DIY aviation blackbox

Discussion in 'The Projects Forum' started by ALT2016, Feb 13, 2007.

  1. ALT2016

    Thread Starter New Member

    Feb 13, 2007
    6
    0
    Hi there.

    This is my first post on these forums. My current level of electronics wizkid... I managed to get the LED to burn without it popping:D In other words, I'm virtually clueless.
    I've read through the rules and stuff and consequently did a search for my problem. I came accross something that seems to be in the right direction - Impedance Matching - but the discussion was not exactly matching my question, so here goes:
    I have an airband scanner and would like to make recordings of the conversations between ATC and the pilots. From what I can gather, there are only two usable outputs on the radio - One is for a 4ohm speaker and the other is for a 500ohm headphone. The speaker has to stay, so I was considering using the headphone output to plug into a portable casette recorder.
    The radio is on loan from a relative, so I do not want to make any permanent changes to it, much less cause any damage.

    Can I just go ahead and plug the radio's headphones-out into the recorder's mic/line-in or should I be looking at some resistance between the two devices?

    At a later stage, I would also like to do the recording straight to PC and the same question applies.

    As I said, I'm a total newby to electronics, so for now, I'll put up with the laughter:rolleyes:
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    The headphone output being rated for 4 ohm loads is a measure of it's ability to handle a certain amount of current. For your purposes, it is not too significant. The input resistance of the line-in input of your recorder will be way above 4 ohms, so the scanner output won't be loaded.

    Don't use the mike input, though - it will have extra gain built in and will be very hard to set a level where the scanner output will not be distorted.
     
  3. ALT2016

    Thread Starter New Member

    Feb 13, 2007
    6
    0
    Thanks for your reply, beenthere. Your explanation seems simple enough. Unfortunately, my level of understanding is even simpler. (Yes I know - I should have listened in class all those years back).

    If I understand you correctly, I can just go ahead and plug the headphone-out directly into the line-in of the recorder without having to worry about damage?
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Yes, but start off with the volume at a low level. Adjust it for a clear recording.
     
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