Connect with us


Discussion in 'Electronic Basics' started by DG, Oct 9, 2003.

Scroll to continue with content
  1. DG

    DG Guest


    im very new,

    and i was wondering wondering the possibilty of buliding a PLL transmitter
    that covers the range from 10mhz to 999mhz, and also fits in your hand?

    are the analog 900mhz cordless phones fm modulated?

    is there any type of kit or device that woudl do the same?

  2. default

    default Guest

    Not that good and likely to be expensive. You don't say what you hope
    to achieve with it, and what the power requirements are, and how it
    should be modulated. There maybe something simpler that would achieve
    your ends. And hand held to boot? Unlikely.
    I'm not aware of one. Some info on the web in using cell phones as
    jammers for other cell phones (800MHZ) by sweeping through the cell
    frequencies. Some of the surplus outlets come up with cell phone
    equipment from time to time, but they aren't inexpensive.
    Building radio jammers? phone jammers? What is the goal?

    It "can" be done, but this isn't a newbie project, and hand held would
    be very difficult in an amateur design. Using the transmitter may be
    illegal depending on how and it is used and if you are licensed to use
  3. Spajky

    Spajky Guest

    yes ...

    -- Regards, SPAJKY
    & visit site -
    Celly-III OC-ed,"Tualatin on BX-Slot1-MoBo!"
    E-mail AntiSpam: remove ##
  4. John Fortier

    John Fortier Guest

    It would be possible to build a PLL with that frequency range, but the
    output gain stages would be another matter entirely. And, unless you want
    to spend as much on it's development as, for example, Nokia have spent on
    the development of their cell phones, getting it to fit into the palm of
    your hand would be exceptionally difficult if not impossible. This is not a
    project for someone who is very new.

    One word about messing about with cordless phones; illegal.

    I'm sorry, do the same what?

    I wish I could be a bit more encouraging, but shouldn't you learn the basics
    before tackling a project such as the one you seem to be contemplating?

  5. tim kettring

    tim kettring Guest

    Extreamly unlikely , and probably illegal .

  6. DG

    DG Guest

    would it be easier to build a reciever that pulls off that range?and is

    and no i dont want to jam anything, 10 foot range at most
  7. default

    default Guest

    How did you get from wanting to build a wide range transmitter to a
    receiver? Assume this would also be wide band or is there a frequency
    you are interested in?

    That might be easier, depending on how selective you want it. Bug
    detectors are wide band receivers that indicate that a transmitter is
    nearby. They are sensitive enough but not selective, some have
    demodulated outputs so you can listen in.

    Some commercial scanners will work over wide ranges, and are pocket
    size. (not aware of any 10-900MHZ) Many receivers only allow one or
    two types of demodulation and certain frequencies usually carry
    different modulation. Above say 40 MHZ there is more FM modulation
    (narrow band and wide band), below 32 it is AM, CW, FSK, or SSB.
    There are some receivers that will cover from below the broadcast
    bands to the gigahertz satellite bands. They ain't cheap or small . .

    Since you are new and interested in RF, why not check out Ramsey
    electronics? They have a few frequency
    synthesized (PLL) transmitters (illegal- for the average joe) FM radio
    stations, receivers, and high tech toys in kit form. At least get the
    paper catalog and check it out. This way you can build something
    reasonably advanced and learn from it.

    The American Radio Relay League should also be a starting point for
    radio. They have a pretty good bookstore and promote the hobby of
    amateur radio. I recommend the "Secrets of RF Circuit Design" by
    Joseph J. Carr, ISBN 0-8306-8710-6, Tab Books a division of McGraw
    Hill. I bought mine through the ARRL. It is a good basic book and at
    the same time interesting and up to date. Several circuits you can
    build, antennas and how they work, etc.. Not too heavy and easy to

    The "Encyclopedia of Electronics Circuits" (new volume every year or
    so) is chock full of circuits and interesting. Very little
    explanation, but reference where they found the circuit and give a
    schematic. The past volumes are very inexpensive on or on
    line book stores. New volumes are expensive, but each volume is
    unique with all different circuits.
  8. DG

    DG Guest

    woudl you know of a good starting book, that covers everythign from rf,
    digital and analog? my math level is calculus, if that helps. i cant seem to
    find a good one, art of electronics is way too old and doenst have what i

  9. default

    default Guest

    It would help to know what your interest is. There are lots of
    "starting books" There are none that will take you from knowing
    nothing about electricity to designing electronics.

