K3 and PSK31 Data Mode and ESSB

[Bill Strong]

I presently operate my K2/100 in PSK31 data mode with a 2.8 kHz wide
waterfall on the DM780 Superbrowser. I can click and transmit from about 600
Hz to about 1600 Hz on the Superbrowser waterfall without too much
attenuation of the transmitted signal. I made this determination using a
field strength meter and also in-line watt meter.

I would like to run a 3.5 kHz wide waterfall and be able to click and
transmit in the full width. Does anyone have experience using the K3 in this
way with ESSB and the 6 kHz roofing filter? In my reading of the K3 manual
it seems that this would be possible.

Thanks and 73's
Bill Strong
WA5KPE
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[Dave, G4AON]

I've just checked my K3 and DM780, I have the 6 KHz "AM" filter. The
bandwidth appears to go to 4 KHz on the ESSB menu setting, but in fact
the waterfall in DM780 only shows audio out to 3.5 KHz bandwidth on
receive. I can move the centre frequency of the DSP filter to 2 KHz
(normally it is 1.5 KHz) which sorts out the HF end showing on the LO
and HI settings 0.00 and 4.00 respectively. The 3.5 KHz bandwidth looks
to be fairly easy.

You might like to check with Lyle, KK7P, as to whether 4 KHz is
something that can be incorporated in later firmware without needing to
resort to shifting the centre frequency.

I've not tried transmitting with ESSB/data mode settings.

73 Dave, G4AON
K3/100 #80 f/w 3.03
--------------------------------------
I presently operate my K2/100 in PSK31 data mode with a 2.8 kHz wide
waterfall on the DM780 Superbrowser. I can click and transmit from about 600
Hz to about 1600 Hz on the Superbrowser waterfall without too much
attenuation of the transmitted signal. I made this determination using a
field strength meter and also in-line watt meter.

I would like to run a 3.5 kHz wide waterfall and be able to click and
transmit in the full width. Does anyone have experience using the K3 in this
way with ESSB and the 6 kHz roofing filter? In my reading of the K3 manual
it seems that this would be possible.

Thanks and 73's
Bill Strong
WA5KPE
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[Dave, G4AON]

Bill, testing on PSK31 TX, using USB and ESSB set to 4 KHz, centre freq
at 1500 Hz (normal K3 DSP setting)... I can obtain full power from 300
Hz to 3500 Hz on the waterfall, the power drops off abruptly above 3500
Hz. By moving the centre frequency to 2000 Hz I can transmit up to 3700 Hz.

On Data A, the upper limit is 2900 Hz, I don't think ESSB works on Data
A. Although the menu suggests it is turned on, there is no "+" on the
LCD display.

The advantage of using Data A (as opposed to SSB) is that you
automatically select the appropriate mic or line input, per mode. Maybe
wider data modes could be incorporated in a firmware update.

73 Dave, G4AON
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[Bill Strong]

Dave,

Thank you very much for the prompt response and testing of this for me. Once generally known, this ability to operate PSK31 in ESSB with click and transmit across a 3.5 kHz waterfall would I think make the K3 even more attractive to data mode operators than it already is. It would probably be unique at least among affordable radios.

It sounds as though it is feasible now though not quite as convenient as it would be if settings were built into firmware.

73 Bill, WA5KPE

[Jim Brown-10]

On Sun, 22 Mar 2009 07:44:31 -0700 (PDT), Bill Strong wrote:

>Once
>generally known, this ability to operate PSK31 in ESSB with click and
>transmit across a 3.5 kHz waterfall would I think make the K3 even more
>attractive to data mode operators than it already is.

Yes, but: another HUGE advantage of the K3 is its ability to get very
narrow to pull very weak PSK31 (or RTTY) signals out of the noise with
both a selectable fixed roofing filter, and a variable filter that can be
made very narrow filter and tuned around a bit. I would think that PSK
operators would find this quite useful for working through QRM when
contesters forget and accidentally invade their usual haunts.

73,

Jim K9YC


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[K7TV]

I agree with Jim, and not just w.r.t. invading contesters but other PSK31
stations as well. The wider the waterfall, the greater the chance that
another
station within it is stronger than the wanted station, and adversely affects
reception through receiver AGC action. The architecture with an AGC-using
radio producing audio that goes into a soundcard is a bit of a dead end,
the ultimate death of which is postponed by myths that everything will be
OK as long as nobody uses more than 20-30 W. Manual gain control
helps of course, but somewhat defeats the convenience of click-to-tune.
A better approach is to set the K3 bandwidth very narrow, and use
a panadapter to produce a waterfall that is independent of the real
receive bandwidth (and which can thus be much wider than any of the
K3 roofing filters).

