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K3 PSK31 with Digipan

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zibs

K3 PSK31 with Digipan

Just getting my new K3 working on PSK31 and noticed that it seems to be important to limit the range of the transmit frequency. Using Digipan and K3 Data A mode, if I select a transmit frequency on the waterfall that is too high or low, I will get very low (or zero) power output. It seems like one needs to keep this frequency centered in the transmit filter bandpass (I use the 2.7 kHz filter for transmit) -- so should I always transmit near 1.3 kHz? I never noticed needing to limit this range when using my IC-756 with Digipan.

Steve N9SZ

Tim Heasman

Re: K3 PSK31 with Digipan

Hi All,

I have noticed this problem as well, and also with the sdr 1000. I just
widen the tx passband on the sdr 1000, so perhaps we could use the 6 kHz
filter for A mode data transmission.

73

Tim

gm4lmh

----- Original Message -----
From: "zibs" <[hidden email]>
To: <[hidden email]>
Sent: Friday, September 19, 2008 2:12 PM
Subject: [Elecraft] K3 PSK31 with Digipan

>
> Just getting my new K3 working on PSK31 and noticed that it seems to be
> important to limit the range of the transmit frequency. Using Digipan and
> K3
> Data A mode, if I select a transmit frequency on the waterfall that is too
> high or low, I will get very low (or zero) power output. It seems like one
> needs to keep this frequency centered in the transmit filter bandpass (I
> use
> the 2.7 kHz filter for transmit) -- so should I always transmit near 1.3
> kHz? I never noticed needing to limit this range when using my IC-756 with
> Digipan.
>
> Steve N9SZ
> --
> View this message in context:
> http://n2.nabble.com/K3-PSK31-with-Digipan-tp1100818p1100818.html
> Sent from the Elecraft mailing list archive at Nabble.com.
>
> _______________________________________________
> Elecraft mailing list
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KK7P

Re: K3 PSK31 with Digipan

In reply to this post by zibs

> Just getting my new K3 working on PSK31 and noticed that it seems to be
> > important to limit the range of the transmit frequency...

I just swept my K3 in DATA A mode.using the LINE IN jack for sourcing
the Tx audio. It is flat from below 200 Hz to higher than 2800 Hz
using a 2.,8 kHz IF filter.

Be sure you don't have TxEQ set to restrict the transmit bandwidth.
TxEQ is active for *all* Tx audio paths in all modes. For DATA A or
DATA AFSK, it should be flat.

73,

Lyle KK7P

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zibs

Re: K3 PSK31 with Digipan

But in Data A mode, one can expand the receive width out to 4 kHz using the 2.7 kHz filter. If you attempt to transmit below 200 or above 2800 Hz, power output will drop to zero.

The user needs to be aware when clicking on the waterfall as one can receive signals on frequencies in which they cannot transmit.

Steve N9SZ

Lyle Johnson wrote

> Just getting my new K3 working on PSK31 and noticed that it seems to be
> > important to limit the range of the transmit frequency...

I just swept my K3 in DATA A mode.using the LINE IN jack for sourcing
the Tx audio. It is flat from below 200 Hz to higher than 2800 Hz
using a 2.,8 kHz IF filter.

Be sure you don't have TxEQ set to restrict the transmit bandwidth.
TxEQ is active for *all* Tx audio paths in all modes. For DATA A or
DATA AFSK, it should be flat.

73,

Lyle KK7P

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MontyS

Re: K3 PSK31 with Digipan

In reply to this post by zibs

I have not noticed this with my K3, using both a cheap SoundBlaster audio
card and an expensive E-MU card. My first suspicion would be something
impeding the audio getting to the transmitter - K3 equalization, sound card
equalization. Are you using the line in audio source? Check settings for
it. I can run PSK31 with only 2 audio cables between the sound card and
radio line in/line out.

