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K3, sound cards and PSK31

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George Thornton

K3, sound cards and PSK31

I have a question about PSK31, sound cards and the K3.

I am currently set up to use my K3 with the LP-Pan for a pandapter
spectrum display on computer. I am currently using a separate USB sound
card (E-Mu 0202) as the sound card for this interface.

Someone told me that using the same sound card for Panadapter and PSK31
would create problems.

While I know I could run the K3 directly to the computer using audio
in/out connections, using my computer's internal sound card also has
problems, from what I was told.

I am planning to use the K3 for some public service events and I was
hoping to include PSK31 as part of the process. To do this everything
needs to be simple and reliable, we don't want to have to do a lot of
fiddling with equipment during the events.

It has been recommended to me that I get the SignaLink USB interface
because it is easy to work with and reliable.

Am I making this too complicated? Or is it better to have two separate
independent USB sound cards to work things simultaneously?

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Kok Chen

Re: K3, sound cards and PSK31

On Apr 4, 2010, at 11:22 PM, George A. Thornton wrote:

> It has been recommended to me that I get the SignaLink USB interface
> because it is easy to work with and reliable.

The SignaLink USB contains two functions:

(a) a 16-bit sound card (Burr-Brown 2909 chip) and
(b) an audio activated ("VOX") circuit to key the PTT line of a transceiver when audio is present from the computer.

I can't think of any advantage of using an external VOX device when the K3 already has that function in DATA A mode. I.e., the function (b) is already provided by the K3, and with very flexible VOX Gain adjustment using the K3 Menu.

The SignaLink is a decent "interface" for rigs that don't support VOX for digital modes.

With the K3, you can save money by just buying a simple sound card (e.g., http://www.griffintechnology.com/products/imic) instead of the SignaLink USB.

The usual reason given for using a separate sound card instead of the built-in speaker/headphones of the computer is so that chimes, alert sounds and music from the computer don't accidentally go out on the air (especially when the transmitter is keyed through VOX).

Just connect the line-output from the sound card to the line-input of the K3 (note that the K3 line-input is a mono jack) and connect the line-output of the K3 to the line-input of the sound card, and you are done with connecting your computer to the K3. Turn on VOX for DATA-A, and you are ready to go after setting up the audio levels.

73
Chen, W7AY

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Don Wilhelm-4

Re: K3, sound cards and PSK31

Chen has given good advice here, but all jacks on the back of the K3 are
mechanically stereo jacks.

In the case of line-in, only the tip has an electrical contact (which
makes it mono electrical input). So it is convenient to just use a
manufactured stereo 3.5mm plug to 3.5mm plug cable to connect from the
computer sound card to the K3. Only the left channel from the computer
soundcard can be heard by the K3, so make sure your application puts its
audio out only the left channel (most do).

BTW - you *can* use the EMU202 soundcard for both LP-Pan and digital
modes, *but* not at the same time. Using digital modes, one usually has
a waterfall display showing the spectrum of interest, and IMHO, the
panadapter display is superfluous during those periods, your mileage may
vary on that point.

Using the default computer soundcard is only a problem if you are trying
to use VOX - windows sounds, should they occur will be transmitted as a
SSB signal. If you are using PTT generated by the PSK31 application,
that problem is not present.
Another soundcard is the easiest answer to many potential problems.

73,
Don W3FPR

Kok Chen wrote:
> Just connect the line-output from the sound card to the line-input of the K3 (note that the K3 line-input is a mono jack)
>
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n7ws

Re: K3, sound cards and PSK31

In reply to this post by Kok Chen

FWIW. I more or less successfully used the K3 for RTTY and a brief taste of PSK (too slow, like watching paint dry) with the internal sound card in my T400 Lenovo laptop.

I say more or less, because on occasion, the computer would refuse to output audio to the transmitter. The display would indicate that the signal was being generated by MMTTY but nothing went to the transmitter. This was verified with headphones on the audio out. The effect was seldom using MMTTY standalone, more frequent using AXETTY and nearly unusable using N1MMlogger and MMTTY. This suggests that it was *not* an RFI issue, but a timing issue. Closing and reopening the program would bring it back but this got old.

Other than this I had no issues, VOX worked fine, there were no ground loops, levels were easy to set, etc.

Nevertheless, rather than fussing with it further, and having another radio that could benefit by it, I opted for the SignaLink USB. Installation wasn't as smooth as advertised, but once done, it runs flawlessly. The interface cables are overpriced but I bought them anyway, one for the K3 and another for the TS870, and I sprang for the header plug that allows easy reconfiguration.

