Willi, Thanks for remembering! Linear power supply/voltage regulator is always a good solution for low noise applications. Unfortunately, sometimes we cannot use them.
Actually, now I'm using the original "chopper" with better filtering. You may add 47uF capacitor parallel to C7 and double the values of L2, L3, C8 and C9. Be careful though, the chopper DC1 (NMA1215S) is very sensitive to all kind of overloads - even to the higher inrush current of the output filter capacitors! That's why higher inductance values will be needed. My suggestions are beyond the recommendations of the manufacturer and naturally, you violate the guarantee rules of FlexRadio, too. Anything you modify is totally at your own risk and responsibility. It may be my good luck only, that this modification has worked three years in my oldest SDR-1000 and about two years in the two other sets. For anybody else I suggest buying (or building) a quiet power supply with well filtered output voltages +13.8V and ±15V (±12V). 73, Ahti OH2RZ On 25/09/06, Willi Reppel <[EMAIL PROTECTED]> wrote: > Chris, > > This subject has already been a topic three years ago on the Forum and so > far I remember > > _______________________________________________ > FlexRadio mailing list > FlexRadio@flex-radio.biz > 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 FlexRadio@flex-radio.biz 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
