Order of magnitude of deviation in crt due to earth magnetic field

I estimated the deviation of the electron beam in a TV set due to earth’s magnetic field to be about 2 cm. I would have expected this to be much less, but to be honest I am not sure what to expect here.

This is for a l=40 cm long tube, a magnetic field B=1e-5 T and U=4 kV acceleration voltage.

For simplicity I assumed the magnetic field to be perpendicular to the electron beam. I calculated the velocity of the electrons to be:
$$
v=sqrt{frac{2e U}{m}}=37509467~mathrm{m/s}
$$

Then I calculated the radius of the circular path in the field to be
$$
R=frac{vcdot m_e}{ecdot B}=4,2~mathrm{m}
$$

and from here found the deviation via:
$$
x=R-sqrt{R^2-l^2}=2~mathrm{cm}
$$

My question: Does the calculation make sense (apart from the fact that I took a perpendicular field)? Is the size of the deviation realistic?

I could imagine that it is technically not that difficult to compensate for this deviation since the magnetic field is static.