Thread: Is it possible to run two leads from single OTA to reduce splitters

I have two 722k with OTA, an FM receiver and three TV. The most distant stations are 35 miles away and my signal is in the 70-77 range. Would signal improve if I ran second lead and eliminated some of the splitting. Was considering Wineguard pre amp AP 8780, but would prefer not to use preamp.

How are you going to run cables without splitting?

You can't just run 2 lines off the antenna connection points. That affects the antenna impedance match and would do more damage than splitter loss.

Right; you have to have a splitter somewhere, unless you want to install a second antenna. It helps to have the splitter as close to the first output terminal as possible, though. If your 722s are on top of each other, the splitter should be right behind the boxes. But if one is in another room, the closest one to the antenna should host the splitter, and then a single, short run from that splitter to the second unit.

A preamp will help overcome losses even more, especially if you're talking about more than 50' from the antenna to the first 722. Unless you're in a really noisy area or 3 miles from the towers, go ahead and invest in a preamp.

handymantoo, If you are talking about running (2) 300 ohm antenna transformers connected to the antenna and separate coax for each TV down the mast should work but I think the ohms law is you would need (2) 150 to 75 ohm transformers to properly do that or you could just run (1) coax down replace the main splitter with a low noise figure distribution amplifier. cap/terminate any unused f-connectors.

Originally Posted by roashru

handymantoo, If you are talking about running (2) 300 ohm antenna transformers connected to the antenna and separate coax for each TV down the mast should work but I think the ohms law is you would need (2) 150 to 75 ohm transformers to properly do that or you could just run (1) coax down replace the main splitter with a low noise figure distribution amplifier. cap/terminate any unused f-connectors.

Ohms law has nothing o do with it is an Impedance mismatch problem.
Use a preamp and a high quality splitter with a low db loss at each port. also make sure your spliter is swept tested for 2200 mhz or above and cap any unused port with the 75 ohm terminators. I have a 8 way splitter on my antenna and I dont see any loss.

Originally Posted by dodge

also make sure your spliter is swept tested for 2200 mhz or above

Why? I mean, since broadcast TV doesn't get over 700MHz anymore...

Technically, the problem is that each Balun would have about 3 db of loss.

The next problem as we both know is that wire is rated in loss per a foot at X frequency.

The loss at channel 2 - even at 100 feet for a good communications grade RG 6 Quad Shield wire such as the Belden 1829 AC series 6.

Since we know that channel 2 occupies a frequency of about 66 - 72 Mhz - we know that the Belden wire has a loss rate of about 1.4 Db per 100 feet.

At the same time, channel 51 - which is our highest frequency - occupies a frequency of around 692 - 698 Mhz. The loss rate of the same wire might be around 4.6 Db per 100 feet.

So at channel 2 - you would have more then twice the amount of signal at the television after 100 feet of good RG 6 then you would if you wanted to receive channel 51. That is because we know that about 3 db = a loss or gain rate of 50%

To compensate for this, we use some type of amplification to boost the signal to compensate for line loss. The problem with trying to amplify the signal is that a amplifier also produces it's own noise. So we need to keep in mind that we must use a amplifier that has a very low noise factor and does not produce too much amplification or else we will experience over load.

For a fringe signal, that is not a problem, but with FM radio stations in the neighborhood that transmits around 88 - 92 Mhz, it will make more problems than it solves, especially if we are trying to receive something in the low VHF band 2 through 6.

The problem then is - if you tried to use two drops and two Baluns that you would actually increase the amount of loss proportionally with the amount of wire that you attached to the antenna. You would gain nothing and you would loose twice as much signal - which was the reason why you wanted to run two wires in the first place.

Splitters all have loss. A good 2 way splitter usually has about 3.7 Db of loss.

When you move up to a 3 way splitter, you will find that one or more ports might have as much as 7 Db of loss. The reason is that multi way splitters ports are not unilateral.

If a splitter was unilateral, if you walked in the input port, two identical people would walk out of the outputs. Their heads and their hands and their torso's would all be the same exact size.

Unfortunately, it just doesn't work that way. With a 3 way splitter, one person might come out half as big and the other two comes out 1/4 as big as the person that walked into the port.

When you add wire, after the splitter, the loss rate of the wire is proportional to the amount of wire that you add. No matter if the other televisions are turned on or off, you will have a loss rate of the combined length of all the wires connected to the outputs on the splitter.

So if you have 100' of wire after the splitter and 100' of wire before the splitter, you will have a loss rate of the same as if you moved your antenna 200 feet away from the house.

To compensate for this, we sometimes use a distribution amplifier. The problem is - the distribution amplifier also injects noise into the system. So everytime we add a amplifier we are actually making the signal more muddy.

The problem then becomes, you need to have as good of a antenna as you can possibly afford, it needs to be the right size to do the job and it needs to be pointed in the right direction to take advantage of as much signal as it can possibly receive.

