Another little tip, you can use the 1/4 wavelength X4R antennas from amazon. They are WAAAY longer than the stock xm+ antennas and allow you to position your antennas anywhere on any frame.
People will probably say you shouldn't use teh 1/4 length since it's not what the xm+ uses, but it has worked fine for me. If you do play on flying at range though, I suggest getting a GPS and a battery powered buzzer. I've gone down in teh middle of a wheat field and my buzzer was covered up. Plugged the coordinates into my phone and it led me within 2 feet of my quad. Never would have found it otherwise
Ipex4, can confirm because i just replaced one this week
nidici 5pcs 2.4G IPEX4 Feeder Line Antenna for FRSKY X4R / X4RSB / S6R / D Series / TF Series Receiver https://www.amazon.com/dp/B01M2BR2ZD?ref=yo_pop_ma_swf
Would this be the correct antenna replacement? https://www.amazon.com/NIDICI-IPEX4-Feeder-Antenna-Receiver/dp/B01M2BR2ZD/ref=sr_1_5?ie=UTF8&qid=1500407522&sr=8-5&keywords=x4r+antenna