Tim, Thanks again for your suggestion which I carried out a long time ago. It remains to do something about the electrical noise of the fan. I see 20 dBm of noise spred out over the lower sideband in the 15 m band which disappears when disconnecting the fan. While the purist argue about 1/f noise and freezing of the SDR-1000 to 0 K to reduce thermic noise, I am looking for a engi-neering change order (ECO) to get rid of the more substantial electric fan noise.
Best 73 Willi ----- Original Message ----- From: "Tim Ellison" <[EMAIL PROTECTED]> To: "Willi Reppel" <[EMAIL PROTECTED]>; "Bill Nagle" <[EMAIL PROTECTED]>; <FlexRadio@flex-radio.biz> Sent: Tuesday, May 23, 2006 8:50 PM Subject: RE: [Flexradio] noisy fan Yep, That was me who reported it. There is a little too much back pressure generated between the fan and the vents. You can trace a nice octagon around the air intake holes by drawing tangents on the existing holes. 5 minutes with a Dremel tool and a cutting wheel and you are in business. -Tim --- Integrated Technical Services "Whoa-oh, Smokestack Lightning, shining just like gold. Why can't you hear me crying. Whoa-oh, stop your train, let a hobo ride. Why can't you hear me crying. " --Howling Wolf -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Willi Reppel Sent: Tuesday, May 23, 2006 2:34 PM To: Bill Nagle; FlexRadio@flex-radio.biz Subject: Re: [Flexradio] noisy fan Bill, Many months ago somebody suggested on the forum to make a large opening in the cabinet wall behind the fan instead of letting the cooling air pass through many small holes. The OM reported a sub-stantial noise reduction and mentioned that the small holes in the cabinet together with the adjacent fanwheel create a whining sound like a siren . Willi ----- Original Message ----- From: "Bill Nagle" <[EMAIL PROTECTED]> To: <FlexRadio@flex-radio.biz> Sent: Tuesday, May 23, 2006 6:14 PM Subject: [Flexradio] noisy fan > Does anyone have a suggestion as to quiet the fan noise on the sdr1000? > Perhaps slowing it down a bit with a series resistor? > > > Bill Nagle > > > > _______________________________________________ > FlexRadio mailing list > FlexRadio@flex-radio.biz > 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 > _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz 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 _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz 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
