While they may not be perfectly isotropic, they are far from being directional (most TV transmitters are monopoles with uniform azimuthal radiation) and would s

While they may not be perfectly isotropic, they are far from being directional (most TV transmitters are monopoles with uniform azimuthal radiation) and would still not be distinguishable from background radiation (regardless of its distribution) at more than a light year or two away [0]. Highly directional radio emissions an order of magnitude more powerful than the strongest transmitters on Earth would only be visible at approximately 100 light years away [1]. [0] https://physics.stackexchange.com/a/245562 https://physics.stackexchange.com/a/245562 [1] https://arxiv.org/pdf/astro-ph/0610377.pdf https://arxiv.org/pdf/astro-ph/0610377.pdf