I have the same supply and have never had any birdie problems with it in 9+ years of use (although being antenna-challenged, I don't operate much on 160). In the QST reviews of switching supplies several years ago the Alinco did pretty well compared to most of the competition, but I suspect that some supplies are more prone to these issues than others.
I solved most of my birdie issues by switching from a CRT to a LCD monitor on the shack computer. 73, Bob N7XY On Jan 11, 2010, at 5:32 PM, Bill K9YEQ wrote: > Exactly why I sold mine. It is noisey and basically worthless to me. > Perhaps the newer ones work better. I am using other more recent > switching > supplies that don't give me any issues and they are a whole lot less > expensive. > > > 73, > > Bill > K9YEQ > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Bob > Sent: Monday, January 11, 2010 6:30 PM > To: [email protected] > Subject: [Elecraft] How to Eliminate Power Supply Birdies? > > I have an Alinco DM-330MVT power supply that has significant > birdies on > 160M. The power supply has a nice feature that allows you to move the > birdies, which makes it obvious that the birdies are originating > from the > power supply. The birdies are at least 1 S-unit above the > background noise. > Here's what I've done to try to eliminate them: > - added a filter connected to the DC output consisting of 4 toroid > beads > (type 77) in series on each side and 0.1 caps across the leads and > from each > lead to ground. I also have both leads going about 10 turns > through a type > 77 toroid to filter common mode birdies. > - I've put 2 snap on type toroids on the AC line as well as wound > the ac > cord through a T200-1 toroid (which I had lying around) . > - I shielded all of the power leads from the power supply to all of > the > equipment that it powers (mostly my K2, KAT100 and external speaker/ > amp), > with the shields connected to both the power supply and the K2 chassis > grounds. > - I've moved the power supply away from my K2 (about 5' away). > > All of this seems to have absolutely no affect on the birdies. > To add to > the mystery, the birdies are there only when I have an antenna > connected to > the K2, so it would appear that the Power supply is radiating, but > with all > of the wires to it filtered and the DC lines shielded, where can it be > radiating from - (as a test I put the whole power supply inside a > metal file > box and grounded that to no effect. > > So, can anyone explain this? Other than buying a new power > supply, what do > I do now? Except for the birdies on 160M, this is a nice power > supply that's > small enough to fit into an attaché case with my K2, KAT100, mic > and key. > > Thanks. > > Bob W1SRB > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
