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

[zamar23]

Yes, I would like to avoid modding the motor if at all possible, separate motor commands by a power passing diplexer as you suggested, but then insert a power inserter down the line after motor commands from several receivers are combined with a splitter, so that 18V power and DiSEqC commands were sent along the same line to the motor. In my current setup the motor is powered first from the receiver, then coax line goes back to my switch matrix. So, why would one need to separate motor power and its DiSEqC commands at the motor in the modified setup above, if usually they're delivered along the same cable? It looks like a solution to me to avoid modding the motor, while separating its power supply from an STB. Or it's not?

 

[pendragon]

Still, can you explain how exactly you derive the required pad resistance? You mentioned in another thread that a BLSA type device can possibly be modeled with a PC Card tuner. Would it help to analyze one's signal distribution system irregularities and compensators required without a Spectrum Analyzer?

One needs to derive the attenuation, not resistance I do this by checking LNB outputs on my spectrum analyzer at the wall plates. If the level is too low, I add amplification at the LNB. If adding an amplifier would saturate some component along the path, I may have to insert attenuation before the amp to hit the 'window'. I'm normally aiming around -30 to -40 dBm for the absolutely hottest signal that LNB can receive, but if it's several dB lower, I know it doesn't matter.

This may sound simplistic, and it is simple because I worked out all the gains ahead of time for my distro design, instead of trying to hack away afterwards. If the signal comes out of the last cable in the right 'window', I know everything else along the way is optimized. I used my spectrum analyzer to test each component in the signal path before starting, so I have a very thorough understanding of what each does best.

There's no doubt a bench spectrum analyzer is very useful for purposes like this, but a BLSA or a PC tuner spectrum sweep should do the job if they are calibrated. I will likely do this for the Prof cards I'm working on and I assume the same can be done for the BLSA. The BLSA will provide more frequency resolution, but that won't be necessary for a task like this. I just posted an example of a Prof 7301 sweep in the compendium thread over in the PC subforum.

 

[pendragon]

Yes, I would like to avoid modding the motor if at all possible, separate motor commands by a power passing diplexer as you suggested, but then insert a power inserter down the line after motor commands from several receivers are combined with a splitter, so that 18V power and DiSEqC commands were sent along the same line to the motor. In my current setup the motor is powered first from the receiver, then coax line goes back to my switch matrix. So, why would one need to separate motor power and its DiSEqC commands at the motor in the modified setup above, if usually they're delivered along the same cable? It looks like a solution to me to avoid modding the motor, while separating its power supply from an STB. Or it's not?

No, if you drop the power inserter where you indicated in the diagram, the DiSEqC commands will be blocked because DiSEqC commands look like DC to a power inserter. You need to superimpose the DiSEqC command modulation on top of the DC power. There are a number of easy ways to do this, but you would probably have to build an enclosure for a custom, if trivial, circuit. It was easier for me to modify the motor.

 

[zamar23]

It's time for a splitter newbie to look in the primer again.

"An attenuator is an electronic device that reduces the amplitude or power of a signal without appreciably distorting its waveform. An attenuator is effectively the opposite of an amplifier, though the two work by different methods. While an amplifier provides gain, an attenuator provides loss, or gain less than 1. Attenuators are usually passive devices made from simple voltage divider networks. Switching between different resistances forms adjustable stepped attenuators and continuously adjustable ones using potentiometers."

"The http://en.wikipedia.org/wiki/Electrical_resistance"][I]electrical resistance[/ of an object is a measure of its opposition to the passage of a steady electric current. An object of uniform cross section will have a resistance proportional to its length and inversely proportional to its cross-sectional area, and proportional to the resistivity of the material."

 

[zamar23]

Adding Power Inserters

No, if you drop the power inserter where you indicated in the diagram, the DiSEqC commands will be blocked because DiSEqC commands look like DC to a power inserter. You need to superimpose the DiSEqC command modulation on top of the DC power.

How about using a Dish Pro Plus Power Inserter for this? It looks like it passes DiSEqC commands, as depicted on the attached diagram, and works with legacy DN receivers as well, which presumably don't bandstack or convert frequencies, at least of DiSEqC commands. There may be similar Power Inserter models available for general FTA use with extended passing freq range spec - or not?

 

[pendragon]

Yes, you could use this device, and I evenconsidered mentioning it but for the fact that it will exacerbate your constraint of only having one coax downlead. I thought the reason we got to this point was (1) you don't want to mod your motor and (2) you don't want any extra coax or other cables for DiSEqC commands, power and/or mutiswitch outputs. The DN inserters also tend to be on the heavy side with voltage, and this may cause problems or reduce the life of FTA components not designed for that.

I feel we're playing a guessing game of what's behind your curtain. You state a problem, and we offer a solution. Then out comes a constraint, not previously specified, that invalidates the solution, or something like this situation that on the surface appears to violate a constraint you threw at me in the past. If you really want help on designing a system within your and other signatory authorities' comfort zones, I believe you need to explain once and for all (1) what you want to put on your roof in terms of dishes, motors, LNBs and the like, (2) what your wiring constraints are in terms of number of coax or other downleads, (3) where you want to put any switches and whether there is power availability at that location, (4) how many receivers you want to run and some ops concept for how they will be used - e.g. are they completely independent or will only one be on at a time and of course (5) all known constraints. At the moment we on this forum are playing a weird game of 20 questions with you where we are neither allowed to ask the questions nor know the answers. You're wearing out at least my patience.