Wes N7WS

--- On Mon, 4/5/10, Kok Chen <[hidden email]> wrote:

>
> On Apr 4, 2010, at 11:22 PM, George A. Thornton wrote:
>
> > It has been recommended to me that I get the SignaLink
> USB interface
> > because it is easy to work with and reliable.
>
> The SignaLink USB contains two functions:
>
> (a) a 16-bit sound card (Burr-Brown 2909 chip) and
> (b) an audio activated ("VOX") circuit to key the PTT line
> of a transceiver when audio is present from the computer.
>
> I can't think of any advantage of using an external VOX
> device when the K3 already has that function in DATA A
> mode. I.e., the function (b) is already provided by
> the K3, and with very flexible VOX Gain adjustment using the
> K3 Menu.
>
> The SignaLink is a decent "interface" for rigs that don't
> support VOX for digital modes.
>
> With the K3, you can save money by just buying a simple
> sound card (e.g., http://www.griffintechnology.com/products/imic) instead
> of the SignaLink USB.
>
> The usual reason given for using a separate sound card
> instead of the built-in speaker/headphones of the computer
> is so that chimes, alert sounds and music from the computer
> don't accidentally go out on the air (especially when the
> transmitter is keyed through VOX).
>
> Just connect the line-output from the sound card to the
> line-input of the K3 (note that the K3 line-input is a mono
> jack) and connect the line-output of the K3 to the
> line-input of the sound card, and you are done with
> connecting your computer to the K3. Turn on VOX for
> DATA-A, and you are ready to go after setting up the audio
> levels.
>
> 73
> Chen, W7AY
>

John Ragle

Re: K3, sound cards and PSK31

Wes Stewart wrote:
> FWIW. I more or less successfully used the K3 for RTTY and a brief taste of PSK (too slow, like watching paint dry
Good Morning, Wes...

I think you'll be pleased with the SignaLink box. You are right
about BPSK31 -- it is a bit slow. My take on this is that people like to
fill the buffer and sit back to watch, and I know that some (perhaps
75%) of the users have trouble keeping up on the keyboard with the
transmit rate anyhow.

If you watch for it, you will find people (particularly the European
PSK crowd) who use PSK63 or even PSK125 or PSK250. I am a good typist,
and even so I find it takes care and attention just to keep up with
PSK63. The other modes are of course even faster.

If you're into watching paint dry, try one of the modes like Olivia
16/500. No sweat like when you break a pencil-lead copying CW at 40 wpm.
On the other hand, if you like the mystery of having signals come out of
nothing, like the Great Pumpkin rising from the Pumpkin Patch, the
Olivia modes are great.

There are lots of people (again many in the European digi-crowd) who
like RTTY. and nowadays it is noise-free (no coffee grinder in the
background, no paper tapes to load). I use fldigi and the SignaLink box
for all these modes, and it works out just fine. I have used it with my
ASUS 910 EEE toy computer and DigiPan...makes a very portable arrangement.

For an amusing variation, try a QSO using one of the Hellschreiber
modes...see

http://www.nonstopsystems.com/radio/frank_radio_hell.htm

and have fun! SignaLink does that, as well...

John Ragle -- W1ZI
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lstavenhagen

Re: K3, sound cards and PSK31

wow - hand copying 40wpm? My hat is off to you hi hi. When I took my Extra exam back in the early 90's, it was right at the limit of my ability to scribble to copy down the text at 20wpm and you had to do a full 5 minutes of it. My right arm was burning pretty good at the end of the tape...

Nowadays I just copy with my chin sitting in my hands even at speeds below 20wpm and jot down highlights.....

I just can't send worth a darn and I never have been able to master the paddles; again at my Extra exam I was sooooo glad they'd long since changed the rules and I wasn't going to have to send at 20wpm for 1 min with no mistakes hi hi.
So I'll gladly give up the paddles for the keyboard on CW. I got to listen to a great conversation on 40M last night between two gentlemen describing 350+ countries worked _while mobile_ using a couple of hamsticks. It was all going on somewhere between 25 to 30wpm and I was having a great time "reading the mail", but dismayed that I couldn't have joined in using just my paddles. Yeah I know, practice practice hi hi. But soon as I get the laptop working on the table, sorry, the Bencher is going in the bag with the K2 for portable ops hi hi.

