K3 - DSP IF Width Increment

[Doug Joyce]

To the Group:

Having ordered a K3 at Dayton, I've been following the recent discussion on
DSP vs. Roofing Filter for bandpass width determination with great interest.
In that regard, I have a quick question  - what is the width increment
available by adjusting the DSP.  Based on some of the recent postings it
seems like it might be 50 Hz but would someone please confirm.

Thanks & 73

Doug Joyce,  VE3MV


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[Brett Howard]

Yes its 50Hz.

On Tue, 2008-07-08 at 20:55 -0400, Doug Joyce wrote:

> To the Group:
>
> Having ordered a K3 at Dayton, I've been following the recent discussion on
> DSP vs. Roofing Filter for bandpass width determination with great interest.
> In that regard, I have a quick question  - what is the width increment
> available by adjusting the DSP.  Based on some of the recent postings it
> seems like it might be 50 Hz but would someone please confirm.
>
> Thanks & 73
>
> Doug Joyce,  VE3MV
>
>

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[gm3sek]

Doug Joyce wrote:
>
>Having ordered a K3 at Dayton, I've been following the recent
>discussion on DSP vs. Roofing Filter for bandpass width determination
>with great interest. In that regard, I have a quick question  - what is
>the width increment available by adjusting the DSP.  Based on some of
>the recent postings it seems like it might be 50 Hz but would someone
>please confirm.
>

This may be a good moment to repeat the request for width/shift/hi/lo
increments to scale down automatically with the bandwidth. At SSB
bandwidths, 50Hz increments feel smooth and continuous, which is exactly
how they should feel; but at narrow bandwidths a 50Hz change is a big
jump, and much more tricky to select.

Obviously  this isn't a trivial piece of coding, but it would be good to
know that "IOTL".


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73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek
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[Brett Howard]

I agree that the 50Hz jumps do feel like much bigger schwacks in the
lower bandwidths but I don't feel them un-reasonably so...  How narrow
do you wish things to get?  25Hz?  10Hz? 1Hz?  Personally I don't know
what the right value is but I do think that 1Hz increments would be too
"smooth".  To the point of SLOW.

On Wed, 2008-07-09 at 07:09 +0100, Ian White GM3SEK wrote:

> Doug Joyce wrote:
> >
> >Having ordered a K3 at Dayton, I've been following the recent
> >discussion on DSP vs. Roofing Filter for bandpass width determination
> >with great interest. In that regard, I have a quick question  - what is
> >the width increment available by adjusting the DSP.  Based on some of
> >the recent postings it seems like it might be 50 Hz but would someone
> >please confirm.
> >
>
> This may be a good moment to repeat the request for width/shift/hi/lo
> increments to scale down automatically with the bandwidth. At SSB
> bandwidths, 50Hz increments feel smooth and continuous, which is exactly
> how they should feel; but at narrow bandwidths a 50Hz change is a big
> jump, and much more tricky to select.
>
> Obviously  this isn't a trivial piece of coding, but it would be good to
> know that "IOTL".
>
>

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[Gary, W7TEA]

On CW, I find the 50hz increments to work well for varying the bandwidth
but prefer a smaller (I am used to 10hz) increment for Shift.  Tweaking the
shift or PBT function often enhances readability for me, even with the
narrow filters the K3 provides.  

73, Gary W7TEA


<quote author="Brett Howard">
I agree that the 50Hz jumps do feel like much bigger schwacks in the
lower bandwidths but I don't feel them un-reasonably so...  How narrow
do you wish things to get?  25Hz?  10Hz? 1Hz?  Personally I don't know
what the right value is but I do think that 1Hz increments would be too
"smooth".  To the point of SLOW.

[N5GE]

On Wed, 9 Jul 2008 07:09:49 +0100, Ian White GM3SEK <[hidden email]>
wrote:

>Doug Joyce wrote:
>>
>>Having ordered a K3 at Dayton, I've been following the recent
>>discussion on DSP vs. Roofing Filter for bandpass width determination
>>with great interest. In that regard, I have a quick question  - what is
>>the width increment available by adjusting the DSP.  Based on some of
>>the recent postings it seems like it might be 50 Hz but would someone
>>please confirm.
>>
>
>This may be a good moment to repeat the request for width/shift/hi/lo
>increments to scale down automatically with the bandwidth. At SSB
>bandwidths, 50Hz increments feel smooth and continuous, which is exactly
>how they should feel; but at narrow bandwidths a 50Hz change is a big
>jump, and much more tricky to select.
>
>Obviously  this isn't a trivial piece of coding, but it would be good to
>know that "IOTL".

