Adding a Preamp to OTA antenna

[Sarcoptic]

I had my voom installed around 2 weeks ok and opted not to use the supplied winegard antenna but the one I already had mounted on my roof. I have 3 boxes all using diplexers from the multiswitch. I was looking at getting this preamp: ChannelMaster Preamp

As you can see its designed to draw power from a satellite reciever. From the detailed sheet the preamp needs aroudn 100ma of power. I was wondering if my voom boxes with the diplexers should be able to power the preamp since this is basically how the winegard GS2000 works. Thanks!

 

[Superjfly]

Good question. Did you find anything out about this?

Because of the single line being run from the dish/antenna, can the amplifier only be put near the antenna?

Superjfly

 

[TYORK]

Good question. Did you find anything out about this?

Because of the single line being run from the dish/antenna, can the amplifier only be put near the antenna?

Superjfly

should work if you multi- switch has a power pass on the antenna port if not then you will have use a diplexer before the multi swith and than it should work

 

[Superjfly]

should work if you multi- switch has a power pass on the antenna port if not then you will have use a diplexer before the multi swith and than it should work

I was just installed yesterday, I haven't been on the roof to see what was all done. The installer said the antenna signal was not amplified. I have two lines coming down from the antenna and dish total, each one going to a different receiver. The receiver closer to the antenna pulls in 12 locals, the one further away (+50 ft) pulled in 10 initially but dropped to about 7 later last night.

The lines are screwed into a diplexer that is attached directly to the Voom boxes. Where do I amplify the signal?

Thanks.

 

[TYORK]

I was just installed yesterday, I haven't been on the roof to see what was all done. The installer said the antenna signal was not amplified. I have two lines coming down from the antenna and dish total, each one going to a different receiver. The receiver closer to the antenna pulls in 12 locals, the one further away (+50 ft) pulled in 10 initially but dropped to about 7 later last night.

The lines are screwed into a diplexer that is attached directly to the Voom boxes. Where do I amplify the signal?

Thanks.

did he install the Sensor II antenna?

 

[Superjfly]

did he install the Sensor II antenna?

It isn't their normal antenna he said. It is huge if you ask me, I am right on the fringe of most signals 45-49 miles away. It looks similar to this...
http://www.solidsignal.com/prod_display.asp?PROD=ANC3671&xzoom=zoom#xview

 

[Superjfly]

Since being installed on Monday my reception of local channels has been decreasing and doing strange things.

I went from 12 locals to 8. Five of those are PBS. I am getting channels from the opposite side of the antenna and not from the right side. Does that make any sense? On top of that, I am pulling in the right channels on the TV that is further away.

I bought a preamp last night from Home Depot. It said it was a 25db amplifier for VHF/UHF/FM. I tried differed scenarios but the best result was to put it between the diplexer and the box. I gained 4 in signal to about 86 on the channels besides PBS (94). Is there a better amplifier than this? Its not worth the $35 for the little it does. Any suggestions?

 

[SeattleVoomer1]

I'm not sure what is causing your problem. Maybe someone else will help you.

But I can tell you that most of the preamps from Home Depot and such are not very good. Some increase the noise so much they degrade the pic. However, when we needed one (prior to VOOM) with an indoor RS antenna I searched around and found the Channel Master 7775 highly recommended. Worked great here in Seattle although we had to be careful of overload on a couple on channels on our Samsung STB.

Good luck.

Still watching HDTV under partly sunny (!) Seattle skies, Gill

 

[snaggerbob]

gill, what do you mean by overload? can you get too much signal?

 

[Superjfly]

I have heard the same thing. Over amplifying can actually decrease your signal.

As far as my problem I think I am going to attept to run seperate lines from the antenna to the receivers and see how much that helps. (When it gets warmer)

Superjfly

 

[r.jones1116]

I was just installed yesterday, I haven't been on the roof to see what was all done. The installer said the antenna signal was not amplified. I have two lines coming down from the antenna and dish total, each one going to a different receiver. The receiver closer to the antenna pulls in 12 locals, the one further away (+50 ft) pulled in 10 initially but dropped to about 7 later last night.

The lines are screwed into a diplexer that is attached directly to the Voom boxes. Where do I amplify the signal?

Thanks.

I had the same problem. went to radio shack and got a twenty dollar signal amp. The thing I learned is you have to amplify the signal before the multiswitch connection.

 

[Sooner]

Also, make sure you do not have a DC filter on the multiswitch antenna pass when you add the preamp. If the installer used the Terk BMS34 multiswitch and you currently have a non amplified antenna, you more than likely will have a DC filter attached. Only remove this filter if you install a preamp, if you remove it and allow power to a non amplified antenna, you will short out your satellite signal and get nothing (this was explained on another thread in here).

The other issue you described about losing channels is not new to me either. I have 3 STBs installed and one would have lower signal strengths than the others with frequent channel drop out. I removed the OTA module from the back of the suspect STB and replaced it with a known good module form one of my other STBs. Wouldn't you know it, the module was bad. You can do this by removing the attahced motorola diplexor and then removing the OTA module. Pop the other good one in there and do a channel scan. If the new module picks up the channels, you will need to call Voom for a new STB. I tried to get them to just send me a module, but they would have none of that.

 

[VMsat]

Got a new antenna, CM 4228 and preamp CM7777. My question is where do I put the power supply for the preamp. Before the initial Diplexer (the one closest to the antenna)? I had the antenna coax from the second diplexer going into the power supply, but could not tell a difference when I unplugged the power supply. Then I put is before the second diplexer (I put the single coax coming into the house form the first diplexer into the power supply) then out of the power supply into the second diplexer. This greatly improved my OTA picture quality but then I could not get any satellite channels at all. So can someone help before I have to run a new coax into the house from the antenna to see if this works. Thanks

 

[Sooner]

If your multiswitch (the box that has the two satellite feeds and the antenna feed on one side and the single coax feed to the STBs on the other) allows power to pass to the antenna lead, it will have a 12V etched below the output to antenna conector and you will not need a power supply for your preamp. If the 12V is there, remove any DC filter attached to it. This would be a little in-line connector approximately 2 inches long. If you have this set-up, you do not need the power supply that came with your preamp, because your STB is powering the preamp.

The preamp should be mounted at the antenna mast. The antenna leads should go directly into the preamp then the coax output from the preamp to the multiswitch . The diagram provide by r.jones in this thread shows the setup well.

 

[SeattleVoomer1]

Sorry, just got back on after a couple of days off the board

gill, what do you mean by overload? can you get too much signal?

I'm no expert about overloading but when doing research going on two years ago for a preamp setup for our Samsung STB read that STBs could be overloaded which would cause a loss of that channel(s). Maybe someone such as TYORK or one of the installers who post here can set us straight.

However, at this point enjoying HDTV via VOOM under mostly cloudy Seattle skies, Gill

 

[crash331]

Yes, you can overload a channel. Sometimes if one channel is already very strong but you need a preamp to boost the other channels, you have to buy a single channel attenuator. They make them for all channels. Like if you got ch 11 really stong, but the rest were weak, if you boost the signal, 11 might be overloaded. So you buy a ch 11 attenuator and it will reduce the signal for that one channel.

 

[SeattleVoomer1]

Thanks for the info.

Yes, you can overload a channel. Sometimes if one channel is already very strong but you need a preamp to boost the other channels, you have to buy a single channel attenuator. They make them for all channels. Like if you got ch 11 really stong, but the rest were weak, if you boost the signal, 11 might be overloaded. So you buy a ch 11 attenuator and it will reduce the signal for that one channel.

Still enjoying HDTV even if a Drought Emergency has been declared in Seattle, Gill