Why is video inverted for transmission?

Discussion in 'Digital Photography' started by Green Xenon [Radium], Sep 20, 2007.

  1. Green Xenon [Radium]

    Clark Martin Guest

    I've seen those leaded glass blocks used for viewing portals into
    radiation treatment rooms. They had a fairly strong yellow tint, as in
    everything was in black and yellow.

    That was the original use for uranium, yellow coloring. And thorium was
    used in dental powder.

    Guess what. Uranium IS used for radiation shielding. I used to work
    for a company that makes linear accelerators. In some models a plate of
    depleted uranium is used as there isn't much room. Uranium is something
    like 2.5 times as dense as lead.

    It can only be used in the low energy machines. The high energy
    machines produce neutrons and those you don't want around uranium.
     
    Clark Martin, Sep 26, 2007
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  2. I already have a 22" HP monitor that will do 2048 * 1536. I use it
    on the computer that I use for graphic work and web design.


    All I watch is local news, and a little Sci-Fi Channel. Cable TV
    costs me about $15 a month for that. I can't get the Sci Fi channel
    without paying for a tier of sports channels that I don't have time to
    watch. The cheapest package with the Sci-Fi channel is ?$45 a month on
    Direct TV, and Dish network wants $30 a month.


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
     
    Michael A. Terrell, Sep 26, 2007
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  3. I carreied a spare capacitor, pouints and distributor cap with me in
    my vehicle's tool box, so i didn't ned to improvise critical parts away
    from the shop.


    A large tesla coil do in a pinch.


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
     
    Michael A. Terrell, Sep 26, 2007

  4. Hi res display, and zero digital or HD channels...

    Yeah, you're a real brain, bozo.
     
    ChairmanOfTheBored, Sep 26, 2007
  5. Green Xenon [Radium]

    Jerry Avins Guest

    Wrong attribution, but no harm done.
    I assume you meant powDered carbon detector. That's a new one on me. I'm
    familiar with another form of coherer, one that used powdered nickel and
    silver. (Filings from a dime and a nickel worked nicely.) That kind of
    coherer is bistable. Once contact is established by RF, it is permanent
    until disrupted by shaking. For that reason, we fastened the coherers we
    made to the clapper of a bell or buzzer it controlled.

    Commercial coherers are evacuated to minimize oxidation. We just
    replaced the filings when they got "stale".
    http://home.luna.nl/~arjan-muil/radio/coherer.html

    Jerry
     
    Jerry Avins, Sep 26, 2007
  6. Green Xenon [Radium]

    Don Bowey Guest

    You are a mouthy POS. Why not put a cork in it?

    Perhaps he likes the quality for watching DVDs, not that it's anyone's
    business.
     
    Don Bowey, Sep 26, 2007
  7. Green Xenon [Radium]

    Jerry Avins Guest

    Gene E. Bloch wrote:

    ...
    A spell checker ought to be an OS service. That way, any additions such
    as frequently encountered names become universal.

    Jerry
     
    Jerry Avins, Sep 26, 2007
  8. Green Xenon [Radium]

    Jerry Avins Guest

    The capacitor -- even the ones in radios were called condensers then --
    forms a resonant circuit with the coil. When the points open, L-C
    ringing raises the coil voltage until the plug arcs over. (Because of
    the half-cycle delay, leakage in wet wires can drain a lot of the energy
    so spark potential would never be reached. Creating a second gap by
    pulling the wire out of the coil but leaving it close eliminates that
    loss and will often let a wet engine start.) With no capacitor, severe
    arcing at the points dissipates much of the coil energy, making for
    unreliable ignition at best. Some coils, -- I've seen it in a car --
    have enough self capacitance to work reasonably well. In any case, the
    original condenser had to come out; it had shorted.

    Jerry
     
    Jerry Avins, Sep 26, 2007
  9. Green Xenon [Radium]

    Jerry Avins Guest

    Nor are they steeped in potable liquids.

