>From G3PLX: Jack:
I have seen tuning clicks on the higher bands with my own software driving the SDR1000 kit. Some of these clicks are the DDS stepping, as Eric described, but these will only be audible if there's a strong signal nearby - in effect the click you hear is the 'keyclick' of this strong carrier stepping sharply, and you will hear it even if the signal in question is outside the passband. If there is nothing but bandnoise for miles either side, you shouldn't here anything when the DDS steps. There can probably never be a fix for this effect when using a DDS direct as a local oscillator (which the SDR1000 does). It didn't happen with the older phase-locked VCO technology because the frequency changes much more slowly. Another source of tuning clicks I found was noise from the parallel port cable between the PC and the SDR1000. When the PC sends a frequency-change to the DDS along this cable there is a burst of fast switching activity here, and this is strong enough to be audible on the higher bands. It was specially noticable if I was scanning across the band, when it's almost a buzzing sound . On my set-up it's not too bad and I have not bothered to try to fix it, but maybe changing to a screened printer cable would help. Of course if the DDS control is done by another method (USB?), then this comment doesn't apply. 73 Peter _______________________________________________ FlexRadio mailing list [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
