Detemining the transmitters power

Discussion in 'Wireless & RF Design' started by Teebonks, Jun 6, 2013.

  1. Teebonks

    Thread Starter New Member

    Jul 20, 2011
    Hi guys,

    Can anyone give me a clue as to how can I determine the distance in which data can be sent with a transmitter, for example I wanna Know before I even design any transmitter circuict how far will the circuit transmitt data, can anyone help guys just need a guidelind.
  2. Papabravo


    Feb 24, 2006
    Power is only one aspect of the system and arguably not the most important. How far your signal will propagate on any given day and time is determined by factors you do not control. In short there is no single easy answer to your question.
  3. wmodavis

    Distinguished Member

    Oct 23, 2010

    What you are asking is indeterminate. Unless you specify an isotropic antenna in free space and specify output power and the transmission line loss.

    Guideline -
    1. more power = more distance
    2. higher antenna gain = more distance
    3. lower transmission line loss = more distance
    4. higher receiver gain = more distance
    5. lower receiver noise = more distance
    6. less T to R obstructions = more distance
    7. lower atmospheric loss = more distance

    etc. etc. etc.

    Other from that (and any forgotten factors) it's rather simple.
  4. vk6zgo

    Active Member

    Jul 21, 2012
    You've got it backwards:

    How far do you need to send the data?
    Fast or slow data rate?

    Once you know those things,you can work out what would be the best RF solution.
    I would strongly suggest you use some ready made system which was designed by Engineers with RF experience,rather than try to throw something together almost as an afterthought.

    NASA has sent & received data from spacecraft orbiting Mars.
    Of course,the equipment used was fairly costly.

    Hams send low speed data via Moonbounce,at a lot cheaper cost,but the common denominator in both cases is that they know what they are doing.