From: Burkhard P. <pl...@ip...> - 2008-03-07 14:12:48
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Hi, Stefan M. Fendt schrieb: > Hello Burkhard, > >> Microwave oven works at 2.45 GHz, S-Video bandwidth is below 10 MHz >> -> No interference > > Erm,... > > ... Burkhard, have I offended you somehow ??¿¿?? No. > >> Next time somone blames the earth radiation.... > > so why do you offend me? I didn't mean to offend you. "Someone" does not necessarily mean you :) It was more a joke. > To make you one thing clear: I do not have won my degree in the lottery. neither me. I design microwave components for a living. But no Kitchen-microwaves. We work above 100 GHz mostly. > The radiation inside(!) the microwave-oven hopefully remains inside the > microwave-oven, as otherwise you would have some very big but different > problem... (Typically _this_ radiation *can* *not* come out of the > microwave-oven anyways (if it is halfway-intact). These devices are > typically very well shielded: Faraday Cage...) Agree. > Nonetheless, you might come here and take a look: I *have* a microwave > which interferes with TV. TV != S-Video cable (see below) > I also have a hair-dryer, which interferes > with UHF-Radio (oh, have I forgot to mention that this one (the > Hair-dryer) does use 14 GHz? *LOL*) > > FYI: MicroWaveOvens do not only radiate on 2,4 GHz. And HairDryers > despite not having any RF-Circuit at all, can perfectly radiate > Frequencies up to 500 MHz and above if electrically not well designed > (Remember the first RF-transmitters used sparks to create a very broad > spectrum). There just does not exist any electrical device which will > not radiate any RF. Yes, hair dryers and other devices are broadband. > I never have stated (or please show me!) that the interference was > caused by 2,4 GHz direct radiation of the microwave. And the > Micro-Controller-Board inside of my MWO has an oscillator-frequency of > near 50 MHz with a broad spectrum above (even and odd multiples). And > well, I can detect that spectrum a few ten meters away. Ok but even 50 MHz and it's harmonics are still much higher than the S-Video bandwidth :) > How do you come to the idea to put a technophile engineer on the same > level as those technophobe gibberish idiots(#) blaming earth radiation > (whatever that may be *Sigh*) for their headaches and lack of > intelligence? As I said, I didn't want to offend you or anyone else on this list. From my experience, one thing can always safely be blamed for any kind of EMC problem: Switched power supplies. Very broad spectrum from several 100 KHz up to many MHz. Even your 14 GHz radio can be disturbed, because it has a lower intermediate frequency inside :) In the time of CRT monitors, they were also candidates with their multi-khz sawtooth voltage. Burkhard |