Can I use diplexer to get antenna feed to my multiswitch?

[stedman99]

Hello-

I have searched the forums and I apologize if a similar question has already been answered. On to my question:

I have a dual LNB dish with 2 coax lines running from the attic, down 2 stories and into the basement where my terk 3x4 multiswitch is. The previous homeowner did not run a line for a roof antenna. It would be very difficult to run another coax strand to the multiswitch. I was wondering if I could take one of the existing coax lines and use a diplexer to feed the antenna input on the multiswitch. My thought was that I could put another diplexer in the basement to split the antenna back off and then connect it to the antenna terminal on the multiswitch. Will this work? Thank you.

[greywolf]

It will work half the time. If you diplex into the line that goes to the 18V input on the multiswitch, you'll only get OTA signals when the last channel chosen on the receiver where the output diplexer is came from an even numbered transponder for example.

[stedman99]

It will work half the time. If you diplex into the line that goes to the 18V input on the multiswitch, you'll only get OTA signals when the last channel chosen on the receiver where the output diplexer is came from an even numbered transponder for example.

I would be breaking the antenna feed back out and connecting it to the antenna input on the multiswitch (which is currently unused). Would it still only work half the time?

[carl6]

Why would it work that way Greywolf? Is there some inherent property of a diplexer that only allows it to work when the powered leg is powered?

Carl

[greywolf]

You need to connect diplexers to every input of a multiswitch. The 18V input is dedicated to even transponders and the 13V input is dedicated to odd transponders. You can use a splitter and two diplexers or a dual diplexer such as http://www.solidsignal.com/prod_display.asp?main_cat=20304&CAT=&PROD=SPTDX32

[Mike500]

I have a supply of JVI quad diplexors that can be used with your setup or a Phase III dish. SEnd me a PM, if you need one. It's less than the Terk dual delivered.

[greywolf]

A quad diplexer could work just fine. Do be aware it will cause a 7db drop in OTA strength per line due to splitting alone rather than 3.5db with a splitter or dual diplexer. It's rare that would be a problem though.

[boba]

Why would it work that way Greywolf? Is there some inherent property of a diplexer that only allows it to work when the powered leg is powered?

CarlUsing a pair of diplexers will work quite well I would suggest using a signal amplifier on the OTA line before feeding it into the 3X4 multiswitch unless you have a real strong antenna signal. I think greywolf is assuming you are using a 2X4 multiswitch instead of the 3X4 you stated.:)

[greywolf]

It would be very difficult to run another coax strand to the multiswitch. I was wondering if I could take one of the existing coax lines and use a diplexer to feed the antenna input on the multiswitch. He ruled out going to the 3x4 in the original question.

[boba]

He ruled out going to the 3x4 in the original question.
No he ruled out running another line down to the 3x4 but he is still planning on using the 3rd(antenna input).:)

[carl6]

So the OP's proposed installation should work just fine, correct?

dish 13V ---------------coax a--------------multiswitch 13V input
dish 18V to diplexer input \ / diplexer output to multiswitch 18V input
. . . . . . . . . . . . . . . . . coax b
Antenna to diplexer input / \ diplexer output to ant input on multiswitch

And, I would expect you could swap the 13/18 volt sides, in other words it shouldn't matter which line you diplex on.

Carl

[greywolf]

Now I get the picture. Sure, that's fine until it's time for a 5LNB dish.

[stedman99]

So the OP's proposed installation should work just fine, correct?

dish 13V ---------------coax a--------------multiswitch 13V input
dish 18V to diplexer input \ / diplexer output to multiswitch 18V input
. . . . . . . . . . . . . . . . . coax b
Antenna to diplexer input / \ diplexer output to ant input on multiswitch

And, I would expect you could swap the 13/18 volt sides, in other words it shouldn't matter which line you diplex on.

Carl

Thanks. This answers my question exactly. I want to use the antenna input on the multiswitch but cannot easily run another coax cable. Thanks again all.

[slapshot1959]

I'm wanting to do something similar but not sure if it will work long term.
I'm mounting a roof antenna and don't want to run a new line all the way across the roof down the side of the house,as I don't have a ladder tall enough to do a nice clean install.So I thought I'd run a short line through my roof vent to the attic (where the 4 lines from the dish are) and use one of those quad diplexers. Those 4 lines run inside my house to my basement where my multiswitch is (Eagle Aspen 5x8).Should I separate the off air from the sat lines and run it into the antenna input on the switch or just feed the 4 lines with the combined signals into the switch and then just use diplexers where needed on each tv? Any advice/experience?