orman wrote:

> I am using it for wide-frequency viewing, which is why I made my request as
> such re: 192kHz. I definitely want a 24bit card for the reasons you
> mentions. You also have mentioned the noise floor - this is very important
> to me. I'm often operating in non-optimal conditions, so every little bit
> helps.
>
> I posted requesting feedback on 192kHz sound cards (I should have specified
> 24-bit or better) specifically for a reason. You've basically hit the
> hammer on the head for the reasons. :)
>
> As to the falloff, can you point me to a thread so I can understand it? If
> it's something the PX3 (which I also own) compensates for, I can probably
> write code to do the same in my favorite applications.
>
>

Jim Brown-10

Re: Suggestions for good 192kHz external sound card fordigital modes

In reply to this post by Alan Bloom

On Tue,11/11/2014 8:14 PM, Alan wrote:
> Even a 16-bit sound card theoretically has 96 dB dynamic range. True,
> it is probably not that good in practice,

In the pro audio world, we think of a 16 bit card as being more like 90
dB, which is FAR more than we need as an audio interface for a radio.
The 6dB difference is due to noise and non-linearity of the A/D and D/A
converters at the low end of their range. As noted, the 24-bit and
higher bit rate cards are appropriate for uses like SDR and LP-Pan.

73, Jim K9YC

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