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Marrietta, GA: OTA amp recommendations

post #1 of 14
Thread Starter 
I will be installing an antenna. I need a good recommendation for how to amplify the signal. I'll explain any splits/runs.All lengths are approximate.

From antenna, 10' until a splitter.
Leg A will run 10' into a receiver.
Leg B will run 30' into another splitter (legs C & D)

Leg C will run 50' to receiver.
Leg D will run 30' to splitter, then immediately into receivers.

Amps can only be placed at the beginning of leg B (ideal) after the splitter, around the 30' mark (or more) of leg C, and right before the splitter on leg D.
I was thinking just one good amp at the beginning of leg B.

Also, think I will be attic mounting this antenna. I was thinking of mounting it so the appropriate degree/angle would have the antenna point at the slits in the attic. The slits have a small wire mesh over them to keep rodents out. Will this be a problem?

Any help is appreciated.
post #2 of 14
How is reception in your area? Post your tvfool results so we can see if an amp is even necessary. In general I like to test to 1 tv first, then as I add on more splitters and TV's I check if I start to lose channels. Then I know I need an amp.

If you put the antenna outside, you gain more signal strength, thus possibly eliminating the need for an amp.
I have 4 tv's in my house off 1 outdoor antenna, and no amp.
Edited by mikepier - 12/3/12 at 7:08pm
post #3 of 14
Thread Starter 
I was more concerned with the run lengths before they reach a tv (60-80')
The signal is pretty good. I don't know how the power affects cable run length. Most likely the antenna would end up in the attic.
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3dcc499f63687c72
I'm only concerned about channels 2.1, 5.1, 11.1, 17.1, 36.1, 46.1, and 43 (wupa/cw)
post #4 of 14
I have an outdoor, rooftop antenna. My RG-6 cable run is about 100' to the garage where the cable inputs to a drop-amp signal booster (I left it in place from the old analog days when one of my stations was a bit snowy from time to time). From there the signal is split to three tv's using the existing in-house RG-56 cable. Reception is perfect and trouble-free, even in bad weather. The suggestion of hooking up one tv first with no amps is a good one. Keep it simple and go slow.
post #5 of 14
Quote:
Originally Posted by dg1972 View Post

I was more concerned with the run lengths before they reach a tv (60-80')
The signal is pretty good. I don't know how the power affects cable run length. Most likely the antenna would end up in the attic.
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3dcc499f63687c72
I'm only concerned about channels 2.1, 5.1, 11.1, 17.1, 36.1, 46.1, and 43 (wupa/cw)

Seems like you are close enough to the towers that an amp might not be necessary. Try it out. Make sure you aim your antenna towards the SE where the towers are, and see with 1 tv first what you get, then go from there.
post #6 of 14
Thread Starter 
I will need an amp. From what I can tell, the only difference between a preamp and amp is the method in which the power is supplied.
Can I use a preamp AFTER the first split? This is preferable as there is no easy way to get power to an amplifier, and there is an unused coax nearby that can feed power.
post #7 of 14
In my experience, it is better to get the amp closer to the antenna and before the first splitter. Then you avoid losing signal strength. It can be done with a remote power supply, but all splitters involved must have a one port power pass with the coax connected to the power supply and the power passing port. It is also recommended to use voltage blocks on the ports going to the other TVs. See voltage block description at Denny's Antenna Service for a detailed explanation of the proper installation. I like the Motorola BDA dist amps which can also be used preamp style but you must purchase the additional remote power supply. And the PCT/Channel Master dist amps are also recommended and can also be used with a remote power supply.
post #8 of 14
Thread Starter 
I'm looking at the Winegard preamps, and understand the concept of providing power via coax and the special splitter that allows power.
In my setup, I've got the first split about 5 feet from the attic mounted antenna. One leg has a tv 10' away, and I'm pretty sure an amp before that split will overpower the signal. It's on that 2nd leg from the splitter that has long runs to the other tvs. That's why I want to put the preamp right after the first split. No way to get house AC power there, but an unused coax is nearby and runs to an unused room, and that can provide power. I'd assume there wouldn't be need for a voltage block on the "ant in" side of the preamp, but I'd like confirmation, just in case.
post #9 of 14
I'm confused....there shouldn't be ANY DC Voltage being applied to the INPUT of the Preamp.

