Splitters, diplexers, power inserters, tap couplers, attenuators, in-line amps

[zamar23]

OK guys,

I consider myself a newbie to this hobby. And I have the task at hand: splitting a signal coming from my STB's Pass Through port btw 2 lines: one going to an Add-on card mounted inside the STB, another to one of my Sat Card PC tuners mounted inside a PC. I looked around for a high frequency splitter, and found several types, including non-power passing, DC power passing on one OUT port, and DC power passing on both OUT ports. I assume, they are dual-directional (or not?), i.e. DC is passed from IN to OUT splitter port(s), and in opposite direction (not blocked from OUT to IN).

I want to control my motor and be able to select sats & channels independently from both the STB and PC Tuner. I will mostly use one receiver at a time or the other, but sometime both.

Which type of splitter do I need for my application and why? Should it allow DC power to pass in both directions: In and Out?
What splitter makes and models will do the best job - low noise and signal degradation?
Other suggestions (be gentle please, I'm "almost" new!).

 

[guapoharry]

If I understand, you want to control a motor from a PC tuner connected to the loop out port of a receiver that can control the same motor..

What for?

OK guys,
...What splitter makes and models will do the best job - low noise and signal degradation?
Other suggestions (be gentle please, I'm new!).

New? With 723 posts on this website? No entiendo.... whatever

 

[zamar23]

F-Tee Coax Adapter

I'm new to splitter side of this hobby. Kind of "back to basics" stuff, never had time to figure out.

The PC is in a different room, and connected to a different monitor, so its more convenient to control the motor by a PC tuner, when using the PC. Any suggestions on splitter choice?

Will a F-type Tee Splitter do the job? When a Tee splitter is preferable to a power passing on both ports splitter depicted above?

 

[pendragon]

Don't use a F-tee. It will mess up the impedance on the RF side. There was a fair amount of discussion here a few months back on this and related issues; I would start there and follow-up on specific questions.

To summarize in a nutshell: use a satellite rated (950-2150 MHz) power-passing (both ports) splitter to connect the STB and PC tuner inputs to the coax coming in. If only one unit is on at any given time, you will be able to command the motor and select polarization and any 22 kHz/DiSEqC switching. If both are on, you will get only one polarization (unless you are using bandstacked LNBS) and motor switching/22 kHz/DiSEqC switching may be erratic or only provide only certain combinations. The latter part can be avoided with a more complex design, like multiswitches.

 

[zamar23]

Thanks. I started this 'Back to Basics' topic because I couldn't find any info in the forum's FAQ about...splitters. That sounds unbelievable, it's presumed that any FTA fan definitely knows such basic stuff, no explanation required. Nothing can be further from reality. In fact, most startup FTA systems experience various reception problems despite a picked dish, because their owners don't know how to "design" a basic signal distribution system. But the problems are often attributed to other system components, like Dish size and quality, LNB, etc. While most newbies will look for an old (cable TV or Dollar store) splitter in their Tool Box long before they start thinking about buying a sat signal switch.

Good simplified guidance on designing Signal Distribution System is long overdue. Comprehensive Info on this is scars on the web - look f.e. at Sadoun's site, I consider a good example of a sat dealer site - empty pages, when it comes to splitters. The only site addressing in some depth the signal distribution topic I found is Digital Home, and mostly due to Stampeder's efforts, who managed design and installation of signal distro systems for years. I appreciate, you're paying close attention to the topic as well, probably because of college "sound reinforcement" experience. Will try to locate here F-tee info you mentioned (any hint?). You don't recommend using F-tees, but I noted them mentioned often in your posts. What do you use them for?

