range in RF module

Discussion in 'General Electronics Chat' started by bug13, Apr 22, 2015.

  1. bug13

    Thread Starter Well-Known Member

    Feb 13, 2012
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    Hi guys

    I am reading this application note/report from Microchip:
    http://ww1.microchip.com/downloads/en/AppNotes/00001629A.pdf

    On page 15, all the modules have bigger range without acknowledge, but have a small range with acknowledge. Why is that?? I can't think of a reason myself what with ACK would effect the range.

    Thanks guys!
     
  2. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    IIRC "Broadcast" packets are (spectrally) 'narrower' and, hence, of greater effective (i.e. 'time-distributed') ERP (Do note the adjective 'effective'! ;)) -- That said, the range disparity, while measurable, should be so slight as to be negligible in most applications...

    Best regards
    HP
     
    Last edited: Apr 22, 2015
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  3. bug13

    Thread Starter Well-Known Member

    Feb 13, 2012
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    When you said 'narrower', did you mean the package is very small?
     
  4. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    No, Spectrally narrower (i.e. narrower RF bandwidth) :)

    Best regards
    HP
     
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  5. bug13

    Thread Starter Well-Known Member

    Feb 13, 2012
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    Interesting, I would think they use the same bandwidth in all transmission (when not doing frequency hopping).
     
  6. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    I believe the 'unicast' protocol entails FHSS operation (re: acknowledgement 'bursts'). While, in theory, owing to error correction and general (NB) interference 'immunity', such might be expected to increase range, the FHSS 'bursts' are commonly 'attenuated' (actually, transmitted at reduced power) in the interests of economy and RFEF exposure compliance - with the result that the range 'breaks even' or, indeed, falls short of correspondent NB range...

    Please note: The, IMO, dubious, use of the terms 'broadcast' and 'unicast' in this context is entirely down to Microchip! --- 'Tho I am obliged to adopt the manufacturer's jargon am I to communicate - Pun not entirely not intended;););)

    Best regards
    HP

    PS: Please be advised that my responses on this thread are based 90% upon memory and 10% on 'guesswork' -- hence it's far from 'gospel';):)
     
    Last edited: Apr 22, 2015
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