    Are you at a zero knowledge point? What spurred your interest in
    electronics? What are the things that seem interesting (what types of
    applications?). What do you hope to do with the knowledge?

    I ask those things because if you are interested and enthusiastic
    about some facet of electronics it would be best for you to pursue
    that interest.

    There is a difference between knowledge and understanding. Schools
    are great for imparting knowledge, but understanding is usually fueled
    by curiosity and an intrinsic need to learn. (if you have that need,
    it is a shame to waste it)

    Let's say,for argument's sake,that you are at the starting gate.
    Today, the best way to learn on one's own, in my opinion, is with the
    Heathkit electronics courses. The individual courses are set up so
    you buy one,do the work, send in the test, get graded and move to the

    I was fortunate to take a job that had as a requirement, for me to
    take the company's own learning program. They used heathkit and I got
    a great set of basic books out of the deal. It was redundant for me
    and I breezed through the one year program in two weeks, but the books
    are still on my shelf and I still use them. They went from DC
    electronics to digital and microprocessors.

    They were quite reasonable in 1980 when I went through them. (~$40)
    The company gave me DC electronics through digital electronics, I
    added op amps, microprocessors, opto electronics, and a few others.
    They picked up the cost by reimbursing me.

    Heathkit wants you to buy their "trainer" and the course comes with
    parts to "breadboard" the circuits and see how they work. I didn't
    actually do all that, just took the tests.

    If you are dead broke or nearly so, the "Basic Electricity and
    Electronics," US navy book is on the market, still published by Dover
    Books. "Advanced Electronics," is also there but a little dated.

    The basic AC and DC theory is never outdated.

    Heathkit is drifting off in making computer/network courses now, but
    their basic "core" learning modules are still there and still
    available in "individual learning" formats.

    Electronics is far too advanced to learn it all. You're going to
    specialize or compromise somewhere - the basics are going to be
    necessary in everything you do. So start at DC and AC electronics
    theory, then semiconductor components, then circuits - by then you'll
    see more possibilities and interests and can chart your course.

    Another resource might be a mentor. Some old geezer with time on his
    hands that will help you stay interested and learning.

    The other choice is a college or community college - but you really
    have to shop around to find a good one. Lots of people are selling
    degrees these days. If it were my money, I'd want to make sure I got
    some real understanding, not just a piece of paper.

    Sit in on a course, look for bright enthusiastic teachers and
    students. Stay away from the guy that gets in front of a class and
    drones, while the drones in the seats take notes. Learning should be
    fun. Hell, learning is fun - some teachers can suck the fun out of
    it. Learning is the active roll, teaching is the passive roll. The
    best teachers guide, they don't dictate or just put in a days "work."
  10. default

    default Guest

    The books are listed as paperback. Mine are looseleaf with the binder
    supplied and the pages shrink wrapped (when they were shipped)

    This was found on searching under "books" and Heathkit

    That won't get you the components or heath graded test or certificate,
    but the knowlege is there, and it is an inexpensive way to find out if
    you want to do it.

    Semiconductor Devices Zenith Educational Systems Heathkit
    » Paperback, 1983 - Buy it for $3.75 (Save 71%)

    Dc Electronics Zenith Education Systems Heathkit
    » Paperback, 1983 - Buy it for $4.99 (Save 61%)

    This is number 5 or 6:
    Digital Techniques: A Step-By-Step Introduction Zenith Educational
    Systems Heathkit » Paperback, 1983 - Buy it for $9.00 (Save 39%)

    Ac Electronics Zenith Educational Systems Heathkit
    » Paperback, 1983 - Buy it for $3.75 (Save 71%)

    This one was/is extra curricular:
    Electronic Communications Zenith Educational Systems Heathkit
    » Paperback, 1983 - Buy it for $6.50 (Save 49%)
  11. To do this would be illegal. You have to have an FCC license to work on
    transmitters and receivers in allot of those frequencies you want to cover.
    Not to mention the separate licenses you would need to transmit,
    If you are a newbie to electronics and you want to work with transmitters
    and receivers it would be best to get the ARRL technicians study book then
    take a simple no code tech HAM test then you can play around with that stuff
    once you are licensed on the allowable frequencies.

  12. DG

    DG Guest

    thanks for the infor,

    i on specialzing in wireless data tranmsision and interfacing with comptuer,
    but this project had nothing to do with that.

    thanks a ton
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Similar Threads
There are no similar threads yet.
Electronics Point Logo
Continue to site
Quote of the day