I'm using an extended range nRF24L01+ module and antenna, like this one:
I've made a small battery-powered transmitter using an Arduino and the module. I'm getting some weird results which are baffling me a little and I wondered if anyone could shed any light. Symptoms are as follows.
My TX circuit can send data a distance of 30m or so, which is all I need, BUT it only works when I hold it in certain ways. After some experimentation, I found the following two positions were most reliable at making it work:
a) Holding the antenna between finger and thumb about halfway to 2/3 from the tip to the elbow.
b) Lightly pressing my thumb over the nRF24L01+ chip, near the module's header.
Without doing this or something similar, data fails to transmit even when the two modules are right next to each other.
I had the circuit wrapped in a ziploc bag while I was trying this, so I know I was making no electrical contact between the circuit and my body, but I must have somehow been affecting the way the radio waves propagated.
I'd be very interested to know what's making it behave like this, and what I can do to maintain the range when it's enclosed in a plastic box and I can't touch it to make it transmit properly!
 Changed title to make it more descriptive