Expert: Jerry Hinshaw - 10/2/2009

Question
I need to know about residential cellphone bi-directional antennas. Do they work? What all do I have to purchase and where is a reputible place to buy one. I live in a cellphone dead zone. Can you hear me now? No!

Answer
Hello Dee,
Yes, a cell phone bi-directional amplifier (BDA) with a remote antenna can work to give you better cell phone coverage.  They work by placing a directional antenna in a good location to "see" the phone cell site and relay that signal to a (usually) indoor antenna closer to your cell phone.  The system is in essence a higher-gain antenna for your cell phone.
If there is no cell coverage at all in your area the BDA won't work. If coverage is poor at ground level or inside your house, an outdoor antenna and BDA may help greatly by placing the roof-top antenna in a good spot and carrying that signal indoors via cable to be re-transmitted near your cell phone.
I'll assume you want this for your house.   Here's a quick test you might try, if it is safe:  Take your cell phone up onto the roof.  Does it work well enough there?  If yes, a good antenna and BDA can probably give you coverage inside your house.
You need to purchase the rooftop gain antenna, a mount for the antenna, cable, BDA, power supply and the indoor antenna.  You can find these as a package on-line. Try searching for "cell phone BDA" to find suppliers.  
Keep in mind that there are two frequency bands for cellular phones in the USA.   One band is near 800 MHz, the other about 1900 MHz.   Get a BDA and antenna that matches your service.  There are dual band systems to cover both bands simultaneously.  
Regards,
Jerry