Trouble with OTA antenna using diplexers

[reservoirreb]

Hello.

I am new to this forum, so bear with me.

I am having an issue with an OTA antenna I am using with a Dish Network HD/DVR receiver. Actually, It's not really the receiver that is the issue, for this is also happening when I use the ATSC tuner built in to my Samsung 40" LCD.

What happens is this. When I use diplexers on with the OTA antenna (of course with my satellite signal) my signal from the antenna basically disappears. If I bypass the diplexers completely, I get a signal around 80% on around 13 channels. This is without even having the antenna outside, but rather inside my house. However, when I use the diplexers my signal almost goes non-existent.

I even tried using the diplexers 20 feet apart, just for troubleshooting purposes and the signal was barely visible.

Am I doing something wrong, or do diplexers really degrade the signal from my OTA antenna this much? My satellite signal comes in with no loss at all.

I just don't see how diplexers could make a signal drop that much over 20 feet.

Any help or advice would be appreciated.

Here is some more information that may help:

I have a Dish VIP 612 HD/DVR
Dish 1000
Samsung 40" LCD HDTV
Using 2 Holland Diplexers


Thanks

 

[StevenD]

You might have a bad diplexer. Buy a quality pair and see if that fixes your problem. If you are getting an '80' for signal strength, quality diplexers shouldnt knock it down that much.

 

[boba]

Try another pair of diplexers and be sure you are connecting to the right input/outputs.

 

[reservoirreb]

Appreciate the replies...

However, this is the second pair of diplexers I have used. Both were given to me by Dish Network installers. They are both Holland Diplexers.

What would be a good brand diplexer to try?

 

[chainblu]

Were the diplexers installed properly? The single port on each diplexer should face each other on the 'shared' cable.

 

[RandallA]

Holland diplexers are recommended by Dish Network and they're very good. The problem might just be with the installation like chainblu mentioned above.

Here is a picture showing how to install them with Dish Network:

https://rweb.echostar.com/departmental_content/TechPortal/content/tech/equipment/accessory.shtml

 

[vegassatellite]

Diplexers attenuate the signal somewhat. Also, you introduce noise with the addition of diplexers. As signal levels drop towards the noise floor and the noise floor is raised, you can introduce problems with the signal because your signal to noise ratio is reduced. Try amplifying the signal before it goes in to the diplexers and see if you get your signal back. The amplifier will raise your signal so you are above the noise floor, which will be increased somewhat as well, albeit not as much as your signal.

 

[reservoirreb]

I am sure I have the diplexers hooked up right....

Also, I am applying a 18db amplifier on the antenna signal right before I plug it into the ATSC tuner.

How do you go about putting an amplifier on the outside of my house? Wouldn't that need a power outlet?

 

[vegassatellite]

Also, I am applying a 18db amplifier on the antenna signal right before I plug it into the ATSC tuner.

How do you go about putting an amplifier on the outside of my house? Wouldn't that need a power outlet?

You need an amplifier that has remote power insertion. These typically require a separate coax run to it from a room where you can connect the coax wire to a power transformer. That room doesn't necessarily have to be the same room as the 722.

 

[RandallA]

The signal loss for diplexers is about -2.0 dB per diplexer. We're only talking about 20 ft. here, are not? If that's the case, the antenna should work. What kind of OTA antenna are you using? Inside or Outside antenna?

 

[TheKrell]

How much current does the 1000 take? If it's anywhere near what a DPP44 needs, then you need the blue Holland diplexers, not red.

I am inclined to think that they are not cabled up correctly, or there is something hidden somewhere in between the diplexers. What is your antenna? If it's amplified, and came with a power injector, that power would not make it through a diplexer even if you did cable it up correctly. An unpowered external amplified antenna might pass very little signal.

 

[AdamGott]

You need an amplifier that has remote power insertion. These typically require a separate coax run to it from a room where you can connect the coax wire to a power transformer. That room doesn't necessarily have to be the same room as the 722.

I read somewhere on the net (so it must be true, right?) that diplexers won't pass the DC bias necessary to power the remote line amplifiers. Is this true? If so one would need to put the power injector inline before the coax hits the diplexer.

 

[reservoirreb]

The antenna type is a MANT940

from Phillips. It is an indoor / outdoor antenna.

Like I said, it works great sitting on top of my entertainment center right now, plugged directly into the TV.

I even had the antenna outside where my dish is currently (before the dish was installed) and it worked great there also.

 

[RandallA]

What happens if you don't use the power amplifier and go directly to the receiver (no diplexers)?

The Holland diplexers will pass power only on the satellite leg only. I'm thinking that you're barely getting signal on that antenna and when you add the diplexers you get nothing. Like Vegas said the signal will attenuate when you introduce the diplexers and if your signal is marginal, you'll get low or no signal.

I found this review on a search for the antenna:

http://reviews.ebay.com/Philips-MANT940_W0QQugidZ10000000006961132

 

[chainblu]

No, the Red Hollands do not power pass on the UHF side of the diplexer.

 

[tastim]

I read somewhere on the net (so it must be true, right?) that diplexers won't pass the DC bias necessary to power the remote line amplifiers. Is this true? If so one would need to put the power injector inline before the coax hits the diplexer.

Correct... the VHF/UHF port on the Holland Diplexers do not pass current.... so the diplexor is killing the amplification.... you need to somehow put the amplifier after BOTH deplixers(between the second diplexer and the receiver with the signal you are getting, apparently... )... but that will require an attic run to bring a second cable down, in which case you might as well just run another line from the antenna and remove diplexors entirely.

OR just go buy some diplexors from Lowes or Radio Shack that will pas current down both lines (make sure it will handle at least 2150 mhz on one side)

 

[PATECO]

Correct... the VHF/UHF port on the Holland Diplexers do not pass current.... so the diplexor is killing the amplification.... you need to somehow put the amplifier after BOTH deplixers(between the second diplexer and the receiver with the signal you are getting, apparently... )... but that will require an attic run to bring a second cable down, in which case you might as well just run another line from the antenna and remove diplexors entirely.

OR just go buy some diplexors from Lowes or Radio Shack that will pas current down both lines (make sure it will handle at least 2150 mhz on one side)

You can also purchase a power passing diplexor that passes voltage on both the Sat and VHF/UHF ports. use just one of these for your outside diplexor and use a line powered amp on the outside of the house by your ota antenna. Here is a picture of the ones I use for powered OTA antennas.

 

[reservoirreb]

I am using the Blue Holland Diplexors....

And I have the 18db amplifier that comes with the antenna plugged in after the last diplexer, right before it goes to the receiver.

 

[reservoirreb]

RandallA, if I bypass the diplexors...

completely, I get around 80% signal on my best channel....Sometimes better.

If I add the diplexors, I barely get a signal.

 

[RandallA]

completely, I get around 80% signal on my best channel....Sometimes better.

If I add the diplexors, I barely get a signal.

When you bypass the diplexers, do you disconnect the power amp on the antenna? I'd ljust like to know what happens without the diplexers and without the power amp.