Back when having a five-CD changer in your car was new and impressive, I had one that sat in my trunk and sent songs to my FM radio. It worked on one of only four frequencies, all at the lower end of the dial, but one of them was unused in my area, so it was fine as long as I didn't drive to New Jersey.

That was a long time ago, particularly in electronics years, which has me wondering why the Griffin iTrip, a good-looking iPod attachment based on the same idea, is so hard to get along with.

I invested in one (about $30 on several sites, or $35 at griffintechnology.com) after reading some promising things on Mac discussion sites. I'd been using a cassette-like gizmo that connected to my iPod via a wire plugged into the headphone outlet. It had worked well long enough, but eventually, its moving parts, even without tape inside the cassette, began to wear, and squeaks became part of the sound.

To use the iTrip, you first transfer a series of five-second "songs," each representing an FM frequency, into iTunes and import them into the iPod. Then you find an FM frequency not in use and "play" that frequency on the iPod with iTrip's hardware affixed to the top.

It's slightly laborious and quirkier than seems justified, but those ought to be only minor complaints; once tuned in, you should be able to just set it to that frequency and leave it, no? Well, no, but even if so, here's the larger complaint:

It just doesn't work that well.

In my experience, music from the iPod sent through iTrip too often sounds like it's being played on an iSock, muffled just enough to be maddening. At its best, fidelity is merely acceptable, but in a moving vehicle, conditions are rarely ideal.

First, it's not that easy to find a clear FM frequency, a baffling fact in an era when there's nothing on radio worth hearing. But try it yourself: Tune up and down the dial one notch at a time, and you'll find that most of them, if not carrying a signal, are carrying bleed-over from a neighboring frequency or signal-skip from who knows where.

Common sense says that you shouldn't need a completely clear channel, since your transmitter is mere inches from your radio receiver, which ought to make up for its low power. But practice has shown that those signal ghosts do interfere. And, of course, if you drive even 20 or 30 miles, you get a different set of interferers, which returns you to the first complaint: If you've got to retune often, then it ought not be laborious or quirky.

At least on longer trips, the low-grade hassle of plugging in and activating iTrip seems justified. But unlike when I could let the cassette sit in the player and just plug my iPod in, I've found on shorter trips that I'd rather stomach the latest "expert" try to defend Grady Little on AM 850 than stumble down the iTrip's steps.