After the loss of internal power the spacecraft could only be tracked using the tiny radio transmitter in the lunar capsule.

BBC: 1962: First US rocket lands on Moon

Ranger IV was also equipped with a seismometer and radio transmitter, designed to be released in a small capsule from the rocket before impact and land on the Moon in sufficiently good condition to measure the frequency of natural earthquakes in the body of the Moon.

BBC: 1962: First US rocket lands on Moon