I have bought the external antenna version of the Edison.
Someone mentioned that you can cause damage to the Edison by powering it without an antenna connected, here http://electronics.stackexchange.com/questions/135916/connecting-external-2-4ghz-antenna-to-intel-ed... rf - Connecting external 2.4GHz antenna to Intel Edison - Electrical Engineering Stack Exchange
Is this true? I would think that there would be protection against this, but maybe I am wrong.
Thank you for your interest in our products. We'll be glad to assist you.
I would like to take a look at the board you're using, or at least know the product code of the board you bought, it would be helpful for us.
Regarding your question. It is indeed stated in the Hardware Guide of the Edison Module (page 13) not to connect an external antenna to a board with an internal antenna, the u.FL connector is there only as a manufacturing test point. However, some other users have stated that it's very unlikely to get a better performance with an external antenna due to the onboard antenna working pretty well.
I believe the Edison won't get damaged, however, the antenna will not work. Take a look at this video https://www.youtube.com/watch?v=8zTG420RWo4 https://www.youtube.com/watch?v=8zTG420RWo4 to check this customer's experience trying to get it working.
I have the external antenna version of the board. The product code is EDI2.SPOF.AL.S. I understand that the internal antenna version's u.FL connector is just a test point which is why I didn't buy that model.
As I said, I saw on a forum that the unit could be damaged if no antenna was connected. I just want to ensure that is not the case.
There is no issue if you don't connect an external antenna (aside from the obvious limitations of not connecting an antenna). You don't need to worry about your board getting damaged because of this.