Not to mention that any device CAN be made nearly completely free of emissions...by building a gaussian surface around it. Sure, you have to bond every panel to each adjacent panel, but it can be don
Hi, Scott, In fact, I made a number of similar modifications to one of the Astron SS- family (like Paul's) after I got one about six years ago. I was not pleased with the RFI before the mods but afte
Hasn't anyone tried to ground/shield/filter these things ? We used them at the place I used to work, and I got them quieted down to the point where I couldn't measure any noise with a scope hooked di
Author: RMcGraw@Blomand.Net (Robert & Linda McGraw K4TAX)
Date: Mon Mar 10 17:58:11 2003
Oh, there are better supplies than the Astron. But at a much higher cost. While a 50% failure rate is out of anyone's range of acceptable, I'd say that in reference to "He said they had a 50% failure
Author: RMcGraw@Blomand.Net (Robert & Linda McGraw K4TAX)
Date: Mon Mar 10 18:15:37 2003
I totally agree, all switchers do create noise. It's just that some manufacturers do a better job of keeping the "noise in the box" than some others. There's 2 types of noise, radiated and conducted.
"You may cringe at such a blanket statement, but *all* switching mode power supplies generate noise. That is another thing nice about the Alinco switcher: its gives you a control to move a perceived
Author: RMcGraw@Blomand.Net (Robert & Linda McGraw K4TAX)
Date: Mon Mar 10 18:31:35 2003
OK, that takes care of conducted noise on the output, now what about radiated noise? That is usually a significant part of the problem. 73 Bob, K4TAX at the blanket users SMPS nearer RFI
SHEILDING! copper flashing, solder, etc. -- Scott Rosenfeld ARS N7JI 541-684-9970 Eugene, OR Land o' much rain If you find me on the air, I'm probably in my car ham@w3eax.umd.edu http://w3eax.umd.edu
Author: RMcGraw@Blomand.Net (Robert & Linda McGraw K4TAX)
Date: Mon Mar 10 19:17:35 2003
Well yes, copper or aluminum works but that is just one part of the story. The secret is to have the box RF tight, thus the covers need to be adequately overlapped and electrically bonded. I've seen
Remember, S9 is 50uV at the antenna input, or about 50 picowatts at 50 ohms. And that's for S9. A few picowatts is enough to make a very audible signal. (and that's not much power!!!) -- Scott Rosenf
Well.... I mentioned "shield". That takes care of radiated if the shield is complete and well grounded. We had a problem at work where the supply was powering a sensitive printing system. Didn't have
I bought an 11 amp switching supply from Ten Tec when I bought my Scout. The supply was marketed by Ten Tec but was made a company called TPS. Its small an light and doesn't make any hash. Bob WB2VUF
I use a Samplex 1223 23a switcher and haven't noticed any hash. Of courst 99.44% of my operation takes place with a 526 & few switchers have hash that high. (I have other wierd birdies from outside i