User's Guide

SureCall | 48346 Milmont Drive, Fremont CA 94538 | 1-888-365-6283 | [e-mail]
8
Chapter 3: Planning The Installation
Note: You may not need antennas on every oor of a multistory building, depending on factors such as building
material, BDA gain, etc.
3.4 Antenna Separation
Proper antenna separation prevents signal oscillation (feedback) that can interfere with the radio tower. Separation is
measured in a straight line from the exterior antenna to the closest interior antenna. The closest allowable distance
depends on a number of factors, such as BDA gain level, building material, etc. Recommended separation distances
are:
Amplier gain Min. separation (ad)
40 dB 5’-6’
45 dB 15’-20’
50 dB 50’
55 dB 60’
65 dB 75-80’
70 dB 100’
75 dB 100’-120’
80 dB 120’-180’
Vertical separation is more important than horizontal separation. If you are unable to obtain the required separation
horizontally, try raising the exterior antenna. You may also try reducing the BDA gain as described in Chapter 5 of this
manual.