Monty K2DLJ

KK7P

Re: K3 PSK31 with Digipan

In reply to this post by zibs

zibs wrote:
> But in Data A mode, one can expand the receive width out to 4 kHz using the
> 2.7 kHz filter. If you attempt to transmit below 200 or above 2800 Hz, power
> output will drop to zero.
>
> The user needs to be aware when clicking on the waterfall as one can receive
> signals on frequencies in which they cannot transmit.

At present there is no wideband Tx in DATA A. You can prevent the
problem by not enabling a wider filter in receive for Data modes.
Currently the filter configuration does not support separate filters for
DATA and SSB modes, so this would also inhibit ESSB operation.

We'll put it on the list.

Thanks!

73,
Lyle KK7P

>
> Steve N9SZ
>
>
>
> Lyle Johnson wrote:
>> > Just getting my new K3 working on PSK31 and noticed that it seems to be
>> > > important to limit the range of the transmit frequency...
>>
>> I just swept my K3 in DATA A mode.using the LINE IN jack for sourcing
>> the Tx audio. It is flat from below 200 Hz to higher than 2800 Hz
>> using a 2.,8 kHz IF filter.
>>
>> Be sure you don't have TxEQ set to restrict the transmit bandwidth.
>> TxEQ is active for *all* Tx audio paths in all modes. For DATA A or
>> DATA AFSK, it should be flat.
>>
>> 73,
>>
>> Lyle KK7P
>>
>>
>> _______________________________________________
>> 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-4

Re: K3 PSK31 with Digipan

In reply to this post by zibs

Steve,

I would think that most users are aware that they are transmitting
through the 2.7 kHz (or 2.8) filter - after all, they set it up that way
in the menu (and if they did not, they would get a TX FL error message).
So I should think that they would not expect to transmit an audio tone
outside the bounds of that filter.
If the user has configured a wider filter for receive than for transmit,
the "problem" you state should be fairly obvious.
The signal outside the 2.7 kHz bandpass will be significantly weaker
than if it were inside the passband. The soundcard may still be able to
decode it, but I see nothing that really needs any kind of alert in the
manual, it is simply a natural consequence of 'how things work'.

73,
Don W3FPR

zibs wrote:

> But in Data A mode, one can expand the receive width out to 4 kHz using the
> 2.7 kHz filter. If you attempt to transmit below 200 or above 2800 Hz, power
> output will drop to zero.
>
> The user needs to be aware when clicking on the waterfall as one can receive
> signals on frequencies in which they cannot transmit.
>
> Steve N9SZ
>
>
>
> Lyle Johnson wrote:
>
>> > Just getting my new K3 working on PSK31 and noticed that it seems to be
>> > > important to limit the range of the transmit frequency...
>>
>> I just swept my K3 in DATA A mode.using the LINE IN jack for sourcing
>> the Tx audio. It is flat from below 200 Hz to higher than 2800 Hz
>> using a 2.,8 kHz IF filter.
>>
>> Be sure you don't have TxEQ set to restrict the transmit bandwidth.
>> TxEQ is active for *all* Tx audio paths in all modes. For DATA A or
>> DATA AFSK, it should be flat.
>>
>

Joe Subich, W4TV-3

RE: K3 PSK31 with Digipan

In reply to this post by zibs

> But in Data A mode, one can expand the receive width out to
> 4 kHz using the 2.7 kHz filter. If you attempt to transmit
> below 200 or above 2800 Hz, power output will drop to zero.

Perhaps all of the data modes should be limited to 2.8 KHz
of DSP bandwidth (or even 2 KHz). That's more than enough
for any reasonable amateur data mode and will keep users from
shooting themselves in the foot.

> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of zibs
> Sent: Friday, September 19, 2008 10:28 AM
> To: [hidden email]
> Subject: Re: [Elecraft] K3 PSK31 with Digipan
>
>
>
> But in Data A mode, one can expand the receive width out to 4
> kHz using the 2.7 kHz filter. If you attempt to transmit
> below 200 or above 2800 Hz, power output will drop to zero.
>
> The user needs to be aware when clicking on the waterfall as
> one can receive signals on frequencies in which they cannot
> transmit.
>
> Steve N9SZ
>
>
>
> Lyle Johnson wrote:
> >
> > > Just getting my new K3 working on PSK31 and noticed that
> it seems
> > to be > > important to limit the range of the transmit frequency...
> >
> > I just swept my K3 in DATA A mode.using the LINE IN jack
> for sourcing
> > the Tx audio. It is flat from below 200 Hz to higher than 2800 Hz
> > using a 2.,8 kHz IF filter.
> >
> > Be sure you don't have TxEQ set to restrict the transmit bandwidth.
> > TxEQ is active for *all* Tx audio paths in all modes. For
> DATA A or
> > DATA AFSK, it should be flat.
> >
> > 73,
> >
> > Lyle KK7P
> >
> >
> > _______________________________________________
> > 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
> >
> >
>
> --
> View this message in context:
> http://n2.nabble.com/K3-PSK31-with-Digipan-tp1100818p1100983.html
> Sent from the Elecraft mailing list archive at Nabble.com.
>
> _______________________________________________
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Richard Ferch

Re: K3 PSK31 with Digipan

In reply to this post by zibs

Users of narrow-band digital modes such as PSK31 need to remember the
difference between transmit and receive in the way we perceive dynamic
range.

On transmit, a 10 dB difference is a factor of 10 in power. If your power
meter only goes up to 5W when you were expecting 50W, you will likely
perceive this as a serious issue. Even a 3 dB difference shows up as a
factor of 2 in transmitted power.

On receive, a difference of 10 dB is only a couple of S-units and well
within normal signal variability on HF. Looking at a normal waterfall, a 10
dB variation across the receive bandpass is barely noticeable as a slight
change in colour or intensity of the background noise.

Even within the transmit filter bandpass, relatively small variations in
response will be more easily detectable on TX than RX. K8ZOA's plot of the
2.7 kHz filter response shows a ripple of around 2 dB, which is probably
next to undetectable on RX, but is easily noticeable on TX as a change in
transmitted power.

With wide DSP bandwidth settings, the K3 can receive signals at frequencies
where the transmitted power level through the transmit filter would be very
low.

The simplest way to avoid this problem is not to use DSP width settings that
are wider than the transmit filter bandwidth. That way you won't receive
normal signals at frequencies where your transmitted power would be at QRPp
levels. You should also avoid using the shoulders of the filter response,
i.e. the last 200 Hz or so at either edge of the 2.7 kHz filter bandwidth.

Alternatively, you can use a wide DSP bandwidth for scanning the band, but
once you find a signal you want to work, move your dial so that the desired
signal falls within the optimum range.

Many PSK31 programs have an "align" or "optimize" macro capability, which
allows you to center a signal in the waterfall with a single mouse click. It
does so by retuning the radio so the chosen signal ends up on the designated
frequency (e.g. 1500 Hz). Unfortunately, AFAIK DigiPan does not have this
capability.

On a related point, in order to suppress audio harmonics I also like to try
to avoid transmitting digital modes on low audio frequencies. This is not a
significant problem on voice modes, but audio harmonics on PSK31 show up on
the air as spurious transmitted signals. Using a wide filter on transmit
could make it harder to avoid transmitting harmonics of your audio signal,
so personally I would not want to use wideband TX in DATA A.

