Creating network indoor: simple antenna or cable?

Hi, I would like to make an indoor network for test.
Let’s image this would be my future network (using routerboards instead PCs):

I would like make this network indoor, so I would ask this:

  1. can I use a piece of wire as antenna (I think use 14 dB antenna in a room is not suitable)?
    should I set some particular configuration to use several antennas in a room?

  2. if I connect directly the n connectors through cable and I set the tx power to 0, would I damage pci radio modules?

Thanks.

you must connect your pc (or routerboard eth) to a revolutionary new device, called switch :laughing:

Sorry, I’m not explained: this would be a future wireless network, but I have to test it indoors.
I haven’t enough antennas for indoor (I have only 18 dB panels).