On 3/23/2011 11:56 AM, John Lemay wrote: > It seems to me that the noise is being radiated by the screen itself, and no > amount of cabinet scraping will reduce this.
That's entirely possible -- but it's also possible that the cables are involved. Many RFI problems have more than one cause, or more than one component, or a combination of causes, both of which must be present for the RFI to happen. In this example, a hand or finger next to the display allows RF to capacity-couple to the body, and the resulting RF current radiates the noise. Take the fingers away, and if there's still noise, another coupling mechanism may be present. On the other hand, I've never felt the urge to have my fingers next to the P3 screen. :) I don't operate 2M for weak signal work, because I'm blocked by a high ridge to all of North America, so I can't comment on noise from my own display. :) I don't recall details of the P3 construction, nor the display, but the display is a potential break in shielding, and even a potential RFI source. Ideally, the display should be bonded to the shielding enclosure and be constructed in a manner that there is no break in the shielding, and any current driving the display should flow in a loop with very small area to minimize any magnetic field. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
