alangeering Posted December 23, 2013 Share Posted December 23, 2013 Edit: ignore me, I misread the situation. Do try the screenshot idea anyway just to eliminate an on screen image causing the frequency spike. Given your specific situation I have the following to add: The presenter screen has a set format. This coupled with the refresh rate can set up peaks of a set frequency. Try the following things:1. Take a "print screen" of the interface. Then put this full screen where PowerPoint had been and see if the problem occurs. This will allow you to know whether its PowerPoint's use of settings or just the screen it is rendering in presenter view.2. Change the display timing (i.e. 80Hz rather than 60Hz) on the monitor showing the presenter interface. I know it might sound crazy but please try it. I work with screens with a very fixed interface and the signal lines (despite shielding) have a very predictable rf signature. As has been mentioned above a better quality VGA cable will reduce the interference emitted... Unless of course it's coming from the monitor. Hope this helps,Al PS The NSA etc. Have probably designed gadgets that can read your display by reading given off interference from cables/monitors. Maybe we'll hear about it in 80 years Link to comment Share on other sites More sharing options...
Brian Posted December 23, 2013 Share Posted December 23, 2013 PS The NSA etc. Have probably designed gadgets that can read your display by reading given off interference from cables/monitors. Maybe we'll hear about it in 80 yearsNo need to wait, it's well known about. There's even a design standard for equipment to prevent it. Search on 'Tempest'. Link to comment Share on other sites More sharing options...
charl.ie Posted December 23, 2013 Share Posted December 23, 2013 What are you using to drive the monitors? Some computers (such as Macbook Pros) switch between a lightweight integrated graphics card and heavy duty external one depending on what's being used. It could be that powerpoint is forcing the computer to use the external card, which may be causing issues. Is it only powerpoint that's causing the issue, or can you reproduce it with other applications? Link to comment Share on other sites More sharing options...
scjb Posted December 23, 2013 Share Posted December 23, 2013 Hey chaps. Just to say the moderation by Bobbsy seems to have split off a question that was posted to an old thread... Link to comment Share on other sites More sharing options...
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