2.0.16 sounds more like the correct noise figure for the FLEX-3000. Gerald
Gerald Youngblood, K5SDR President and CEO FlexRadio Systems(TM) 13091 Pond Springs Road, #250 Austin, TX 78729 Phone: 512-535-4713 Ext. 202 Email: [email protected] Web: www.flexradio.com <http://www.flex-radio.com/> Tune In Excitement (TM) PowerSDR(TM) is a trademark of FlexRadio Systems On Fri, Nov 12, 2010 at 4:59 PM, Clay W7CE <[email protected]> wrote: > I tried the comparison again, this time in a more controlled manner. I > connected a 50 ohm termination to the antenna input of the 3000. In CW mode > with a BW of 500Hz (50.192600 MHz), PowerSDR 2.0.8 shows the noise floor to > be -142.5 dBM, which corresponds to a noise figure of 4.5 dB. PowerSDR > 2.0.16 shows the noise floor to be -139.6 dBm, which corresponds to a noise > figure of 7.4 dBm, which is 2.9 dB worse. Both measurements were taken with > RX1 meter set to "Sig Avg", and in the Setup Dialog, "Show Decimal" was > checked, the meter Average Time was set to 10000 ms, and Digital Refresh was > set to 1000 ms. Shorter averaging times give similar values, but the > digital meter display fluctuates around the center value. The preamp was > set to Pre2 for both versions. > > I hope the additional data helps. > > 73, > Clay W7CE > > > On 11/12/2010 2:03 PM, Clay W7CE wrote: > >> Gerald, >> I tried what you suggested and reset the database for both 2.0.8 and >> 2.0.16. PowerSDR 2.0.16 still shows the noise floor, as measured by RX1 >> Meter in "Sig Avg" mode, to be 3 dB higher than 2.0.8. Using SpecJT, both >> versions show the same average noise power when AF and AGC-T are set to 50 >> and 60, respectively. It appears that something has changed in the way the >> S-Meter reading is calculated. Rough calculations based on RX noise figure >> and current sky temperature, lead me to believe that the 2.0.8 reading is >> more accurate. >> >> I'm getting ready to hook up my 5000A, which I just got back with the V/U >> upgrade, and will see if it behaves similarly. I'll also try the 1500 >> later. >> >> 73, >> Clay W7CE >> >> On 11/12/2010 6:11 AM, Gerald Youngblood wrote: >> >>> Clay, >>> >>> Try starting with a clean database on both versions. This is probably >>> calibration data in the database and not an actual change in the noise >>> floor. >>> >>> Gerald >>> >>> >>> Gerald Youngblood, K5SDR >>> President and CEO >>> FlexRadio Systems(TM) >>> 13091 Pond Springs Road, #250 >>> Austin, TX 78729 >>> Phone: 512-535-4713 Ext. 202 >>> Email: [email protected] <mailto:[email protected]> >>> Web: www.flexradio.com <http://www.flex-radio.com/> >>> >>> Tune In Excitement (TM) >>> >>> PowerSDR(TM) is a trademark of FlexRadio Systems >>> >>> >>> On Fri, Nov 12, 2010 at 1:39 AM, Clay W7CE <[email protected] <mailto: >>> [email protected]>> wrote: >>> >>> I just installed 2.0.16 on a Win7 Ultimate 64-bit machine >>> (upgrading from 2.0.8). Initially, I'm running it with a Flex >>> 3000, and it upgraded the firmware in the 3000 to 2.0.4.1. The >>> FlexRadio Firewire driver stayed the same at 3.5.2.8028. After >>> initial manual setup, I checked the local noise floor on 6M with >>> the antenna pointed in what is typically my quietest direction and >>> with the antenna elevated 40 degrees (to minimize the effects of >>> any man-made QRN). The noise floor seemed high, so I shutdown >>> 2.0.16 and started 2.0.8. It seems to work with the firmware >>> upgrade, so I went to the same frequency and the indicated noise >>> floor is 3 dB lower (better). Several iterations of switching >>> versions yielded the same results. As far as I can tell, the two >>> versions are configured identically. Both versions of the >>> software are set to USB, 2.7k BW with the NB and SR off. Also the >>> RX1 Meter is set to "Sig Avg" in both cases, and they both have >>> AGC-T set to 69 and Pre2 selected. I've also noticed that the >>> noise displayed in the panadapter seems to have a larger range of >>> min and max peaks on 2.0.16 compared with 2.0.8. >>> >>> Why do the two versions show a different noise floor when used >>> with the same receiver and antenna? Also, if there is a reason >>> for the difference, which is more accurate? >>> >>> Tomorrow I should get a chance to try 2.0.16 with a Flex 5000A and >>> a 1500. It will be interesting to see if there are differences in >>> the indicated noise floor on those two receivers when I switch >>> PowerSDR versions. >>> >>> 73, >>> Clay W7CE >>> >>> _______________________________________________ >>> Flexedge mailing list >>> [email protected] <mailto:[email protected]> >>> http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz >>> This is the FlexRadio Systems e-mail Reflector called FlexEdge. >>> It is used for posting topics related to SDR software development >>> and experimentalist who are using beta versions of the software. >>> >>> >>> >> _______________________________________________ >> Flexedge mailing list >> [email protected] >> http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz >> This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is >> used for posting topics related to SDR software development and >> experimentalist who are using beta versions of the software. >> >> > > _______________________________________________ > Flexedge mailing list > [email protected] > http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz > This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used > for posting topics related to SDR software development and experimentalist > who are using beta versions of the software. > _______________________________________________ Flexedge mailing list [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used for posting topics related to SDR software development and experimentalist who are using beta versions of the software.
