Wireless Phone Service Where There Is None

Cell phone reception on our property is very weak.  Outside you may or may not be able to pick up a signal depending on where exactly you are, the weather, and the level of foliage on the trees. On a typical day, text messages can be sent and received with no expecation of them being transmitted immediately.  Email on my cell phone sometimes works, and there was one spot on the 2nd floor of the cabin where I could make a call if I used a headset and held the phone in a particular spot on a window. The battery rarely lasts over night, even without use. Some might say I should go without cellular service.  We can get land-line service at the cabin, but I plan on teleworking and would like Internet access that is better than dial-up and a reliable cellular connection would make 3G cellular data an option for Internet access. Fortunately, I was able to measure a signal level of -86 dBm for Verizon Wireless service at a point above the roof of our cabin. That equates to about 2 bars on your typical cell-phone signal meter which should be good enough to hold a conversation if I can extend that signal into the house.  Also, having a stronger signal would make the cell phone battery last longer.

I decided I wanted a dual-band repeater so that any carrier's phone could be used at the cabin, if a strong enough signal could be received.  Since carriers are continually expanding their networks, I don't want to have to buy another repeater should I decide to switch carriers later.

If you search the Internet for cellular signal boosters, you'll find advertisements for a whole slew of products, but only a few models are worth considering.  It seems that, in general, you get what you pay for. There are quite a few people who have complained in online forums that certain repeaters don't work at all. If you understand a few basic ideas, you can get a cellular repeater to work for you if there is an adequate signal outdoors (-90 dBm or better). While not rocket science, you can't just put up antennas wherever they look good or wherever it is convenient.

One problem to look out for is oscillation. Think of oscillation as being similar to the squeal of feedback that you get when you place a microphone too close to its speaker.  If the outdoor antenna receives the signal from the indoor antenna (if the two antennas are too close together), you can have oscillation.  The better repeaters detect this and step down the transmit power on the indoor antenna, but then your indoor coverage is reduced and the benefit of the repeater can all but disappear.  You may have increased signal strength only within a few feet of the indoor antenna in such a setup.  This is probably the reason for most of the complaints about poorly performing repeaters.

Another problem that you can run into is severe signal loss from the cable you are using.  If you have to separate your antennas by 50 feet or more (not uncommon) to get adequate signal, you need to make sure that the gain you get from the amplifier more than makes up for the cable loss.  If you're using common RG-58 TV antenna cable, then the cable loss will exceed most amplifier's capabilities after only a 30 foot cable run, or less. A good repeater manufacturer will offer low-loss cabling as an option or even require it.  It may cost more, but low-loss cable will provide you with a better experience.

Yet another reason for poor repeater performance is the use of the wrong type of antenna. If you have line of sight to a cell tower (i.e. no obstructions such as trees, buildings, or hills), then a Yagi antenna may provide enhanced performance.  Yagi antennas can be extremely directional and provide much more gain than other types of antennas.  This can be very helpful if you have an extremely weak signal.  If there is no line of sight, then an omni-directional antenna will probably work better. Omni-directional antennas can receive signals from any and all directions, so you can pick up reflections off of mountains and buildings that may be stronger than the shortest path signal coming from the cell tower.

The indoor antenna selection is equally important.  Dome antennas radiate the repeated signal in all directions, but don't cover more than one floor very well.  Panel antennas radiate in a wedge shaped pattern on one side of the antenna. The signal from a panel antenna spreads vertically, too, although vertical coverage is not as wide as the horizontal coverage.

In my case, I didn't have line of site to the tower, my house isn't big enough to separate antennas by 50 feet, and the house has two stories (with a steel roof). I chose an omni-directional antenna for the outdoor antenna and mounted it above the steel roof. I chose a panel antenna for the indoor antenna and mounted it at the height of the floor for the second story in an area with a cathedral ceiling so that I could cover both floors with one antenna and to make sure the signal stayed under the steel roof, limiting interference with the outdoor antenna.

I ordered the Wilson Electronics DB Pro kit because it offers 62 db of amplifier gain and uses RG-6 cabling which is present in many homes in satellite TV installations.  Using existing cable runs means you don't have to drill a hole through an exterior wall.  Users have many good things to say about Wilson Electronics' products online, so I felt comfortable with my decision. Unfortunately, the retailer I ordered from was sold out of the DB Pro kit I ordered.  They offered a substitute product from Cellphone-Mate.  The specs were very similar except that the Cellphone-Mate product used a much thicker cable.  The price was great, and I needed the repeater as quickly as possible, so I accepted the substitution.

So how did it all work out?  Well, here are some pictures of my temporary installation (only for testing purposes, as the kit comes with a 30-day satisfaction guarantee). Later I will mount the outdoor antenna much higher on the house, and mount the indoor antenna so that the cables aren't draped all over the window and floor.

The outdoor omni-directional antenna is
mounted above the steel roof so that it
can be placed closer than 50 feet from
the indoor antenna.

The indoor panel antenna is located high
enough to provide coverage to both floors
of the cabin.

I was impressed with the results. I now have four bars in many areas of the house where previously I couldn't get a signal at all. I expect further improvements when the outdoor antenna is raised another 16 feet or so. The Verizon USB data modem connection is performing at about 500 kbps, fast enough for me to do my work.  Voice calls sound great, so I'm very happy!

For those who might be interested, my RSSI readings inside the house went from -101 to -78 in the 850 MHz band (Verizon), and from -105 to -101 in the 1900 MHz band.


Resources
Cellphone-Mate: http://www.cellphone-mate.com/
Wilson Electronics: http://www.wilsonelectronics.com/
Wi-Ex: http://www.wi-ex.com/

Powerful Signal: http://www.powerfulsignal.com/