The reason, I wanted to split the signal at the STB's Loop Out port is that I plan to deal mostly with stronger signal clear channels like Music stuff using this sat card (Twinhan 1020A) and the Add-on card, while the STB is often used to watch a lot weaker channels, since I can't claim getting 90Q on most of the Arc, as some reported with NFusion, despite employing only high consumer grade LNBs and other components. I have a separate STB and S2 sat card combo setup for weaker sensitive signals reception, and it needs to be integrated into a common distro system as well. The biggest limitation seems to be punching extra coax holes, while for many its a non-issue. I wonder, if current DTV efforts and equipment on a single coax home signal distro system can be adapted some day for FTA, but it seems to be hardware specialized at the moment, narrowed to DTV signals combo. It's certainly worth considering when developing new FTA systems, but the problem culminates in non-systemic approach in designing new equipment for FTA.

Are you saying, splitting signal at STB's Loop Out won't work, or can damage the Add-on card? What kind of splitter would suite best for that? I looked at splitting coax before the STB and possibly using a 13dB in-line trunk amp you use, but Channel Master's manual for the amp says, it can't be installed closer than 100 feet from LNBs to avoid saturation and spectrum nonlinearities, and better be placed in the middle of coax run. Hence it sounds less suitable for my setup with shorter coax runs. May be a lot weaker in-line amp will do a better job if at all required.

 

[Mr Tony]

Thanks. I started this 'Back to Basics' topic because I couldn't find any info in forum's FAQ about...splitters. That sounds unbelievable, it's presumed that any FTA newbie definitely knows such basic stuff, no explanation required. Nothing can be further from reality.

OK I'm going to throw a couple questions out and my comments

Guapo is right...800 posts and you keep saying you're a newbie? It seems like you seem to do all this research on items then ask the same questions because you dont like the answers you got from google or hacker sites. Then after someone responds to your posts you go and edit your post. Hard to keep it legit when the previous info keeps changing
Case in point...your post above mine....created at 9:26 and edited at 9:54...how can someone keep up with the correct info when you keep changing it?

Wording threads with sentences like "Can someone step out of "can't use Flex ports" verbiage" in the post and you wonder why only I responded in that case? Why do you think there are lots of views but no responses? I guess some of the folks here who have TRIED it and couldnt get it to work or tried it and blew it up did it for sh*ts and giggles. Most of this stuff has been tried before by folks here.

As to why we dont have anything in the FAQ about splitters....simple

IT ISNT RECOMMENDED TO USE THEM unless its specific circumstances. Most folks who are new to FTA and have 2 or more receivers probably would want to see both polarities on a satellite. You always post about "keeping it simple" yet telling a newbie you need a high frequency splitter, dc blocks and then you only get one polarity on the 2nd receiver and if it isnt right you might fry the receiver...how is that simple for newbies?

Most folks on here dont use a splitter unless they usually have a unique situation
-bandstacked LNB's
-C-Band setup with 4DTV and DVB receiver
-they only want one polarity on a 2nd receiver
-they dont want to use the loop out

I haven't used a satellite splitter in a while...ever since I took down the bandstacked C-Band setup...why? Because I wanted to get both polarities and in my case, multiswitches work better with the setups and have more flexibility for channel viewing

The switch FAQ that Anole did was designed for simplicity for folks who want to get into FTA and need to know what they will need to use to optimize their setup.

Why dont you just run a cable for the 2nd receiver?

 

[zamar23]

Iceberg

I see a lot of good points in keeping stuff simple as you do. There is no need to keep tone confrontational, as you try lately, not because I'm not good at it, but cause its not productive, and I don't use confrontation in info exchange on purpose. Now, some stuff may look a bit provocative to draw interest of newbies to the subject matter, as we all want more people to get interested in FTA and make their 1st steps a success, since it results in better equipment and hopefully channel choice for everyone. I don't know, why you keep trying to label every other site a hacker site, but I'm not that good at labeling. In fact, Digital Home is one of the harshest for signal hackers site in NA. Many edit their initial posts, if some relevant info was missed, this feature is common for most web forums. If something commonly used like coax splitters was tried in FTA and not recommended, its good to mention it in FAQ. Pls keep your tone permanently down, and thanks for the good suggestion. This site content can definitely be improved as every other site, so expect more suggestions and critique from members to come over time for sure.

