Clarification re interim use of diplexer for OTA

1337 Views 16 Replies 10 Participants Last post by Groundhog45, Dec 2, 2006

jbongiovi

Discussion Starter · Dec 1, 2006

My understanding from other posts is that the Ka band and the OTA frequency conflict so one line cannot carry both signals. My further understanding is that the Ka frequency/bandwidth won't come into play until sometime in '07.

With this in mind my question is, can I use OTA with a diplexer with my AT9 dish and HR20 receiver until the Ka frequency/bandwidth comes online? Can I set my HR20 up like my HR10 and piggyback the OTA signal onto the coax after the multiswitch and then split it at the receiver without any problems until the relevant time in '07?

The reason I ask is I don't already have a dedicated line running from my OTA to each receiver (it goes only to the multiswitch box) and my local CBS affiliate has not yet signed a deal with D*TV for carriage of the HD signal (and about 80% of what we watch is on CBS).

Thanks for any assistance.

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Meklos

· #2 · Dec 1, 2006

jbongiovi said:
My understanding from other posts is that the Ka band and the OTA frequency conflict so one line cannot carry both signals. My further understanding is that the Ka frequency/bandwidth won't come into play until sometime in '07.

With this in mind my question is, can I use OTA with a diplexer with my AT9 dish and HR20 receiver until the Ka frequency/bandwidth comes online? Can I set my HR20 up like my HR10 and piggyback the OTA signal onto the coax after the multiswitch and then split it at the receiver without any problems until the relevant time in '07?

The reason I ask is I don't already have a dedicated line running from my OTA to each receiver (it goes only to the multiswitch box) and my local CBS affiliate has not yet signed a deal with D*TV for carriage of the HD signal (and about 80% of what we watch is on CBS).

Thanks for any assistance.

The problem is between the Ka LNB and the BBC. The Ka LNB block downconverts the Ka signal (or part of it?) into some of the same frequency space as OTA. The BBC then upconverts it to a much higher frequency range. (Two conversions? Were the engineering groups even talking to each other?)

If you put both diplexers (input and output) on the receiver side of the BBC, after it has already converted the 'offending' signal to the higher frequency range, then we shouldn't have a problem... except for the possibility of higher signal loss on the Ka due to the longer run at a higher frequency.

jbongiovi

Discussion Starter · #3 · Dec 1, 2006

Meklos, thank you for responding. I apologize for my ignorance but I'm not sure I understand.

Would my set up then be to diplex into the satellite line at my smartbox (but after the multiswitch) and then diplex out of the single line at the wall behind the TV before and then after the BBC dongle? Again sorry if I'm being dense.

Dave_S

· #4 · Dec 1, 2006

jbongiovi said:
Meklos, thank you for responding. I apologize for my ignorance but I'm not sure I understand.

Would my set up then be to diplex into the satellite line at my smartbox (but after the multiswitch) and then diplex out of the single line at the wall behind the TV before and then after the BBC dongle? Again sorry if I'm being dense.

There is a post on here that described it in detail, can't find it right now...but essentially you can connect the BBC's to the output side of the multiswitch, then put your OTA signal in the line with a splitter, and take it out at the HR20 with the diplexer.

Edit: Here it is

Meklos

· #5 · Dec 1, 2006

jbongiovi said:
Meklos, thank you for responding. I apologize for my ignorance but I'm not sure I understand.

Would my set up then be to diplex into the satellite line at my smartbox (but after the multiswitch) and then diplex out of the single line at the wall behind the TV before and then after the BBC dongle? Again sorry if I'm being dense.

Nah, it's a complicated scenario. Let's see if I can explain it better. Here's a graphical view... If you install it as

LNB - Multiswitch - BBC - DiplexerIn - DiplexerOut - Receiver

it should work. If however you do it any of the following ways:

LNB - Multiswitch - Diplexer - Diplexer - BBC - Receiver
LNB - Diplexer - Multiswitch - Diplexer - BBC - Receiver
LNB - BBC - Multiswitch - Diplexer - Diplexer - Receiver

it won't work (for various reasons). The core problem is the signal from the LNB to the BBC. It is in the same freq range as OTA. To get the signal 'out of the way' of OTA, the antenna-facing diplexer has to be placed 'after' the BBC.

Bad Rex

· #6 · Dec 1, 2006

Meklos said:
... If however you do it any of the following ways:

LNB - Multiswitch - Diplexer - Diplexer - BBC - Receiver
LNB - Diplexer - Multiswitch - Diplexer - BBC - Receiver
LNB - BBC - Multiswitch - Diplexer - Diplexer - Receiver

it won't work (for various reasons). The core problem is the signal from the LNB to the BBC. It is in the same freq range as OTA. To get the signal 'out of the way' of OTA, the antenna-facing diplexer has to be placed 'after' the BBC.

