[Elecraft] P3 Unexpected Control Operation ...

[Vic Rosenthal]

I've had my P3 for some weeks (I admit to being an ft so please don't everybody jump on 
me) and I agree with Joe. I STILL always turn the knob the wrong way when I go to adjust 
the ref level.

On 8/9/2010 7:57 AM, Joe Subich, W4TV wrote:
>
> Bill,
>
>   >  Alan N1AL may want to respond but I don't believe either is a bug.
>   >  Both are consistent with more sensitivity in the clockwise direction,
>   >  which is consistent in my opinion.
>
> While both controls, in fact, increase a behavioral parameter with
> clockwise rotation, the behavior is still inconsistent with other
> controls on both the K3 and P3.  If the controls were arranged to
> adjust an underlying behavioral parameter instead of an absolute
> value, the WIDTH control on the K3 should be reversed so that it
> increases SELECTIVITY (less width) with increasing clockwise
> rotation.
>
>   >  We need to remember the P3 is not a spectrum analyzer (mainly used
>   >  for measuring spurious signals down from a reference carrier but a
>   >  panadapter (mainly used for identifying weak signals above a noise
>   >  floor).
>
> I don't see how this makes any difference.  The P3 controls are labeled
> REF LVL and SCALE and not "MIN/MAX SENSITIVITY" and the values they
> control have specific numeric values.  Their behavior is backward based
> on both the numeric values and the behavior of other controls in the
> K3/P3 system.
>
> Although one could conceivably argue that REF LVL is ergonomically
> correct in that counterclockwise rotation moves the reference level
> (baseline) DOWN on screen, I find SCALE to be very confusing since
> increasing rotation results in less visible range and a smaller (min
> to max) size scale.  After all the control is SCALE not amplitude
> or trace size.
>
> 73,
>
>      ... Joe, W4TV
>
> On 8/9/2010 10:01 AM, Bill W4ZV wrote:
>>
>>
>> Joe Subich, W4TV-4 wrote:
>>>
>>>
>>> Rotary controls in the K3 and P3 increase their parameter as the
>>> encoder is turned clockwise except in two cases.
>>>
>>> 1) The P3 "REF LVL" is decreased with clockwise rotation.  Maximum
>>>       reference level is -10 dBm with the encoder fully counterclockwise
>>>       while it is minimum -160 dBm with the encoder fully clockwise.
>>>
>>> 2) The P3 "SCALE" (range) is decreased with clockwise rotation.
>>>       Scale is minimum (10 dB) when the encoder is fully clockwise
>>>       and maximum (80 dB) when the encoder is fully counterclockwise.
>>>
>>> Both of these controls violate the principle of "expected" behavior
>>> and consistent operation.
>>>
>>
>> Alan N1AL may want to respond but I don't believe either is a bug.  Both are
>> consistent with more sensitivity in the clockwise direction, which is
>> consistent in my opinion.  In the case of REF LVL, turning clockwise until
>> the noise floor becomes visible seems correct (i.e. like turning RF GAIN
>> clockwise in a traditional radio).  In the case of SCALE, it means less
>> visible range above the noise floor which means more resolution of weak
>> signals.
>>
>> After using the P3 I find the current conventions intuitive.  While they
>> might not be technically consistent (in terms of the values being set) I
>> believe both are consistent and intuitive in terms of practical use.  We
>> need to remember the P3 is not a spectrum analyzer (mainly used for
>> measuring spurious signals down from a reference carrier but a panadapter
>> (mainly used for identifying weak signals above a noise floor).  Either
>> *can* be used the other way around, but I believe the controls of both are
>> set up differently for good reasons.
>>
>> 73,  Bill
>>

-- 
Vic