[EMAIL PROTECTED] said: > I can confirm that the choice of 75 Ohm for telecom use indeed is > because of the low attenuation. The first use of coax was for > "Carrier Frequency" systems, where a number of telephone conversations > were AM modulated on individual carriers, usually 4 kHz apart.
What's the attenuation mechanism? I thought the old 10 megabit vampire-tap Ethernet picked 50 ohms because of lower attenuation. The story I remember is that for a given outside diameter, the inside diameter was bigger at a lower impedance. The main losses were resistive on the center conductor due to skin effect. A bigger center conductor had more area at a given skin depth and hence lower losses. -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
