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How Much Separation Is Required Between Inside & Outside Antennas?

We get asked frequently how much separation is required between interior and exterior antennas? What happens if it is less?

Signal feedback (otherwise known as oscillation) can interfere with the cell tower, and that is why it is vitally important that there’s proper antenna separation. This separation between antennas is a straight-line measurement from the closest interior antenna to the exterior antenna.

Please note that the stronger the outdoor cell signal, the more separation is required. Less separation may be sufficient for less cell signal. There are a number of factors that determine the closest allowable distance, and these include building materials, amplifier dB gain level, and so on. Please see below for the recommended separation distances.

Booster Gain (dB) Minimum Separation:

20 dB booster = 2 ft. to 3 ft.

30 dB booster = 4 ft.

40 dB booster = 6 ft.

45 dB booster = 15 ft.

55 dB booster = 55 ft.

65 dB booster = 70 ft.

68 dB booster = 80 ft.

70 dB booster = 110 ft.

80 dB booster = 125 ft.

Above separation recommendations are general and may vary depending upon the materials between the two antennas (inside antenna and outside antenna). Sometimes the separations have thick concrete between them and therefore will not require a lot of separation. Sometimes the separations only have a little drywall type material betwen the donor antenna (exterior) and the receiving antenna (interior). Amplifier itself will be the best indicator because it will confirm with its indicator lights whether separation is enough or not. What do each color cell phone signal booster indicator lights mean? Alternating red and yellow lights mean that external and internal antennas are too close together and they are causing something called an oscillation or feedback loop. This is when you can increase the distance between both antennae.