Found a good way of mounting the radio receiver antenna on this frame from one of RCModelReview’s youtube videos.
You need, one zip tie and a heat-shrink tube per antenna. The Frsky radio receiver has two antennas (two wires), so I will be using two each.
Put cable tie through any holes you can find on the top plate, zip it like this.
Put zip tie and the antenna wire through the heat-shrink tube. Heat up the heat-shrink tube, so it holds the cable tie and antenna wire tight.
No more worries that the antenna wires will get sucked into the propellers anymore!