RF Repeater

Discussion in 'Wireless & RF Design' started by Masud, Mar 18, 2010.

  1. Masud

    Thread Starter New Member

    Oct 4, 2009
    Hello Dear experts,

    I am newly joined in the sectro of Radio communication as well as in this forum.Need to get information about GSM Repeater(single/dual band).

    I want to make a repeater for GSM 1800 with a gain of 60db. which things do i need to start this work ? i have few knowledge about RF circuits and related things.

  2. rjenkins

    AAC Fanatic!

    Nov 6, 2005
    I don't think an active GSM repeater is a practical DIY project.

    The GSM protocol relies on very fast changeover between transmit and recieve and if this is not done accurately it woudl act as a jammer rather than a repeater.

    They also need to re-transmit a signal they are receiving, so need two antennas a LONG way apart. Too close and you get feedback, like with a microphone and loudspeakers.

    For the frequencies involved, you need to be thorougly familiar with high frequency RF techniques, like stripline circuit design and using surface mount components.

    I've been designing electronics, including RF gear, for almost 30 years and it is not something I would undertake lightly.

    If it's a one-off it is far cheaper to buy something (that you can send back when it does not work), if you are thinking of manufacturing then you must also consider the regulations and approvals required before you can sell this type of equipment.

    A passive repeater is easy - a cell antenna outside in a good location linked by good quality (eg. satellite dish type) coaxial cable to another cell antenna in the room or location with the bad signal. Instant improvement!
  3. Papabravo


    Feb 24, 2006
    I'll second that recommendation. A budget of $500,000 to $1,000,000 for test equipment materials and supplies would not be out of the question for such a project. This is not the kind of project you can just walk into and do based on datasheets. In my experience the guys who do this have to go and characterize the devices before they even think about laying down a circuit. Last point is that 60 dB at those frequencies will present certain practical challenges which I believe you are unprepared to meet.
  4. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
    Not to mention the LEGALITY (or potential lack thereof) of this project.