home *** CD-ROM | disk | FTP | other *** search
- Newsgroups: sci.electronics
- Path: sparky!uunet!usc!sol.ctr.columbia.edu!ucselx!newshub.sdsu.edu!chemteca.sdsu.edu!massoud
- From: massoud@chemteca.sdsu.edu (Massoud Ajami)
- Subject: Re: Cable, Stereo, and VCR Questions
- Message-ID: <massoud.20@chemteca.sdsu.edu>
- Keywords: Cable TV Stereo VCR
- Sender: news@newshub.sdsu.edu
- Nntp-Posting-Host: 130.191.227.22
- Organization: San Diego State University
- References: <1992Jul27.133817.11872@lonex.rl.af.mil>
- Distribution: usa
- Date: Tue, 28 Jul 1992 18:38:35 GMT
- Lines: 48
-
- In article <1992Jul27.133817.11872@lonex.rl.af.mil> Brian R. O'Hern (BRO'Hern) writes:
-
-
- > I have three questions:
-
- >1. I have a lot of RG-58C (50 ohms) and was thinking of using it to
- >connect my Marantz 200W amp to a pair of Klipsh Heresy speakers.
- >Are my calculations showing that nearly 86% of the signal would be
- >reflected back from the 8 ohm load? So, not only "no" but "hell no"
- >I shouldn't use coax to drive my speakers?
- > However, my instinctive feelings tell me that at because the line
- >is not infinite (transmission line theory), the connection is
- >analyzed as a RC circuit showing the characteristic impedence of the
- >line is close to the load value so reflection isn't a problem. Also,
- >at 30pF a foot, an audio signal would hardly notice. In fact, it
- >seems connections using coax would be better than a zipcord (~150
- >ohms) or even a twisted pair and much less noisy than both?
-
- >1a. Side Ques: I heard that the "Heresy" name came about because its
- >design (Conventional paper cone) is not the standard (does not
- >follow the Klipsh design doctrine). Any truth to this?
-
- >2. Is there a FAQ list on VCR problems? It seems that everyday there
- >is at least one question about VCRs... speaking of which... I have
- >a RCA that stops a couple seconds after pushing play no matter where
- >you are on the tape.
-
- >3. I have a couple of coax splitters that I acquired in college from
- >my cable connection. I would like to use them to split an antenna
- >signal (one to TV one to FM stereo). Is there any truth to the
- >rumor that the splitters filter out high UHF? I.E. I won't get
- >channel 68 (~795MHz) through it.
-
- >Thank you for any comments.
-
-
- >BRO'HERN
- >STD DISCLAIM APPLIES ('disClaim dat I make is no lie...)
- >This medium is subject to monitoring. Use of this medium constitutes
- >consent to such monitoring.
-
- If the length of your speaker wire was longer than 2.5 kilometer, then
- you can use transmission line theory. 2 E8(signal velocity)/20kHz.=10000
- meter. Rule: if the propagation delay was less than 1/4 of rise time of
- the signal (@ max. frequency), then the medium acts as a transmission line.
-
- 3- Some cheap splitters do the filtering by means of higher insertion loss
- at higher frequencies, but still you can get ch. 68.
-