73,
Erik K7TV

----- Original Message -----
From: "Jim Brown" <[hidden email]>
To: <[hidden email]>
Sent: Sunday, March 22, 2009 9:02 AM
Subject: Re: [Elecraft] K3 and PSK31 Data Mode and ESSB

> On Sun, 22 Mar 2009 07:44:31 -0700 (PDT), Bill Strong wrote:
>
>>Once
>>generally known, this ability to operate PSK31 in ESSB with click and
>>transmit across a 3.5 kHz waterfall would I think make the K3 even more
>>attractive to data mode operators than it already is.
>
> Yes, but: another HUGE advantage of the K3 is its ability to get very
> narrow to pull very weak PSK31 (or RTTY) signals out of the noise with
> both a selectable fixed roofing filter, and a variable filter that can be
> made very narrow filter and tuned around a bit. I would think that PSK
> operators would find this quite useful for working through QRM when
> contesters forget and accidentally invade their usual haunts.
>
> 73,
>
> Jim K9YC
>

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[Joe Subich, W4TV-4]

> A better approach is to set the K3 bandwidth very narrow, and
> use a panadapter to produce a waterfall that is independent of
> the real receive bandwidth (and which can thus be much wider
> than any of the K3 roofing filters).

Absolutely!  I've been playing with an RFSpace SDR-IQ and a beta
version of Spectravue.  It provides panadapter and waterfall that
can be set anywhere from 1 to 190 KHz wide ... clicking on it will
tune the K3 to put the narrow filters in the right place.  N8LP's
LP-Pan and PowerSDR should also be able to provide the same
capability.

SDR-IQ and SpectraVue work very well with microHAM Router since
SpectraVue's new external panadapter function can use Router's
2nd CAT port to control the K3 at the same time as a logger and
digital mode package like DXLab Suite or HRD/DM780.

73,

   ... Joe, W4TV
 

> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Erik N Basilier
> Sent: Sunday, March 22, 2009 5:52 PM
> To: Jim Brown; [hidden email]
> Subject: Re: [Elecraft] K3 and PSK31 Data Mode and ESSB
>
>
> I agree with Jim, and not just w.r.t. invading contesters but
> other PSK31 stations as well. The wider the waterfall, the
> greater the chance that
> another
> station within it is stronger than the wanted station, and
> adversely affects reception through receiver AGC action. The
> architecture with an AGC-using radio producing audio that
> goes into a soundcard is a bit of a dead end, the ultimate
> death of which is postponed by myths that everything will be
> OK as long as nobody uses more than 20-30 W. Manual gain
> control helps of course, but somewhat defeats the convenience
> of click-to-tune. A better approach is to set the K3
> bandwidth very narrow, and use a panadapter to produce a
> waterfall that is independent of the real receive bandwidth
> (and which can thus be much wider than any of the K3 roofing filters).
>
> 73,
> Erik K7TV
>
> ----- Original Message -----
> From: "Jim Brown" <[hidden email]>
> To: <[hidden email]>
> Sent: Sunday, March 22, 2009 9:02 AM
> Subject: Re: [Elecraft] K3 and PSK31 Data Mode and ESSB
>
>
> > On Sun, 22 Mar 2009 07:44:31 -0700 (PDT), Bill Strong wrote:
> >
> >>Once
> >>generally known, this ability to operate PSK31 in ESSB with
> click and
> >>transmit across a 3.5 kHz waterfall would I think make the K3 even
> >>more attractive to data mode operators than it already is.
> >
> > Yes, but: another HUGE advantage of the K3 is its ability
> to get very
> > narrow to pull very weak PSK31 (or RTTY) signals out of the
> noise with
> > both a selectable fixed roofing filter, and a variable
> filter that can
> > be made very narrow filter and tuned around a bit. I would
> think that
> > PSK operators would find this quite useful for working through QRM
> > when contesters forget and accidentally invade their usual haunts.
> >
> > 73,
> >
> > Jim K9YC
> >
>
>
> ______________________________________________________________
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[Bill Strong]

I am in agreement with all of the above about the narrow filter capabilities of the K3 which I considered a given when I made my original post. I have also considered the panadapter solution but that would complicate matters to a degree. I probably live in a quieter radio environment than many hams and am able to use a wide waterfall without much problem.

