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I agree that the fan should pull air from outside into the enclosure for the very reason as mentioned. Too many vent holes to control air flow if fan is used as an exhaust fan.<br>I was lucky to find a 24 Vdc fan pulled from an old printer. It runs fairly quiet.<br>Some diodes in the leads sounds like a good idea also. Cheap current limiters.<br>My HPSDR is up and running very well. I've even been able to calibrate it using my Z3801 and an attenuator. Confirmed calibration with HP-8920B.<br>This setup has allowed me to determine that my SSB Electronics LTS 6 gain is not what it should be. Looks like a good piece of test gear.<br>Looking forward to getting Alex.<br>73, Bill, wf4r<br><br><br><br>W.B.Runyon,Sr.<br>Amateur Radio WF4R (FM16ts)<br>Chesapeake, VA<br><br>Jul 11, 2009 04:25:41 PM, <a href="mailto:jeffrie@talktalk.net" class="parsedEmail" target="_blank">jeffrie@talktalk.net</a> wrote:<br><blockquote style="border-left: 3px solid rgb(102, 153, 204);">***** High Performance Software Defined Radio Discussion List *****<br><br>Dear All,<br><br>My cup runneth over, HPSDR fully functional, Pandora and LPU arrived, <br>and the little fiddling part necessary to get HPSDR fully functional <br>arrived from America within three days of ordering it here in Blighty, <br>does life get any better?<br><br>I've assembled LPU, and put all my kit and caboodle into Pandora along <br>with a fan, switched on and have something that sounds like a wind <br>tunnel. Remembering what others have said with regard to the fan being <br>noisy I played around, and have found that with a combination of cheap <br>draft excluder at each corner of the fan to act as a buffer between it <br>and Pandora, and dropping the voltage to the fan from 13.8 V to 9 V by <br>using 8 silicon diodes in series housed in heat shrink tube, the noise <br>is reduced to a quite tolerable level.<br><br>Now then, to suck or to blow that is the question, and it seems very <br>reasonable to conclude that under normal circumstances one would wish to <br>vent hot air from inside Pandora to be replaced by cooler air. But I <br>wonder if that would work with Pandora, it has so many ventilation slots <br>that I feel very little air would be drawn in from its far end, and <br>would probably be mainly drawn in from the slots closest to the fan. So <br>I have set my fan to blow air into Pandora and in particular against the <br>heatsink of U2 the 5 V regulator, which I've noticed gets very hot if <br>the fan is not on.<br><br>Any other thoughts?<br><br>Jeff Cook, G0AFQ.<br><br>_______________________________________________<br>HPSDR Discussion List<br>To post msg: <a href="mailto:hpsdr@openhpsdr.org" target="_blank" class="parsedEmail parsedEmail">hpsdr@openhpsdr.org</a><br>Subscription help: <a href="http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org" class="parsedLink" target="_blank">http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org</a><br>HPSDR web page: <a href="http://openhpsdr.org" class="parsedLink" target="_blank">http://openhpsdr.org</a><br>Archives: <a href="http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/" class="parsedLink" target="_blank">http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/</a><br></blockquote></body></html>
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