Still with PSK31, trying it out with cocoaModem, I find I can't keep the buffer full. I can get ahead on simple plain language but throw some numbers and punctuation in there and the buffer catches up pretty quick. 45 baud RTTY is able to keep up with me no problem.

Anyway, OT I know...

73
LS
W5QD

Joe Subich, W4TV-4

Re: K3, sound cards and PSK31

In reply to this post by John Ragle

> I think you'll be pleased with the SignaLink box.

There is no value to the Signalink that can't be provided
by much less expensive USB based soundcards (e.g., UA-580
for $28.95 at Byterunner) or even the $9.95 "dongles" used
to support a headset. Since the K3 provides VOX in the
DATA A and AFSK A modes, Chen is completely correct and
the SignaLink is a waste for what it is/what it does.

If one wants more capability that a basic USB soundcard,
there are plenty of multi-function devices that provide
CAT, CW, specialized controls, hardware support for some
of the special features in fldigi, etc. Even though they
are more expensive than Signalink, if the other features
are of use (e.g., USB rig control, pFSK/qCW for fldigi,
Icom accessory interface, etc.) in your particular
shack, the multi-function devices can provide far better
value.

73,

... Joe Subich, W4TV
microHAM America
http://www.microHAM-USA.com
http://groups.yahoo.com/group/microHAM
[hidden email]

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wb6rse1

Re: K3, sound cards and PSK31

On Apr 5, 2010, at 9:48 AM, Joe Subich, W4TV wrote:

There is no value to the Signalink that can't be provided
by much less expensive USB based soundcards
___________

The SignaLink schematic shows the same type of isolation transformers already standard in the KIO3.

http://www.tigertronics.com/sl_mods.htm

73 - Steve WB6RSE

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Jim Brown-10

Re: K3, sound cards and PSK31

In reply to this post by Kok Chen

On Sun, 04 Apr 2010 23:58:42 -0700, Kok Chen wrote:

>The usual reason given for using a separate sound card instead of the
built-
>in speaker/headphones of the computer is so that chimes, alert sounds and
>music from the computer don't accidentally go out on the air (especially
>when the transmitter is keyed through VOX).

There's a simple fix for this. Go into Windoze Control Panel, open the
"Sounds and Audio Devices" setup screen, click on the "Sounds" tab, and
select "No Sounds" for the Sound scheme. Click OK and you've slain that
dragon.

>Just connect the line-output from the sound card to the line-input of the
>K3 (note that the K3 line-input is a mono jack) and connect the line-output
>of the K3 to the line-input of the sound card, and you are done with
>connecting your computer to the K3. Turn on VOX for DATA-A, and you are
>ready to go after setting up the audio levels.

Yes. I've always used the sound card built into my Thinkpad laptops for PSK,
RTTY, and to play voice messages for SSB contests. Works fine.

See my tutorial/app note on Ham Interfacing for simple wiring methods to
avoid hum, buzz, and RFI. http://audiosystemsgroup.com/HamInterfacing.pdf

There's nothing WRONG with using a Signal Link or something like it, but it
is money you don't need to spend if you follow the simple directions in my
tutorial.

73,

Jim Brown K9YC

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Kok Chen

Re: K3, sound cards and PSK31

In reply to this post by lstavenhagen

On Apr 5, 2010, at 4/5 7:33 AM, lstavenhagen wrote:

> Still with PSK31, trying it out with cocoaModem, I find I can't keep
> the
> buffer full. I can get ahead on simple plain language but throw some
> numbers
> and punctuation in there and the buffer catches up pretty quick. 45
> baud
> RTTY is able to keep up with me no problem.

One thing to keep in mind is that PSK31 (also with DominoEX and
Olivia) uses Varicode which encodes lower case characters into fewer
bits than upper case characters.

Not only will you be sending text faster by using lower case, but
there is also a corresponding lower character error rate (for the same
SNR) than when using upper case characters.

Something to keep in mind when you engage in a pileup or a digital
mode contest :-).

With BPSK31 Varicode, average English text (mostly lower case) takes
about 6-1/2 bits per character, yielding about 5 characters per
second, or just about 48 WPM if an average "word" is 5 characters plus
a space.

Standard Baudot RTTY is 60 WPM. So BPSK31 is a little bit slower than
Baudot RTTY even when you type mostly lower case in PSK31. PSK63 will
feel (and is) quite a bit faster than RTTY, but also has larger
character error rate than PSK31 for the same SNR, and if you like
sending fast exchanges, PSK125 is yet faster (and even less error free).

