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kx3 px3

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Fred Moore-2

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: [hidden email]
[hidden email]
phone: 321-217-8699

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Don Wilhelm

Re: kx3 px3

Fred,

See the PX3 manual page 16 "Adjusting the Amplitude".
First set the bottom of the spectrum display so the band noise level (or
receiver noise floor) is at the bottom (REF).

Then set SCALE to adjust the vertical gain.
I think it is best to ignore the S-x amplitude and set SCALE so the
strongest signals are near the top of the display. You can easily see
the relative strength of the various signals. For me the vertical scale
is more useful when displaying dBm rather than S-units.

73,
Don W3FPR

On 4/1/2017 6:38 PM, Fred Moore wrote:

> 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
>
>

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Cady, Fred-2

Re: kx3 px3

In reply to this post by Fred Moore-2

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 <[hidden email]> on behalf of Fred Moore <[hidden email]>
Sent: Saturday, April 1, 2017 4:38 PM
To: [hidden email]
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: [hidden email]
[hidden email]
phone: 321-217-8699

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

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Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html
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Fred Moore-2

Re: kx3 px3

Thanks Fred, I have the book will look at it.. Fred

Fred Moore
email: [hidden email]
[hidden email]
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 <[hidden email]> on behalf of Fred
> Moore <[hidden email]>
> *Sent:* Saturday, April 1, 2017 4:38 PM
> *To:* [hidden email]
> *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: [hidden email]
> [hidden email]
> phone: 321-217-8699
>
>
> ______________________________________________________________
> 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]
>
> --
> This message has been scanned for viruses and
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> believed to be clean.

Fred Moore-2

Re: kx3 px3

In reply to this post by Cady, Fred-2

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: [hidden email]
[hidden email]
phone: 321-217-8699

On 4/1/17 8:13 PM, Cady, Fred wrote: