PSK31 on the K2

[Paul Huff]

Hi everybody,

I know that the new K3 has been getting most of the attention lately but I'm considering the purchase of a K2.  I'm primarily a CW op but I also like to do a little PSK31 from time to time.  With the SSB option installed does the K2 offer the necessary back panel connections for PSK31 or do you need to do all of this through the microphone connector?

Thanks and 73,
Paul - N8XMS
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Don Wilhelm-3]

Paul,

The only microphone input on a 'stock' K2 is at the front microphone
jack.  The audio output can be either from the front panel headphone
jack or the external speaker jack.

There are several solutions to the soundcard interconnect situation for
PSK31 and other data modes listed on Sverre Holm's 'LA3ZA Unofficial
Guide to K2 modifications' at >
http://www.qslnet.de/member/la3za/K2/mod.html

You can also see my implementation of both a mic/soundcard interface box
as well as a fixed level audio output for the K2 at my website
http:w3fpr.qrpradio.com

73,
Don W3FPR


Paul Huff wrote:
> Hi everybody,
>
> I know that the new K3 has been getting most of the attention lately but I'm considering the purchase of a K2.  I'm primarily a CW op but I also like to do a little PSK31 from time to time.  With the SSB option installed does the K2 offer the necessary back panel connections for PSK31 or do you need to do all of this through the microphone connector?
>
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[G0HVS]

Paul Huff wrote:
> Hi everybody,
>
> I know that the new K3 has been getting most of the attention lately but I'm considering the purchase of a K2.  I'm primarily a CW op but I also like to do a little PSK31 from time to time.  With the SSB option installed does the K2 offer the necessary back panel connections for PSK31 or do you need to do all of this through the microphone connector?
>


My solution to this has been to use a Heil adapter, so there are jack sockets connected all the time to the mic connector.  This way I can easily change between SSB and RTTY/PSK (Heil headset for SSB).  It seems to be the simplest solution that gives the most flexibility.

Cheers
Dave
G0HVS






      ___________________________________________________________
Yahoo! Answers - Got a question? Someone out there knows the answer. Try it
now.
http://uk.answers.yahoo.com/ 
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Igor Sokolov-2]

I have made brake up box for microphone/sound card connection with isolating
transformers. I find K2 to be pretty poor performer on PSK31. Has it
something to do with VFO stability of phase shift in the filters - I do not
know. But weak signals coming from my IC765 get easyly decoded by the
program while if I use K2 the same program can decode only solid signals. I
am not pleased with SSB performance of K2 either. Especially on TX. Having
said that it is pretty good as CW contest rig and is almost on the par with
my main radio.

73, Igor UA9CDC


Paul Huff wrote:
> Hi everybody,
>
> I know that the new K3 has been getting most of the attention lately but
I'm considering the purchase of a K2.  I'm primarily a CW op but I also like
to do a little PSK31 from time to time.  With the SSB option installed does
the K2 offer the necessary back panel connections for PSK31 or do you need
to do all of this through the microphone connector?
>


My solution to this has been to use a Heil adapter, so there are jack
sockets connected all the time to the mic connector.  This way I can easily
change between SSB and RTTY/PSK (Heil headset for SSB).  It seems to be the
simplest solution that gives the most flexibility.

Cheers
Dave
G0HVS






      ___________________________________________________________
Yahoo! Answers - Got a question? Someone out there knows the answer. Try it
now.
http://uk.answers.yahoo.com/
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Julian, G4ILO]

On 8/6/07, Igor Sokolov <[hidden email]> wrote:

> I have made brake up box for microphone/sound card connection with isolating
> transformers. I find K2 to be pretty poor performer on PSK31. Has it
> something to do with VFO stability of phase shift in the filters - I do not
> know. But weak signals coming from my IC765 get easyly decoded by the
> program while if I use K2 the same program can decode only solid signals. I
> am not pleased with SSB performance of K2 either. Especially on TX. Having
> said that it is pretty good as CW contest rig and is almost on the par with
> my main radio.
>
> 73, Igor UA9CDC
>