Btw, you may be surprised how easy it is to use WB68 switch Flex ports with a PC Card, if and when Zinwell will throw required code sequence out. Also, did you notice, more questions are now getting posted in common area, after AZBox stuff get moved to a separate section - thanks for that. Its now a lot easier for folks to find AZBox info, so flow of repetitive AZbox posts and "manuals" went down. Again, thanks for your efforts in keeping FTA section simple. :up

 

[AcWxRadar]

Zamar,

I have been under the impression that a "splitter" of any type could not be used for FTA endeavors or with FTA equipment. It was my understanding that only bandstacked LNBFs (primarily DBS equipment) had a niche on this application. I am referring to Dish Network DishPro receivers (i.e. dual tuner models), DishPro LNBFs and DishPro compliant splitters and combiners.

This is all a very specific application designed expressly by and for DN's DishPro systems. DirecTV may also have such a system of their own, but I am not very familiar with their equipment.

In the FTA world, splitters and combiners are not used as far as I know. A FTA receiver would have to be purposely designed to control/process/function with such devices and I personally don't know of any. Beyond that, if there was such a receiver, I would expect that you would have to use two identical receivers (so no mixing of other receivers that don't support this).

Also, you were asking to control the motor from two separate receivers. Even if such splitters/combiners would pass the motor control signals, this would still create a conflict no matter how you look at it. Which receiver would take control if both were trying to send the motor a command? How would you differentiate between the two?

Perhaps there may have been some older C-Band equipment that was able to support such setups, but I wouldn't know about them personally and I sincerely doubt it. I would be surprised if otherwise.

For what you are requesting, about the best approach would be some sort of an A-B switch. I don't think that this is a good idea either, unless there was some sort of a solid state type of A-B switch that could handle the frequency range. You wouldn't want to use any mechanical A-B switch (the switch mechanism could arc when switched and cause damage to other components or the receivers).

If anyone has evidence or can cite specific setups where splitters/combiners have been applied to FTA with positive and proper results, I would be eager to listen and learn. However, I am sure the entire notion is just not practiced in FTA systems.

I have read this subject being discussed many times in the past and this was always the final answer or conclusion that was derived.

Please understand that I am not saying that this is absolute. Many things are possible and I could be wrong, after all I haven't researched every receiver or system that is available.

RADAR

 

[zamar23]

Example of splitters use was given in one of switch matrices posted here. Looking at others' posts, I guess a lot more FTA folks use splitters just cause they are cheap and commonly available than switches. I'm not saying its always a good practice, just that it's a common move that needs to be addressed in FAQ. At the same time, using a pre-amp and splitter based signal distribution is frequent in signal delivery systems, but as you mentioned more often used when a system is designed as a whole, i.e. functionality is properly balanced. Loop Out ports in FTA receivers impose extra limitations, but they're not related to splitters. Trying to control a motor simultaneously from several points would seems to always result in a conflict even when a switch is used.

 

[pendragon]

There is nothing wrong with F-tees if they are used for the right purpose, such as splitting power and DiSEqC commanding. I have them all over my system. But they should never be used to pass through a signal from a LNB. We can go into the physics if that matters, but most people should not be employing them in their FTA systems because they only fit very narrow needs.

I think both you and Iceberg are uncovering the dilemma one can have on this forum where there is a dramatic range of people from a lot of different backgrounds trying to do different things and with different engineering and hands-on experiences. If I post some arcane technique that may help an expert solve an unusual problem, it may come back to haunt me when a less experienced member misapplies it somewhere else. There are lots of gadgets and approaches that can be used and the trick is to know when to use them. If I mention a particular switch, amp, F-tee, etc. because it works for me, there is no magical property that will make it the best choice or even an option for a different system.

Contrary to many here, I am a big proponent of amplifiers. But most people here don't need them and they often wreak havoc when misapplied. I use them for several purposes: (1) some of my cable runs are long, (2) the size of my system requires lots of switches, taps and connections, all of which introduce losses and tilts, (3) I have a spectrum analyzer and losses/tilts look very unappealing on it and (4) I know from long experience, including sound reinforcement , that paying attention to details like this reduces problems that pop out of nowhere and simplifies troubleshooting efforts when something goes wrong.

