Nervous about your investments? A device called Pocket Quote Receiver lets you monitor your portfolio 16 hours a day, seven days a week.

About the size of an overgrown calculator, the receiver utilizes "FM subcarriers" (the unused portions of commercial FM signals) to let subscribers tap into the New York and American Stock Exchanges the NASDAQ National Market, and all four options exchanges. To use Pocket Quote you program in any combination of 20 stock and option symbols from the 3,000 stocks and 9,000 options available. Then, anytime from 8:00 a.m. to after midnight (eastern time), you can check your investments' prices (high, low, and last) and transaction volumes by punching a couple of keys. Another key lets you review prices for your entire portfolio.

The unit also broadcasts opening dollar and London gold prices, along with general financial bulletins: price indices, retail sales figures, and national and world news headlines. If there is late-breaking news affecting any of your 20 stocks, a loud beep alerts you to call your broker.

All these messages appear on the receiver's calculatorlike LCD screen. For a clear reception, though, you must be within 50 miles of a major metropolitan area. Also, all quotes are delayed 15 minutes. That gets the service out of paying a hefty stock exchange fee, which would increase the cost to subscribers.

Developed by Telemet America Inc. in Alexandria, Va., Pocket Quote Receiver broadcasts are now available in Boston, New York, Chicago, Detroit, Denver, Dallas, Los Angeles, Cleveland, Philadelphia, Washington D.C., and Miami, Fla. The receiver itself costs $349, with a one-year subscription tagged at $239 -- all, of course, tax-deductible to bona-fide investors. For more information, call Telemet America at (800) 368-2078.