Question

Condition for duct propagation is _________

(a) \(\frac{dμ}{dh}\)  is -ve

(b) \(\frac{dμ}{dh}\)  is +ve

(c) \(\frac{dμ}{dh}\)  is zero

(d) \(\frac{dμ}{dh}\)  is unity

I got this question in an interview for job.

My question is based upon Space Wave Propagation topic in section Space Wave Propagation of Antennas

Answer 1

Right option is (a) \(\frac{dμ}{dh}\)  is -ve

Best explanation: The height v/s the refractive index graph of duct propagation is as follows

To determine the presence of duct propagation (T.I.L) and \(\frac{dμ}{dh}\)  is -ve.