    Jerry
     
    Jerry Avins, Sep 26, 2007
  10. Green Xenon [Radium]

    Jerry Avins Guest

    Michael A. Terrell wrote:

    ...
    This was a friend's boat and I trusted him. It turned out not to be
    equipped with RDF (not unusual in the late 40s), compass, bailing pump
    or even bucket, to say nothing of ship-to-shore radio. I nearly lost my
    life, and I actually lost my naiveté. Since then, I check a boat's
    equipment before I accept a joyride.
    The pilot had a broken leg. My friend improvised a windbreak from the
    broken-off wing, and made fire by soaking clothes from his suitcase in
    fuel. I don't know how he made his interrupter. His 300 or so pounds --
    mostly blubber -- probably insulated him. It may also have contributed
    to the plane's breakup on touching down.

    Jerry
     
    Jerry Avins, Sep 26, 2007
  11. Green Xenon [Radium]

    G Guest

    I said carbon because I was not sure what was in it. I really thought it was a
    diode of some sort. I must have been in third or fourth grade when I first
    opened up the bus and looked inside. The coherer looked like a fuse
    with stuff inside.

    greg
     
    G, Sep 26, 2007
  12. My comments were in reference to your proposed use of a 32" Sony HDTV
    as a computer monitor. Most (not all) have limited dot resolution.
    I've had a few bad experiences with customers attempting to use such
    large HDTV displays for computer monitors. Most of the time, they
    find that the 1366x768 screen appears as a relatively small picture,
    surrounded by a large black border. In order to make the display
    useful, I've had to install VGA to video converters.
    Kevin Martin, FCC Chair has been issuing anual press releases
    indicating his support for ala carte cable programming. Here's the
    lastest:
    <http://www.pcmag.com/article2/0,1759,2174261,00.asp>
    Even AT&T has at time expressed their "support":
    <http://www.usatoday.com/tech/news/2005-11-30-at&t-ala-carte_x.htm>
    Of course, nothing ever really happens. The big problem is that the
    FCC has also forced the cable companies to carry local broadcast
    channels. In addition, the highest cost channels to the CATV carrier
    are the sports channels, which are only affordable because literally
    everyone pays for them. If users were allowed to select their own
    channel lineup, local advertisers will lose their free ride, and the
    sports channels will become very expensive.

    You can still get ala carte programming via 4DTV, but as the feeds
    switch to digital, it will probably be dead in a few years. However,
    the picture quality if noticeably better than DBS or cable with
    excessive compression:
    <http://www.skyvision.com/pages/information_center/4dtvguide.html>
    <http://www.motorola.com/content.jsp?globalObjectId=5050-8100>
    <http://www.faqs.org/faqs/Satellite-TV/4dtv/>
    <http://www.4dtvforum.com>

    Programming is mostly ala carte:
    <http://skyvision.com/programming/alacarte.html>>
    If all you want is the Science Channel, you can get that for $42year.
    The catch is that you have to subscribe to a minimum of 10 channels to
    get that price. Assuming you go for a mix of cheapo channels, that's
    about $500/year, which isn't much of a bargain. However, it is ala
    carte and is probably a good predictor of what will happen when ala
    carte arrives on DBS or CATV.
     
    Jeff Liebermann, Sep 26, 2007
  13. Green Xenon [Radium]

    Jerry Avins Guest

    G wrote:

    ...
    :) !
    We used glass tubing plugged with bits of cork and sealing wax. A small
    cartridge fuse would have worked, but it was a hassle to get the end
    caps off.

    Jerry
     
    Jerry Avins, Sep 26, 2007

  14. Sorry, I forgot the smiley.


    They have been beating this dead horse since the early '80s, when I
    designed and built CATV headends.


    Yes. The old "Must carry" regulations. They were a pain in the '80s
    when the switching equipment wasn't versatile enough, and reliable
    enough to block some programming, so some channels that people wanted
    added to a system required someone to manually switch when something
    actually started or stopped. Local ball games that weren't sold out had
    be blocked, along with a lot of other crap.


    the same local advertisers who try to sell me overpriced furniture
    and vehicles, I neither need, nor want. As far as the sports channels,
    I wouldn't care if they ALL went bankrupt.


