Preamp Hook Up With Diplexor

[Amphicar770]

Hi All,

After reading a few posts I am more confused than ever.

Having used an OTA antenna in the past I know I can benefit from a mast mounted signal amplifier. The installed VOOM antenna is just a standard yagi without a preamp, running through the diplexor.

The amp has two parts. Part one mounts to the mast, part two plugs in near the television and provides power to the mast component.

Since I am using teh diplexor, can I still use an amp. If so, do I still need the powered piece by the TV or will the voom box be sending adequate power up the coax? If I use the pre-amp plugged in will that cause any problems with the dish or stb?

Bottom line, how do I hook up me preamp on the antenna when using a diplexor.

Thanks,

Mike

 

[al]

If your diplexor is power passing on both the Satellite and OTA legs, you can insert the pre-amplifier into the cable at the antenna, and the VOOM receiver will power it. If the diplexor is not power passing on the OTA side, pre-amp will not work.

Al

 

[Amphicar770]

Thanks. Yes, I tested with a voltmeter and found that diplexor will not pass power through to the antenna.

I thus decided to tap into the BIG channelmaster 8 bay which until now was a dedicated run to another TV. I simply put a splitter on the dedicated line and then ran that to diplexor. This seemed to do the trick and now I get LOTS of OTA channels. The interesting thing is that STB 3 gets about 5 fewer OTA channels than STB #2. I suspect that this may be due to the length of the cable run to STB #3. I may try swapping STB's just to confirm this. I suppose I could run an in-line signal booster earlier along the line that feeds STB #3.

Thanks.

 

[VMsat]

Okay let me make sure I understand this as I have a similar situation. I have the original sensar II antenna which is powered by the Voom box apparently and the coax cables are run through a diplexer currently so is must be a power passing diplexer. I have ordered a CM 4228 antenna and a CM 7777 preamp. If i keep my current wiring and the diplexers you are saying that I don't need to use the power supply. The voom box will power the CM 7777. Right?

 

[Sarcoptic]

I too would like to know the answer to this question. I noticed channelmaster makes special preamps that are suppose to be powered by the satellite receiver such as this:
Channel Master PreAmp

Are these the ones we should be buying rather than the titan series?

 

[Sooner]

Sarcoptic and VM,

If your setup includes both a diplexor on the back of the STB and a multiswitch out by the dish and antenna, check to see if the multiswitch has a 12V symbol where the antenna cable hooks into it. Chances are there is if you currently have a sensor II installed and a single coax run from the multiswitch to the STB. If you see the 12V, then you can install a preamp on the other antennas without additional power.

I experimented the other day with a Channelmaster Spartan 3 preamp on my deep fringe antenna. worked great, but overamped two of my 8 channels. Decided to live without the preamp as the two channels I lost were more important than the other 3 I was making better.

 

[Amphicar770]

Sounds like there are twoo different types of diplexors being used depending on type of antenna. My voom installed antenna was never the amplified type to begin with. In my case, when I hooked up the preamp on the TV side and then used a meter at the antenna end, there was no power being passed. I then went to another antenna set up so did not bother experimenting any further.

 

[al]

There are two types. Typically, a diplexer is only used to combine and seperate OTA and DBS signals. Therefore, you only need power on the SAT side, as this is needed to power LNBF(s). There is no need to pass power on the OTA leg UNLESS you have a preamp that needs power. Thus the need for dual power pass diplexers. You also have to be careful only to use ONE dual power pass diplexer if you have more than one DBS receiver connected and diplexed for OTA signals. If you power the preamp with TWO or more receivers, you could fry the preamp ;-)

Al