Myth Buster: Cell Phone Reception Boosters: Do they really work?

Do cell phone signal boosters work? Here is a faux empirical study. Why faux? Well, the controls and measurements were not as strong as in a true scientific experiment but still good enough from a home improvement project point of view. Let's see the Table A below. It shows cell phone signal strength on a languid Saturday afternoon at various locations in my home. I measured using my business Blackberry (BB). It's not that hard. Just select "Options" and then select "Status" to view the strength of the signal measured in dbm. As far as I recall this is measured as a ratio of milliwatt on a log scale. But don't believe me. If you really want to drill down, then better check out Wikipedia. I have tried to take these readings every 60 seconds but to tell you the truth I wasn't using a clock. Therefore, depending upon the goodness of my estimate and whether or not I was talking with my wife, these readings could be anywhere from 45 to 120 seconds apart. Well, that just proves my point that this was a faux experiment.

Table 1

Location A	Location B	Location C	Location D	Location E
-107 dBm	-102 dBm	-110 dBm	-107 dBm	-107 dBm
No coverage	-107 dBm	-94 dBm	-110 dBm	-110 dBm
-110 dBm			No coverage	-94 dBm
-96 dBm				-110 dBm
-102 dBm				-94 dBm
-94 dBm				-102 dBm
-95 dBm
-102 dBm
-110 dBm
-94 dBm
-110 dBm

Accurate measurement or not, the reality is that I was dropping calls quite frequently. Whenever, my BB got a "No Coverage" message, I dropped a call. At -110 dBm signal strength, the quality of sound was really bad.

My guess is that my Verizon BB phone works on 800 MHz and 1900 MHz both. Therefore, I bought a cell phone signal booster that works on both frequencies. There are lots of cell phone signal boosters available in the market. You can Google, Bing or Yahoo to find several signal booster products. Bare antennas will hardly ever work. In fact, signal booster is a misnomer. These electronic devices don't boost cell phone signal. They pick-up the signal from a suitable location and repeat broadcast it in a small area. Therefore, the right name for these devices would be cell phone signal repeater. Well, this is exactly what we proved from this faux experiment.

I measured cell phone signal at several locations in my house. Finally, I found a location F (Table 2), which was getting an excellent signal. This is where I installed a yagi antenna for 800 MHz and a panel antenna for 1900 MHz cell phone frequencies.

Table 2

Location F
-87
-94
-88
-94
-88
-92
-94
-94
-85
-92
-84

Location F is showing a strong cell phone signal. At this location I pointed the yagi and panel antennas in the direction of maximum signal strength.

Table 3

RG-6	RG8/LMR400 (Single core)
-86	-87
-107	-87
-94	-94
-110	-84
-82	-110
-94	-87
-107	-82
-82	-102
-102	-94
-107	-107
-87	-87
-107	-87
-88	-85
-94	-84

The cell phone signal booster device came with a 50 ft UHF RG-6 cable for connecting the antenna to the device. Initially, I used this RG-6 cable to connect the antenna to the cell phone device. RG8 cable reduces the signal loss and improves the signal strength but is the gain really worth the trouble of connecting the RG8 cable. Personally, I don't think so. RG6 cable is good enough. Table 3 shows comparison between the signal strength after the cell phone signal booster device is connected to the antenna using RG6 cable versus RG8 cable.

Final Verdict

1. Cell phone signals in Table 3 are still weaker than the signal at Location F shown in Table 2. Clearly, the cell phone signal booster device is not boosting the signal.
   
2. However, the "cell phone signal booster" device is repeating the signal found at Location F all over the house (Table 3), therefore the cell phone reception is now much better.
   
3. Dropped calls which used to be frequent are now rare.
   
4. This cell phone signal booster device works but it is not a "booster", it is a cell phone signal repeater device.
5. If you can find at least one spot anywhere in your house that has a decent signal reception, then you can install the antenna there, connect the antenna to the cell phone signal repeater device and broadcast the signal all over your house. But if you don't have any spot in your house that gets a signal, then don't waste your time and money on these devices.
   

Post Script: After upgrading the cable to single core RG8 (LMR400), I certainly feel that the difference is significant. The signal is now more stable and voice clarity is substantially better. If you are planning to upgrade the cable from the stock RG6 to single core RG8. Here are some links that you may want to check out:

RG8 single core cable by foot: http://www.universal-radio.com/catalog/cable/coax.html
How to solder PL259 connectors: http://www.hcarc.us/articles/soldering%20PL-259%20connectors.htm