Thanks Jim. I always have an updated version of your tutorial on my laptop!
Eric alluded to some type of internal change and that is what I was hoping to get info on. But I will certainly try your suggestions (most likely either way) if I can't find the info or it turns out to be unfeasible with my version of that supply. I have not really had too many problems with RF noise with this unit. I use it when I'm portable and have noticed if I use a ladder line fed doublet, that if the ladder line is in close proximity I will pick up some noise (sweeping noise). If I use a small length of coax to a balun with the ladder line (pushing the ladder line further away), I don't notice the noise as much. Anyway, thanks for the info as always. 73, Dave W8FGU On 4/7/2012 1:42 PM, Jim Brown wrote: > On 4/7/2012 10:24 AM, Dave Van Wallaghen wrote: >> I would be interested to see if I could >> make the change myself. > > I cleaned up a couple of cheap switchers that I bought at a hamfest by > adding a line-voltage rated capacitor across the AC line, an RF cap > across the DC output, and serious multi-turn ferrite chokes to both the > AC line and the DC output. I also added a couple of clamp-on cores to > kill the stuff on 2M. > > Total cost of my clean-up was about $10 (I bought the cores as part of a > group purchase for $4 each), and the power supplies cost me $10 each. > Doing it right when they built them would probably have added less than > a buck to the cost, and most of doing it right is circuit layout, not > components. See my RFI tutorial for guidelines on winding the chokes, > and also for detailed info about line-voltage rated capacitors. Hint -- > they must be rated for the surges of several kV that often occur on the > AC line. > > 73, Jim K9YC ______________________________________________________________ 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
