No it's not. There has been radiation observed from that old horn (tool) but the hyothesis that it came from the BB is not verifiable
Of course it is. There has been considerable observation, since Bell workers thought a Pigeon had crapped in their receiving equipment. You're quite mistaken. Also it's not a hypothesis, its a bonified testable scientific theory. For which there are other evidences.
"
During the 1990s, the first peak was measured with increasing sensitivity and by 2000 the
BOOMERanG experiment reported that the highest power fluctuations occur at scales of approximately one degree. Together with other cosmological data, these results implied that the geometry of the universe is
flat. A number of ground-based
interferometers provided measurements of the fluctuations with higher accuracy over the next three years, including the
Very Small Array,
Degree Angular Scale Interferometer (DASI), and the
Cosmic Background Imager (CBI). DASI made the first detection of the polarization of the CMB and the CBI provided the first E-mode polarization spectrum with compelling evidence that it is out of phase with the T-mode spectrum.
In June 2001,
NASA launched a second CMB space mission,
WMAP, to make much more precise measurements of the large scale anisotropies over the full sky.
WMAP used symmetric, rapid-multi-modulated scanning, rapid switching radiometers to minimize non-sky signal noise.
[55] The first results from this mission, disclosed in 2003, were detailed measurements of the angular power spectrum at a scale of less than one degree, tightly constraining various cosmological parameters. The results are broadly consistent with those expected from
cosmic inflation as well as various other competing theories, and are available in detail at NASA's data bank for Cosmic Microwave Background (CMB) (see links below)"
en.wikipedia.org