Tutorial Please

[dougmcbride]

Well - after just three days of having Voom, I've already had one of my HT buddies decide to sign up for a two room system. Hopefully if we can keep the subs growing our beloved Voom will continue to provide service into the distant future...

Being an old C-Bander and Voom being my first foray into the small dish world, I'm still uninformed about some of the technology used for an unmovable dish that may pick up multiple satillites (in the future). And, since I only have a single TV and therefore a single STB, I'm not really familiar with what is needed to go multi-STB (and my buddy relies on me for intelligent conversations around his stuff). So, I was wondering if anyone had a link or could provide some info on how that works.

I'm pretty sure the multi-switch comes into play here, right? How many cable runs are needed for multiple STBs, and where in the coax line does the split occur? How does polarity switching come into play if you have more than one STB - in a C-Band system the polarity is switched in the LNB - same for the small dish? Etc., etc.

Any pointers, links, or discussion would be appreciated from this knowledgeable crowd.

Thanks,

Doug

 

[Ilya]

It's still not clear to me how this will all work with the future multi-satellite dish, but currently a typical multi-room setup involves a multiswitch and diplexers. The multiswitch would normally have three inputs: two coming from the LNB (one for each polarity) and one for the OTA antenna. If the OTA antenna has a pre-amp, that OTA input should pass DC voltage. If the OTA antenna is not amplified, then the OTA input should not pass DC voltage. The multiswitch would have several outputs (typically 4): one going to each STB. A diplexer attached to the back of the STB would separate satellite and OTA signals. Polarity is switched within the multiswitch by selecting one of the two LNB inputs. That's about it.

 

[dougmcbride]

Thanks Ilya - now I understand it better. So there are two lines running from the LNB, one for each polarity and the MS determines which one is needed for the selected channel. Also sounds like the MS at the dish end also has a diplexer built in, right? I wasn't sure how that part worked either.

Thanks again!

Doug

 

[Ilya]

That's right. Basically when the STB needs to switch polarity, it increases the voltage. If you have one STB, the polarity switching occurs within the LNB. In multiswitch scenario, two sides of the LNB (it's a dual-LNB) are pre-set to low and high voltage accordingly. So the multiswitch gets both polarities at once, but only sends one or another to each STB depending on the voltage set by that STB.

I described the most common (and the easiest) configuration where multiswitch integrates a diplexer. There are of course other possible configurations with separate diplexers or with non-diplexed OTA connections, but those are more complex and require more wires...

 

[riffjim4069]

Sure would be nice to run RG-6 or Cat5e and patch the hole in my basement ceiling...

Last month I added two receivers (three total) and ran separate coax for Sat and OTA. I ran an extra coax from the multiswitch to the STB which I plan to replace with a multiple tuner HD DVR. However, I still haven't patched a hole I created in the basement ceiling since I will need to run RG-6 or Cat5e to support Whole Home Networking. I sure wish VOOM would tell us how these devices are going to be connected: (1) I have a three acre lot and once the grass starts growing I won't have time to run cables or patch holes in walls. (2) Wife is getting tired of seeing the hole in the ceiling and wants it repaired.

There are only 73 more days (max) prior to deployment of the DVR. So what is it gonna be...Coax or Cat5e? I can't believe someone at VOOM doesn't know the answer to this question at this late hour. And I can't believe they wouldn't wish to pass along this information as quickly as possible. Anyone from Installs Inc. out there? My DVR install should be a piece of cake since I plan to have the cable installed and tested prior to installation.

A little off-topic, but just a few other questions: First, as I understand it version 1.0 of the HD DVR will have DVI and will not support Whole Home Networking...correct? Second, another version of the HD DVR, rumored to be released in mid-summer, will support Whole Home Networking and MPEG-4. Will this box also offer HDMI, larger hard drive, beefed up memory/processor and will it support firewire?