lutful
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join:2005-06-16
Ottawa, ON
| reply to sporkme
Re: Min Distance from VHF Antenna
said by sporkme  :Curious, what's the spectrum that ethernet uses (100MB FE)? Fast Ethernet transmission uses 125Mbps "raw" data rate which is carried in a 62.5Mhz "MLT-3" waveform.
There is not much VHF coming out of properly twisted portions of the cable - most noise is coupled in the small untwisted section near the connectors. |
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sporkme
drop the crantini and move it, sister
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join:2000-07-01
Morristown, NJ
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| said by lutful :said by sporkme :Curious, what's the spectrum that ethernet uses (100MB FE)? Fast Ethernet transmission uses 125Mbps "raw" data rate which is carried in a 62.5Mhz "MLT-3" waveform. So you're saying that ethernet is centered at 62.5 MHz or goes from "0"-62.5MHz?
said by lutful :There is not much VHF coming out of properly twisted portions of the cable - most noise is coupled in the small untwisted section near the connectors. I was thinking more about RF from other sources getting into the ethernet cable and providing a hard to diagnose failure or near-failure.
So anything with a strong harmonic that lands somewhere below 100MHz could be bad news, right? Technically, ethernet is RF, correct? |
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lutful
Premium
join:2005-06-16
Ottawa, ON
| Here are various Ethernet baseband spectrum. Properly twisted CAT5 cable has 50-100dB VHF rejection. |
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