Alan, Thanks for the excellent answers. So, if you created a signal level calibration would the Elecraft XG2 be a bitting and accurate signal source? Or, would some lab equipment be needed. Actually, I don't really know how the XG2 compares to some lab quality equipment, it may be just as accurate.
PEH On Sep 4, 2010, at 11:42 AM, Alan Bloom wrote: >> My first question is: what is a reasonable setting? > > It's kind of a "season to taste" -- whatever gives a pleasing display to > your eyes. When the waterfall is turned on, I find that it's best to > adjust the REF LVL so that the noise level is right at the bottom of the > spectrum screen. That seems to make weak signals easiest to spot on the > waterfall. > >> I am not quite sure how accurate this is. > > I would guess that typically it should be within a few dB. Let's say > within one S-unit (6 dB). I plan to add a feature so you can calibrate > it against an accurate signal source. > >> ...and noticed that this particular SSB signal on 17 meter band this morning >> read peak about -100 dBm or about a 32 dBm strength over the minimum reading >> on the scale. I would like to equate this to a rough idea of an S meter >> reading. By my calculations, this should be a little bit above an S4 >> reading. Can someone confirm that I am in the right ball park? > > What I do is to remember that S9 is -73 dBm (an easy number for a ham to > remember) and there's 6 dB per S-unit. So -100 dBm is (100-73)/6 = 4.5 > S-units below S9. So between S4 and S5. > > Another item on my "to-do" list is a MENU option to change the scale > from dBm to S-units and dB over S9. It's not all that hard to do, I > just need to clear some higher-priority tasks off the list first. > > Alan N1AL > > > On Sat, 2010-09-04 at 09:12 -0700, Phil Hystad wrote: >> I am trying to get a better understanding of the P3 signal level scale (left >> vertical scale) with respect to absolute signal levels and the S meter >> readings. >> >> I have my REF LVL set to -132 dBm. My first question is: what is a >> reasonable setting? I merely am guessing at the value of -132 dBm and also >> I am not quite sure how accurate this is. According to the P3 manual, this >> is essentially the signal strength at the antenna terminal of my K3 (taking >> into account the pre amplifier which I happen to have Off). >> >> Also, I was monitoring a signal using the PEAK reading capability of the P3 >> and noticed that this particular SSB signal on 17 meter band this morning >> read peak about -100 dBm or about a 32 dBm strength over the minimum reading >> on the scale. I would like to equate this to a rough idea of an S meter >> reading. By my calculations, this should be a little bit above an S4 >> reading. Can someone confirm that I am in the right ball park? >> >> Thanks for the help. >> 73, phil, K7PEH >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[email protected] >> >> 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