Strong clean signals are not a problem if I cut back on the RF gain. The fact is that in my style of operating I point and click probably 98% of the time. I like being able to see the activity around me and being able to plan my next move. DM780 can read signals that rub up against each other if they are clean signals.

For the other 2% I move to the QSO window where I can center the signal in the passband and apply narrow filters; however, this does not help much with the usual problems of splatter/IMD distortions that are usually the reason that I move to the QSO window. One of the challenges I face continually is the W1AW code practice on 80M which distorts the entire waterfall, filters or not.

It is interesting to me that a few months ago I was 100% CW but now am 100% keyboard digital. I was about to quit altogether because my fist would lose control after about 10 minutes secondary to carpal tunnel syndrome. Then I discovered PSK31. I have not heard the audio on my radio in weeks. It is all visual now.

I do appreciate all the comments.

73 Bill WA5KPE

Rig: Elecraft K2/1ØØ 3ØW  Ser # 4454
SW: HRD + DM78Ø
ACC: SignaLink USB and kk7uq IMD Meter  
ATU: MFJ-993B and DXE 1Ø KW Balun
Ant: Cobra Ultralite 14Ø ft Doublet up 3Ø Feet

P.S. I have the KAT100 but it won't tune 160M on my system whereas the MFJ does it with ease. The 993B is not quite as convenient in use as the KAT100.

[Jim Brown-10]

On Sun, 22 Mar 2009 16:44:40 -0700 (PDT), Bill Strong wrote:

>I probably live in a quieter radio environment than many hams and
>am able to use a wide waterfall without much problem.

There's no QRN where you live?  

73,

Jim K9YC





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[Bill Strong]

<There's no QRN where you live?> 

Plenty of QRN on the low bands especially in the summer. I meant the local man-made stuff.

73 Bill WA5KPE





_

[Jim Brown-10]

On Sun, 22 Mar 2009 19:15:39 -0700 (PDT), Bill Strong wrote:

>Plenty of QRN on the low bands especially in the summer. I meant the local
>man-made stuff.

I understand, and that was my point. Reducing the total bandwidth at the
input of the sound card from 2.8 kHz to 200 Hz will make a signficant
improvement in the signal to noise ratio. It won't matter on strong
stations, but it can help a lot on weak stations.

My QTH is fairly quiet too, but never dead quiet (unless the band is dead).
A few nights ago, K6SRZ (about 80 miles N of me) spotted 4U1UN as "ESP on
the West Coast" on 160M. He was ESP at my QTH too, with some QSB -- at 250
Hz bandwidth. I screwed the IF down to 100 Hz and was able to copy him, just
barely. I waited for his signal to peak, and worked him. This was CW, but
the same laws of physics apply to PSK31. :)

73,

Jim K9YC


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[David Woolley (E.L)]

Jim Brown wrote:

> I understand, and that was my point. Reducing the total bandwidth at the
> input of the sound card from 2.8 kHz to 200 Hz will make a signficant
> improvement in the signal to noise ratio. It won't matter on strong

Doing so only acts as a roofing filter.  With a good enough sound card
and good enough algorithms, the terminal program ought to be able to
eliminate the interference as well as using a narrow filter in the K3 DSP.

If the sound card is adding IMD products or the terminal program isn't
designed to detect the signal in the presence of noise, you may benefit
from using the K3 DSP as a roofing filter.


--
David Woolley
"The Elecraft list is a forum for the discussion of topics related to
Elecraft products and more general topics related ham radio"
List Guidelines <http://www.elecraft.com/elecraft_list_guidelines.htm>
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[Jim Brown-10]

On Tue, 24 Mar 2009 08:28:57 +0000, David Woolley (E.L) wrote:

>Doing so only acts as a roofing filter.  With a good enough sound card
>and good enough algorithms, the terminal program ought to be able to
>eliminate the interference as well as using a narrow filter in the K3 DSP.

I disagree, for two reasons.

1) IDEALLY, the soundcard should be good enough to reject interfering
SIGNALS, but computer sound cards are notoriously poor. Thus, a good
roofing filter for the sound card (in the form of a narrow IF, and even a
good audio filter) is a very good thing.

2) Noise that appears anywhere in the passband is broadband in the audio
spectrum, and raises the overall noise level at the sound card. When we
improve that signal to noise ratio without degrading the magnitude and
phase response for the desired signal, the soundcard has a better chance of
decoding a weak signal.

73,

Jim Brown K9YC


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