Some businesses -- small-cap defense stocks among them -- are just inherently volatile. So I can't really fault signal-processing and surveillance contractor Applied Signal (NASDAQ:APSG) for variability in its revenue and order patterns. It's no more to blame for its lumpy results than, say, energy companies like ExxonMobil are for the price of oil or gas (contrary to popular opinion).

In Applied Signal's decidedly mixed second quarter, revenue was up 36%, slightly beating analyst estimates -- and that's a good thing. Though both operating income and net income fell from last year's levels as reported, excluding a meaningful amount of stock-option expense would have left those numbers up a bit year over year.

I get a bit more curious about Applied Signal's order book. Orders rose about 14% as reported, but management suggested that a lot of the growth in the first half of this year came from orders that should have been booked last year, but weren't. This "slippage" made growth look better than it otherwise would have. I may be guilty of reading too much into management's comments on the conference call, but it sounded to me like the outlook wasn't quite as strong as everybody had hoped a quarter or two ago.

That said, order flow in this sector can be difficult to forecast. Customers' budget allocations and supplemental spending make a difference -- particularly for a company like Applied Signal, where one or two orders can make a more meaningful impression on sales. It's also true that Applied Signal has allied itself with the likes of L-3 (NYSE:LLL) and Lockheed (NYSE:LMT) -- companies that are also competitors from time to time -- on certain projects and bids. What is the relevance of these alignments to forecasting order flow?

I'm not a big player in defense stocks, but I just don't see a compelling attraction to a stock like Applied Signal. There's nothing really bad about the business, but I can't find a "hook" that separates it from every other small-cap defense contractor looking to play the increased need for electronic surveillance and reconnaissance equipment. If it got really, really cheap, I might change my mind, but otherwise, it seems like more trouble than it's worth.

Further defensive Foolishness:

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Fool contributor Stephen Simpson has no financial interest in any stocks mentioned (that means he's neither long nor short the shares).