One of the remaining rationales for pagers -- yes, I know, does anyone even know someone who still has a pager? -- is that deep inside some buildings, cell phone service is lost. Some people -- doctors, for example -- keep pagers precisely because service is able to reach them regardless of where in the hospital they are. Once the technology is available to stop cell service from dropping, breaking up, and otherwise confounding users inside a building, though, the writing on the wall for pagers will become billboard-sized.

Airvana (NASDAQ:AIRV) is bringing to cell-phone users the scaffolding to put up those billboards. Called femtocells, the technology is a small cellular base station designed to be used in homes and office buildings. It connects with a service providers' network through a broadba nd connection. Think of it as Wi-Fi for your cell phone.

The technology is beginning to catch on. Sprint Nextel (NYSE:S), which needs something --anything! -- that will click with mobile users, began a launch last year of a Samsung femtocell. Airvana is signing up its own big names, including Motorola (NYSE:MOT). Qualcomm (NASDAQ:QCOM) is even an investor in the company.

Screening for likeability
Airvana showed up on a screen of companies that have enjoyed growing investor support after starting off the year on the outs. Airvana jumped from a two-star Motley Fool CAPS rating (out of five) in January to four stars today, while it also enjoys a valuation below that of the market.

CAPS is a 105,000-plus-member investor community that rates thousands of stocks on whether they will outperform or underperform the market. Although not a predictive service, in its first year of operation, the trailing returns of the stocks in the CAPS universe correlated precisely with their relative CAPS ranking. Four- and five- star stocks outperformed lowly one- and two-star stocks and the market as a whole.

Here are a few other companies enjoying significant investor support, as found with the help of our CAPS screener:

Company

CAPS Rating, January

CAPS Rating, Today

P/E

PEG

Airvana

**

****

2.9

NA

CAI International

**

****

14.5

0.8

D&E Communications (NASDAQ:DECC)

**

*****

10.3

NA

Integral Systems (NASDAQ:ISYS)

**

****

18.8

0.8

SWS Group (NYSE:SWS)

**

****

15.6

1.1

Source: Motley Fool CAPS, Yahoo! Finance; NA = not available.

Naturally, this is not a list of stocks to buy and sell -- rather, it's a starting point for further analysis. Investors have raised their outlook significantly on these companies, and there may still be room to move.

A fine mesh filter
Airvana and other femtocell providers still have to work out some issues, such as the limited number of phones that can be on a service and problems with interference that may disrupt a connection. However, investors think this is one of the next advances in mobile communications. CAPS investor WizeMoney thinks cell phone users will be able to finally untether themselves from their land lines. Here's an excerpt:

Femto technology will enable customers to ditch their landlines entirely. This is already [happening] throughout Japan and parts of Europe. The company has [original equipment manufacturer] partnerships with Alcatel-Lucent, Nortel, Qualcomm and most recently Motorola. They currently sell their high speed wireless technology to Sprint and Verizon. ... They are represented worldwide in booming India and China, Korea and the UK. The market research firm ABI Research expects that as many as 150 million people could be using 70 million femtocells by 2012.

Take a CAPS bow
There are many ways to screen for stocks to beat the market. You can use the new CAPS screener to find other stocks you're going to want to own. And if you want to see what other stocks CAPS investors are marking up to four and five stars, head over to Motley Fool CAPS now -- it's completely free to join.