Antenna---Splitter---Preamp---PowerInsertionModule---OtherTV.

Winegard Power Insertion Module has separate Coax connection to the DC Power Supply,
which is then sent up the Coax to the Preamp's RF OUTPUT. There is no need for any
DC Blocks in the system.....there is no DC Voltage being passed to Preamp's RF INPUT
or down the Coax to the OtherTV.

PS: If you suspect the Preamp is close to overload, the extra 4+ dB of attenuation in the
first RF Splitter (and Coax) may be just what you need to get closer to maximizing the SFDR
(Spurious Free Dynamic Range) as I've discussed elsewhere and in my DTV Preamp Signal
Overload Calculator Spreadsheet: http://imageevent.com/holl_ands/files/ota
Edited by holl_ands - 12/11/12 at 10:45pm
post #10 of 14
Remember that every passive splitter is just a combination of one or more cascaded 2-way splitter (which just divide the incoming RF power by one-half).

If you haven't already run all the lines, try using a three-way splitter at the first point. Let the two output's that are marked "-7.0 dB" feed the ten foot and fifty foot runs.
The other leg of the three-way splitter is only down "-3.5" dB (it's only gotten split one time, so far), so run that one to the "D" location, where you plan to split it to two receivers.

That keeps all the splits balanced, so you only have to contend with the high-frequency roll-off of the cable itself.
You probably have enough signal strength to drive all of this, assuming a good antenna and good-quality cable and splitters, in the metro Atlanta area.
post #11 of 14
Thread Starter 
Thanks for all the replies. The cables were already run with no hope of change. The first splitter is actually a 3 way, with an unused -7, the other -7 going to the nearby tv, and the -3.5 starts the long run. The really strong channels last through leg "D", with some weakening, but loses an important weaker channel. I haven't tested leg "C" yet. Since I was afraid of over-powering the the nearby tv (from the 3way), I was going to put the amp after the first splitter. Once I get a 2way splitter, the 3way will get replaced. The only reason I'm using a preamp is lack of power option in the attic.
post #12 of 14
Quote:
Originally Posted by dg1972 View Post

The only reason I'm using a preamp is lack of power option in the attic.

That's not really true. You can put a pre-amp anywhere in this cabling, and get power to it, provided you connect everything correctly. A pre-amp has only two coax connections. One for RF in from the antenna. The other has a dual function, providing RF out to wherever you want, and DC power in. You can connect the DC power injector anywhere along the line as long as you make sure that the DC only goes to the pre-amp, and not through a splitter and back to a receiver. some splitters have the ability built-in to block DC through more that one output and others don't. If yours don't, the you would need the DC blocks mentioned earlier.
post #13 of 14
Thread Starter 
I realize I can put power anywhere on the line, and use power blocks if necessary. The thing is that there is an unused coax, near the first splitter, that runs into an unused room. This would be perfect for preamp power.
post #14 of 14
Playing off this same theme of long coax runs and splitters , I am requesting some feedback:

How can you tell if a PreAmp is even working or powered ?(I have the RCA 17db brand) but there are no power lights on the unit. I have it in place at the end of 100' coax in my basement furnace room AND immediately in place before the three way splitter that feeds all branches to 1) basement, 2) first floor 3) 2nd floor.

I was surprised to see improvement in upstairs after this setup (ie. Fox at least now has 3 bars and other 4 lost stations now displayed).

Moving the tv down to the 1st floor (ie. shorter total length) was finding Fox to be weaker (WTF). ... the three way was swapped with monster "balanced load" splitter when the amp put in line.

frown.gif re-pulled new rg6 instead of the rg59 for the basement and family room this weekend; hoping it helps.

I am very close to finally pulling plug on Comcast but need to be confident that all floor tv's can get the same strength of signalling (something not confident on right now) but dont know how to actually measure signal strength in each brand. - - please provide tips. thx
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