I don't know how much trouble it would be to program, but wouldn't it be nice if
it was selectable?  Then I could have what I like (10hz like the Orion II) and
you could have what you like.  That would also cover being able to choose large
steps when you're in a hurry and small when your being particular.

 
Tom, N5GE - SWOT 3537 - Grid EM12jq

"Those who would give up
Essential Liberty to
purchase a little Temporary
Safety deserve neither
Liberty nor Safety"

An excerpt from a letter
written in 1755 from the
Assembly to the Governor
of Pennsylvania.

Support the entire Constitution, not
just the parts you like.

http://www.n5ge.com
http://www.eQSL.cc/Member.cfm?N5GE

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[Alexandr Kobranov]

I am afraid that any changes of any steps of anything (from 50Hz to 25
or 10Hz) have to do something with changes of DSP granularity to 10Hz
declared by Wayne as part of some leter f/w updates.

So we have to keep all ideas for that time after this change....

73!
Lexa, OK1DST
K3/10 #727

Tom Childers, N5GE napsal(a):

> On Wed, 9 Jul 2008 07:09:49 +0100, Ian White GM3SEK <[hidden email]>
> wrote:
>
>> Doug Joyce wrote:
>>> Having ordered a K3 at Dayton, I've been following the recent
>>> discussion on DSP vs. Roofing Filter for bandpass width determination
>>> with great interest. In that regard, I have a quick question  - what is
>>> the width increment available by adjusting the DSP.  Based on some of
>>> the recent postings it seems like it might be 50 Hz but would someone
>>> please confirm.
>>>
>> This may be a good moment to repeat the request for width/shift/hi/lo
>> increments to scale down automatically with the bandwidth. At SSB
>> bandwidths, 50Hz increments feel smooth and continuous, which is exactly
>> how they should feel; but at narrow bandwidths a 50Hz change is a big
>> jump, and much more tricky to select.
>>
>> Obviously  this isn't a trivial piece of coding, but it would be good to
>> know that "IOTL".
>
> I don't know how much trouble it would be to program, but wouldn't it be nice if
> it was selectable?  Then I could have what I like (10hz like the Orion II) and
> you could have what you like.  That would also cover being able to choose large
> steps when you're in a hurry and small when your being particular.
>
>  
> Tom, N5GE - SWOT 3537 - Grid EM12jq
>
> "Those who would give up
> Essential Liberty to
> purchase a little Temporary
> Safety deserve neither
> Liberty nor Safety"
>
> An excerpt from a letter
> written in 1755 from the
> Assembly to the Governor
> of Pennsylvania.
>
> Support the entire Constitution, not
> just the parts you like.
>
> http://www.n5ge.com
> http://www.eQSL.cc/Member.cfm?N5GE
>
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[gm3sek]

Brett wrote:
>>
>>I agree that the 50Hz jumps do feel like much bigger schwacks in the
>>lower bandwidths but I don't feel them un-reasonably so...  How narrow
>>do you wish things to get?  25Hz?  10Hz? 1Hz?  Personally I don't know
>>what the right value is but I do think that 1Hz increments would be too
>>"smooth".  To the point of SLOW.

Since 1Hz increments were your own idea, you just answered yourself -
and of course you're absolutely right  :-)

The problem is that the SHIFT/LO and WIDTH/HI encoders are 36 steps
(40?) with a soft detent that gives very little tactile feedback. With
50Hz shift increments and a 100Hz bandwidth, SHIFT covers the whole
bandwidth in two small steps of the control. With a 50Hz bandwidth, one
step takes you clear outside of the passband, so the SHIFT shift
function doesn't work at all.


Gary wrote:
>On CW, I find the 50hz increments to work well for varying the bandwidth
>but prefer a smaller (I am used to 10hz) increment for Shift.  Tweaking the
>shift or PBT function often enhances readability for me, even with the
>narrow filters the K3 provides.
>
>73, Gary W7TEA

On reflection, I'd agree with Gary that  50Hz increments in width are
OK, and the main improvement is needed in the shift.  10Hz increments
are the smallest that can be displayed, and would certainly be a big
improvement at very narrow bandwidths.

However, at wider bandwidths a 10Hz shift increment would take too many
turns of the control to cover the range. As a very simple compromise,
10Hz might be switched in automatically for bandwidths of 500Hz and
below.

Alternatively, this scheme would  give smoother transitions:

10Hz increments (the smallest displayable) for all bandwidths <250Hz

20Hz increments (the next available step) for 250-1000Hz

Keep 50Hz increments for bandwidths >1000Hz.




--

73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek
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[AD6XY]

I agree the main issue is the shift. If you are looking in 50Hz you can not use shift, but you can use the CW offset. Musicians might recoil in horror at a 25Hz error in their sidetone, but it is a reasonable fix for the moment.