The ratings of 3 Wireless Telecommunication Services stocks are down this week, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

SBA Communications Corporation (SBAC) declines this week from a C to a D. SBA Communications Corporation owns and operates wireless communications infrastructure in the United States. The company also gets F’s in earnings revisions and earnings momentum. For more information, get Portfolio Grader’s complete analysis of SBAC stock.

This is a rough week for Philippine Long Distance Telephone Co. Sponsored ADR (PHI). The company’s rating falls to F from the previous week’s D. Philippine Long Distance Telephone Co. Sponsored ADR provides domestic and international long distance and cellular telephone services. For more information, get Portfolio Grader’s complete analysis of PHI stock.

Boingo Wireless, Inc. (WIFI) experiences a ratings drop this week, going from last week’s C to a D. Boingo Wireless, Inc. installs, manages, and operates wireless network infrastructure to provide Wi-Fi services at its managed and operated hotspots. The company also gets F’s in earnings surprise, return on equity, and free cash flow. For more information, get Portfolio Grader’s complete analysis of WIFI stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.