be returned by a nearby scatterer. Even if we assume that this noise is perfectly correlated with the internal receiver noise, it will only produce ripples in the spectrum at the level of a few *ppm* provided that the object, like a tree subtending a few deg$^2$, is more than $\sim100$ m away or a larger object, subtending $\sim100$ deg$^2$ is more than $\sim1$ km away.

Reflections of signals from compact radio sources may also be correlated. In this case the scatterer and the receiving antenna act like an adding interferometer to produce ripples in the spectrum. However, these effects are extremely small since a 1 Jy source results in under 1 mK of antenna temperature for the dipole-based EDGES system and the reflected signal is much smaller still. The ground reflection has been eliminated by placing the antenna on the ground. A brief discussion on the impact of these effects in radio astronomy measurements can be found also in @rohlfs_wilson.

Hardware Configuration {#s_edges_config}
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Following a careful choice of the deployment site for the experiment, the remaining sources of systematic uncertainty result from the hardware design of the system. The EDGES system consists of three primary modules: 1) an 