While a multi-feed receiver consists of an array of individual feed horns, an interferometer consists of an array of individual antennas spread out over a long baseline working together to simulate one large dish. Each single dish acts as a small piece of the synthesized large dish. The signal gathered by each dish is sent to a central computer, which correlates the signals and combines them into one. Over time, the rotation of the Earth causes the array of telescopes to rotate in an ellipse beneath the area of sky that is being observed, thus filling in the gaps between the dishes. In addition, the dishes can be placed on tracks and moved to different locations along the baseline, further filling in the gaps.

Whether the array consists of 27 elements such as the Very Large Array (VLA) in New Mexico with a maximum baseline of 27 kilometers, or the Very Large Baseline Interferometer (VLBI), a collection of dishes located in different countries around the world resulting in a nearly Earth-sized baseline, the results are the same – increased sensitivity (the ability to detect faint signals) and increased resolution (the ability to separate nearby points in the field of view).

Although interferometers are powerful telescopes and can outperform a single-dish when it comes to revealing fine detail in an object, they have their weaknesses.

Because an interferometer does not capture all of the incoming radiation from a source, inaccurate readings of flux density (the apparent signal strength or "brightness" of an object) is a common occurrence. A single-dish does capture all of the available incoming radiation, resulting in an accurate reading of the flux density of an object [6].

In spectral line emission observations, a single-dish telescope is able to produce an accurate reading in a matter of minutes; an interferometer can take several hours to complete the same task.