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WTD: WWVB receiver

Discussion in 'Electronic Design' started by Donald, Mar 14, 2007.

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  1. Donald

    Donald Guest

    I am looking for WWVB receiver to add to an existing product.

    I found at Digikey: 561-1005-ND

    This receiver module: C-MAX CME8000-BUS-LP-01

    Are there other modules like this but cheaper.
    I am looking for 50-100 units.

    Clocks with receivers in them cost $10. So these modules must be cheap
    somewhere.

    Any links to offshore sites would work.

    Thanks

    donald
     
  2. Joerg

    Joerg Guest

    It's the same like it is with LCD modules. A module will always be
    somewhat of a boutique part and thus expensive. Considering your low
    quantity the only way I see is buying a clock and parting it out. But
    you'd have to weigh your engineering time against that effort and quite
    frankly I believe then these modules would be the better deal. With some
    luck you could find a fire sale somewhere but searching for that also
    costs valuable time.

    The only way to get below a few Dollars is to design it all from scratch
    and then produce a gazillion of them.
     
  3. Worse, in fact. LCD modules are actually used in relatively high+
    volume products (I can see several of them in commercial products
    without getting out of my desk chair). If you wanted to duplicate the
    functionality you'd need to add pretty much as many parts as are on
    the module-- there is no micro in them, and really little or no
    duplication.

    You can be sure there is no such module inside a $10 retail product--
    or rather the 'module' is (at best) a discrete chip for the receiver.
    At worst, it could be a corner of a chip.
    They are probably designed around a single chip for the radio portion.
    There are still a few parts outside such as tuning fork crystal
    filters and passives, as well as the ferrite antenna. You can see the
    radio portion on the left-hand part of the module. The right-hand
    portion is what you probably don't need to buy if you already have a
    microcontroller in your product. So, find that ASIC (eg. from Temic
    nee Telefunken) and compare costs including amortized engineering
    time.


    Best regards,
    Spehro Pefhany
     
  4. Jim Thompson

    Jim Thompson Guest

    Anything wrong with these........

    http://www.ntp-time-server.com/wwvb-receiver/wwvb-receiver.htm

    Of course I can't find a price list :-(

    ...Jim Thompson
     
  5. Joerg

    Joerg Guest

  6. Joerg

    Joerg Guest

    Actually, sometimes there is. For example, when my trusty old HP-III
    printer died I parted out the LCD. Lo and behold it was a nice two-line
    version with a HD44780 compatible chip on there. Same in the old Toshiba
    fax (single-line). Same in the old Sanyo fax (two-line again). Sweet. Of
    course, they bought those by the gazillion. But now I don't have to wait
    for a Digikey order if I quickly need to pipe out some alphanumeric
    data. I could even do that in Japanese ;-)
    Yep. Sometimes it is better to use a complete chip, disregard 90%+ of
    its innards and try to tap off a signal at one of its younger stages.
    I've done that a lot with radio comms chips where all I needed was the
    RSSA output.
     
  7. Reliable reception of WWVB in many parts of the country is extremely
    difficult.

    At the very least, a low noise area and an outdoor antenna might be needed.

    I researched this in depth many decades ago and published an Experiments
    with WWVB story in RE, sometime areound 1974 or so.

    The availability of 60 kHz tuning fork crystals for use as a system
    filter does help bunches.

    But, generally, an ultra accurate PLL timebase should track the output,
    being corrected only during early morning hours.

    The fact that the whole service is a second tier backwater tells you it
    sucks.

    --
    Many thanks,

    Don Lancaster voice phone: (928)428-4073
    Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
    rss: http://www.tinaja.com/whtnu.xml email:

    Please visit my GURU's LAIR web site at http://www.tinaja.com
     
  8. August 1973. page 48-51

    --
    Many thanks,

    Don Lancaster voice phone: (928)428-4073
    Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
    rss: http://www.tinaja.com/whtnu.xml email:

    Please visit my GURU's LAIR web site at http://www.tinaja.com
     
  9. Jim Thompson

    Jim Thompson Guest

    I did pretty good in August, 1974, using coherent AGC/detection, with
    an 8" diameter loop antenna wound inside a piece of 1/2" copper pipe
    (insulated couplers used to avoid shorted turn effects from the
    shield). (See the S.E.D page of my website.)

    But I'll grant you that fluorescent lighting will do a number on your
    reception.

