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microphone switching box?

Discussion in 'Home Brew' started by longhaireddwb, Jul 11, 2010.

  1. longhaireddwb

    longhaireddwb W9WDX Amateur Radio Club Member

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    I want to make one of these to show the guys at work how badly there OEM microphones sound by switching from a 636 or a RK56 quickly. I figured A standard 4 pin setup will do just fine.



    With 2 female 4 pin ends and 1 4 pin male end and some wire I should be ok but...

    I'm thinking that I should be able to connect all the ground pins without a problem. I'm not too sure about the RX, TX and audio pins.

    Will I need to put these on a switch so I can only have one set of these wires connected at a time depending on which mic I'm using? What would that switch be called? I don't want to use a relay as this will be used in a truck when it is used.

    Can someone enlighten me on how to go about this? I haven't tried to build one yet. I want some input first.

    Thanks to all who answer and help me make this little tool.
     
    #1 longhaireddwb, Jul 11, 2010
    Last edited: Jul 11, 2010

  2. W5LZ

    W5LZ Crotchety Old Bastard

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    LHD,
    I can think of two ways of doing that switching. One would switch those 4 contacts, the other way would only switch two contacts. That 4-pole switch would be harder to find, or at least I can't remember seeing one lately. That method would be the simplest to -use-, but the hardest to build (availability of the switch). That other method only switches the audio lines of those two mics. The keying lines could be all in parallel, the switch determining which of the two mics is 'hot'. Or, only the keying lines of one mic connected at all, that mic doing the keying, the 'hot' mic being selected for use. That would mean you'd be using both hands though. :)
    It all just depends on what you can find to do the switching. A '4pdt' toggle switch would be nice, never seen one though ('gang' a couple of 'dpdt's?). Ever seen the switches used in an old telephone switch board? Those things came in a number of forms and could even be 'added-to' for more contacts. Haven't seen those thingys in a very long time though.
    Good luck.
    - 'Doc


    And then there are 'wafer' switches!
     
  3. mackmobile43

    mackmobile43 Jock Supporter

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    What 'Doc said but all you need is an SPDT toggle switch, the output leg of the switch is the middle terminal and you connect the audio lead of each mic to the outer terminals of the SPDT switch and have all the other leads paralleled to the mic jack as I'm sure both those mics only use four wires.

    [​IMG]
     
  4. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    You will probably need to switch the PTT line as well otherwise the unused microphone will be switched in the RX position while the microphone you want to use will be trying to switch the radio into the TX mode.
     
  5. longhaireddwb

    longhaireddwb W9WDX Amateur Radio Club Member

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    Sounds about like what I thought. I was figuring I'd have to go with a DPDT switch. Switching the audio and the PTT. But like W5LZ was saying a 4PDT switch would be best if I could find one.

    I wasn't too sure about having the switch the PTT but I think your right.

    I guess what I need to do now is the build this thing and see what happens. Can't cause too many problems beside some mic squeal right? We've all heard plenty of that before!

    If anyone else has a comment, pipe in here. The more the merrier!
     
  6. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    Keep the leads as short as possible and use shielded wire if you can for the audio leads. Even old audio patch cords are OK if they are shielded.
     
  7. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    That just tests a microphone. The original poster wants to switch between two microphones for on-air testing. It may work just as an in-shop bench test of what the mics sound like but on-air is the best way.
     
  8. i thought it connected to the radios mic jack .
    thanks for the correction CK ;)
     
  9. WR0220

    WR0220 Active Member

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    I built a dual mic connection box a few years ago using a switch like this:

    Amazon.com: Rotary Switch 4 Pole 2 Position: Automotive

    As Captain Kilowatt mentioned, you want to use shielded wire. I used 4 conductor shielded cable that I had left over from installing pickups in a guitar. You also want to use a metal box to prevent rf interference. If you use a plastic box you can line it with shielding foil, but a metal box would be cheaper versus the price of a plastic box and shielding foil. You can get the 4 conductor shielded cable (and the shielding foil) at several different online guitar parts suppliers.
     
  10. longhaireddwb

    longhaireddwb W9WDX Amateur Radio Club Member

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    Thanks for the help WRO220. I've got some tiny shielded coax I took out of a scrap radio.

    Thanks Booty but that really isn't want I'm wanting. I've been thinking about buying one of those for the bench but not just yet. I wish it did both jobs!
     
  11. linearone

    linearone King of NY

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    Search 4PDT, ON-ON TOGGLE SWITCH - Grainger Industrial Supply
     

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