Cell Signal Booster Uplink/ Downlink Power in dBm & Frequencies

All cellular devices including tablets and smartphones operate within the radio frequencies that are commonly known as 3G and 4G. Regardless of which cellphone carrier provides sevice to your device (Verizon, AT&T, T-Mobile, etc), when slow internet and dropped calls are experienced, a cell phone signal booster can be used to boost the weak 3G & 4G signals between a cell phone and a cell phone tower.

While cell signal boosters can be used to boost poor 3G and 4G signals between a cellphone and a cellphone tower, it is important to understand how much impact higher or lower signal gain signal booster can have with its uplink and downlink power gain in dBm on various frequencies your mobile service carrier uses. To understand that, we must understand the fine difference between dB and dBm. dB or Decibel in cellular signal boosters indicate the power increase possible with them and called, "Decibel Gain". dBm on other hand, is an absolute measure of mobile signal strength. It is an abbreviation for Decimal Milliwatts, and is calculated as ten times the log of the signal strength in milliwats. It indicates actual wireless signal strength at a particular location, at a particular time.

It is of course best to choose cell phone signal booster that provides maximum downlink and maximum uplink power gain measured in dB or decibels, but even the least uplink and downlink gain powered signal boosters also provide tremendous in-building and in-vehicle coverage improvement. Let us explain that clearly with basic stance from a layman's perspective, or scroll below to review the table that shows correlation between "decibels" and "power".

Signal from a cellular device to a cell tower is known as the uplink, while signal coming in from a cell tower to a cellular device is known as the downlink. These signals are more commonly known as upload and download.

During a voice call, it often happens that you can hear the person on the other side, but they can’t hear you, or vice versa. That happens when downlinks or uplinks are disrupted. 3G is more susceptible to this than 4G because it actually uses two frequency bands, 850 and 1900 MHz, one for downlinking (listening), and the other for uplinking (talking).

How Cellular Service is affected by Uplink & Downlink Power.

Cell phone signal strength is measured in decibels (dB) and operates within a signal level of between -50 dB and -120 dB. All phones and cellular devices for all carriers in the USA and Canada operate roughly at this level.

-120 dB represents poor signal (near dead zone), while -50 dB represents the best signal (full bars).

Cell phone reception problems normally happen within a signal strength range of -90 dB to -100 dB. Although a working signal is possible within the -101 dB to -120 dB range, service is severely affected.

As cell signal decibels are exponential, a "small" signal difference of +3 dB represents 2x the power! This however also means that -3 dB means half the power. Thus, it is important to understand the co-relation between decibels and power because even a single decibel gain increase makes a huge impact in boosted cellular coverage.

The correlation between decibels and power is shown in the table below.

Decibels	Amplified Power
+1	1.3x
+3	2.0x
+6	4.0x
+10	10.0x
+20	100.0x

 

Cell coverage is affected by many factors, including the cell phone service carrier frequency used, distance from a cell tower, building material, outside interferences, internal impediments, and the user’s location. Just about anything and everything will therefore affect the quality of both incoming and outgoing signals.

How Uplinks & Downlinks are Improved by Enterprise Signal Boosters.

Although commercial cell phone boosters approved by the FCC are legally capped at a max of +70 dB gain, this potentially adds a tremendous boost to coverage and signal strength. Although enterprise boosters have a maximum gain of +70 dB, the factors mentioned above will generally limit real-world gains to between +3 dB and +42 dB for most users. This represents at least 2x amplification of 3G and 4G signals.

This boosted signal results in more powerful uplinks and downlinks, leading to two major benefits of using a signal booster - increased coverage and faster internet data speeds.

When comparing the power output of two top-of-line Wilson Pro cell signal boosters, the Wilson Pro 4000R and the Wilson Pro 70 Plus, we can see the following:

Uplink and Downlink Power of WilsonPro 4000R versus WilsonPro 70 Plus:

Downlink power:

The downlink power for both models averages out at 10.62 dB and 10.43 dB respectively over all frequencies. Based on the decibel / power table shown above, this translates to the downlink power being boosted by a factor of 12.5x.

Uplink power:

An uplink power is however substantially different for the two models, with the 4000R averaging out at 26 dB, and the 70 Plus at only 22.16 dB across all frequencies. The 4000R therefore has an average of 3.84 dB more uplink power than the 70 Plus. Once again using the decibel / power table shown above, this translates to the 4000R being 2.11x more powerful than the 70 Plus.

This translates to slightly more than double the coverage. The Wilson Pro 70 Plus provides coverage of up to 50,000 square feet, while the Wilson Pro 4000R provides coverage of up to 100,000+ square feet.

When fleet and vehicle units Drive 4G-X and Drive 4G-M are compared and the results analyzed, we obtain the same type of results:

Uplink and Downlink Power of Drive 4G-X versus Drive 4G-M:

Downlink power:

The downlink power for both models averages out at 2.47 dB for both models over all frequencies. Based on the decibel / power table shown above, this translates to the downlink power being boosted by a factor of 1.8x.

Uplink power:

Uplink power is however substantially different for the two models, with the 4G-X averaging out at 23.66 dB, and the 4G-M at only 20.66 dB across all frequencies. The 4G-X therefore has an average of 3 dB more uplink power than the 4G-M. Once again using the decibel / power table shown above, this translates to the 4G-X being 2x more powerful than the 4G-M.

This results in up to 2x the reach to the nearest cell tower while on the road or out in the field, which is especially handy in remote, rural areas when signal and carrier service is often limited. Higher uplink power helps make wireless connections when farther away from a cell tower.

Cell Phone Signal Booster Uplink and Downlink Frequencies.

Uplink frequency is the specific frequency that is used to send a signal from the phone to the cell tower, while the downlink frequency is the specific frequency used to send a signal from the cell tower to the phone. Please see blue chart shown at the top of this post for details how various cellular service providers such as Verizon Wireless, AT&T Wireless, T-Mobile, and Sprint use varied frequencies for uploading and downloading voice & data signals.

These broad definitions don't however mean anything to those who are not familiar with these terms. To understand the benefits of a cell signal booster, it is always good to understand cell phone signal strength in terms of dB and the differences in models by looking at uplink and downlink power output. Let us examine how two different brand and type of signal boosters offer different downlink power on various different freqiencies.

WilsonPro 1000 versus SureCall Fusion5X 2.0 Downlink Power Comparison:

Downlink Frequency	Fusion 5X 2.0 Downlink Power	Wilson Pro 1000 Downlink Power
LTE Lower (728-748 MHz)	13.1 dBm	15.2 dBm
LTE Upper (748-757 MHz)	13.7 dBm	14.6 dBm
Cellular (869-894 MHz)	15.7 dBm	14.8 dBm
PCS (1930-1995 MHz)	15.3 dBm	14.6 dBm
Cellular (869-894 MHz)	16.6 dBm	11.9 dBm

 

Per specifications provided by the respective cell phone signal booster manufacturer, Downlink Power Comparison between SureCall Fusion 5X 2.0 versus Wilson Pro 1000 above shows Fusion5X 2.0 has more Downlink Power than the Wilson Pro 1000 in 3 out of 5 bands providing larger indoor coverage area for those three respective frequency bands. Pro-1000 provides more Downlink Power than Fusion-5X 2.0 in 2 of 5 bands providing more indoor coverage area for those two respective band frequencies.