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Discussion in 'DirecTV TiVo Powered PVRs & Receivers' started by feldon23, Jan 1, 2004.
thnx for reply
I've searched some but had no success finding a DC block. Have you got any links to them? How much do they cost?
Updated/Rewrote the Standalone/OpenCable HD TiVo section.
Did you try using google with the search term "dc block"?
Channel Master #7264 is a DC block: http://www.channelmaster.com/pages/TVS/Passives.htm
And the other question is what exactly do they do?
In a stacker/destacker situation, I could care less about power surges. The only reason I'd get a DC block is to prevent dumping power into the MDU system.
I don't know how many amps a multiswitch sends up the wire, but shouldn't we be worried? I did some searches and found power draws of anywhere from 180 - 275 mA when switching. If 10 apartments switch at the same time, that's a 2.75 Amp spike! I wouldn't want to be screwing around in the distribution closet when that happened!!
So, can a DC block stop the 13 and 18 volt signal?
If so, I'm going to recommend a DC block be used for each Destacker installation.
Interesting how they range from $2.99 to $75!
Any given coax connection wouldn't have that draw; even if a powered multiswitch used the power from the receiver to do anything (which I don't believe is the case -- it's just being detected to determine what the multiswtich should do), the powered multiswitch is always going to be sending power to the LNB's and will always have all 4 signals available, and each switching circuit in the multiswitch would be independently operating, always connecting some signal to the receiver.
13v and 18v are DC; if it's blocked, it's blocked.
It's just a capacitor. Here's an article on DC blocks: http://www.inmetcorp.com/PDFILES/MWRF8535E_article12-00.pdf
Yes, 100 apartments each sending 180-250 mA of power to try to power a dual LNB.
Maybe they already have DC blocks in the distribution closet.
But each one of those is over its own cable; the multiswitch(es) aren't doing anything with it except looking at it to see which signal to provide.
Even if the multiswitch just shunted the connections, the LNB wouldn't be drawing that much power from every receiver.
A non-powered multiswitch does need to operate off power from the receivers, but a powered multiswitch doesn't.
I had posted links earlier, I'll try to find the thread. Radio shack has them for a few dollars. My main concern is that normally you would put a destacker before each lead before it enters the multiswitch. I'm guessing the destacker removes the voltage or adjusts it to play nice with the stacker. By removing the destacker between the odd side of the MS and the stacker that line can send voltage straight to the stacker.
DSwallow, my point was the destackers may be altering the voltage/removing it before getting to the stacker. When you throw in a multiswitch and remove the stacker from one side, the MS might be sending voltage up the line that the stacker doesn't like.
Here's the Sonora catalog which include diagrams of the operation of the stacker, destacker and voltage inserter... http://www.pdi-sat.com/html/pdf/SonoraCatalog_PDISAT.pdf
They show how the DC power is passed or blocked (there's destackers that pass or that block).
Frankly, my head hurts trying to figure out where this statement originated from and following the path between receiver and destacker(s) and multiswtich(es), so maybe someone who knows can look at that and decide if it'd be necessary.
Just a thought, could we take this discussion off to another thread? I thought this one was for the unit specifically vs. installation.
I'd split it into a separate thread but I don't have that button.
How about this thread then?
First, I would like to add another big time thanks to feldon23 for the amazing work he's put into the "HD TiVo and HD DirecTV TiVo FAQ" including all the updates to keep it current. Also many thanks to all the contributors here who have provided lots of depth of information (including contributing to the technical information in the FAQ) as well.
We got our first HDTV two weeks ago and other than a few high def xbox games in 720p (that look amazing) have not yet had the HDTV experience yet with, well..TV but I would like to change all that ASAP. I have read through from message #1 (the FAQ) to present and just want to make sure I understand what I need to do the upgrade.
Have 2 Hughes standard def GXCEBOTDs DirecTivos (both unaltered 35 hour units in the family room, lovingly known as Tivo1 and Tivo2). The four coax lines (1 pair in each Tivo) come from the basement and a 4x4 multi-switch from an 18" dual (single arm) LNB dish pointed at Sat 101.
I plan to call DirecTV and try to get the $99 customer retention HD upgrade dealo for the included Phase III elliptical Trible LNB (3 arm) dish, HD receiver and installation. I also plan to pre-order the HD-DVR250 but depending on when the upgrade is done I would at least have an HD receiver to get us through for a month or so. In the spring we plan to look into adding a roof antenna to get the OTA HD locals.
Until we have the HD-DVR250, we'd like to continue to have both GXCEBOTDs hooked up and add the HD Receiver. When the HD-DVR250 arrives we would add that to the mix as well. Maximally, we could eventually have hooked up to the same HDTV...
-Two standard def GXCEBOTD DirecTivos (2 pairs of 2 DTV coax feeds). Might put one Tivo to rest once we have the HD-DVR250.
-1 (free DirecTV) HD Receiver. (1 DTV coax feed). Not sure if we would keep this going once we have the HD-DVR250.
-1 HD-DVR250 (2 DTV coax feeds).
-1 OTA antenna (1 OTA coax feed).
So as a max I see 8 coax feeds coming into the family room if we kept everything but we'll probably take either one GXCEBOTD or the (free) DirecTV HD Receiver out of the mix once the HD-DVR250 is on board. Just not sure at this stage so I want to be ready for the max situation.
OK, here come the questions...
1. 4x8 or 5x8 multi-switch? For the max situation, where I want 8 coax feeds into the family room, would I need a 4x8 or 5x8 multi-switch? If I understand correctly, the odd input on the 5x8 could be used for the OTA antenna input? Is there any reason I shouldn't just feed the coax from the antenna directly into the family room (and the single OTA input on the back of the HD-DVR250) and bypass the multi-switch? If I don't need a powered multi-switch now (with my 4x4), would I need one for any reason for the upgrade to the 4x8 or 5x8?
