title_body: Can I mount my RX and VTX antennae next to one another? I've heard that it is bad practice to mount a 2.4 GHz RC receiver antenna next to a 5.8 GHz FPV VTX antenna because the transmitting antenna will negatively impact the receiving antenna's reception. For example, this is said to be true in this Rotor Riot video at 1:40.
  
  Is this true? If so, how close is too close and how can I mount the two antennae to minimize the interference between the antennae?
upvoted_answer: The distance is dependent on the wavelength of the lowest frequency. You can calculate the wavelength $\lambda$ (m) from $\lambda = c \div f$, where $c$ is the speed of light in a vacuum (ms-1) and $f$ is the frequency (Hz.) Taking the centre frequencies of the ISM bands we get:
  2.4 GHz: $$\frac{299 792 458 }{ 2 450 000 000 } ≈ 0.12 = 12 cm$$
  5.8 GHz: $$\frac{299 792 458 }{ 5 800 000 000 } ≈ 0.05 = 5 cm$$
  (Quick 'sanity check' tip: 5.8 GHz is about twice 2.4 GHz, so we expect the wavelength to be about half; looks good.)
  The smallest separation is usually recommended as a quarter of the longest wavelength, which for 2.4 GHz is only 3cm - quite manageable. That said, greater separation helps so put them as far apart as your frame practically allows.