Hello, I research cardiovascular physiology and work in a small lab that uses telemetry to measure blood pressure and heart rate. This means that a small device in teh subject emits a radio signal that is picked up by a receiver hooked up to the computer so that it can transfer teh radio signal into BP/HR data. The problem is that the monitor is emitting interference at a comprable frequency to the telemetry device that is being picked up by the receiver and destroying the validity of the data. I can't turn the monitor off because I need to see it in order to do my research. Any suggestions on a kind of housing I can build around the monitor to dampen the interference? Any help would be greatly appreciated. Thank you. Sincerely, Dave K FSU

Doubt you could dampen the interference, a flat LCD is an alternative as it gives of no interference ________________________ MSI KT8 NEO Athlon 64 3200+ @ 2.0ghz 1.0 GB DDR PC3200 2X 160 GB HDD Hightech Excalibur Radeon 9800 Pro Iceq 128mb ( Core 425 MHz and Memory 380 MHz )

You could isolate the interference from the monitor by enclosing it in a Faraday Cage. However, this is nor a practical solution as you would be looking at the monitor through a metal grill. http://en.wikipedia.org/wiki/Faraday_cage An LCD monitor is by far the best solution. Stuart

The above answer is not true. LCD screens can be worse(!) than CRT monitors. You may just have to find some local RF "expert." I don't know the size of your locale, but an ideal candidate might be a local two-way radio tech or broadcast tech that is also an amateur operator. You COULD conceiveably find some copper screening, build an enclosure around the monitor around a frame, and solder all joints. You would also have to bring in special "rf bypassed" conductors and connectors for the power and video leads. I actually (and may yet) thought about taking my favorite monitor apart, gluing bare copper wire tabs into the various plastic pieces of the housing, and spraying over the entire inside with conductive paint, maybe even screening over the display area. I also thought about cutting off the video connector, stretching some coax ground braid over the video cable, and re-installing the connector. You would then have to ground this pigtail to the computer case (By the way dont neglect the case--make sure all shields are in place, including the blanks over unused card slots, and metal covers over unused drive bays. Sometimes grounded copper screening over fan in/outlets helps. This may not be necessary. Different monitors cause different interferance, and also, your screen resolution settings change the interferance. So just trying a different monitor or changing display settings may offset the interferance frequency enough to alleviate the problem. As an amateur and short wave listener, I'm constantly maddened by just about everything that causes the rf noise floor to increase, and nowadays, just about ANYTHING will cause this. Switching powr supplies, as for the typical laptop, or regulated supplies and wall worts, as for scanners and printers. Wall lamp dimmers, touch lamps, various types of flourescent lamps and other arc-discharge lamps. TV sets, heck, the clocks and other microprocessors in microwave ovens and kitchen ranges--all these things are potential sources of noise and interferance. Now, the damned power companies want to put internet out over the power lines--BPL--if any of you who use radios don't think this will be a huge problem, think again.

Ever put a desktop fan next to a CRT monitor and the monitor screen jumps up and down so bad it's unreadable, LCD's don't do this, yes LCD emits electric interference but way way less then CRT I have a friend who is an electrical engineer and has degrees in it and really knows his stuff, and even he agrees that LCD doesn't cause interference ________________________ MSI KT8 NEO Athlon 64 3200+ @ 2.0ghz 1.0 GB DDR PC3200 2X 160 GB HDD Hightech Excalibur Radeon 9800 Pro Iceq 128mb ( Core 425 MHz and Memory 380 MHz )

Well, he's full of crap. As a person who uses MF, HF, VHF, and UHF radio every single day, I can tell you that flat LCD screens put out in some cases more hash than CRT's. I use radio every single day somewhere in the spectrum from 1.8 to 30 mhz, and 144-450mhz, and I used to maintain and install radio sites as well as 911 radio/telco equipment. This is not something I've read somewhere, it's something I've BEEN THERE DONE THAT The thing you mention with the fan has absolutely NOTHING to do with this problem. CRT's work by magnetically moving an electron stream inside the CRT, causing the beam to hit the CRT face where needed. When you put speakers, or any high power AC device, like a fan or transformer operated power supply, you are potentially causing this magnetic field to be disturbed. You can also cause picture disruptions by having TWO crt's too close together--same effect.