My dream: a full-spectrum DVR

I don’t remember who exactly first gave me this idea. It was clearly a long, long time ago, because at one time it went like this:

“What if there was a VCR that, instead of recording one channel, could record all of them at the same time?”

So obviously the idea goes back a while.

It still sounds really interesting. What if there were a DVR capable of pulling in all 6 satellite signals (I’ll explain the number 6 in a minute) and recording all of them. Not just one channel but the whole signal. If you had such a device, you could essentially choose any program to watch from any time in the past that the recording was still active. It would be like a psychotically powerful of DIRECTV’s 72-Hour Rewind feature. It would be every channel, period. It wouldn’t matter what you missed or if it was available on streaming. It would just all be there.

OK, so now I’ll explain the number 6.

DIRECTV’s SD and HD satellite signals come in one of four “flavors.” It doesn’t so much matter what satellite location is in use, the signals all end up being either Ku-band or Ka-band, “odd” or “even.” The oddness/evenness is due to the satellite transponders being assigned to one or the other signal, which lets the cable from the dish carry twice as many channels. This whole scheme was built around the fact that garden-variety RG6 cable can only carry so much stuff in the frequencies for which it’s built. In order to accommodate all the possible channels DIRECTV wants to provide, they needed to split things up a bit. The end result, whether you’re using SWM technology or the older legacy technology, is that only the fraction of the signal that you really need is provided on the cable at any given time. There are four choices: Ku-odd, Ku-even, Ka-odd, Ka-even.

Oh, that’s right, I said 6 not 4. The other two choices will eventually be used for 4K and they’re frequencies that were used originally only to send stuff to the satellite, not down from the satellite to the home. These are called “Reverse Band” and there are two choices, “odd” and “even” just like the other frequencies. As long as I’m dreaming, I may as well dream future-proof.

So in order to record the entire satellite signal, what you’d need is a DVR with 6 inputs, each feeding a tuner that could see the entire signal on that cable. That part’s not impossible.

The impossible part comes when you talk about cost. It’s hard to know what a DVR like that would cost. $5,000? $10,000? You’re talking about spreading the development costs out, but still the hardware itself is going to be very expensive, just like DVRs once were. Remember that TiVo’s original 6-hour, single-tuner DVR was $1,000 in 1999.

And then there’s hard drive space. Let’s assume that you’re going to need SSDs because you’re going to need very fast write speeds. I don’t think a hard drive could keep up. The best math I’m able to do says that you would need about 200GB/hour to store those signals. So let’s say this DVR recorded everything on a fixed three-day loop. That’s 14TB of space, and with SSDs going for about $400/TB as I write this, you’re talking about adding $5,600 in hard drives alone to this box.

All that math tells me that consumers will probably never see a box like this. It’s possible it exists in some corner of one of DIRECTV’s massive broadcast facilities, used to monitor the signals that come down from the satellite, but it’s most certainly a one-off, custom-built situation that would never get close to customer hands.

And really, this tells me that you have to be glad for something like 72-hour rewind that gives you almost everything from DIRECTV’s most popular major networks, so you don’t have to worry about it. Still, would be nice…

About the Author

Stuart Sweet
Stuart Sweet is the editor-in-chief of The Solid Signal Blog and a "master plumber" at Signal Group, LLC. He is the author of over 8,000 articles and longform tutorials including many posted here. Reach him by clicking on "Contact the Editor" at the bottom of this page.