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No RFI from LCD computer monitor



I recently bought a new PC and an 18.1-inch NEC LCD monitor.  The LCD monitor replaces an old 15-inch CRT monitor.  The CRT monitor's sweep circuits generated harmonics that were very noticeable on the ham bands from 20m up to 2m.  To hear a weak signal on a frequency that coincided with one of the harmonics, I had to change the screen resolution to "re-tune" the monitor harmonics.  It was definitely a nuisance.

Last night I searched for harmonics coming from the LCD monitor.  I tuned around and couldn't find ANY harmonics coming from the LCD monitor.  That's not surprising because the LCD monitor doesn't have high-voltage sweep circuits.  In hindsight, it's obvious that a LCD monitor will generate far less RFI than a CRT monitor.  But I hadn't thought of that before I bought the LCD monitor.

If you are undecided about buying an expensive LCD monitor for your hamshack, the lack of RFI might tip the scales in favor of the LCD.  Of course the other benefits are much sharper display, lower power consumption, and smaller depth.  The main disadvantage is that an LCD monitor usually only performs well in its "native" resolution.  That is, your video resolution setting must match the number of pixels in the monitor.  For 15-inch LCD monitors that is usually 768x1024 pixels.  For 17-inch and larger LCD monitors that is usually 1024x1280 pixels.  The result is smaller (but sharper) text than what many people are accustomed to.  Don't buy an LCD monitor if you need to use low screen resolution because of vision problems.

73, and happy RFI-free weak signal reception,
Wayne Estes W9AE

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