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K3 SMTR Settings for S9

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engineercm

K3 SMTR Settings for S9

Last night I was adjusting the sound levels into my sound card from a new LP-Pan2 and could not get to S9 using my XG3 at -73 dbm unless the preamp is ON. I also noticed the S meter was reading S7. I checked the S meter calibration using the procedure in the manual and found I needed to adjust SMTR OF to 20 instead of the default 24. I checked two bands 20m and 40m and got the same results. The XG3 is connected to the RX Ant and the ATU is BYPASS.

My K3 has all of the latest firmware updates. SMTR MD is ABS so the preamp is OFF. I've triple checked the settings on the rig to see if there is something I missed (like RF gain) but all check out. Should the SMTR OF setting that is almost 20% off the factory default be an indication that something is amiss in the receiver gain chain? As far as I can tell, the K3 is working fine except I can't drive the sound card output to S9 without the preamp?

73 de Clark/WU4B

Joe Subich, W4TV-4

Re: K3 SMTR Settings for S9

> Should the SMTR OF setting that is almost 20% off the factory default
> be an indication that something is amiss in the receiver gain chain?

No, my K3 is farther than that from the default. I've calibrated the
S meter using the XG-3 and done the RF gain procedure. There is no
issue with levels from the IF output and showing normal (calibrated)
signal levels at -107dBm (S3), -73dBm (S9) and -33 (S9+40) dBm on
either the P3 or SDR-IQ.

73,

... Joe, W4TV

On 2015-03-10 9:35 AM, engineercm wrote:

> Last night I was adjusting the sound levels into my sound card from a new
> LP-Pan2 and could not get to S9 using my XG3 at -73 dbm unless the preamp is
> ON. I also noticed the S meter was reading S7. I checked the S meter
> calibration using the procedure in the manual and found I needed to adjust
> SMTR OF to 20 instead of the default 24. I checked two bands 20m and 40m
> and got the same results. The XG3 is connected to the RX Ant and the ATU is
> BYPASS.
>
> My K3 has all of the latest firmware updates. SMTR MD is ABS so the preamp
> is OFF. I've triple checked the settings on the rig to see if there is
> something I missed (like RF gain) but all check out. Should the SMTR OF
> setting that is almost 20% off the factory default be an indication that
> something is amiss in the receiver gain chain? As far as I can tell, the K3
> is working fine except I can't drive the sound card output to S9 without the
> preamp?
>
> 73 de Clark/WU4B
>
>
>
> --
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Don Wilhelm-4

Re: K3 SMTR Settings for S9

In reply to this post by engineercm

Clark,

It is difficult to say whether you have a receive problem or not from
that information.
Since you have the XG3, use the -107dBm level and measure the MDS of
your K3. You can make the audio output measurements as indicated in the
XG3 manual or better yet, use the dBV indication of the K3 display.

If you have a receiver problem, it will show up in an MDS measurement -
compare your result with the K3 spec. and/or Sherwood's MDS listings for
the K3.

The real determination of receiver sensitivity will be revealed by how
well it can receive weak signals. The fact that your setting for the
S-9 level does not agree with the default is not a large concern,
especially when using SMTR MD = ABS.
The factory default is for SMTR MD = NORmal.

Note that all the above has to do with the K3 display S-meter reading.
It has nothing to do with soundcard levels or the level of the signal on
whatever software you are using for the panadapter display. First
adjust the K3 for proper S-9 reading on the K3 S-meter and after that,
use the soundcard gain controls and the controls in the panadapter
software to adjust that applications display as you wish. There is a
lot of information about the levels shown in the panadapter display at
N8LP's website www.telepostinc.com. You can also signup for the LP-Pan
yahoo group and ask questions related to LP-Pan and the various software
applications that provide the panadapter display.

73,
Don W3FPR

73,
Don W3FPR

On 3/10/2015 9:35 AM, engineercm wrote:

engineercm

Re: K3 SMTR Settings for S9

In reply to this post by Joe Subich, W4TV-4

Thanks for Joe and Don all is okay. I made an assumption that if the IQ signal wasn't were it should be using a S9 signal, something must be wrong with the K3. Silly me. After putting SMTR MD back to NOR and using the Preamp (according to the Manual), the S meter was showing S9 to agree with the input signal from XG-3.

So, back to the Telepost procedure for LP-Pan. What could I be doing wrong? Simple--had the Sub receiver ON which drops the signal by 3DB. Turning it off and the signal being ready by the digital meter popped up into the zone I expected. Now I have enough headroom for whatever comes my way.

Learned a few things about the K3 I didn't know before. I love this radio stuff!

Clark/WU4B