Cell Booster FAQ's
Why do some cell boosters have automatic shutdown?
If equipped, many boosters include an automatic shutdown feature that prevents oscillation, or noise, from your booster. When oscillation is detected in the uplink and/or downlink features of your amplifier, the appropriate warning light(s) will begin flashing red and the power light will also turn red. If the problem is not resolved, the affected side controlling a signal band will shut down after 30 seconds. After 30 seconds, the booster will wake back up. When this occurs, the power light will be green. If oscillation resumes, the lights will flash as previously described. These 30-second cycles will continue for 15 minutes or until the problem is resolved.
If the problem is not resolved within 15 minutes, the booster will shut down (all lights off except the power light, which is red) and must be reset by unplugging it from the power supply and plugging it back in. To resolve oscillation, increase the antenna separation.
What is dB Gain?
In layman's terms, a gain value represents the relative level of signal enhancement a booster and/or antenna is capable of providing. A booster with a higher gain value will provide a stronger signal and/or a coverage area than one with a lower gain value.
Technically, gain is the ratio of a booster's or antenna's output power relative to the input power. Gain is usually expressed in decibels, abbreviated as dBs.
What is adjustable dB Gain?
Many models of boosters come with adjustable dB Gain at 1 dB increments because full power is not always your best option. Your goal is to obtain a usable cellular signal in as many areas of the building as possible. A successful installation means that you can make calls that do not drop and/or have a reliable data connection. Do not expect to see 5 bars of reception everywhere in the building as this is practically impossible. Also, signal strength in dB can vary significantly without necessarily affecting the number of bars displayed because different phone and data card manufacturers handle bars slightly differently. A good rule of thumb is that increasing gain by 6dB doubles the coverage distance of the interior antennas. Start at the lowest gain setting and increase gain gradually as needed. For further information, consult a online PDF of our Enterprise booster guides.
Does the length of cable between the signal boosters and antennas decrease signal strength?
Yes, cable length does decrease signal strength. Typically, for every 100 ft. of cable it decreases decibel, or dB, strength by 3-4dBs on the 800 Cellular band and 7dBs on the 1800/1900 PCS band. As you can see, the higher the frequency, the more the signal decreases. For the 700 LTE bands, it would decrease signal strength 3-4 dBs as on the Cellular band. For the AWS 4G band, signal strength would decrease similar to the PCS band, 7dBs, for every 100 ft. of cable length.
If a long length of cable is needed between a cell amplifier and antenna, in-line boosters with lower signal strength are sometimes used to extend the signal along the cable line.
Attenuation of CM400:
30 MHz = 0.7dB of loss per 100 feet
50 MHz = 0.9dB of loss per 100 feet
150MHz = 1.5dB of loss per 100 feet
220MHz = 1.9dB of loss per 100 feet
450MHz = 2.7dB of loss per 100 feet
900MHz = 3.9dB of loss per 100 feet
1500MHz (1.5GHz) = 5.1dB of loss per 100 feet
2400MHz (2.4GHz) = 6.65dB of loss per 100 feet
5800MHz (5.8GHz) = 10.8dB of loss per 100 feet
So, for an example, 100 ft. of cable from antenna to amplifier would decrease the 1800/1900 MHz PCS frequency by approx. 7-8dBs and decrease the 800 MHz Cellular frequency by 3-4dB. The same could be said about the 700 LTE frequency.
The Times Microwave site has a nifty little dB attenuation cable calculator online.
How many phones/data cards can be supported simultaneously?
With our direct connection units, only one phone or data card can be supported at one time. With our wireless units, the quantities of users vary depending on the outside signal. The better starting signal you get outside, the more coverage and users you can support.
Why, all of a sudden, do I have less coverage than before?
There’s not one straight answer for this question, it could be a number of things. Could be that somehow the outside antenna was physically damaged or that the separation wasn’t sufficient enough for the gain. Could also be that the connections could have been knocked or screwed loose. The important fact of the matter is to
1) Have the correct separation for the gain ( please refer to the gain chart above )
2) Mount the amplifier, antennas, and cables in a place where there won’t be much traffic or obstruction.
3) Keep away from direct sunlight.
4) Make sure the everything is connected very snug and secure
I’m getting good reception close to the inside antenna, but when I walk away, I don't?
Where is the best place to put an outside antenna?
The best method is to find an unobstructed spot on your rooftop away from other antennas where you can make cell phone call. Rather than risk injury, the next best method is to find out which corner of the house receives the best signal and install the outside antenna in that corner.
Do cellphone boosters or amplifiers need any maintenance?
We strive to make our amplifiers extremely user friendly, Please use the following checklist to perform an amplifier maintenance checkup.
Check amplifier for temperature
Check amplifier for any loose connections
Check cables for any sort of damages
Check both inside and outside antenna
Power-cycle the amplifier by turning it off, then back on.
What if I don’t have enough separation between inside and outside antennas?
What do bars mean?
Bars on a cell phone usually are not an accurate measure of cell phone strength. They are like a gas gage, they give you an idea of what a the signal is, not the actual strength. You can have two different brands of cell phones next to each other using the same carrier and they might show different bars. Some carriers have bragged they have more bars than anyone else. Once the carrier knows you have enough signal to make a call and talk, bars can be displayed anyway they want and the caller does not know the difference.
What is a cellular frequency?
All cellular phone networks worldwide use a portion of the radio frequency spectrum designated as ultra-high frequency, or "UHF", for the transmission and reception of their signals. The ultra-high frequency band is also shared with television, Wi-Fi and Bluetooth transmission. The cellular frequencies are the sets of frequency ranges within the ultra-high frequency band that have been allocated for cellular phone use.
Antenna Separation for Installing Amplifiers
Proper cellular antenna separation is essential in order to prevent signal oscillation, or feedback, that can interfere with the tower or shut your cellular booster down, temporarily. Separation is measured in a straight line from the exterior antenna to the closest interior antenna. The closest allowable separation depends on factors such as an booster's dB gain level, building location, or the building materials of the structure.
| 30 dB | 4 feet separation |
| 40 dB | 6 feet separation |
| 45 dB | 15 feet separation |
| 55 dB | 55 feet separation |
| 62 dB | 65 feet separation |
| 65 dB | 70 feet separation |
| 68 dB | 80 feet separation |
| 70 dB | 90 feet separation |
| 75 dB | 110 feet separation |
| 80 dB | 125 feet separation |