73,
Rich VE3KI

Steve N9SZ wrote:
>
> But in Data A mode, one can expand the receive width out to 4 kHz using
the
> 2.7 kHz filter. If you attempt to transmit below 200 or above 2800 Hz,
power
> output will drop to zero.
>
> The user needs to be aware when clicking on the waterfall as one can
receive
> signals on frequencies in which they cannot transmit.
>
> Steve N9SZ
>
>
>
> Lyle Johnson wrote:
> >
> > > Just getting my new K3 working on PSK31 and noticed that it seems to
be

> > > important to limit the range of the transmit frequency...
> >
> > I just swept my K3 in DATA A mode.using the LINE IN jack for sourcing
> > the Tx audio. It is flat from below 200 Hz to higher than 2800 Hz
> > using a 2.,8 kHz IF filter.
> >
> > Be sure you don't have TxEQ set to restrict the transmit bandwidth.
> > TxEQ is active for *all* Tx audio paths in all modes. For DATA A or
> > DATA AFSK, it should be flat.
> >
> > 73,
> >
> > Lyle KK7P
> >
> >

Dave Quick - KØEKL

RE: K3 PSK31 with Digipan

In reply to this post by Joe Subich, W4TV-3

I'd like to be able to transmit in Data-A mode through my 6 Khz AM filter.
Being able to see ~6 Khz of spectrum in the waterfall window would be great.

-Dave Quick KØEKL

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Joe Subich, W4TV
Sent: Friday, September 19, 2008 11:55 AM
To: 'zibs'; [hidden email]
Subject: RE: [Elecraft] K3 PSK31 with Digipan

> But in Data A mode, one can expand the receive width out to
> 4 kHz using the 2.7 kHz filter. If you attempt to transmit below 200
> or above 2800 Hz, power output will drop to zero.

Perhaps all of the data modes should be limited to 2.8 KHz of DSP bandwidth
(or even 2 KHz). That's more than enough for any reasonable amateur data
mode and will keep users from shooting themselves in the foot.

> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of zibs
> Sent: Friday, September 19, 2008 10:28 AM
> To: [hidden email]
> Subject: Re: [Elecraft] K3 PSK31 with Digipan
>
>
>
> But in Data A mode, one can expand the receive width out to 4 kHz
> using the 2.7 kHz filter. If you attempt to transmit below 200 or
> above 2800 Hz, power output will drop to zero.
>
> The user needs to be aware when clicking on the waterfall as one can
> receive signals on frequencies in which they cannot transmit.
>
> Steve N9SZ
>
>
>
> Lyle Johnson wrote:
> >
> > > Just getting my new K3 working on PSK31 and noticed that
> it seems
> > to be > > important to limit the range of the transmit frequency...
> >
> > I just swept my K3 in DATA A mode.using the LINE IN jack
> for sourcing
> > the Tx audio. It is flat from below 200 Hz to higher than 2800 Hz
> > using a 2.,8 kHz IF filter.
> >
> > Be sure you don't have TxEQ set to restrict the transmit bandwidth.
> > TxEQ is active for *all* Tx audio paths in all modes. For
> DATA A or
> > DATA AFSK, it should be flat.
> >
> > 73,
> >
> > Lyle KK7P
> >
> >
> > _______________________________________________
> > 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
> >
> >
>
> --
> View this message in context:
> http://n2.nabble.com/K3-PSK31-with-Digipan-tp1100818p1100983.html
> Sent from the Elecraft mailing list archive at Nabble.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

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Don Wilhelm-4

Re: K3 PSK31 with Digipan

Dave,

OTOH, best results with AFSK is to use a narrow receive filter. It
keeps strong undesired signals out of the passband.
Strong undesired signals in the passband cause a reduction of receiver
gain because the AGC reacts to them.
Sure, the computer can handle and display them, but if the receiver gain
is reduced because of a strong signal that just came on, your chances of
maintaining solid print is reduced.

Do as you choose, but I prefer to tune my data mode signals just like
any other - with the VFO knob, and use a narrow filter to get rid of the
'other trash' on the band.

