NICE AND EASY: Why does a SWM-30 only support 26 tuners?

The first DIRECTV SWM ever made was the SWM-5. Although it never reached large-scale distribution, it supported 5 tuners. The first SWM multiswitch that went out into the world was the SWM-8, which supported 8 tuners. The SWM-16 followed, supporting 16 tuners, and at one point there was even a SWM-32, which supported (you guessed it) 32 tuners. Less well known was the SWM-13, a commercial-only product that supported 13 tuners on one run (previous SWM devices supported only 8 on one run.)

And then came the SWM-30. It supports… 26 tuners.

Say what?

That’s right. The SWM-30 supports 26 tuners. Now, that’s not necessarily the same as supporting 26 devices. If you’re confused by the difference between tuner support and device support, you’ll want to read our tutorial on tuner math. But let’s assume you understand that part. It still doesn’t explain why this particular multiswitch doesn’t follow the now-standard naming scheme that DIRECTV’s used since about 2008.

Actually, it does. But in order to understand, we have to backtrack a little bit.

A little about how SWM works

Now, some of the more technical folks will probably wince at this simplified explanation. But it’s not really the point of the article.

DIRECTV’s Single Wire Multiswitch technology was designed to solve a specific problem. In the 2000s, installing DIRECTV was expensive. The technology was all new and the cost of copper was high. The technology required that a wire was run from every receiver all the way back to the dish. That wasn’t too much of a burden when you had two receivers, but as people’s needs expanded, it got to be a bit of a problem. DVRs of the day required two cables each, and if you had four DVRs, as many did, that was a lot of wiring and a lot of holes in the wall.

SWM technology was designed to make cabling easier and take advantage of existing conduits in the home. By stacking up to 8 satellite signals on a single wire, it became possible to use splitters throughout the home. This cut down on installation times and wiring costs.

Later iterations of SWM used two SWM channels of 8 tuners each (SWM-16) or four SWM channels of 8 tuners each (SWM-32) for larger installs.

Enter Digital SWM

The next generation of SWM technology was the so-called Digital SWM. Of course all satellite signals are digital, but the original SWMs used analog processing to move those digital signals. By switching over to a pure digital system, the space between those stacked signals could be reduced and the amount of total bandwidth used could be increased. In theory this increased the number of stacked signals on a single line from 8 to 21.

As frequencies get higher, signal loss increases so the space for tuners 16-21 really didn’t end up being as reliable as anyone had hoped. But still, 15 tuners on a single wire was pretty good.

The SWM-30 was designed to provide support for two runs of 15 tuners each using digital filtering technology. This was perfect for the 5-tuner Genies at the time and meant that a SWM expander with four SWMs could serve 24 apartments in a very compact package. (In case the math isn’t making sense, that’s three Genies per run, two runs per SWM, four SWMs per expander.)

Here’s where the real problems happen

First of all, today’s Genies use 7 tuners and can reserve up to 11 tuners depending on the situation. That means realistically you can use only one Genie on every SWM run. But that’s not the biggest problem.

There are plenty of cases where you want to have multiple receivers instead of a Genie DVR. Genies aren’t allowed in commercial installs, for example. So, you should be able to max out that SWM-30 by running 15 receivers on a single line. Except, you can’t.

DIRECTV’s newest receiver, the H25, was designed and built in 2011. It’s a tough soldier and keeps on working out there in the field. But, its tuner chips just don’t understand the new digital SWM technology the way they should.

When a receiver is connected to a SWM system, it reserves one of those signals for itself. Today’s receivers, built a decade ago, simply can’t count higher than 13. They can reserve signal 1. They can reserve signal 2. And so on. But ask them to reserve signal 14 and they just won’t do it. This means that the 14th and 15th signals on a SWM-30 go unused. The effect is two runs of 13 tuners, and that’s 26.

What happens if you connect 15 receivers to a SWM-30?

Two of them won’t work. You won’t be able to predict which two. It’s a bad deal overall.

Hope for the future?

It wouldn’t take much to address this issue. Just make a new line of receivers that can tune all 15 available slots. And I have every confidence that it will happen. But until we can guarantee a new install will go in with all new receivers, we’ll continue to recommend 26 receivers on a SWM.

If you’re looking for a custom-built commercial DIRECTV installation, call us at 888-233-7563 during East Coast business hours. Solid Signal is here to help!

 

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.