Regardless of what CM may say, I invariably use their amps as close to the LNBs as I can get them because they have very high headroom. This is the best way to rid noise and the results are easily demonstrated on test equipment. The Trunkline amps are not as good: a bit noisier and lacking the headroom of the CMs. But the Trunklines are half the price and easy to find at one of our sponsors. They are perfect for my toroids/bandstacked LNBs because the LNB output levels are lower and I have so many of them. The CMs would not materially improve anything for this application and cost a lot more. But on my big dishes with higher output LNBs, the Trunklines would be a disaster. From an engineering point of view, each is better in a different domain, but someone who does not understand the rationale can easily take the above out of context as a universal recommendation and have a train wreck.

To get back to the subject at hand, you can take the loop output from the STB and feed your PC tuner with it. It will work, but there's a very good chance you will have to have the STB on for this to work at all and an even better chance it will be completely slaved to the STB - the STB will have to do all commanding of motors, switches and polarization. If you must live with one coax downlead, there are hacks and tricks, but they can get ugly, complicated and expensive. Multiswitches are the better way to go 98% of the time. Learn to love a hole saw and use it.

 

[pendragon]

In the FTA world, splitters and combiners are not used as far as I know. A FTA receiver would have to be purposely designed to control/process/function with such devices and I personally don't know of any.

I'm not trying to quibble, but I use splitters a fair amount. I would agree they are not that useful for most FTA applications. I'll outline a few that might make sense:

1. You have a bandstacked LNB that feeds more than one receiver.

2. You have DiSEqC switches, 22 kHz switches and/or a motor and your older receiver cannot command this. You could slave it to another receiver through a loop out if that exists, or you could use a splitter.

3. You have multiswitches but they do not have enough outputs. Instead of cascading them, you split each of the LNBs to feed two or more multiswitches.

4. You want to monitor a signal line feeding a receiver with a test instrument like a spectrum analyzer or a BLSA.

5. You want to compare two different receivers under similar test conditions.

I have a number of other uses, but my point is they can be very handy in the right application.

 

[zamar23]

Learn to love a hole saw and use it.

Believe it or not, I tried to fall in love with a hole saw, hammer drill and such. That love was certainly not shared well by others around.

 

[Mr Tony]

Iceberg

I see a lot of good points in keeping stuff simple as you do. There is no need to keep tone confrontational, as you try lately, not because I'm not good at it, but cause its not productive, and I don't use confrontation in info exchange on purpose.

I'm not being confrontational...I'm just pointing out info

I don't know, why you keep trying to label every other site a hacker site, but I'm not that good at labeling. In fact, Digital Home is one of the harshest for signal hackers site in NA.

I'm very familiar with Digital Home. I am a member there. For a while you seemed to post links that went to hacker sites that might have a "legit" FTA area which is not tolerated here. I'm not labelling "every" other site as a hacker site. I do know the difference

Many edit their initial posts, if some relevant info was missed, this feature is common for most web forums.

The problem is if you post at say 10:00 and 2 people respond at 10:05 & 10:07, then you go back and edit your post at 10:15 that makes it confusing to follow

 

[Mr Tony]

1. You have a bandstacked LNB that feeds more than one receiver.
2. You have DiSEqC switches, 22 kHz switches and/or a motor and your older receiver cannot command this. You could slave it to another receiver through a loop out if that exists, or you could use a splitter.
3. You have multiswitches but they do not have enough outputs. Instead of cascading them, you split each of the LNBs to feed two or more multiswitches.
4. You want to monitor a signal line feeding a receiver with a test instrument like a spectrum analyzer or a BLSA.
5. You want to compare two different receivers under similar test conditions.

hey we think alike

Most folks on here dont use a splitter unless they usually have a unique situation
-bandstacked LNB's
-C-Band setup with 4DTV and DVB receiver
-they only want one polarity on a 2nd receiver
-they dont want to use the loop out

 

[B.J.]