    ...Jim Thompson
     
  10. Joerg

    Joerg Guest

    Ahm, they have improved transmit power since then. Big time.
     
  11. Rich Grise

    Rich Grise Guest

    Or, if you pick the right offshore factory, you could produce a Brazillion
    of them. ;-P

    Cheers!
    Rich
     
  12. Rich Grise

    Rich Grise Guest

    FWIW,
    http://www.google.com/search?q="wwvb+receiver"
    returns "about 557" hits.

    But I'm wondering, how hard would it be to slap together an ordinary
    60 KHz TRF receiver, and just look at its output? Decoding it, of course,
    would be left as an exercise for the student. ;-)

    Good Luck!
    Rich
     
  13. So have the local am noise sources.
    Even bigger time.

    --
    Many thanks,

    Don Lancaster voice phone: (928)428-4073
    Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
    rss: http://www.tinaja.com/whtnu.xml email:

    Please visit my GURU's LAIR web site at http://www.tinaja.com
     
  14. A straight decode would likely be useless.

    Instead, you would need a PLL that gets modified only when data is
    consistently valid.



    --
    Many thanks,

    Don Lancaster voice phone: (928)428-4073
    Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
    rss: http://www.tinaja.com/whtnu.xml email:

    Please visit my GURU's LAIR web site at http://www.tinaja.com
     
  15. Joerg

    Joerg Guest

    I can remember people in California telling me back then that WWVB was
    just not strong enough. Nowadays it is. Right in front of me is a WWVB
    clock that synchronizes every single night (it shows when it failed)
    except on rare occasions where a nightly thunderstorm hit the area. Ok,
    it took a while to find the "right" spot for the clock but then again
    the building is completely insulated with AL-backed fiber in all walls.
    Including some interior ones.

    BTW the first set of batteries lasted a whopping five years. And this is
    a low cost edition ($19.95 at Sam's Club). If the OP would part one of
    those out he'd get a mighty fine WWVB receiver plus a humongous LCD
    display for other nice projects. Like a DVM that can be read at age 100
    without glasses :)
     
  16. DaveM

    DaveM Guest

    I live in Florida, and have several of these clocks hanging in my house. I also
    have an elcheapo watch that I bought about 5 years ago from WallyWorld for less
    than $5 (they were on clearance). All work perfectly, and all sync up every
    night.
    The watch syncs up perfectly even when I wear it to bed. The instructions say
    that in order to get a reliable signal, the watch should be oriented so that the
    top of the watch faces Boulder, CO. I have no idea which direction it's facing
    when I'm catching those serious ZZZs, but it never fails. And Florida is a bit
    further away from Boulder than California is... {:>)
    Had to replace the battery in the watch just before Xmas, so it lasted about 5
    years. Not bad for $5.

    Cheers!!!

    --
    Dave M
    MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
    address)

    Life is like a roll of toilet paper; the closer to the end, the faster it goes.
     
  17. Joerg

    Joerg Guest

    If you have the crystal or better yet two of them, not very. I did that
    back in high school since our geology teacher wanted the kids to listen
    to the signal. I used lots of plain old opamps and IIRC a couple of
    AF126. In them days opamps didn't have enough GBW, today you could do it
    with two. This was for 77.5kHz because it was a German school. You could
    see the signal nicely on a scope (from the physics lab) and this was at
    about 8:30am, not midnight. A crystal was in the "not affordable"
    category back then, so lots of LC.

    The deal was sweet: I was forgiven all homework the previous day if I'd
    build the receiver.
     
  18. Jim Yanik

    Jim Yanik Guest

    did your loop antenna have an internal 60Khz amp?

    The Spectracom WWVB antenna (ferrite bar antenna) I used while at TEK had
    one in it,and I was able to use the (8161)system inside our office that had
    metallized window glass,and was chock full of fluorescent fixtures.

    The amp was a simple transistor one(2 xstr,IIRC) using silver mica caps to
    BW-limit the amp.DC power was fed thru the coax.
     
  19. Neither of those cost $10 retail. I suppose that it's barely possible
    to see an LCD module in a $10 retail item, but I have not seen it.

    I tried subbing an OLED 2 x 20 module into my Siemens phone base
    station but it didn't work (probably a timing issue). Another 2-line
    HD44780-based module did work. A little hot glue and it's good for
    another year or two.
    Also a useful approach with some of the PC related I/O stuff. Ignore
    all the unnecesary stuff and extra leads.


    Best regards,
    Spehro Pefhany
     
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