While the "PSK31," "PSK63" and "PSK125" nomenclature may appear weird,
their speeds are really just a factor of two from one another. The
symbol rate for PSK31 is 31.25/second, for PSK63 it is 62.5/second and
for PSK125 it is 125/second. The "31", "63" and "125" are just
rounded from 31.25, 62.5 and 125. (The symbol rate is equivalent to
the bit rate in BPSK, and equivalent to the dibit rate for QPSK). I
suspect that most programs simply re-decimate the input signal to get
a BPSK63 demodulator from a BPSK31 demodulator; that is how cocoaModem
implements PSK63 and PSK125. You just need to change the input
bandpass filter.

Why such a weird number as 31.25 baud? It has to do with ease of
implementation when using 8000 samples/second or 16000 samples/second
with a sound card. 31.25 baud is simply 1/(32 millisecond). Similar
to the reason why Baudot RTTY uses 45.45 baud and not 45.0 baud. The
"45.45" comes from 1/(22 millisecond).

73
Chen, W7AY

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Joe Subich, W4TV-4

Re: K3, sound cards and PSK31

In reply to this post by wb6rse1

> The SignaLink schematic shows the same type of isolation
> transformers already standard in the KIO3.

Which are redundant when used with the K3/KIO3. Again,
no value over the inexpensive USB "soundcard."

73,

... Joe Subich, W4TV
microHAM America
http://www.microHAM-USA.com
http://groups.yahoo.com/group/microHAM
[hidden email]

> -----Original Message-----
> From: [hidden email] [mailto:[hidden email]]
> Sent: Monday, April 05, 2010 1:11 PM
> To: Elecraft Reflector
> Cc: Joe Subich, W4TV
> Subject: Re: [Elecraft] K3, sound cards and PSK31
>
>
>
> On Apr 5, 2010, at 9:48 AM, Joe Subich, W4TV wrote:
>
> There is no value to the Signalink that can't be provided
> by much less expensive USB based soundcards
> ___________
>
> The SignaLink schematic shows the same type of isolation
> transformers already standard in the KIO3.
>
> http://www.tigertronics.com/sl_mods.htm
>
> 73 - Steve WB6RSE
>

George Thornton

Re: K3, sound cards and PSK31

Thanks everyone for the suggestions.

I have decided to purchase a less expensive sound card for dedicated use
with PSK31. While I could do this through the other sound card or the
computer, it is easier to set things up this way.

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Joe Subich, W4TV
Sent: Monday, April 05, 2010 1:08 PM
To: [hidden email]; 'Elecraft Reflector'
Subject: Re: [Elecraft] K3, sound cards and PSK31

> The SignaLink schematic shows the same type of isolation
> transformers already standard in the KIO3.

Which are redundant when used with the K3/KIO3. Again,
no value over the inexpensive USB "soundcard."

73,

... Joe Subich, W4TV
microHAM America
http://www.microHAM-USA.com
http://groups.yahoo.com/group/microHAM
[hidden email]

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Bob McGraw - K4TAX

Re: K3, sound cards and PSK31

I agree with you Jim. For years I've operated digital modes with a direct
connection between the IN's and OUT's of the sound card to the radio. Using
the VOX to control the T/R sequence {and any radio worth it's salt has a
good VOX, although many don't} does the trick nicely.

Now, if you end up with humm or buzz that indicates that you have other
issues that need to be addressed in your station. These are typically RFI
or ground loops. Addition of transformers for isolation is a Band-Aid fix
as the typical transformers have serious ringing when not correctly
terminated. Also they are very prone to introduction of humm from power
supply sources.

With this approach, using available free software, one can record audio
direct from the receiver and play it back direct to the transmitter to give
other stations an idea of how their signal sounds at your QTH. I've done
this many times to assist others in getting an idea of how their transmitter
and audio path sounds on the air.

73
Bob, K4TAX

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Rick Prather

Re: K3, sound cards and PSK31

Playback can also be done very nicely, without involving your computer, with the very slick KDVR3 in the K3.

Rick
K6LE

On 4/6/2010, at 6:55 , Bob McGraw - K4TAX wrote:

>>Snip

> With this approach, using available free software, one can record audio
> direct from the receiver and play it back direct to the transmitter to give
> other stations an idea of how their signal sounds at your QTH. I've done
> this many times to assist others in getting an idea of how their transmitter
> and audio path sounds on the air.
>
> 73
> Bob, K4TAX

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