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- Newsgroups: rec.org.mensa
- Path: sparky!uunet!noc.near.net!ns.draper.com!newsgate
- From: skh4161@mvs.draper.com (Kjeld Hvatum)
- Subject: Re: Re: Howard Stern
- Message-ID: <01GSX4Q7QBWYADDE0L@ccfvx3.draper.com>
- Sender: mmdf@ns.draper.com (MMDF Master)
- Organization: Draper Laboratory
- Date: Wed, 30 Dec 1992 03:14:00 GMT
- Lines: 46
-
-
- >From: "Vance R. Haemmerle" <vance@cco.caltech.edu>
- >Message-ID: <1hqmfnINNg8s@gap.caltech.edu>
- >
- >In article <01GSW3HOEK82ADDCB5@ccfvx3.draper.com> skh4161@mvs.draper.com (Kjeld
- > Hvatum) writes:
- >>
- >>In general, the traditional broadcast spectrum is full. It may be
- >>"fuller" in your part of the country than you think.
- >>For example, the fact that your TV doesn't pick up a strong station on
- >>every channel is not sufficient to say the spectrum in your area isn't
- >>full because, by law, you can't have transmitters on adjacent
- >>TV frequencies in the same area (practical TV filters don't have
- >>sufficiently sharp frequency drop-offs to reject an adjacent channel).
- >>In other words, in any city, almost half of the channels will show
- >>nothing but snow with a modest antenna. There are exceptions because
- >>some adjacent channels are not frequency-adjacent.
- >>
- >
- >In Los Angeles there is a Channel 4 (NBC) and Channel 5 (Ind.). The
- >break between low VHF and high VHF is between 6 and 7. So they are
- >in adjacent 6MHz bands and I don't remember any interference problems.
-
- Wrong! Channels 4 and 5 are not adjacent - there is a 4 MHz gap
- between the two, placing those two channels almost as far apart
- as a two channel difference usually does. The allocations are
- as follows:
-
- Channel Frequency band (MHz)
- ------- --------------------
- 2 54 - 60
- 3 60 - 66
- 4 66 - 72
- 5 76 - 82
- 6 82 - 88
- 7 174 - 180
-
- So, yes, channels 4 and 5 appear together in a number of areas,
- just as they do here in Boston too.
-
- >I think this was a problem with earlier. Television tuners, but is no
- >longer true (i.e. look at cable systems).
-
- Not necessarily a valid comparison. Cable signals all tend to be of the
- same strength. The biggest problem is when the adjacent signal is
- stronger.
-