The K2 has been my only radio for many years and I have made more
PSK31 contacts than any other mode and I find the performance to be
excellent. I have never had any trouble decoding weak signals - except
for the day to day variations probably caused by the ionosphere,
especially in northerly regions - and find it gives a very clean
signal on transmit, IMD products -34dB when I measured using another
receiver. The only annoyance is the fact that the frequency jumps by a
few Hz when switching filters due to the limited resolution of the VFO
DACs.

I have also had complimentary reports on SSB (and it has always
sounded good when I monitor it, as well.)

I wonder if there is some problem with the SSB alignment on your K2.
Perhaps the radio is close to a magnetic field such as a transformer
which is modulating the VCO a little. When I made a power supply for
my K2 I had to use a toroidal transformer for this reason.

--
Julian, G4ILO K2 s/n: 392  K3 s/n: ???
G4ILO's Shack: www.g4ilo.com
Ham-Directory: www.ham-directory.com
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Jim Brown-10]

On Mon, 6 Aug 2007 17:24:03 +0600, Igor Sokolov wrote:

>Has it
>something to do with VFO stability of phase shift in the filters - I do not
>know. But weak signals coming from my IC765 get easyly decoded by the
>program while if I use K2 the same program can decode only solid signals.

I agree with others that it is probably a filter alignment issue. There are
excellent resources in the Elecraft community to help you fix that.

>I am not pleased with SSB performance of K2 either.

First, you must remember that the K2 started out life as a QRP CW rig. As
that, it's spectacularly good. The K2/100 is also a very good CW contesting
rig, but for the excessive wideband phase noise that makes you very
unpopular with your neighbors if you use it to drive an amp.

I agree. The widest RX filter is the TX filter. It has very good magnitude
and phase response, and it sounds great. But the "stagger-tuning" of the CW
RX filters to provide narrower SSB RX produce a VERY bumpy audio response
(both magnitude and phase) that only the programmer's mother could love. It
sounds awful, and it degrades intelligibility.

>Especially on TX.

I agree with you, but there are some very good fixes that can improve it
significantly. Many of them are written up on user websites, with links from
the Elecraft webpage. The fundamental problem is that the K2 audio path is
low on gain. The gain is also a bit lacking further on in the signal chain.

I developed a simple mod that helps a lot. On the SSB board, change R14 to
2K, change C34 to 0.22 uF, and add 2.2 uF in series with R15. This provides
6 dB additional gain for the mic, which allows you to hit the compressor
harder and increase the average loudness. It also rolls off the low end a
bit, which prevents "pops" from activating the compressor, making the
compressor work better.

>Having said that it is pretty good as CW contest rig and is almost on the
>par with my main radio.

Yep!  

Jim Brown K9YC



_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Igor Sokolov-2]

> On 8/6/07, Igor Sokolov <[hidden email]> wrote:
> > I have made brake up box for microphone/sound card connection with
isolating
> > transformers. I find K2 to be pretty poor performer on PSK31. Has it
> > something to do with VFO stability of phase shift in the filters - I do
not
> > know. But weak signals coming from my IC765 get easyly decoded by the
> > program while if I use K2 the same program can decode only solid
signals. I
> > am not pleased with SSB performance of K2 either. Especially on TX.
Having
> > said that it is pretty good as CW contest rig and is almost on the par
with

