Good question, likely to cause lots of discussion! See http://www.edn.com/article/CA47191.html?industryid=2853&q=+2000+Why+50%3 F%3F%22+ and http://www.edn.com/index.asp?layout=article&articleid=CA60931
Robert. G8RPI. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Peter Vince Sent: 10 May 2007 13:39 To: [email protected] Subject: [time-nuts] 50 vs 75 ohm cables I came across some telecom equipment the other day which had reference outputs marked as 75 ohms. I work in television, not telecoms, and we use 75 ohm connections for video, but with most RF stuff being (I believe) 50 ohms, and certainly all the HP and other counters seem to have 50 ohm inputs, I rather assumed telecoms used 50 ohms - obviously not! Can anyone tell me how and why the 50/75 ohm distinction came about? Was it perhaps a VHS/Betamax type issue with different manufacturers going their own ways, and then with so much equipment out in the field, neither side was willing to change? Thanks, Peter (London) _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts -------------------------------------------------------- Genetix Limited - Queensway, New Milton, Hampshire, BH25 5NN Registered in England No. 2660050 www.genetix.com Any opinions expressed in this email are those of the individual and not necessarily Genetix Ltd (Genetix) or any company associated with it. This email and any files transmitted with it are confidential and solely for the use of the intended recipient. If you are not the intended recipient or the person responsible for delivering to the intended recipient, be advised that you have received this email in error and that any use is strictly prohibited. If you have received this email in error please notify Genetix by telephone on +44 (0)1425 624600. The unauthorised use, disclosure, copying or alteration of this message is strictly forbidden. This mail and any attachments have been scanned for viruses prior to leaving Genetix network. Genetix will not be liable for direct, special, indirect or consequential damages as a result of any virus being passed on, or arising from alteration of the contents of this message by a third party. -------------------------------------------------------- _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
