Nomad Zaxnet antenna and ground planes

[bendybones]

I've recently purchased a few options to move Nomad's zaxnet antenna to elsewhere in the bag.

 

I then noticed a post from Glenn stating that, an antenna with a ground plane should be chosen if extending.

(post 11 here)

 

Firstly, what problems could occur when extending an antenna without a ground plane?

 

Secondly,

 

Is there anything in the specs of an antenna that will tell me if it has a ground plane (besides overtly stating it)?

 

I have looked at many antennae over the last few days and haven't seen this mentioned.

 

For the record, these are the items I bought (some of them thanks to Tom Visser and José Frias)

 

http://www.ebay.co.uk/itm/2-4GHz-5dBi-Omni-WIFI-Antenna-SMA-MALE-for-wireless-router-/290848539329?ssPageName=ADME:L:OC:IE:3160

 

http://www.ebay.co.uk/itm/2-4-GHz-5-dBi-Omni-wifi-Antenna-BNC-for-wireless-router-/300479593163?ssPageName=ADME:L:OC:IE:3160

 

http://www.ebay.co.uk/itm/290607815327

 

http://www.ebay.com/itm/U-fl-to-BNC-female-with-nut-pigtail-cable-/330313219623?ssPageName=ADME:L:OU:IE:3160

 

And a pair of these (although these will live directly on Nomad and QRX 235 if used)

http://www.digikey.com/product-search/en?x=0&y=0&lang=en&site=us&keywords=931-1119-ND