> > my main radio.
> >
> > 73, Igor UA9CDC
> >
>
> The K2 has been my only radio for many years and I have made more
> PSK31 contacts than any other mode and I find the performance to be
> excellent. I have never had any trouble decoding weak signals - except
> for the day to day variations probably caused by the ionosphere,
> especially in northerly regions - and find it gives a very clean
> signal on transmit, IMD products -34dB when I measured using another
> receiver. The only annoyance is the fact that the frequency jumps by a
> few Hz when switching filters due to the limited resolution of the VFO
> DACs.
>
> I have also had complimentary reports on SSB (and it has always
> sounded good when I monitor it, as well.)
>
> I wonder if there is some problem with the SSB alignment on your K2.
> Perhaps the radio is close to a magnetic field such as a transformer
> which is modulating the VCO a little. When I made a power supply for
> my K2 I had to use a toroidal transformer for this reason.
>
> --
> Julian, G4ILO K2 s/n: 392  K3 s/n: ???
> G4ILO's Shack: www.g4ilo.com
> Ham-Directory: www.ham-directory.com

Thanks for your comments Julian. I do not think VCO modulation is the
reason. The radio is pretty far from the magnetic field sources. SSB (filter
and BFO) are aligned with the help of Spectrogram program.
I heard other K2 on the air and SSB signal was pretty similar to mine -
average and dim and  lacking high frequencies and punch. That will do for
day to day QSO but not for contests and pile ups. Anyway I will keep on
trying to do something about it before I give up:)

73, Igor UA9CDC

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Igor Sokolov-2]

> >Has it
> >something to do with VFO stability of phase shift in the filters - I do
not
> >know. But weak signals coming from my IC765 get easyly decoded by the
> >program while if I use K2 the same program can decode only solid signals.
>
> I agree with others that it is probably a filter alignment issue. There
are
> excellent resources in the Elecraft community to help you fix that.

I do not think so. I did filter calibration with Spectrogram.

>
> >I am not pleased with SSB performance of K2 either.
>
> First, you must remember that the K2 started out life as a QRP CW rig. As
> that, it's spectacularly good. The K2/100 is also a very good CW
contesting
> rig, but for the excessive wideband phase noise that makes you very
> unpopular with your neighbors if you use it to drive an amp.
> I agree. The widest RX filter is the TX filter. It has very good magnitude
> and phase response, and it sounds great. But the "stagger-tuning" of the
CW
> RX filters to provide narrower SSB RX produce a VERY bumpy audio response
> (both magnitude and phase) that only the programmer's mother could love.
It
> sounds awful, and it degrades intelligibility.
>
> >Especially on TX.

When I mentioned PSK31 I should have state that I am trying to use just
those narrow filters for RX. On Spectrogram they look reasonably good
provided the bandwidth is less then 1 kHz. With more then 1Khz settings  the
ripple in the passband makes them of very little use.

> I agree with you, but there are some very good fixes that can improve it
> significantly. Many of them are written up on user websites, with links
from
> the Elecraft webpage. The fundamental problem is that the K2 audio path is
> low on gain. The gain is also a bit lacking further on in the signal
chain.
>
> I developed a simple mod that helps a lot. On the SSB board, change R14 to
> 2K, change C34 to 0.22 uF, and add 2.2 uF in series with R15. This
provides

I have actually removed R14 all together. It gives me some extra gain but
still not enough to compensate for the losses caused by RC chain wich I put
at the mike input trying to boost high frequencies a bit. Besides the noise
gate which is build into the mike IC started to be noticable. My
correspondents report "step type" distortions on my signal. Then AF
compression is not as efficient as RF compression. All together that make
SSB signal dull and not as penetrative as one needs for SSB contesting. I am
now thinking of additional mike amp to improve the situation.

> 6 dB additional gain for the mic, which allows you to hit the compressor
> harder and increase the average loudness. It also rolls off the low end a
> bit, which prevents "pops" from activating the compressor, making the
> compressor work better.

I will try your mode  but I feel it may not be enough at least with the
present cheep computer grade electret microphon. Still this very mike works
pretty well with my main IC-765 radio.


73, Igor UA9CDC

>
> >Having said that it is pretty good as CW contest rig and is almost on the
> >par with my main radio.
>
> Yep!
>
> Jim Brown K9YC
>
>
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com