4DTV Satellite receiver:
Page 5 Ins and outs
For a device so clearly aimed at the high end of the home-theater market, the 4DTV's back panel makes some surprising omissions. First, there's no component-video output. This is no big deal for analog C-band signals, which are strictly composite in nature. On the other hand, DigiCipher signals originate and are transmitted in the component domain, and should therefore benefit (at least in theory) from such a connection to an appropriately equipped video display. The 4DTV unit does have the next best thing to a component output—an S-video connector—but this is active only when viewing a DigiCipher channel; it goes black when you tune to an analog signal. GI argues that equipping the unit with a high-quality comb filter (which separates the composite analog signal into its Y and C components and feeds them to the S-video jack) would add too much to its cost.

Perhaps, but in my opinion, it would be well worth it. Having to constantly switch between composite and S-video inputs on the video monitor is annoying, to say the least. DigiCipher signals do appear at the composite output jack, so you could watch everything in composite. But for a video geek like me, using a lesser connection than you have to is simply out of the question.

After a few days, I got tired of hearing my wife yell, "Honey, the TV isn't working again!" Fortunately, I had a Crystal Vision VPS-1 digital comb filter on hand. I connected the 4DTV's composite and S-video outputs to the filter and routed the filter's S-video output to my A/V switcher. This let me leave the TV's S-video input active all the time, and it further improved the picture on analog sources. I highly recommend this solution to all 4DTV owners.

Also absent from the 4DTV unit is any form of digital audio output. Again, the unit's analog/digital split personality makes implementing a digital output more complicated than on an all-digital product such as DSS. The 4DTV receiver would have to incorporate an analog-to-digital (A/D) converter to generate a digital signal when viewing analog channels.

Similarly, although the unit bears a Dolby Digital logo, it is not equipped to provide a discrete 5.1-channel output, only a two-channel stereo feed (albeit with matrixed Dolby Surround when this is present in the source signal). According to GI, virtually no programmer broadcasts Dolby Digital 5.1 signals via C-band, so there's little need for 4DTV to handle such signals at this time. Yes, the latest DSS units do have this capability, but it's useful only for a few PPV broadcasts. I consider the lack of 5.1 capability no big deal; if I want to watch a movie with 5.1-channel sound, I can buy or rent a DVD.

As for HDTV, C-band will certainly be a prime—if not the prime—signal source for many people, especially those who live outside one of the "major markets" where HDTV broadcasting will soon begin. The 4DTV receiver is equipped with a high-speed data port, which will pass HDTV signals to an outboard decoder box. General Instrument—a member of the Grand Alliance that created the DTV standard—tells me that the only thing holding up the decoder is the lack of a digital-interconnect standard to deliver the DTV signal to the display device. I'm also told that the decoder will have full Dolby Digital 5.1-channel capability.

Conclusions
As far as this channel surfer is concerned, the General Instrument 4DTV system is manna from heaven. But it's certainly not right for everyone. Compared to its arch rival DSS, a 4DTV rig is undeniably more expensive to purchase and install, somewhat more complicated to use, and definitely less space-efficient. But if you're building a high-end home theater and want the ultimate A/V program-delivery system, this is undoubtedly it. In terms of video performance, flexibility, choice, and long-term value, no other broadcast signal source even comes close. Don't let anyone tell you otherwise—in this case, size really does count.