Saturday, 28 June 2014

Transportable WiFi Repeater

Testing the Chinese import WiFi repeater yesterday revealed a few good features, but also one very major and disappointing one. On the plus side, it is actually rather easy to set up, although it is easier to do so using the RJ45 LAN port than by wireless, if only due to the fact that as soon as its connected to a network, it becomes 'transparent' and cannot be 'seen' by the devices on the network! This means you cannot reconfigure it without a hard reset, as you can't access the devices IP address!

The big downside is its power supply. Physically, the two pin mains connector is very poor, and is so loose in an adapter for UK mains that just knocking the device causes it to reboot. I feel that this is a dangerous situation and have complained to the supplier.

Today was Toms birthday party, and with less than an hour to go, we found that the professional audio system we had for the music would not work. It seems it runs on internal batteries, and these were dead. Both the mains and the DC power input are charge circuits, neither bypasses the batteries and allows the unit to run! It is also a 24V system. So I had to desperately strip the unit, disconnect the batteries, find a way to bring the cables out, and rig a temporary 24V DC supply

The spade terminals I had were too big, so I had to cut them down using tin shears. The power came from two 12V 38Ahr SLABs in series.

In order to build the proposed transportable WiFi repeater, I need some suitable coax connectors to allow connecting various 2.4GHz antennas. Notably, in order to use collinears or Yagis. The old Hirshmann TV transposer cards on my shelf yielded two short SMA coax leads, as seen in the photo below

 These are ideal. All I need now is a 12V to 5V regulator board, a 7Ahr SLAB, and a suitable metal box with a handle to build it into!

I have also finally installed the coax switch in the shack. This is mounted above the ATU and is between the ATU and the transceiver. It will allow me to connect other radios, in particular my MKARS80 and the PSK-20, to the main antenna. This switch has a center position which puts everything to ground as well, so when im not present I can ground the station and antennas for safety.

I still need to find an old PS/2 mouse (or keyboard) to yield a data cable for my FT-857D, plus a spare USB lead to finish the USB soundcard that will be boxed as part of this interface.

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