Just checking to see if I understand this. The third setup would work, but only if there was a BBC on all of the lines from the LNB to the multiswitch. So this setup would require 4 BBCs, whereas you really only need one if you are diplexing to one STB. If however you wanted to diplex, to 5 or more STBs, it would be more efficient to put 4 BBC's ahead of the multiswitch. Is that correct?

Also, while I'm here, Dave_S suggested:

LNB -- Multiswitch -- BBC -- Splitter(?) -- Diplexer -- Receiver

Can a splitter really be used this way?

jbongiovi

Discussion Starter · #7 · Dec 1, 2006

Thanks again. One last (potentially obtuse) question. The BBC is the Ka band dongle that comes with the HR20, right?

dpfaunts

· #8 · Dec 1, 2006

I have a Terk 5X8 multiswitch, I run the 4 lines from the AT-9 plus my antenna into the it. I have a several receivers including the HR20 with the BBC still connected to the back of it. I am able to watch my OTA on the receivers with that capability. I know that might not work in mid-07 when the start to use the new satellites.

Radio Enginerd

· #9 · Dec 1, 2006

jbongiovi said:
Thanks again. One last (potentially obtuse) question. The BBC is the Ka band dongle that comes with the HR20, right?

Yes it is.

To confirm you want to diplex as follows:

LNB - Multiswitch - BBC - DiplexerIn - DiplexerOut - Receiver

jimbo713

· #10 · Dec 1, 2006

I've enjoyed this dialouge - and I'm glad to see it's going to be easy to get OTA into the HR20 without the need for a seperate line from the antenna. Thanks!

Radio Enginerd

· #11 · Dec 1, 2006

jimbo713 said:
I've enjoyed this dialouge - and I'm glad to see it's going to be easy to get OTA into the HR20 without the need for a seperate line from the antenna. Thanks!

A word of caution I've heard from others... You'll want to limit the amount of cable between the BBC and the HR-20 to less than 50ft.

Meklos

· #12 · Dec 1, 2006

Bad Rex said:
Just checking to see if I understand this. The third setup would work, but only if there was a BBC on all of the lines from the LNB to the multiswitch. So this setup would require 4 BBCs, whereas you really only need one if you are diplexing to one STB. If however you wanted to diplex, to 5 or more STBs, it would be more efficient to put 4 BBC's ahead of the multiswitch. Is that correct?

Also, while I'm here, Dave_S suggested:

LNB -- Multiswitch -- BBC -- Splitter(?) -- Diplexer -- Receiver

Can a splitter really be used this way?

You know, I'm not sure if you could put the BBC between the LNB and multiswitch, but my gut tells me you can't. I *think* the BBC is signaled with voltage and frequency just like the multiswitch and LNBs are signaled (i.e. 22KHz, 13v or 18v) . And remember the 4 lines from the dish are actually coming from another multiswitch. Any signal could theoretically come on any line from that multiswitch.

I guess if you could lock the signals where you knew exactly which line was being used for what signal (between the dish multiswitch and the house multiswitch), you could put the BBC on that line Ka feed only. But that also brings up the problem of I don't know how the signaling is being done. Will the house multiswitch simply pass the signal from the receiver, or does it have to do something as well?

lpctv

· #13 · Dec 1, 2006

Radio Enginerd said:
A word of caution I've heard from others... You'll want to limit the amount of cable between the BBC and the HR-20 to less than 50ft.

And, as others have also cautioned, the BBC is not intended for outdoor use. So, make sure it's indoors or in a weatherproof enclosure.

Radio Enginerd

· #14 · Dec 1, 2006

lpctv said:
And, as others have also cautioned, the BBC is not intended for outdoor use. So, make sure it's indoors or in a weatherproof enclosure.

Good point, thanks for throwing that into the mix..

Looks like you all have everything you need to make magic happen.

Tom Robertson

· #15 · Dec 1, 2006

You do have choices. Unless you absolutely can't run another line, sure you can run the equipment as described here--if you can get the cable length down, the BBC indoors, and all that. And you probably could wait for FTM (frequency translator module) and likely spend money. But I'd really, really suggest you find a way to run that other line. Life will be so much easier that way.

Cheers,
Tom

jbongiovi

Discussion Starter · #16 · Dec 1, 2006

Thanks all. I appreciate the feedback. If I run into problems, I'll let you know.

Groundhog45

· #17 · Dec 2, 2006

Someone mentioned a splitter. That will not work in the equation. I'm using the diplexers on the line to my H20 with no problems but I'm not sure how it will work after the new MPEG4 content starts being broadcast. Hopefully we'll all be still good.

GH

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