Does the Cosmic microwave background also lies in radio frequency spectrum? I heard the CMB is the electromagnetic radiation from the big bang. It is 13.7 b years old but isnt it only in the microwave range of the spectrum (300MHz - 300GHz) . Can a FM radio receiver (87-108MHz)pickup the noise from the CMB ?
I don't think it has neat boundaries...
 A: So Cosmic Microwave Background radiation corresponds very neatly to a blackbody spectrum of temperature 2.7K. This is an image which shows data collected by satellites:

The key thing to understand is that it is a spectrum, not a set of discrete frequencies that are present. So to answer your question, theoretically yes a FM radio receiver (87-108MHz) could pickup the noise from the CMB, but since CMBR has a very low intensity in the first place, as well as radio waves making up only a tiny part of CMBR's spectrum, in practise it's unlikely.
A: The CMB has a blackbody spectrum at T = 2.7 K, which peaks in the microwave range ($\lambda \approx 2\,{\rm mm}$).  The intensity of the blackbody spectrum is given by Planck's Law: $$B(\nu,T) \propto \frac{\nu^3}{e^{h\nu/kT} -1},$$ which decays but is nonzero at lower frequencies.
A: yes, it does. if you have an old analog television receiver, you can tune it to an unused channel in the UHF band and look at the random static on the screen. about 10% of that static comes from the CMB.
