Special receivers -- mostly expensive tabletop models -- have to be bought to pick up the signals. And the sound improvement, while noticeable, is not all that startling on FM. 'For most people, FM is quite sufficient,' said Richard Robinson, an analyst at iSuppli. The very name HD Radio seemed full of promise in this era of high-definition television, or HDTV. But the HD in radio technology does not stand for high-definition. In fact, it stands for nothing. As iBiquity Digital, which owns the HD Radio brand, admits on its own Web site: 'It does not mean either hybrid digital or high definition, it is simply the branding language for this new technology.' OK, then. So maybe what was needed to boost the popularity of HD Radio was a hand-held player like the iPod. Earlier this month Best Buy's house brand, Insignia, introduced a $50 FM-only portable HD Radio player with headphones, armband carrier, USB charger and built-in LCD screen to show the station name, artist and song title when available. Alas, this little set, bulkier than an iPod but able to fit in the included armband, does little to make up for the shortcomings of HD Radio.The sound upgrade that's supposed to be the hallmark of HD Radio is hard to hear on the Insignia player, in large part because of the substandard ear buds that come with it. Reception is hit-or-miss. Inside the Los Angeles Times' downtown office building, I could receive only a handful of stations, and none strong enough to get HD sound. Moving to a window helped greatly, but the best reception was outside. At least you can use the player to get digital-only channels, but mostly they're just rebroadcasts of existing stations or automated all-music services. The Insignia product would be a lot more attractive if it played MP3s. That way, if the user was stuck in a situation where reception of HD Radio was problematic -- or no good channels were available -- it would be easy to switch over to uploaded tunes. Microsoft has said that later this year it will bring out a model of its Zune portable player capable of playing both HD Radio and MP3s. Looking to the future, Robinson said the format could gain a lot more interest if adopted widely into car radios. That may be the case. But for now, the initials in HD radio may as well stand for humdrum. 