  We provide an overview of various mechanisms, and corresponding powers, of
precursor emission to compacts' mergers to be detected by LIGO-Virgo-KAGRA
(LVK) collaboration. Expected peak powers, $\leq 10^{43}$ erg s$^{-1}$, are not
sufficiently high to be detected by all-sky high-energy satellites (unless
beamed). The best chance is the detection of possible coherent radio emission,
producing observable signals up to $\sim$ Jansky of flux density. Low-frequency
phased array telescopes like LOFAR, the MWA and DSA-2000 are best suited due to
their large instantaneous sky coverage. Time-wise, in addition to LIGO early
warning alerts up to a minute before the merger, the dispersive delay at lower
frequencies of $\sim$ 300 MHz can be of the order of minutes. Optical
detections are the most challenging.