If you take crap and butt it into a piece of crap wire and then amplify that crap, all that is going to come out the end is more crap.

If you take a good clean signal and amplify it one time, run it through the best wire and the best terminals and use some type of corrosion protection inside of the terminals, you might get a pretty good signal to come out the other end, with or without some type of amplification - depending on how strong the signals are at your home location.

At the same time, a FM tuner will interfere with your television reception.

It is better to use a dedicated VHF antenna, at a proper distance away from the antenna you use for your television to receive FM signals then to try to use one antenna to receive everything.

In the analog days, it really didn't matter because even if you had signal degregation - you didn't notice it because the signals was transmitted in two parts. You had the audio which was FM and the video which was AM and transmitted at a much higher power level due to the fact that AM was more susceptable to interferace - noise.

Even if you had a poor signal, there might be some snow and some static on the sound, but you could still watch it. With the new lower power Digital signals it is all or nothing.. Either you have a perfect picture and sound, or you have no sound and pixelation or you have no signal at all.

There is nothing in between!

If when you was a kid and you watched cartoons, sooner or later one of the cartoons would have someone strapped to a log and cut in half by a buzz saw.

Each half of the person was the same size - but only half as big in diameter and only had one eye, one hand and one foot. That is what a splitter does. It cannot magnify what ever is coming in, it can only chop it in half and make two smaller size portions.

As I said before with the wire connected to the output ports, the more wire you add, the more loss you will incur.

Old Red Green up there has a magical 8 way splitter that has no loss at any of the ports. When in fact he probably is loosing 12 - 14 db just in the splitter.

To split a signal 8 times, you would need a distribution amplifier, even then it would have some loss because it would inject noise into the equation.

The proper way to split a signal 4 times is to use 3 - two way splitters.

First your split the signal two ways and then you make two small leads which will connect the two ports to two more splitters. Each port on each of those splitters would then be unilateral and each port would have a loss of around 7 Db.

Now you are wondering why would we want to do this?

The reason is because we do not know which ports will have the most amount of loss until we hook a wire up to them. Chances are one television would have good reception - say a upstairs bedroom, while the downstairs living room television might have little or no reception at all in a fringe area.

With a CATV signal, this is not a problem, because the original signal was amplified several thousand times at the head end and the signal coming into your house is very strong.

With a OTA signal, this is not good, because we might have a signal of .00006 milliwatts per a meter of diapole which might be watchable with a pre amplifier and one television, but would be unwatchable with several televisions and no amplification.

So we have to do everything possible to protect that signal.

Holy crap! There is just so much wrong with what you are saying JB Antennaman, I just don't know where to begin to correct you. I'm not quite sure I want to take the time to correct everything. So I'll just correct (and explain) some things that really stick out.

I'll start off with this:

we know that channel 2 occupies a frequency of about 66 - 72 Mhz

What we know is you are wrong. In reality ch 2 occupies a 6MHz space between 54-60 MHz. Channel 4 occupies the 66-72MHz band.

When you move up to a 3 way splitter, you will find that one or more ports might have as much as 7 Db of loss. The reason is that multi way splitters ports are not unilateral.

Actually the first sentence is correct. However this is called an unbalanced 3 way splitter. There is however a balanced 3 way splitter that has equal loss at all ports.

So if you have 100' of wire after the splitter and 100' of wire before the splitter, you will have a loss rate of the same as if you moved your antenna 200 feet away from the house.

Well what you REALLY have is a loss rate of 200' of cable as well as the added loss of the splitter.

The proper way to split a signal 4 times is to use 3 - two way splitters.

This is a completely bogus statement. Not just for the fact that there are now more connection points that can fail. But the fact that there is more loss incurred than using just one 4 way balanced splitter. You need to add an additional 1 dB loss to the splitters 3.5dB loss per 2way splitter. This is due to the .5dB loss for each connection point per splitter.

To split a signal 8 times, you would need a distribution amplifier, even then it would have some loss because it would inject noise into the equation.

Again, this is completely wrong. If the signal is strong enough (ie...reception antenna is close to transmiter location) an 8 way can be used without a distribution amp. But that isn't where you have no idea what you are talking about. Noise from an amplifier has no effect on signal loss, but does affect the quality of the signal.

The reason is because we do not know which ports will have the most amount of loss until we hook a wire up to them.

Wrong, wrong, wrong. We do know which port has the most loss. This is known because we (supposedly) know the input level and we know what the loss is from the splitter itself as the loss is labeled as such.

With a CATV signal, this is not a problem, because the original signal was amplified several thousand times at the head end and the signal coming into your house is very strong.

Your vast knowledge amazes me. The original signal in a CATV headend is not "amplified several thousand times". Not even a tenth of that amount. While the signal into a home is supposed to be (and usually is) strong, it is far from being "very strong".

Damn, this is tiring making all these corrections.

BTW, what is a "diapole"? I presume you meant 'dipole'? Or is there a new piece of equipment only you know about?