73,
Don W3FPR

Dave Quick - KØEKL wrote:

> I'd like to be able to transmit in Data-A mode through my 6 Khz AM filter.
> Being able to see ~6 Khz of spectrum in the waterfall window would be great.
>
> -Dave Quick KØEKL
>
>
>
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Joe Subich, W4TV
> Sent: Friday, September 19, 2008 11:55 AM
> To: 'zibs'; [hidden email]
> Subject: RE: [Elecraft] K3 PSK31 with Digipan
>
>
>
>> But in Data A mode, one can expand the receive width out to
>> 4 kHz using the 2.7 kHz filter. If you attempt to transmit below 200
>> or above 2800 Hz, power output will drop to zero.
>>
>
> Perhaps all of the data modes should be limited to 2.8 KHz of DSP bandwidth
> (or even 2 KHz). That's more than enough for any reasonable amateur data
> mode and will keep users from shooting themselves in the foot.
>
>
>
>
>

Bob Cunnings NW8L

Re: K3 PSK31 with Digipan

Yes, many of us know all this, but it's still nice, under benign
conditions, to operate using a wider waterfall for both transmit and
receive. I often operated PSK on my Orion using the 6kHz filter, it's
fun to see pretty much all the PSK activity on the band at once -
context, right? When I've opened up the BW like this I always disable
AGC anyway. When the going gets tough, I narrow the BW.

Since I paid for the 6kHz filter, I'd like to use it on DATA A if I
choose, since there is no technical limitation in the K3 preventing it
AFAIK.

Bob NW8L

On Fri, Sep 19, 2008 at 1:35 PM, Don Wilhelm <[hidden email]> wrote:

> Dave,
>
> OTOH, best results with AFSK is to use a narrow receive filter. It keeps
> strong undesired signals out of the passband.
> Strong undesired signals in the passband cause a reduction of receiver gain
> because the AGC reacts to them.
> Sure, the computer can handle and display them, but if the receiver gain is
> reduced because of a strong signal that just came on, your chances of
> maintaining solid print is reduced.
>
> Do as you choose, but I prefer to tune my data mode signals just like any
> other - with the VFO knob, and use a narrow filter to get rid of the 'other
> trash' on the band.
>
> 73,
> Don W3FPR
>
>
> Dave Quick - KØEKL wrote:
>>
>> I'd like to be able to transmit in Data-A mode through my 6 Khz AM filter.
>> Being able to see ~6 Khz of spectrum in the waterfall window would be
>> great.
>>
>> -Dave Quick KØEKL
>>
>>
>>
>>
>> -----Original Message-----
>> From: [hidden email]
>> [mailto:[hidden email]] On Behalf Of Joe Subich, W4TV
>> Sent: Friday, September 19, 2008 11:55 AM
>> To: 'zibs'; [hidden email]
>> Subject: RE: [Elecraft] K3 PSK31 with Digipan
>>
>>
>>
>>>
>>> But in Data A mode, one can expand the receive width out to
>>> 4 kHz using the 2.7 kHz filter. If you attempt to transmit below 200 or
>>> above 2800 Hz, power output will drop to zero.
>>>
>>
>> Perhaps all of the data modes should be limited to 2.8 KHz of DSP
>> bandwidth
>> (or even 2 KHz). That's more than enough for any reasonable amateur data
>> mode and will keep users from shooting themselves in the foot.
>>
>>
>>
>
> _______________________________________________
> 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-4

Re: K3 PSK31 with Digipan

Bob,

Receive should work, but transmit will not - I believe it is restricted
in the firmware.

73,
Don W3FPR

Bob Cunnings wrote:

