P3 lvl cal?
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Hello All,
Question about the Lvl cal operation of the P3. I have noticed a 2 S unit diff between the K3 and P3. I used the XG-1 to make sure the K3 was set properly. Using Lvl cal, I noted the default was -5.4 and my P3 was -9.6. To get a K3 S meter reading of S4 to equal S4 on the P3, I had to increase the Transfer gain to -30.0! This seems excessive. Would appreciate some guidance on how to resolve this issue. 73 Tom CX7TT ______________________________________________________________ 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 |
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Tom,
There are several reasons why the signal level can be different on the P3 and K3, as explained in the "How to Set Up and Interpret the P3 Display" section of the P3 Owner's Manual. The main reason is that the effective bandwidth of the P3 is narrower than the K3, so more of the signal gets through to the K3 S meter than a single pixel on the P3 display. For that reason, the signal or noise level on the P3 can appear quite a bit lower than on the K3 S meter. Alan N1AL On 4/14/2013 3:46 PM, [hidden email] wrote: > Hello All, > > Question about the Lvl cal operation of the P3. I have noticed a 2 S > unit diff between the K3 and P3. I used the XG-1 to make sure the K3 > was set properly. Using Lvl cal, I noted the default was -5.4 and my P3 > was -9.6. To get a K3 S meter reading of S4 to equal S4 on the P3, I > had to increase the Transfer gain to -30.0! > > This seems excessive. Would appreciate some guidance on how to resolve > this issue. > > 73 > Tom > CX7TT > > > ______________________________________________________________ > 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 > > 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 |
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Hi Alan,
I would guess that running Peak on the P3 and having the S meter on the K3 set to PEAK ON should give roughly the same results. Correct? Or does the same discrepancy you advised below exist? Peak and PEAK ON similarity is what I'm seeing here on the K3 / P3. 73, matt W6NIA On Sun, 14 Apr 2013 16:19:17 -0700, you wrote: >Tom, > >There are several reasons why the signal level can be different on the >P3 and K3, as explained in the "How to Set Up and Interpret the P3 >Display" section of the P3 Owner's Manual. The main reason is that the >effective bandwidth of the P3 is narrower than the K3, so more of the >signal gets through to the K3 S meter than a single pixel on the P3 >display. For that reason, the signal or noise level on the P3 can >appear quite a bit lower than on the K3 S meter. > >Alan N1AL > > >On 4/14/2013 3:46 PM, [hidden email] wrote: >> Hello All, >> >> Question about the Lvl cal operation of the P3. I have noticed a 2 S >> unit diff between the K3 and P3. I used the XG-1 to make sure the K3 >> was set properly. Using Lvl cal, I noted the default was -5.4 and my P3 >> was -9.6. To get a K3 S meter reading of S4 to equal S4 on the P3, I >> had to increase the Transfer gain to -30.0! >> >> This seems excessive. Would appreciate some guidance on how to resolve >> this issue. >> >> 73 >> Tom >> CX7TT >> >> >> ______________________________________________________________ >> 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 >> >> >______________________________________________________________ >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 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 |
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Hi Matt,
If they matched it would be a coincidence. For example, if the P3 is set to 45 kHz span, then each frequency point on the P3 display is about 100 Hz wide. If the K3 bandwidth is 2.7 kHz, then on a wideband signal like band noise or SSB, 27 times (14 dB) as much signal is getting to the K3's S meter as gets to each frequency point of the P3. So you'd expect the average signal level on the P3 to be about 14 dB (2 or 3 S-units) lower. To illustrate this without a P3, try this: Set the K3 to the normal 2.7 kHz bandwidth, tune in an SSB signal and note the S meter reading. Now change the K3 bandwidth to 100 Hz and note the S meter reading. It will be much lower. Alan N1AL On 4/14/2013 4:37 PM, Matt Zilmer wrote: > Hi Alan, > > I would guess that running Peak on the P3 and having the S meter on > the K3 set to PEAK ON should give roughly the same results. Correct? > Or does the same discrepancy you advised below exist? Peak and PEAK > ON similarity is what I'm seeing here on the K3 / P3. > > 73, > matt W6NIA > > On Sun, 14 Apr 2013 16:19:17 -0700, you wrote: > >> Tom, >> >> There are several reasons why the signal level can be different on the >> P3 and K3, as explained in the "How to Set Up and Interpret the P3 >> Display" section of the P3 Owner's Manual. The main reason is that the >> effective bandwidth of the P3 is narrower than the K3, so more of the >> signal gets through to the K3 S meter than a single pixel on the P3 >> display. For that reason, the signal or noise level on the P3 can >> appear quite a bit lower than on the K3 S meter. >> >> Alan N1AL >> >> >> On 4/14/2013 3:46 PM, [hidden email] wrote: >>> Hello All, >>> >>> Question about the Lvl cal operation of the P3. I have noticed a 2 S >>> unit diff between the K3 and P3. I used the XG-1 to make sure the K3 >>> was set properly. Using Lvl cal, I noted the default was -5.4 and my P3 >>> was -9.6. To get a K3 S meter reading of S4 to equal S4 on the P3, I >>> had to increase the Transfer gain to -30.0! >>> >>> This seems excessive. Would appreciate some guidance on how to resolve >>> this issue. >>> >>> 73 >>> Tom >>> CX7TT >>> >>> >>> ______________________________________________________________ >>> 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 >>> >>> >> ______________________________________________________________ >> 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 > ______________________________________________________________ > 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 > > 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 |
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In reply to this post by CX7TT
I have been using the following work around for this discrepancy.
