[Elecraft] P3 Phase noise/HighSignal Response?

[K5MWR]

Jim

Really appreciate this information and going over it now to make sure I 
understand the limits.  The presentation is well done.

How did you capture the SVGA images?

Dave K5MWR



On 3/13/2017 10:53 PM, Jim Brown wrote:
> Hi Dave,
>
> The P3 is quite good for measurements, and the SVGA card is even 
> better.  Here's a collection of work I've done with whatever rigs and 
> amps I could get my hands on to measure.
>
> http://k9yc.com/P3_Spectrum_Measurements.pdf
>
> In my experience, if you keep the K3 within its linear region, you'll 
> get good data from the P3 if you understand the measurements you're 
> making.  Limitations -- the dynamic range is 100 dB, but you can only 
> display 80 dB on screen. For all of the operation I do, I use the P3 
> with a lot of averaging and a slow waterfall, fairly large waterfall.  
> For measurements, I use the P3 in Peak reading mode and let it 
> accumulate peaks for a while. I make the amplitude display pretty 
> large, set it for 80 dB, and adjust levels to fill the amplitude screen.
>
> When I'm checking CW bandwidth, I send a series of dits in the range 
> of 35 WPM for at least 20 seconds I reset the peak a second or so 
> after I've started sending dits so I don't see any initial transient 
> that might be present. Notice that I set the span for a fairly narrow 
> bandwidth.
>
> The annotations you see for bandwidth are obtained by moving the 
> cursor to each data point and writing down the readings, and they are 
> the DIFFERENCE between the high and low points.
>
> If you want to show data more than 80 dB below the peak of the signal, 
> you can repeat the measurement with the reference level reduced by 20 
> dB.  More than that and the P3 will overload.
>
> 73, Jim K9YC
>
> On Mon,3/13/2017 6:03 PM, K5MWR via Elecraft wrote:
>> I am trying to use my P3 to evaluate signals from other hams here in 
>> my community.  While I know the K3s is excellent, I am not sure what 
>> to expect out of the P3 in terms of phase noise or response under 
>> high signal conditions. I can always pad to lower the signal but that 
>> will not help with any P3 internal phase.
>
>
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