[Elecraft] P3: Span control logic

Sun Aug 7 21:34:42 EDT 2011

Sorry, Lu ...

> I am quite familiar with spectrum analysers. And I can understand
> the issue you raise, because in spectrum analysers, yes, SPAN
> functionality as its illustrated on the P3 makes sense... within the
> context of a spectrum analyser!

The P3 - or any panadapter - is precisely a spectrum analyzer.  The
span control has no relationship to the K3's "width" control (but
I would have preferred the K3 "Width" control to have been labeled
"selectivity" and worked backward <G>).

> So, taking into account the K3 width control's logic, what's wrong
> with the option to make it either way, via a menu setting, other than
> time and resources?

Only if you're going to provide an option to reverse the sense of the
"Width" control as well <G>.

73,

    ... Joe, W4TV

On 8/7/2011 9:02 PM, Luis V. Romero wrote:
> Don:
>
> Do you understand TV waveform monitors?  When you look at a NTSC transmitter
> output waveform, the white level is on top and the sync tip is at the
> bottom.  This is upside down, as the sync tip is peak transmitter modulation
> and white is low modulation.  But the graphical representation was designed
> for a USER, who is tasked with adjusting levels on a camera, and not a
> transmitter, and it is easier, logically, to deal with the adjustments when
> white is at the TOP of the graphical representation instead of the bottom.
>
> I am quite familiar with spectrum analysers.  And I can understand the issue
> you raise, because in spectrum analysers, yes, SPAN functionality as its
> illustrated on the P3 makes sense... within the context of a spectrum
> analyser! Yes, I understand what SPAN is; and if the unit was a actual stand
> alone "spectrum analyser" lab instrument, you would be completely accurate
> logically, because it wouldnt have the width control on the K3 to clash
> with.  But its not a spectrum analyser lab instrument, it is a "receiver
> accesory" with a "graphical display" of the K3 signal reception conditions.
>
> We are showing the WIDTH of the filter in the picture representation of the
> K3 filter WIDTH.  And it makes sense in the graphical representation of the
> action because as you turn the knob to widen the bandwdth, the picture
> "icon" widens.
>
> This behavior then clashes with the SPAN control, which shows a graphical
> representation of the WIDTH of the scan.  Using the original logic as
> defined in the K3 WIDTH control, it is backwards from the established
> control logic of the K3 width control.
>
> It wont make me lose sleep, and I may ultimately adjust, but I am simply
> stating the clash of the control's behavior as applied to the usage of the
> instrument for its intended purpose.  Since the logic of what we are doing
> here is to show the WIDTH of the spectrum we are displaying, the logic fails
> because when we turn to the left, it gets bigger and when we turn to the
> right it gets smaller, and, the following is important, it does this against
> the convention set by the K3 width control.
>
> However, if the width control worked like it works on Yaesu equipment, there
> would be no clash.  I remember a similar discussion about the K3 Width
> control on the reflector a few years back and all the angst because it
> worked "backwards". Simply stated; Product Management needs to choose a
> standard and stick with it across the product for the sake of the user!
>
> So, taking into account the K3 width control's logic, what's wrong with the
> option to make it either way, via a menu setting, other than time and
> resources?
>
> Do other minds think like mine?
>
> -lu-w4lt-
>
>> -----Original Message-----
>> From: Don Wilhelm [mailto:w3fpr at embarqmail.com]
>> Sent: Sunday, August 07, 2011 7:17 PM
>> To: lromero at ij.net
>> Cc: elecraft at mailman.qth.net
>> Subject: Re: [Elecraft] P3: Span control logic
>>
>> Lu,
>>
>> I am sorry, but you will have to divorce your concept of
>> width with the SPAN of the P3.  Instead of looking at the
>> width of the signal, look at the range of the display - that
>> is what SPAN has meant for many years to those familiar with
>> spectrum analyzers - it is the difference between the
>> frequency on the left of the screen and that on the right of
>> the screen.
>>
>> Yes, the width of the signal being observed will shrink as
>> the span is increased.  The SPAN term has no relationship to
>> the width of any particular signal, it is only the extent of
>> the display frequencies on the screen.
>>
>> Alan, please do not change it - it makes sense to many
>> (hopefully most) of us.
>>
>> Lu, you may want to think of SPAN as the opposite of WIDTH.
>> I hope that helps..
>>
>> 73,
>> Don W3FPR
>>
>> On 8/7/2011 6:34 PM, Luis V. Romero wrote:
>>> Hi all, especially the K3 Product Management folks:
>>>
>>> I now have some time behind the combination K3-P3, It is a
>> wonderful
>>> combination.  Like fishing with a fishfinder! Now my neighbor has
>>> definitive proof in writing (a screen snapshot) that he is indeed
>>> 6.5kHz wide when he cranks up that Macho Bass to impress
>> his buddies
>>> on 14.250 :)
>>>
>>> The P3 is a wonderful addition to my station's capability, however,
>>> there is one ergonomic detail that drives me absolutely bonkers!  I
>>> wonder if something can be done about it, as I may not be
>> the only one
>>> with this issue.
>>>
>>> SPAN is equivalent to WIDTH to me.  On K3, turning the
>> WIDTH knob to
>>> the left (counter colockwise) makes the width of the
>> bandpass NARROWER
>>> (smaller).  Turning the knob to the right (clockwise) makes the
>>> bandpass WIDER.  I have always loved how this works in this
>> radio, it
>>> is logical and intuitive to me, from my background in
>> video... Video
>>> Production Switchers (Vision Mixers for the Brits among us)
>> Key Clip
>>> controls work this way, and my feeble mind is used to this
>> convention
>>> after many years of mental conditioning.  Equipment with similar
>>> controls (namely Yaesu rigs) are backwards to me.
>>>
>>> Having said that, on the P3, selecting SPAN and turning the knob to
>>> the left (counter clockwise) makes the span NARROWER, and
>> turning it
>>> to the right
>>> (Clockwise) makes the span WIDER!
>>>
>>> Yes, I know... The VISUAL FEEDBACK from the K3 control matches the
>>> screen of the P3, which is good, but the INTENT of the
>> action on the
>>> P3 SPAN control does not!  The WIDTH of the marker WIDENS when you
>>> turn the knob counterclockwise, but the actual EFFECT of the action
>>> you are performing is BACKWARDS from the visual feedback, and also
>>> backwards from the K3 control that does the same thing!
>>>
>>> Its like on a sailboat... Deflecting the rudder tiller AWAY
>> from you
>>> turns the nose of the boat in the OPPOSITE direction from
>> the tiller deflection.
>>>
>>> The chosen behavior of these controls and how they interact
>> with the
>>> action and visual feedback is just absolutely counter intuitive to
>>> me... Any hope that this can be made a user selectable
>> behavior so we
>>> can all have our cake and eat it too?
>>>
>>> Thanks for considering this request.
>>>
>>> -lu-w4lt-
>>> K3# 3192/P3 # 1301
>>>
>>>
>>>
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