Coax cable switch ...?

Discussion in 'General Electronics Chat' started by ramblin, Jul 27, 2016.

  1. ramblin

    Thread Starter New Member

    Jun 15, 2016
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    After much damage to routers and other hardware due to surges coming in on my coax cable from storms I tried to add switches to my coax ahead of my routers to easily disconnect during peak lightning storms. Commercially available switches ( to change from games to tv ) generally only switch the center wire while leaving the shielding ground cables connected. My plan was to use dbl. pole, dbl. throw switches to disconnect both. Problem is this will not work ! I fully expected some RF leakage but did not expect it to not work at all. I even connected some jumpers across the switches thinking maybe it was just a poor connections in the switch. This also failed and I get no signal at all thru my little box with nice new connectors and switches. What am I missing here ?
     
  2. Sensacell

    Well-Known Member

    Jun 19, 2012
    1,133
    267
    Can you post a photo of what you have?

    Most likely, your "switch" is not suitable for RF, it presents a change in impedance in the line that causes a great mismatch and attenuates the signal.

    Put a BNC connector on it and just unplug it before the storm?
     
  3. BR-549

    Well-Known Member

    Sep 22, 2013
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  4. AlbertHall

    Well-Known Member

    Jun 4, 2014
    1,969
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    Lightning can easily generate enough voltage to arc across the switch contacts, so the 'unplug' or purpose built protection would be a better option.
     
  5. Techno Tronix

    Member

    Jan 10, 2015
    140
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    How 'unplug' can be better option?
     
  6. AlbertHall

    Well-Known Member

    Jun 4, 2014
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    If the connection is unplugged then there can be no possibility of damage to the (disconnected) equipment.
    The only problem is that you have to be there to disconnect it, but then the same restriction applies to switching it.
     
    Techno Tronix likes this.
  7. ramblin

    Thread Starter New Member

    Jun 15, 2016
    12
    0
    Like most routers everywhere mine are buried behind the desk and tv and hard to access making it difficult to unscrew the cable. No doubt my cheap switches do present an impedance mismatch. I thought maybe knife switches would work but jumpers across the switches failed so this probably would not work either. Up to this point I haven`t found any commercially available disconnects and would appreciate if any one knows of one. First time I`ve seen those inline surge protectors and will definitely be checking those out. Thanks
     
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