I've been having a hard time understanding much of the discussion above, particularly, it sounds like some references to splitters are really referring to diplexers. However, relative to the use of splitters, I have been using splitters ever since I upgraded my analog system to digital about 13 years ago, and have had splitters in the system ever since, although the types of splitters have varied over time.
I have gone back and forth relative to whether splitters are better than using the passthru ports on receivers.
My original use of splitters, which is probably the same as 99% of people who upgraded a C/Ku analog BUD was first to slave a standalone DCII receiver, and later to slave a DVB receiver. Basically I split the line from each of the 2 LNBs, on leg going to may analog receiver, and the other leg going to my DCII receiver through a DC-block. When I wanted to also use a DVB receiver, I put the DVB receiver in place of the DCII receiver, and used the passthru to feed the DCII receiver, since my DCII receiver didn't have a passthru, and since I didn't want to split more than to 2 devices. Since this at first limited me to only C or Ku at the DVB receiver, I then got a 2x DiseqC switch (the simple A/B pulse type) to select either the line from the C or Ku splitter. This also worked fine, and the signal strength/quality at the end of the line on my DCII hardly changed at all from before. I then got PCI card receiver for my computer, so I inserted that between the DVB STB and the DCII receiver, again using the PCI receiver's passthru port. Again, I couldn't notice the difference in signal at the DCII receiver.

In short, I became an advocate of using passthrus because I intuitively believed that I'd lose half the signal with splitters, so I tried to avoid splitters whenever possible, and signal strength wise, I could observe this on my analog receiver, in that in splitting off the signal to the digital receivers, the signal strength dropped about in half, but it really didn't affect the quality of the analog picture much.

Upon adding even more receivers, I've at times extended to using even 3 passthrus before reaching the last receiver in the line.

HOWEVER, recently, I have come back to thinking that splitters are BETTER than passthrus in a lot of cases. The thing that was fooling me about passthrus is that I wasn't noticing any drop in signal when using a passthru, but that was apparently because many of these passthrus are amplified. So I was starting to see degradation in quality, even though the signal strength was as high as prior to the receiver with the passthru. Recently, I've gone from using the passthru to using a splitter prior to one of my DVB receivers, and I'm now able to lock a couple transponders that I was only able to lock before if I connected directly to the LNB.

Anyway, I started out using splitters, shifted partially away from splitters due to concerns about signal strength, then have gone back to splitters over concerns over signal quality. So there is definately a place for splitters in my system. I've always used them. However I have ALWAYS used them with DC blocks, and have NEVER allowed two receivers to have the possibility of sending DC voltage to each other.
Also, I have found very little difference between the cheap splitters that are used for TV, and only rated up to 1000MHz, and the more expensive splitters that are rated up thru 2000 MHz. There may be some small differences, but I've never noticed anything I couldn't receive using the cheap splitters that I could receive using the more expensive ones.
I also think that the concept of losing 3dB of signal when you use a splitter is not always the case. I think that it depends upon the impedance of the receivers you are using. I think that some of these receivers, even though they are using 70 ohm coax connections, are really higher impedance, and basically, the higher the impedance, the less effect they have on the original signal. Sort of like putting a 20,000 ohm VOM in a circuit will change the voltages, but putting a megohm VTVM or digital meter generally won't affect the voltages being read because they are drawing negligeable current. A lot of concepts regarding power loss in things like splitters is more applicable for transmitting than for receiving. For receiving S/N is more important then signal strength anyway, so splitters often don't affect your signal quality nearly as much as people suspect, since even if there are losses, the noise will also be reduced.

Anyway, just my take on splitters. I use them all the time.

 

[AcWxRadar]

I'm not trying to quibble, but I use splitters a fair amount. I would agree they are not that useful for most FTA applications.....

.....I have a number of other uses, but my point is they can be very handy in the right application.

