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Using an AT Power supply to supply a VHF radio?

Discussion in 'Electronics & Electrics' started by Tas_Dean, Oct 12, 2006.

  1. Tas_Dean

    Tas_Dean Member

    Joined:
    Oct 25, 2005
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    Location:
    Ulverstone, Tas
    Hi All,

    I've had a reasonably good search throught the threads already on here, and I've found some close projects but nothing the same.

    I have a VHF radio (like an amateur radio but a slightly different frequency) that is is supposedly 13.8V but it seems to run happily on a 12v battery, until the battery starts to get too flat.

    Can anyone see any problems in just connecting it to the 12v rail (fused of course) of an old AT power supply? Yes, I know about the live 240V power switch on AT power supplies (I used to be an apprentice electrician). Or should I attempt to volt mod the power supply to get it up closer to 13.8v? I don't really see a need to remove the excess wiring from the PS, just connect up to a 12V line and off we go. Am I correct?

    The radio will only be used for recieving, absolutely no transmitting. I essentially use it as a scanner.

    Last year when I was using it I ran it off a 12v battery jump-start pack, but it used to flatten that even while the charger was plugged in as the radio pulls about 2A on standby.

    Cheers, Dean
     
  2. GooSE

    GooSE New Member

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    If you say it runs fine on 12V, then an AT power supply should be fine unless there is too much of a voltage drop on the 12V rail when you load it.

    There's only one way to find out...
     
  3. dantheman65

    dantheman65 Member

    Joined:
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    Melbourne.
    Yeah.

    Some power supplies though are sketchy with no load on the other rails, or may not even start. You might have to load the 5v rail depending on the PSU.
     
  4. Big Trev

    Big Trev Member

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    Plug it in, check for sparks and smoke...

    :D


    In theory it should be OK. Run the gauntlet son!
     
  5. nux

    nux Member

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    Should work fine.
     
  6. Sadow

    Sadow Member

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    ive been running a car amp off a 300watt AT PSU for about 2 years no problem :)
     
  7. DanielSullivan

    DanielSullivan (Banned or Deleted)

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    Mansfield, VIC
    shouldnt be any problem with it. no harm in hooking it up and trying. usless psu or scanner are severely deformed nothing should go bang
     
  8. Turorit

    Turorit Member

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    Adelaide, South Aust.
    I used to run 2x 12v CB radios off of an old AT power supply, worked fine. The sound of the fan annoyed me though....
     
  9. mAJORD

    mAJORD Member

    Joined:
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    should pwoer up fine, but beware of the switching noise on the line causing poor performance from your scanner.

    They could be suseptable to that sorta thing if there internal filtering isnt too good (becuase of it not being intended for use on anything but linear power or batteries) and sometimes it's not so obvious as it acts to reduce the ability to pick up signal rather than superimpose an 'audible' interference - a bit like when you put a PC next to a poorly sheilded FM radio, you'll find it will just 'loose signal' without any audible clue as to why.

    So perhaps just compare it with clean and AT power.
     
    Last edited: Nov 3, 2006
  10. Sadow

    Sadow Member

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    Location:
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    A vehicle's electrical system is a very bad power supply and most things designed to work on a vehicles power supplky will have very good EMI supression, and will easily be able to filter the noise of a SM PSU
     
  11. cinders

    cinders Member

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    I've been running an FM900 off a cheapo AT PSU for a couple of years now without any issues.
    Just have to be carefull not to press the transmit button on the mike.
     
  12. THELTD

    THELTD Member

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    Location:
    Melbourne
    Im half way through an identical project. AT PSU and UHF 40 Channel Transmitter/Receiver. Tested them together and they work fine.
     

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