The current at the base of an earthed antenna 30 metres high is 20 amperes at a frequency of 1MHz. Calculate the field strength at a distance of 10 Km.(adsbygoogle = window.adsbygoogle || []).push({});

Now in this question do we have to consider that field generated from the antenna and field at the distance 10 Km are same ??

I solved like this....

power generated from monopole ( as given in question that antenna is earthed)

P = 80[∏xI]^{2}[l/λ]^{2}

where l = 2h

and h=30 m

l=60 m

I=20 A

λ=c/f = 300 m

So P=37.86KW

Power density at a distance of 10 Km =P/(4∏[10000]^{2}

= 30.14uW/[m][/2]

=[E]^{2}/120∏

From this i am getting E=106.5mV/m

But the answer is 4.8μV/m

I THINK I AM TOTALLY WRONG..........

Please tell where i am wrong...

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# Homework Help: Electric field of antenna

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