P3 Amplitude vs. K3S S-Meter

[David Ahrendts]

Noticeable difference between the K3S S-Meter level and the displayed S-level on the P3. An S-9 signal on the K3S is seen as much less, maybe an S-3 on the P3. So its not REF LVL, not SPAN. What?

David A., KC0XT, LA



David Ahrendts   [hidden email]  




______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

[Alan Bloom]

On SSB, the K3 S-meter measures the level of everything within the 2.7
kHz bandwidth.  But on the P3, each display point only shows the power
within a small fraction of 2.7 kHz.

For a continuous CW signal, the K3 and the P3 should match.  But for a
signal that is spread out in frequency the K3 reads higher.

See the discussion in the P3 Owner's manual in the section "How to Set
Up and Interpret the P3 Display", the paragraph that begins, "You would
expect the S meter on the K3 and the signal on the P3 display to
indicate the same level..."

Alan N1AL


On 10/19/2015 06:38 PM, David Ahrendts wrote:

> Noticeable difference between the K3S S-Meter level and the displayed
> S-level on the P3. An S-9 signal on the K3S is seen as much less,
> maybe an S-3 on the P3. So its not REF LVL, not SPAN. What?
>
> David A., KC0XT, LA
>
>
>
> David Ahrendts   [hidden email]
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list Home:
> http://mailman.qth.net/mailman/listinfo/elecraft Help:
> http://mailman.qth.net/mmfaq.htm Post:
> mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net Please help support this
> email list: http://www.qsl.net/donate.html Message delivered to
> [hidden email]
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

[k6dgw]

Perfectly normal.  The K3(s) S-meter measures the total envelope power
in whatever BW you have set.  The P3 is a Fourier Transform with a
multitude of "bins" across the horizontal axis, and what you see is the
power in each of those bins.  They sum to the same power as the K3
shows, but the P3 doesn't show the sum, it's a panadapter and not
designed to do so.

Feeding my K3 with my service monitor [one CW frequency], they match.
They never do on real signals.

Incidentally, the P3 has a monochrome waterfall option.  I asked for it
[no color vision], Alan did it for me, I'm not asking for anything else,
I got what I wanted! :-)  A number of visiting ops to my station have
commented that the monochrome WF made it much easier to see very weak
signals.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the Cal QSO Party 1-2 Oct 2016
- www.cqp.org

On 10/19/2015 6:38 PM, David Ahrendts wrote:
> Noticeable difference between the K3S S-Meter level and the displayed
> S-level on the P3. An S-9 signal on the K3S is seen as much less,
> maybe an S-3 on the P3. So its not REF LVL, not SPAN. What?
>
> David A., KC0XT, LA
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]