> Yes, many of us know all this, but it's still nice, under benign
> conditions, to operate using a wider waterfall for both transmit and
> receive. I often operated PSK on my Orion using the 6kHz filter, it's
> fun to see pretty much all the PSK activity on the band at once -
> context, right? When I've opened up the BW like this I always disable
> AGC anyway. When the going gets tough, I narrow the BW.
>
> Since I paid for the 6kHz filter, I'd like to use it on DATA A if I
> choose, since there is no technical limitation in the K3 preventing it
> AFAIK.
>
> Bob NW8L
>
> On Fri, Sep 19, 2008 at 1:35 PM, Don Wilhelm <[hidden email]> wrote:
>
>> Dave,
>>
>> OTOH, best results with AFSK is to use a narrow receive filter. It keeps
>> strong undesired signals out of the passband.
>> Strong undesired signals in the passband cause a reduction of receiver gain
>> because the AGC reacts to them.
>> Sure, the computer can handle and display them, but if the receiver gain is
>> reduced because of a strong signal that just came on, your chances of
>> maintaining solid print is reduced.
>>
>> Do as you choose, but I prefer to tune my data mode signals just like any
>> other - with the VFO knob, and use a narrow filter to get rid of the 'other
>> trash' on the band.
>>
>> 73,
>> Don W3FPR
>>
>>
>> Dave Quick - KØEKL wrote:
>>
>>> I'd like to be able to transmit in Data-A mode through my 6 Khz AM filter.
>>> Being able to see ~6 Khz of spectrum in the waterfall window would be
>>> great.
>>>
>

Bob Cunnings NW8L

Re: K3 PSK31 with Digipan

Yes transmit is restricted - to the 2.7 (or 2.8) kHz filter. Hence the
request to allow transmit using the 6 KHz filter, at least to same
extent as receive (up to 4KHz currently).

Bob NW8L

On Fri, Sep 19, 2008 at 3:22 PM, Don Wilhelm <[hidden email]> wrote:

> Bob,
>
> Receive should work, but transmit will not - I believe it is restricted in
> the firmware.
>
> 73,
> Don W3FPR
>
> Bob Cunnings wrote:
>>
>> Yes, many of us know all this, but it's still nice, under benign
>> conditions, to operate using a wider waterfall for both transmit and
>> receive. I often operated PSK on my Orion using the 6kHz filter, it's
>> fun to see pretty much all the PSK activity on the band at once -
>> context, right? When I've opened up the BW like this I always disable
>> AGC anyway. When the going gets tough, I narrow the BW.
>>
>> Since I paid for the 6kHz filter, I'd like to use it on DATA A if I
>> choose, since there is no technical limitation in the K3 preventing it
>> AFAIK.
>>
>> Bob NW8L
>>
>> On Fri, Sep 19, 2008 at 1:35 PM, Don Wilhelm <[hidden email]> wrote:
>>
>>>
>>> Dave,
>>>
>>> OTOH, best results with AFSK is to use a narrow receive filter. It keeps
>>> strong undesired signals out of the passband.
>>> Strong undesired signals in the passband cause a reduction of receiver
>>> gain
>>> because the AGC reacts to them.
>>> Sure, the computer can handle and display them, but if the receiver gain
>>> is
>>> reduced because of a strong signal that just came on, your chances of
>>> maintaining solid print is reduced.
>>>
>>> Do as you choose, but I prefer to tune my data mode signals just like any
>>> other - with the VFO knob, and use a narrow filter to get rid of the
>>> 'other
>>> trash' on the band.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>>
>>> Dave Quick - KØEKL wrote:
>>>
>>>>
>>>> I'd like to be able to transmit in Data-A mode through my 6 Khz AM
>>>> filter.
>>>> Being able to see ~6 Khz of spectrum in the waterfall window would be
>>>> great.
>>>>
>>
>

Kok Chen

Re: K3 PSK31 with Digipan

On Sep 19, 2008, at 2:32 PM, Bob Cunnings wrote:
> Yes transmit is restricted - to the 2.7 (or 2.8) kHz filter. Hence the
> request to allow transmit using the 6 KHz filter, at least to same
> extent as receive (up to 4KHz currently).

We all agree that you can receive in a wide passband (even as wide as
the 192 kHz that an LP-PAN provides).

For transmit, as long as the emission passband is not too wide to fit
the rig's transmit passband, modify the software to note the receive
offset that you have clicked in the waterfall and use CAT to apply the
offset as XIT (or switch between A/B VFO) when transmitting.

