Splitters, Attenuators, Filters, Diplexers, Other Signal Gear

[stampeder]

Filters, amps, and all this other typical OTA signal gear don't know any difference between digital and analogue signals. It's not until an electronic receiver is hooked up that they get treated separately.

We've discussed ideas about digital signal processing in OTA signal gear from an experimental standpoint only, but nothing affordable or commonplace is out there for consumers.

Do you mean filtering out VHF signals? If so just look up band pass filters in the OTA FAQ and in this thread.

[iamdrumming]

I plan on getting an omnidirectional antenna soon, specifically the Winegard MS-2002. Right now there is 2 satellite dishes on my roof, feeding two TV's. The dishes have DiSEqC switches, so there is only 2 cables coming through the wall. I want to add the omnidirectional using an eave mount so that the Winegard is above the roof line. I would like to know what I will need to get this set-up up and running. Also, I am in Niagara Falls, Canada, and would be looking for someone to do the install.

Thanks!!

[Tom Thumb]

Hi all! I'm looking to buy a splitter so I can feed my antenna reception to more than 1 TV. Is there one that is particularly good, or will any old splitter do? I want to split it to 3 TV's. Will I need an amplifier as well, if so which is a good one? Thanks for any and all help.

[little-infinity]

Hi! Welcome

If you're looking to distribute signal to many outputs, then a simple splitter won't do. Each splitter basically halves the signal, so you're gonna be losing alot of reception unless you have really strong signals.

You're going to need a distribution amplifier, check this thread for more details on amplifiers.

Also be sure to check the OTA FAQ at the top of the page.

[ProjectSHO89]

The choice of whether you can use a passive splitter or you must use a distribution amplifier is dictated by your available signal levels at the point of distribution. Since you don't have appropriate signal measuring gear, you are left with "trial and error' as your choice.

Verify proper operation with a direct signal line to one receiver, preferably the one with the longest cable run. Select a balanced splitter with the number of needed outputs and install it in the line, connecting all outputs to their respective receivers. If you've got adequate reception on all receivers, it's fine. If, on the other hand, you have lost channels or are suffering dropouts (assuming digital), you will need to install a distribution amplifier instead of the splitter.

Each splitter basically halves the signal,

This is quite correct. However, since signal powers are measured on a logarithmic rather than a linear scale and often have a dynamic range of nearly 80 dB (for digital) between overload and dropout, a halving of the power (3 dB) may be done many times provided there is adequate power. There can be a lot of "halves" in a strong signal but few to none in a weak signal. The situation may be complicated by a wide mix in available signal powers, a very common situation in the real world. In such a case, you have to make sure the weakest signals don't get lost while also ensuring the strongest ones don't get pushed into overload territory due to amplification. It's all a balancing act in the end.

As an example, a unity-gain loop antenna 10 miles from a 1,000 kw UHF channel 14 transmitter would be expected (ideally) to develop around -32 dBm of signal power. Since most ATSC receivers are able to decode down to around -85 dBM, this example provides 53 dB of dynamic headroom that is your internal "loss budget". As long as your "expenditures" in terms of splitters and cabling do not exceed the available budget, the system should still work. Of course, the real world suggests that you should definitely pad that budget to provide for a safety margin. 10 dB of margin is the minimum that is often suggested.

If you're still working with analog, the numbers are different but the concept is the same. Since you're going to be digital-only in just over a year, might as well be prepared for that eventuality.

PS89

[JamesK]

Each splitter basically halves the signal

That's true of 2 port splitters (-3 dB). With 4 ports, it's spit 4 ways (-6dB). There are 3 port splitters that can split equally (-4.8 dB) or one port with half power and two with 1/4. Splitters with more ports are available and used by the cable companies, but are rare in the consumer market.

[ProjectSHO89]

That's true of 2 port splitters (-3 dB). With 4 ports, it's spit 4 ways (-6dB). There are 3 port splitters that can split equally (-4.8 dB) or one port with half power and two with 1/4. Splitters with more ports are available and used by the cable companies, but are rare in the consumer market.

Those would be "perfect" splitters. In the real world, add .3 to around 1.2 dB (depending on frequency and the quality of the splitter) to those "ideal" numbers due to internal losses and device inefficiency.

[Tom.F.1]

And, in the real world, we ALL have some of the low power or far away stations that are just on the edge of being receiveable. Those are the ones that are going to drop out when you use a passive splitter.
I use the CM3414, 4-way distribution amp. works great.

[PanaMark]

I found a Monster Cable brand three way splitter at a local store in their discount bin. I boasts a cool 5.7 dB loss per split. I use this with a decent preamp that makes up for the signal loss per split. There is a lot to be said that the preamp is the best tool for keeping weak signals to reaching to a television tuner while a distro amp keeps the signal from being degraded to the television but with their noise figures ranging in the 2-3 dB range and being far away from the antenna, they serve better in setups that are located the 0-60 mile range from transmitters.

[Blackburst]

I would suggest you look at the following Channel Master units.

CM3412 (2 outs)
CM3414 (4 outs)
CM3418 (8 outs)

I use the CM3412, and I'm very happy with it. I had tried other units, but nothing worked as well. These units even act as Pixel drop amplifiers. It really helped me to stay locked on certain DTV stations that I was having problems with.

These units are indoor units. Plugged into a AC outlet. So you will get a db gain. The gain will vary for each unit due to the number of splits it provides.

As usual, please do your homework before you buy anything.

[goforit]

Has anyone used/heard of Perfect Vision splitters? According to Antenna Hacks- PV splitters are the best for joining antennas...opinions?

[RadarBoy]

Hi All;

Quick question for the more knowledgeable than I - I'm using a USVJ splitter in order to attenuate the strong VHF frequencies where I live - would it also act as an FM trap for FM frequencies?

[Jase88]

FM Radio spectrum falls within the VHF TV band. Therefore, if you're using the diplexer's UHF leg to attenuate VHF, you should see the same attenuation for FM.

[okmed]

I use a USVJ splitter and run the VHF side to the antenna input on my Onkyo receiver. I get loads of FM stations now. Using a CM4228

[majortom]

This is kinda interesting.
Had various splitters laying around.

1. an old rat shack 5-600Mhz 2 way
2. an old, it's so old, I can't even read it, 2 way.
3. a 2 way 5-2300 Mhz DC Passive (GE)
4. a 4 way 5-2300 Mhz DC Passive (Phillips).

home made SBGH, Winegard Pre-Amp at the antenna, basically just use 3 drops here.

What I noticed is some intermittent electrical interference is visible in all the Canadian analog channels, from VHF Hi on up thru UHF Channel 56, whenever the newer DC passive Splitters are in use (they pass DC-Daylight). I'd say roughly 3 minutes on to 30 seconds off, real annnoying.

This is obviously also causing the weakest digital stations to degrade. Weakest here in Buffalo would be Canadian stations, CHCH 18, CBLT-20.

Best results are when using the older non-power passive 2 way splitters
in series for one drop at 3.5 dB down, and the other two at 7 dB down.
Cause it completely prevents whatever the electrical interference is
from getting thru to any of the tuners.

That is unless I can find the source of electrical noise/interference.
Wasn't about to go shuttin the whole house down on Mother's Day to
isolate it more but kinda looks like noise u'd see from an electric drill motor with arcing brushes.

Could very well be the Winegard power inserter that I hacked apart and repaired after it failed,
but doesn't seem like it. I think it's comin from outside somewhere in the neighborhood.