cell phone amplifiers

Discussion in 'General Electronics Chat' started by aac9876, Oct 19, 2007.

  1. aac9876

    Thread Starter Active Member

    Dec 9, 2006
    The size of a wifi 2.4g amp,1 watt is tiny. Why are cell phone amps,1 amp, so big?? Would it be that hard to put one together
    from scratch??
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    I can't really follow you. How is 1 amp related to a cell phone, and why is 1 watt related to 1 amp?

    Assuming one had the fab house to make the IC's, it shouldn't bee too hard to scratch-build a cell phone. It's the licensing that will eat you up.
  3. aac9876

    Thread Starter Active Member

    Dec 9, 2006
    I meant that a 1 watt amp for 2.4g use is tiny. an example.
    the 1 watt amps for cell phones are big. too big and way too expensive.
    i was wondering if a guy could make a cell phone amp that was tiny
    and if there might be plans on the web..
  4. Papabravo


    Feb 24, 2006
    Building an RF amplifier at those frequencies is not like flashing a LED. If you think you can do it you should knock yourself out. Trying to get power gain at those frequencies requires more skill in design, construction and layout than you can possibly imagine. Even if you could successfully construct one amplifier, the equipment to tune, test and debug things when they go wrong will eat you alive. A low end network analyzer will cost $20,000 USED!. I suppose you could rent one, assuming you knew how to use one. In the meantime you can google "complex conjugate impedance matching", "smith charts", and the datasheets of some RF Power Transistors.

    It has been my experience in RF work that getting a good antenna has a far greater payoff, than an amplifier. In the HF ranges a 100W transmitter is fairly common. The legal limit is 1500 Watts. The difference is 11.8 dB. This gain is easily bested by switching from a dipole to Yagi-Uda of three or more elements. Once you get the antenna right, then you go for the amplifier. Even the best amplifier driving a crappy antenna won't get your signal across town let alone around the world. A good antenna and an amplifier and your signal will sound like a cannon in Tristan da Chuna. At microwave frequencies nothing beats a dish, a rifle scope, and really dry air.