“Yeah.”
“Sorry to hear that.”
“Me, too. Listen, I also need a copy of the task force database we’ve been compiling.”
Another long pause.
“Paul?”
“You’re joking.”
“No. Back it up on a computer disc and toss it in with the rest of my stuff.”
“Anything else you can think of that might get me canned? How’s about if I punch out Snead for you, too?”
“If it comes up, I’ll say the disc was in my drawer.”
“You’re asking a lot,” said Deluca, lowering his voice. “What do you want that information for, anyway?”
“It’s better you don’t know. C’mon, Paul, will you help me or not?”
“Yeah, I’ll do it,” Deluca sighed. “You’re gonna owe me big on this, paisano.”
“Thanks,” I said. Then, before Deluca could change his mind, “Anybody down there miss me yet?”
“If they do, I’ll start insulting the brass and raising hell at the briefings. No one will even realize you’re gone. Which reminds me. Arnie called. He says he can meet you for dinner if you’re free. That cute brunette he’s boffin’ must be busy tonight.”
“Either that, or his can opener’s busted. Anything else?”
“Nope. Oh, I did notice a couple of message slips on your desk. Gimme a sec.” A pause, then, “One’s from yesterday. A woman, no name.” Deluca read off a Brentwood phone number.
I recognized it as Lauren’s, realizing she that must have tried to reach me at task force headquarters before calling the beach house. “What’s the other?”
“A guy who says he has some information you requested. I took that one myself. Damn, I can barely read my own writing.”
“You and everybody else. What’s the guy’s name?”
“Dexter. Hank Dexter.”
Later that evening I returned to Hank Dexter’s TV shop. The interior of the store had changed considerably since my last visit. Looking as if an army had marched through, it now displayed the ravages of a busy Christmas, including depleted equipment racks, empty merchandise cases, and the few salespeople present clearly suffering postholiday exhaustion.
As before, I found my friend at the service counter in the rear. Glancing up from the innards of a dismantled television, Hank smiled as I made my way back. “Dan,” he said, setting down a pair of needle nosed pliers. “We missed you at the wedding.”
I moved around the counter to shake his hand. “Sorry I couldn’t make it. I’ve been swamped.”
“Tell me about it. With Christmas and the wedding, things have been hectic around here, too. I did finally manage to check on that garage-door opener question of yours, though.”
“Breaking in if you don’t know the code and don’t have access to the original door opener control?”
“Right. It turned out to be more complicated than I first thought. Simpler too, oddly enough,” Hank added, his eyes sparkling with enthusiasm.
“How so?”
Hank thought a moment. “Okay, imagine you’re standing outside a garage that has an automatic door opener. You want to get in, but you don’t know the transmission frequency of the sending unit, or the coded sequence needed to activate the motor. You’ve actually got two problems: You need to know the code and the frequency.”
“There can’t be that many frequencies.”
“Wrong. The FCC has stringent rules concerning the use of unlicensed transmitters like door-opener remotes, but they allow use of the forty point sixty-six through forty point seventy megahertz range, and any frequency above seventy megahertz. As a practical matter, however, most door-opener manufactures stick to carrier frequencies between two-fifty and four hundred.”
“And they all use different ones?”
“Yep.”
“Damn. What about the coding part?”
Hank shook his head. “I encountered problems there, too. Generating sequential digit pulses as I originally suggested won’t work. Nowadays all garage openers have built-in microprocessors, making possible an endless assortment of code combinations, compound bit streams, algorithm controlled signal frames, rolling codes, multiple recognition requirements-”
“Whoa, Hank. You’re giving me more than I need. Cut to the chase.”
“I just wanted you to understand the complexities,” the older man sniffed, sounding disappointed.
“I do. You’re saying it can’t be done.”
“Not taking a straight-on approach. Not in a reasonable period of time, anyway. But then something occurred to me that simplified things. Come back here. I have something to show you.”
I accompanied my friend to a workbench in the back. After clearing a space, Hank placed a toaster-sized piece of electronic test equipment in the center. An array of buttons and a single knob covered the right side of the instrument’s face; a flat, rectangular screen the left. Hank pushed a button in the lower right-hand corner. A calibrated green grid appeared on the screen.
“What’s that?” I asked, leaning over Hank’s shoulder. “An oscilloscope?”
“Sort of. It’s called a spectrum analyzer. It analyzes electronic signals over a wide range of frequencies.” Hank slipped on his glasses, bent over the instrument, and made several adjustments. “There,” he said. “We’re ready.”
“Ready for what?”
“You’ll see. I got the idea from an article I was reading on how stolen cellular phones are reprogrammed with new ID codes snagged off the air. The principle here is the same.”
“I’m not following you.”
“It’ll be easier if I show you. I have the frequency span on our analyzer set to bracket the most commonly used door-opener transmissions. Watch.” Hank opened a drawer and withdrew a garage remote-control unit. He pushed the button. Instantly, a spike popped up on the right side of the analyzer display. “That’s our door-opener signal,” he said, tapping the green trace on the screen.
I watched as my friend twisted a knob, moving a small electronic screen marker to the tip of the spike. “Three hundred and thirty megahertz,” said Hank, reading a number off the display. “That’s the first part.”
I stared at the screen, my interest growing. “What about the code?”
“Easy. Once we know the frequency, we set the analyzer to it and zero-span the range. Anything coming in will now be displayed as a time-domain product of the envelope detector, in effect demodulating the signal.”
“You want to dumb that down a bit?”
“By zero-spanning the instrument, we can examine the components of one particular frequency,” Hank explained. Noticing the blank expression still on my face, he prompted, “The code, Dan.” He made another adjustment to the instrument, then pushed the opener button again. “There. See what I mean?”
I leaned in. The spike on the monitor had been replaced by a series of blocky pulses. “That’s it? The opener code?”
“Right. This particular code string is redundant-repeated twice in a one second period-with several bit reversals in the second frame. Tricky.”
“So anybody with one of these analyzers could sit down the street, wait for some poor sucker to come home, and record his door-opener signal. How close would he have to be?”
Hank glanced at the remote control. “Close. A hundred feet or so, although you could probably pick up the signal farther out if you used a directional antenna.”
“As far away as a block or two?”
“Possibly.”
“Then what? Push a button and rebroadcast the signal when you want to break in?”
