point to point communication

Discussion in 'General Electronics Chat' started by mmuj, Apr 22, 2016.

  1. mmuj

    Thread Starter Member

    Dec 15, 2009
    11
    0
    Hi

    I am working on point to point communication system over dedicated coaxial cable.

    Required Data rate = 100kbps
    cable length = 5km

    I am looking for suggestion/design ideas

    In one of my previous projects I used wire line modem (CMX866) successfully over similar distance but baud rate was 2400.

    Can I use two DSL modem ICs for such communication? are DSL chipset ICs available for Digikey/Farnell? i couldn't find any from product profile of TI, Analog or ST etc.
    I know Broadcomm is a key player in this market but they don't have good reputation for supporting small volume/ niche market customers.


    Any other ideas?


    Thanks

    mmuj
     
  2. SLK001

    Well-Known Member

    Nov 29, 2011
    819
    229
    Three miles of cable? Really?
     
  3. Papabravo

    Expert

    Feb 24, 2006
    10,145
    1,791
    Can you specify the coaxial cable and the carrier frequency?
    If so I would suggest 75 Ohm CATV coax and 300-800 MHz.
    You might need to use either repeaters or substantial power levels.
    Industrial grade RF modems should work for you.
     
  4. mmuj

    Thread Starter Member

    Dec 15, 2009
    11
    0
    Required distance is over 3 miles on an existing coaxial like cable, and to though spanner in the work, with the temperature range of at
    least 150C.

    Thnks Papabravo, can you suggest any suitable chip for FR modem type communication?

    I also thought about using Power line solution from TI using AFE031.
     
  5. Papabravo

    Expert

    Feb 24, 2006
    10,145
    1,791
    I wasn't thinking of chips, but rather complete modules. Doing an RF modem is not a single chip affair, there is more to it, not to mention the cost of the test equipment you'll need.
     
  6. Sensacell

    Well-Known Member

    Jun 19, 2012
    1,131
    267
    The 150 Degrees C. spec is a bitch.

    How about sending the signal as base-band serial data?
    Attenuation in coax is proportional to frequency, direct signaling minimizes the loss.
     
  7. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,542
    1,251
    Not if you build the entire system out of high power MOSFETS and dual Shottkey rectifiers. But other than that, I gotta ask - what task is 3 miles long and 300 F? Distributed sensors around the rim of an active volcano? Inquiring minds...

    ak
     
  8. Picbuster

    Member

    Dec 2, 2013
    374
    50
    it's commercial available look at https://www.scribd.com/doc/114590501/DSL-leased-line-modem-Realgain-4
     
  9. Tonyr1084

    Active Member

    Sep 24, 2015
    535
    86
    Is Fiber Optics an option?
     
  10. mmuj

    Thread Starter Member

    Dec 15, 2009
    11
    0
    You are not that far off :)

    it is a last option
     
    Last edited by a moderator: May 2, 2016
  11. SLK001

    Well-Known Member

    Nov 29, 2011
    819
    229
    Is this for some down-hole logging tool?
     
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