Pendragon,

I don't disagree with you. But, the big picture here is not whether splitters and combiners can or cannot be utilized in any specific application, but if they can always be relied upon with consistency in EVERY application. These devices are highly application specific.

I know that there are many things that can be accomplished in certain applications, even if others report that it WON'T work. I satisfied my own curiousity by trying what others stated could not work, and proved that it did. But, that doesn't apply to all the other diverse setups and equipment that other's may be using. There is always exceptions to the rules.

Obviously, we are a group of malcontents and mad researchers who don't like to follow any rules. We like to make them up to suit ourselves as we go. That's how we determine what truly does and does not work along the way. And we are pretty good at this!

I am all for experimenting and taking risks and dabbling with the unknown, but I personally don't like to speculate or advise anyone of something that is or may be a bit sketchy. Obviously, I don't intend to discredit your personal findings, but you understand that what I recommend is to stick with absolute specifics and precise applications that have been proven over and over again.

In other words, if you have a specific application that can be repeatable, then that is fine and actually quite a plus to be shared. But, if there is any uncertainty at all, then it should be described as a "beta test" scenario and advise of the possible pitfalls and warnings.

I am certain that you understand my position just as well as I understand yours. This is what makes our site really top notch, because we can discuss all sides of technical issues together as a group and develop a really great understanding of how to apply our equipment. This is what we need to focus on to make the FTA experience easier for more people and refine it better.

RADAR

 

[pendragon]

Radar - no problems here. What I write is backed by extensive testing with instruments, but especially by operational use. My career has spanned disciplines where voodoo and magic cannot be tolerated and FTA is no different. But when you get a lot of people together on technical subjects, not all will agree and sometimes there are misconceptions. This can lead to myths that hamper progress. I may go out of my way to ensure physics and engineering are better understood, because there is always a reason something works or it doesn't. Not everyone cares and I respect that. I'm not putting you in any of these categories, by the way.

I should say I always have uncompleted projects, data that seem unphysical or are in disagreement and concepts that may or not work. While I may make off-hand remarks about these, anything that is alpha/beta quality and/or is uncertain is not going to be recommended by me. I prefer to warn people when they are trying to fool Mother Nature, but that doesn't always stop them.

Zamar - we've talked a lot of hypotheticals, and you've opened a number of threads to get people to spill their knowledge and guts on their own systems. If you could articulate what you are trying to do, even with constraints we don't like, we could probably help you a lot more rather than trying to foresee all the things that might go right or wrong.

Iceberg - evil minds think alike.

 

[zamar23]

I have ALWAYS used them with DC blocks, and have NEVER allowed two receivers to have the possibility of sending DC voltage to each other.

A lot of valuable points in your above post. Interesting observation about cheap splitters. Certainly, SNR is more important than signal level for nowadays very sensitive sat tuners and stream integrity reconstruction techniques. Could you post a few (hand drafted) diagrams showing how exactly do you combine splitters and DC blocks in a multi-receiver setup? Did you use such combos on Loop-Out ports and Add-on STB Cards? What references to splitters here did you find in-fact referring to diplexers?

 

[zamar23]

Radar

Would you agree that most systems discussed on this forum are quite specific in terms of often unique combo of the equipment used, hence its hard to develop a universal recipe good for everyone, and basic signal distro blocks like splitters should be given fare consideration, including in FAQ?

 

[zamar23]

Iceberg

I did not post links to hacker sites "for a while", as you put it, except 2 times to legit info sections on sites that you claimed later (again in the irrelevant thread where members requested AZBox section separation) were in your view hacker sites. As I said, I'm not good at labeling and don't read all content on every FTA site, referring only to legit material. This however, has no bearing on the splitter discussion. Please stop posting false accusations and far-fetched guesses at your convenience, whether relevant or not to the thread topic, personally attacking members every time someone asks to improve the site content. Do you want everyone to embrace this practice - it may backfire... I don't think its good for a Moderator.

Regardless, members will continue to post suggestions about the website content improvement whenever they feel the need. Your technical input is always welcome. :up