I calibrated the K3's S-Meter using the XG3. I also calibrated the P3 using the XG3 and found the same problem you see. I have reset the P3's Lvl Cal to show the same S-meter readings as the K3 *WHEN* the P3 is in [PEAK] mode. this way no matter what the span, an S9-20 on the K3 is about the same S9-20 on the P3. I'm sure this is not a scientific way to do it, but it works for me. ymmv -- 73 & GB Sam K5OAI <quote author="CX7TT"> Hello All, Question about the Lvl cal operation of the P3. I have noticed a 2 S unit diff between the K3 and P3. I used the XG-1 to make sure the K3 was set properly. Using Lvl cal, I noted the default was -5.4 and my P3 was -9.6. To get a K3 S meter reading of S4 to equal S4 on the P3, I had to increase the Transfer gain to -30.0! This seems excessive. Would appreciate some guidance on how to resolve this issue. 73 Tom CX7TT </quote> -- GB & 73 K5OAI Sam Morgan ______________________________________________________________ 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 |
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In reply to this post by Alan Bloom
Good points, all. Thanks Alan.
73, matt W6NIA On Sun, 14 Apr 2013 18:13:35 -0700, you wrote: >Hi Matt, > >If they matched it would be a coincidence. For example, if the P3 is >set to 45 kHz span, then each frequency point on the P3 display is about >100 Hz wide. If the K3 bandwidth is 2.7 kHz, then on a wideband signal >like band noise or SSB, 27 times (14 dB) as much signal is getting to >the K3's S meter as gets to each frequency point of the P3. So you'd >expect the average signal level on the P3 to be about 14 dB (2 or 3 >S-units) lower. > >To illustrate this without a P3, try this: Set the K3 to the normal 2.7 >kHz bandwidth, tune in an SSB signal and note the S meter reading. Now >change the K3 bandwidth to 100 Hz and note the S meter reading. It will >be much lower. > >Alan N1AL > > >On 4/14/2013 4:37 PM, Matt Zilmer wrote: >> Hi Alan, >> >> I would guess that running Peak on the P3 and having the S meter on >> the K3 set to PEAK ON should give roughly the same results. Correct? >> Or does the same discrepancy you advised below exist? Peak and PEAK >> ON similarity is what I'm seeing here on the K3 / P3. >> >> 73, >> matt W6NIA >> >> On Sun, 14 Apr 2013 16:19:17 -0700, you wrote: >> >>> Tom, >>> >>> There are several reasons why the signal level can be different on the >>> P3 and K3, as explained in the "How to Set Up and Interpret the P3 >>> Display" section of the P3 Owner's Manual. The main reason is that the >>> effective bandwidth of the P3 is narrower than the K3, so more of the >>> signal gets through to the K3 S meter than a single pixel on the P3 >>> display. For that reason, the signal or noise level on the P3 can >>> appear quite a bit lower than on the K3 S meter. >>> >>> Alan N1AL >>> >>> >>> On 4/14/2013 3:46 PM, [hidden email] wrote: >>>> Hello All, >>>> >>>> Question about the Lvl cal operation of the P3. I have noticed a 2 S >>>> unit diff between the K3 and P3. I used the XG-1 to make sure the K3 >>>> was set properly. Using Lvl cal, I noted the default was -5.4 and my P3 >>>> was -9.6. To get a K3 S meter reading of S4 to equal S4 on the P3, I >>>> had to increase the Transfer gain to -30.0! >>>> >>>> This seems excessive. Would appreciate some guidance on how to resolve >>>> this issue. >>>> >>>> 73 >>>> Tom >>>> CX7TT >>>> >>>> >>>> ______________________________________________________________ >>>> 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 >>>> >>>> >>> ______________________________________________________________ >>> 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 >> ______________________________________________________________ >> 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 >> >> >______________________________________________________________ >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 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 |
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