Posted by
Lu Romero - W4LT on
Aug 08, 2011; 1:02am
URL: http://elecraft.85.s1.nabble.com/P3-Span-control-logic-tp6662585p6662784.html
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:
[hidden email]]
> Sent: Sunday, August 07, 2011 7:17 PM
> To:
[hidden email]
> Cc:
[hidden email]
> 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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