[Elecraft] K3 S meter vs P3 S scale

[Alan Bloom]

Hi Doug,

On Sat, 2011-05-07 at 17:10 +0100, Doug Turnbull wrote:
> Alan,
>    Thank you for this, I have been wondering whether my P3 required
> calibration.   I am not sure if this is mentioned in the manual but if not
> it should be.   

There's a section in the manual titled, "How to Set Up and Interpret the
P3 Display" that covers that and a number of other issues.  Panadapters
and other types of spectrum analyzers are new to many operators so that
section was written to address some of the questions that come up.

73,

Alan N1AL


> The P3 is a new product and some of us are still learning.
> The forum once again proves valuable.
> 
>               73 Doug EI2CN
> 
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Alan Bloom
> Sent: 06 May 2011 23:00
> To: Jim Miller KG0KP
> Cc: Elecraft Reflector
> Subject: Re: [Elecraft] K3 S meter vs P3 S scale
> 
> The reason the P3 reads lower than the K3 on noise or SSB signals is
> that each display point on the P3 screen covers only a small bandwidth.
> As explained in the manual, each display point is about 1/450 of the
> span.  For example, if the span is 45 kHz, then each display point only
> covers about 100 Hz.
> 
> You'd see the same effect on the K3 if you narrowed the bandwidth from
> 2700 Hz to 100 Hz.  The S meter would read 10 * log (2700/100) = 14 dB
> (2-3 S units) lower.
> 
> Alan N1AL
> 
> 
> On Thu, 2011-05-05 at 21:59 -0600, Jim Miller KG0KP wrote:
> > Seems to be quite a difference in the readings between the P3 showing S 
> > scale and he S meter reading on the K3.  The software in both is up to 
> > date(recently at least).  The difference is quite significant with the P3 
> > being considerably lower.  Maybe I don't know how to read the two meters. 
> > On the K3 I read the mostly steady peak reading excluding the static
> crashes 
> > if any.  On the P3 using clear frequency noise as an example, I tend to
> read 
> > the "average" of the noise trace.  Should I be reading the peaks 
> > (disregarding static crashes)?
> > 
> > Is there a calibration I need to do?  To which and where is the procedure 
> > spelled out?
> > 
> > Will I will need to order the new XG3? (please)
> > 
> > TIA, de Jim KG0KP 
> >