    I know better than to hold my breath. I have dealt with Skyvision
    quite a few times, when C-band was the preferred sat service. When word
    got out that I had worked with commercial receive only earth stations, I
    suddenly had lots of friends I'd never met. :(


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
     
    Michael A. Terrell, Sep 26, 2007

  15. No, you're the clown. I got the thing for free, and delivered to my
    door. I took it, because it was offered by a family member. I have a
    life outside of watching TV, you should try it.

    They had it for two years, and have never watched any HD programming
    on it. They simply wanted a big TV because of failing eyesight. Then,
    they just had to have an LCD TV and replaced an almost new TV.

    Last year they gave away a fairly new motor home, when they accepted
    that they weren't in good enough health to take long trips.

    Go play with your troll buddies so they can 'bore' you some more.


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
     
    Michael A. Terrell, Sep 26, 2007

  16. It only takes one serious problem to cost you your life. :(


    I went through the US Army cold weather survival training in '73 at
    Ft. Greely. We dug out enough snow to build a shelter, built from a
    tent half, a few pieces of rope and covered with snow for insulation.
    We were issued two matches each, and a folding shovel. We used what
    wood we could find on the ground, but when it ran out we started
    snapping saplings off by kicking them with the bottoms of our boots. It
    worked up to about 4" trees. The food we were issued was WWII vintage C
    rations. They were so old and dry that a lot was dust when you opened
    the can. It had to be below -20 F before the training started, and
    quickly got colder. We would have a roaring fire, taller than the
    trees, yet you could stand three feet from the fire and barley feel the
    heat.


    Also, while working there, I built a replacement TV tuner for our RCA
    'Demod" used to monitor our transmitted signal. The original was built
    by Sarkes-Tarzan and there were no spares because of the age. It was a
    cheap tuner, built with switch wafers that soon wore out. It had taken
    over a year to go through channels, to RCA then to Sarkes-Tarzan, and
    back down to the station that there was no replacement, but we could
    ship them the tuner, and they would "TRY" to fix it, for a flat $500
    fee, and it could take another 18 months to send it through channels,
    and back.

    I caught a Motorola portable TV on its way to the base landfill.
    Luckily, it was chassis mounted with the extra long shafts. The bad one
    was parallel filaments, but the salvaged tuner was series string. I
    converted the wiring, without disturbing the tuned circuits. (Not easy,
    when the only soldering tool available was a 100 W weller soldering
    gun.) Then I sawed of the shafts to the proper lengths, and carefully
    filed the slots and flats to fit the original knobs. As a final touch,
    I removed the RCA part number label, and put it on the customized tuner.
    :)


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
     
    Michael A. Terrell, Sep 26, 2007
  17. Green Xenon [Radium]

    Allen Guest

    I really have to disagree, Jerry. I think that operating systems should
    be as universal as possible. By putting a spell check in at that level
    would mean, for instance, a US operating system couldn't be used in
    England. Now a stand-alone checker that any application could access
    would be quite desirable. I wish that we could come up with a checker
    that is context-sensitive, but I'm afraid that would be asking too much.
    Allen
     
    Allen, Sep 26, 2007
  18. Green Xenon [Radium]

    Terry Given Guest

    IMHO, hell no! the amount of times I have struggled trying to get my
    effing computer to NOT use American english is beyond belief. despite
    setting the OS, and the relevant programs, to Australian english
    (closest I can get to Kiwi, and the spelling is identical), it still
    doesnt work properly. so I dont bother doing any spell checks, but instead:

    - try not to make any mistakes
    - read anything important once I've finished writing it

    but I am at an advantage, given that I am good at spelling.

    Cheers
    Terry
     
    Terry Given, Sep 26, 2007
  19. http://en.wikipedia.org/wiki/Coherer

    -- glen
     
    glen herrmannsfeldt, Sep 26, 2007
  20. Green Xenon [Radium]

    Jerry Avins Guest

    ...
    I don't mean a spell checker built into the operating system, but rather
    the hooks (in the form of system calls? -- to access the user's
    registered program. Without the OS as an intermediary, each application
    would need to be customized (at installation time?) to access the common
    program.

    Jerry
     
    Jerry Avins, Sep 26, 2007
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