Fred: Turns out I had already read everything you suggested, and did
correctly understand the compensation, however...
-73dbm at the antenna, signal generator only (no noise)
does =S9 on the KX3, and does not = -73dbm on PX3 (Lvl Mode = scale:db)
Per PX3 manual page 23 bottom right paragraph 5th sentence down:
"The indicated dBm level should be the signal level at the signal level
at the KX3 antenna input"
In my case this is not true, I am seeing about a 10-12dBm difference.
In my previous post, I referenced S9 and 50 microvolts, thinking most
people on the list are not use to referencing dBm, that was my error.
After re-reading my original post I even said mV when I intended
micro.. I should have been more specific, and correct..
I do not expect the PX3 to be a precision instrument, however I am
trying to resolve and understand a 10+db error here, huge to me, which
should not exist according to the PX3 manual, but may be in the PX3
specification if its specification is +-10%. As a side note the PX3
scale does appear to be linear, relative to dBm, i.e. the error is the
same through the usable scale..
If that is normal I can live with it, I simply want to understand if
this is what others are seeing.. and make sure this new to me PX3 is
operating correctly..
Fred Moore
email: f...@fmeco.com
f...@safes.com
phone: 321-217-8699
On 4/1/17 8:13 PM, Cady, Fred wrote:
>
> Have a look at the How to Set Up and Interpret the PX3 Display in the
> PX3 manual where this is explained (Or the Why??? section in the KE7X
> KX-Line book). Basically the PX3 and KX3 are different bandwidth
> detectors so the signal levels displayed generally won't be the same.
> They are two different instruments meant to show two different
> things. The KX3 s-meter shows you the signal level you have to work
> with in the KX3 with its bandwidth and signal processing active and
> the PX3 is far more useful to show the relative signals across the band.
>
>
> Cheers,
>
> Fred KE7X
>
> For all KE7X Elecraft books see ww.ke7x.com
>
>
>
>
> ------------------------------------------------------------------------
> *From:* Elecraft <elecraft-boun...@mailman.qth.net> on behalf of Fred
> Moore <f...@fmeco.com>
> *Sent:* Saturday, April 1, 2017 4:38 PM
> *To:* elecraft@mailman.qth.net
> *Subject:* [Elecraft] kx3 px3
>
> Anyone have any thoughts on getting the scale on the px3 to match the
> s-meter on the kx3..
>
> when the kx3 is showing a s9 signal the px3 is showing about s6.. 3
> s-units..
>
> I have the pre-amp set to 20db, with a precision HP signal generator a
> 50mv signal does read S9 on the KX3 like it should, the px3 reads about
> 3 S units lower..
>
> All cables are secure, and are the supplied cables between the kx3,
> and px3
>
> Scale and Reference do not effect the delta between the readings..
>
> surely there must be an adjustment I am missing in the PX3
>
> This is a new PX3 built it yesterday morning, everything else works
> properly.. ?????
>
> latest firmware KX3 and PX3
>
> Regards.. Fred
>
>
> --
> Fred Moore
> email: f...@fmeco.com
> f...@safes.com
> phone: 321-217-8699
>
>
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