2. Does anyone know if as part of the Customer Retention $99 HD Upgrade deal I can get either a 4x8 or 5x8 multi-switch included?
3. Is there any use for my existing 4x4 multi-switch as part of our upgraded HD configuration?
4. Is there anything I'm forgetting or have terribly confused?
I'm sure I have some stuff just plain wrong so please straighten me out. It's late and I've got to get to bed so I'm a bit rushed. Please excuse any glaring stupidity here.
Thanks in advance to any and all for your assistance!
1) You'll have a hard time finding a 4x8 multiswitch; 5x8's are much more prevalent, and you can still choose to bring the antenna directly in on its own cable not using the antenna input on the multiswitch. No big deal -- just cap it off to keep moisture out. Almost all 4x8's and 5x8's are powered. A unit like the Terk BMS-58 (~$100) can be located outdoors and power is delivered to it over another coax cable from the supplied 110v power adapter. But since you'll need the antenna input on the DirecTV HD DVR, too, that'd be 2 places (the $99 deal HD receiver plus that), so you may as well use the multiswitch's capability to distribute the OTA antenna -- it amplifies the signal to accommodate the 8-way distribution and the loss from the diplexer, so you're not really losing anything.
2) Yes, just tell them you already have all 4 connections used and need the installer to bring a 5x8 multiswitch since the HD receiver will make 5; you'll already be getting the Phase III dish as part of the package since you only have a single LNB dish now and need the 3 LNB dish for HD programming. The Phase III dish has a built-in 4x4 multiswitch -- but since you need 5 outputs now, and 7 total later, you still need the 5x8 multiswitch... it'll just be connected to the 4x4 multiswitch on the Phase III dish (meaning the 5x8 multiswitch has to be cascadable -- and most are these days, like the Terk I just mentioned)
3) No. Sell it on E-Bay. Junk it. Save it for another project. Whatever.
4) You've pretty much got it covered.
LOL, well my reasoning was this:
If you combine two multiswitches with high-frequency splitters that doesn't block DC on one leg, you will slowly burn out the LNB. There seemed to be a rash of burned out stackers lately. Since most wiring diagrams always show a destacker on the end of every line in a stacked situation (even with a MS in the loop) I was thinking maybe they somehow regulate voltage on the line. With feldon's diagrams, you take a destacker out on one line with the MS in the loop. So I figured better to be safe than sorry and try throwing a dc block on the line to keep any extra voltage from going up the line. Since the MS locks on to odds or evens and the stackers powered, it doesn't seem necessary for voltage to be sent up the line on that side.
Hi Doug. Thanks for the complete and informative reply. I'm a little confused about the diplexer and what it does. Will it already be part of whatever HD antenna solution I get. I know the HD-DVR250 just takes a single OTA antenna input and can utilize 2 OTA tuners from it so I guess that's where the diplexer somehow comes into play?
Do I need to be concerned that the installer will bring a non-amplified (or otherwise inferior quality) 5x8 and thus do you recommend I be more specific about just what type of 5x8 I need him to bring or would I be better off just taking the hit and purchasing a good 5x8 like the Turk you mentioned? If so, can you recommend where I might order from?
Wired (aka "Doug").
The OTA antenna signal (50-850MHz and below) gets combined with the satellite signal (950MHz-1450MHz) by the multiswitch (or by using a diplexer "in reverse" of how you'd use it at the receiver).
The diplexer at the receiver is used to split the two signals back into separate cables, with the DC voltage coming from the satellite input on the receiver being passed up to the multiswitch.
It's not much more than a special-purpose splitter, but instead of splitting the signal equally, it splits it such that different blocks of frequencies are separated into different cables.
I don't think there's any guarantee what DirecTV provides via the installer for free. But I don't think I've heard anyone here mention getting a 4x8 or a non-powered 5x8. The Terk BMS-58 is available at most chain electronic stores like Circuit City.
From buy.com for $71.99: http://www.buy.com/retail/electronics/product.asp?sku=90118793&loc=111&sp=1
From solidsignal.com for $79.99: http://www.solidsignal.com/prod_display.asp?PROD=SPBMS58
Thanks again Doug. OK... so if..
a) I decide to feed the OTA Antenna coax into the 5th (antenna) input on the 5x8 multi-switch it combines the OTA + Sat freq signals together on each of the 8 outputs and the diplexer at the receiver splits out the feq range to use whatever is appropriate for the input a given coax is fed to - the OTA freq for the antenna input or the Sat freq for both Sat inputs? I want to be sure ... the diplexer is built into the reciever and not something I need to buy, right?
b) Or I can run the OTA antenna coax directly into the receiver. In this case is the diplexer in the receiver even used? Again, I want to make sure that in this case I don't have to purchase a diplexer either?
Does this work and apply the same way regardless if I'm using the HD Receiver from the $99 retention deal or the HD-DVR250?
I'm still not sure I'm fully appreciating the advantage of going with a) over b). Is it because there's some advantage of running the OTA antenna coax into a powered multi-switch.
Sorry if I'm missing the point a bit or being a bit too dense. I think I'm close and just need a little nudge to the finish line
Thanks for the purchase info on the multi-switch. The AC Adapter is included (as opposed to being optional) isn't it? What would happen if the multi-switch wasn't powered (like the 4x4 I have now)?
Finally, has anybody out there done the $99 customer retention deal with DirecTV where you needed the installer to deliver a (5x8) multi-switch? If so, which brand did he bring, was it powered. Any problems?