Yes. The issue with PowerSDR is that you can see tiny spurs that you cannot hear in a normal radio. Furthermore, because the audio output of most transceivers has about 50 dB dynamic range at most, you will not see the spurs in the audio output even if you hook up a good Spectrum program such as spectran. The sensitivity of the panadapter is its greatest blessing and its biggest curse. On the other hand, it has absolutely driven us to experiment and experiment and learn how to do better.
There is a MAJOR difference in the dynamic range of most receivers front ends, and the dynamic range of the audio. With these high end sound cards, for the first time EVER that has been translated to the sound output. It is a major contributing factor to its "sweet sound". I LOVE roses. They are beautiful flowers. I spent hundreds and hundreds of hours tending my mother's prize winning roses as a kid. Yet, I always knew those roses had thorns. The DDS does output spurs. We have been able to mitigate phase truncation spurs. We are not able to mitigate DAC nonlinearities in the DAC in the DDS nor clock leakage except by avoidance. Bob N4HY Dudley Hurry wrote: > I guess the key word here is "see". Only in the SDR can you see the > spurs, even if you can't hear them.. Most of the spurs I see, are gone > by the time they arrive in my passband. Any radio will have some > spurs, but they only worry about the ones that can be heard. I'm sure that > the SW can be taylored to eliminate all the spurs, but I am not sure that > you could afford to run the computer that would be fast or big enough to > run it.. > > 73, > Dudley > WA5QPZ > > > > > >> On Mon, 14 Aug 2006 12:20:59 -0400, Richard Smith <[EMAIL PROTECTED]> >> wrote: >> >> >>> I'm new to the SDR-1000 and have a question about spurs. I've read the >>> reflector, and understand that right now, spur reduction has more to do >>> with moving the spurs out of the filter passband as opposed to >>> eliminating them. However, on the quiet upper bands with very low noise >>> floor, I see serious spurs on the panadapter as I tune across the band. >>> I can often hit frequencies where the entire spectrum lights up like a >>> picket fence and includes spurs within the filter passband as well as >>> across the rest of the 48 kHz of spectrum. On the lower frequency, >>> noisier bands, I notice similar behavior with no antenna, but don't >>> notice the spurs in normal operation once the antenna is connected and >>> the noise floor comes up. Is this normal, or do I have a problem with >>> my SDR-1000? Short of the brute-force algorithm that has been discussed >>> for taming the DDS, is there anyway to fix this abnormal looking >>> behavior? >>> >>> Thanks. >>> >>> Rich W1EZ >>> -------------- next part -------------- >>> An HTML attachment was scrubbed... >>> URL: >>> >>> >> /pipermail/flexradio_flex-radio.biz/attachments/20060814/a548ca48/attachment.html >> >>> _______________________________________________ >>> FlexRadio mailing list >>> [email protected] >>> http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz >>> Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ >>> FlexRadio Homepage: http://www.flex-radio.com >>> >>> >> >> -- >> Using Opera's revolutionary e-mail client: http://www.opera.com/mail/ >> >> >> _______________________________________________ >> FlexRadio mailing list >> [email protected] >> http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz >> Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ >> FlexRadio Homepage: http://www.flex-radio.com >> > > > _______________________________________________ > FlexRadio mailing list > [email protected] > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz > Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ > FlexRadio Homepage: http://www.flex-radio.com > > -- AMSAT VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP/AMQRP, QRP ARCI, QCWA, FRC. ARRL SDR Wrk Grp Chairman "You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat." - Einstein _______________________________________________ FlexRadio mailing list [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