I.e., you can send an absolutely fixed AFSK tone (tones, in the case
of <m>FSK) from software and move the transmitted signal around in the
RF spectrum by using XIT (or A/B VFO). It should be a very simple
change to whatever software that you are using (if you have the
sources to the program, that is), as long as the program has access to
the rig's CAT.

The advantage of doing it this way is that it has no dependency at all
on how flat the rig's transmit audio passband is, since you are
transmitting with the same fixed tone no matter where in the waterfall
you have clicked.

You can also use the built in FSK/PSK generators in modern rigs to
modulate your rig. As long as you know what the tone/tone-pair it
uses is, you can apply XIT to move it to where the received signal is
in the waterfall.

73
Chen, W7AY

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Dave Quick - KØEKL

RE: K3 PSK31 with Digipan

In reply to this post by Don Wilhelm-4

Quite true and when in qso I do try to center the desired signal in the
passband and when the qrm is bad the K3 absolutely shines! It's so much fun
to turn that knob, narrow the passband to a sliver of spectrum and see and
hear every other signal disappear.

Still, it would be nice to be able to at least see the full 6 KHz. Sort of
like a mini-panadaptor. Perhaps it's time to order and LP-Pan!

-----Original Message-----
From: Don Wilhelm [mailto:[hidden email]]
Sent: Friday, September 19, 2008 2:36 PM
To: Dave Quick - KØEKL
Cc: [hidden email]
Subject: Re: [Elecraft] K3 PSK31 with Digipan

Dave,

OTOH, best results with AFSK is to use a narrow receive filter. It keeps
strong undesired signals out of the passband.
Strong undesired signals in the passband cause a reduction of receiver gain
because the AGC reacts to them.
Sure, the computer can handle and display them, but if the receiver gain is
reduced because of a strong signal that just came on, your chances of
maintaining solid print is reduced.

Do as you choose, but I prefer to tune my data mode signals just like any
other - with the VFO knob, and use a narrow filter to get rid of the 'other
trash' on the band.

73,
Don W3FPR

Dave Quick - KØEKL wrote:
> I'd like to be able to transmit in Data-A mode through my 6 Khz AM filter.
> Being able to see ~6 Khz of spectrum in the waterfall window would be
great.

>
> -Dave Quick KØEKL
>
>
>
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Joe Subich,
> W4TV
> Sent: Friday, September 19, 2008 11:55 AM
> To: 'zibs'; [hidden email]
> Subject: RE: [Elecraft] K3 PSK31 with Digipan
>
>
>
>> But in Data A mode, one can expand the receive width out to
>> 4 kHz using the 2.7 kHz filter. If you attempt to transmit below 200
>> or above 2800 Hz, power output will drop to zero.
>>
>
> Perhaps all of the data modes should be limited to 2.8 KHz of DSP
> bandwidth (or even 2 KHz). That's more than enough for any reasonable
> amateur data mode and will keep users from shooting themselves in the

foot.
>
>
>
>
>

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Bob Cunnings NW8L

Re: K3 PSK31 with Digipan

It finally dawned on me that the 6kHz filter could be put to work for
soundcard modes in both transmit and receive by enabling ESSB and
using USB or LSB instead of DATA A. Indeed, it works just fine with BW
set to 4kHz and shift adjusted to put center at 1800 or so. With DM
780 set to max width (3.9 kHz) the waterfall just about fills the
screen and there's almost 3.5 kHz bandwidth for transmit and receive.
This gives a wider field for casual point and click PSK31 operation -
nice for a simple setup like mine where there is no computer control
of the radio, and I want to keep the knob twirling on the rig to a
minimum (the interface consists only of 2 audio cables between laptop
and rig with VOX keying. TX EQ flat, AGC and compressor disabled of
course).

Bob NW8L

On Fri, Sep 19, 2008 at 5:43 PM, Dave Quick - KØEKL <[hidden email]> wrote:

> Still, it would be nice to be able to at least see the full 6 KHz. Sort of
> like a mini-panadaptor. Perhaps it's time to order and LP-Pan!
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