xBee and GPS EM406A potting / encapsulation advice

Hi Guys & Ladies,

I've been trying to do some research about potting / encapsulating an xBee and EM406A GPS module. Obviously I am worried about the reception of both devices. I want to pot these two components along with a battery and few other electronics and it needs to be waterproof. This will be used to track people in watersports.

Regarding the xBee I couldn't really find any information on potting, although I did find a unit you can buy already potted with part of the Antenna sticking out http://www.aprsworld.com/gallery/xbeeModem/XBee_potted_label2

There seems to be the general opinion that potting the GPS unit will detune the receiver.

So my questions are:

  • Has anyone potted a GPS device? Any idea how much reception / performance will it lose once potted?

  • Has anyone potted a xBee? I have a Series 1 Pro unit with wire Antenna. I could possibly pot it like the photo above but am worried about water ingress through the antenna.

  • I am thinking of potting with standard non acetic curing silicone from a hardware store. Will this be sufficient? I want to be able to cut any the mould to get back the electronics if need be (hence silicone as it doesn't adhere to the components?)

Any advice or personal experience will be much appreciated! I am going to partly pot the GPS / xbee units individually to test the ability to remove silicone without damaging components and to test the effect of reception.

Thanks,
Glenn

As a follow up:

  • The partial potting I did using Silicone wasn't very successful for removing the silicone mould afterwards. It stuck to the PCB, metal and ceramic (opposite to what I thought and read).
  • Although at the same time I did a test using hot glue to partially pot it. The hot glue came off very well. So I thought I could apply a thin layer of hot glue over the components as I know this will remove easily and then when it hardens add a thicker layer of silicone to provide the proper waterproofing and durability.

Any ideas on this? Is it a good or bad idea to pot in hot glue?

Once I do this then I can test the antenna reception / transmission of the GPS and xBee modules.