 

[zamar23]

Actually, no-one has an obligation to answer anyone's questions on this or another forum, or talk about their setup. I won't have any problems with that, and will not claim representing others as well. This thread was intended by its header to be a generic thread on using basic signal distribution system components. It's NOT linked to my particular setup in any way, except various hypothetical personalized "what if" scenarios aimed ONLY at finding out how basic components can generally be used in a FTA signal distribution system, since such info is very hard to find. It's merely educational, a valuable learning curve for me and hopefully others. The forum rules do not prohibit asking general questions within a covered by the forum subject, or presenting particular system examples without linking them to own setup. In fact, I found various generalized threads on this forum posted over a long time frame. While people educate each other, like in this thread, new solutions are suggested like using DP 44 Power Inserter for FTA applications, nobody spoken before about, or exploiting a sat tuner capabilities in a motorized system auto setup - its hard to not notice that. Not surprising, new solutions come from different people, not just one or two - no knowledge, ideas or opinions monopoly.

I have no problem saying I don't know an answer if I don't, and will loose nothing admitting that. You don't have to answer, if a question sounds incomplete or too hypothetical, or whatever. That's why still trying to find out, if anyone checked DPP44 Power Inserter will pass DiSEqC commands to a generic switch like Chieta 4x1, or it can only work with DP switches, STBs and LNBs due to employed freq upconversion or non-standard commands passing scheme? Its Spec would be appreciated, but seems very hard to find.

 

[pendragon]

That's why still trying to find out, if anyone checked DPP44 Power Inserter will pass DiSEqC commands to a generic switch like Chieta 4x1, or it can only work with DP switches, STBs and LNBs due to employed freq upconversion or non-standard commands passing scheme? Its Spec would be appreciated, but seems very hard to find.

The DPP44 power inserter has to pass DiSEqC commands for it to work with the switch. It doesn't do any frequency conversions. I don't recall the exact voltage it provides upstream, but I measured mine when I installed it and it was over 20V, and I seem to recall it was well over 20V. That might cause problems for some FTA components. It should turn your motor faster, but I can't say whether it would have the same life expectancy.

Along the same lines my DP legacy converters send much closer to 18V of power and also pass DiSEqC commands. If you have a Superdish-style bandstacked LNB, they will handle the frequency conversion of the upper H band to 950-1450 MHz when 18V is applied by any FTA receiver, or pass the lower V band straight through when 13V is applied. This makes using this type of bandstacked LNB look completely like an ordinary switched FTA Ku LNBF and might be nice for multireceiver installations. On eBay they go for next to nothing.

Dish has no skin in the game to supply parts for FTA. I doubt you'll ever see a spec for either in the wild.

 

[zamar23]

Great! Then DP44 Power Adapter can possibly be replaced with "Anole's" 18V laptop power adapter, and we're done with the motor power supply. Still, I found no experience shared anywhere on the web confirming DP44 Power Inserter will pass DiSEqC commands to Chieta 4x1 or similar FTA switch. Hope, you checked this out or looked at its signal outcome before with a SA. The fact that it works with DP44 Switch might not be enough on its own to draw such conclusion.

 

[pendragon]

Great! Then DP44 Power Adapter can possibly be replaced with "Anole's" 18V laptop power adapter, and we're done with the motor power supply. Still, I found no experience shared anywhere on the web confirming DP44 will pass DiSEqC commands to Chieta 4x1 or similar FTA switch. Hope, you checked this out or looked at its signal outcome before with a SA. The fact that it works with DP44 Switch might not be enough on its own to draw such conclusion.

No I didn't and it's unlikely that I will. But the DPP44 switch uses DiSEqC-style commands and the power inserter would have no reason to intercept them and re-initiate them. The power inserter is a very simple device and likely has a 22 KHz pass-through. Of course I can't say this with 100% certainty, but I've taken many technical gambles on far less evidence and been pretty successful.

 

[zamar23]

DPP Power Inserter

Yeah, that's what the attached DPP 44 Info Sheet says:

"As with all DISH Pro installations, cable and components between the LNBFs, switches, DP Plus Separator and receivers must be rated to 2150 MHZ and pass 22 KHz tone."

And from another document:

"DISH Pro technology includes: DiSEqC 2.0".

Meaning the Power Inserter should be good to go.

Interesting Spec for its Power Adapter SSB-0334:
100~240V 50/60Hz 28/20.5 VDC 1.65A

It looks like its Voltage Output depends on Voltage Input - or what? The spec doesn't look the same on its sticker, but still 2 different voltages are shown. It may possibly supply any voltage within the spec depending on DPP44 Switch & LNB set current power and voltage requirement and voltage drop along the line.

Can its 20.5 V output be decreased to 18V by adding an attenuator or another in-line component to the coax line after the Power Inserter? What would be that extra component required value?

 

[zamar23]

Multiport Splitters

Given the discussed opportunity to control a motor from several receivers via a diplexer - splitter set, another question is obvious: can 3x1 or 4x1 power passing on all ports splitters be used instead of a similar 2x1 splitter to control a single motor from more than two receivers one at a time, while supplying power to it by a single coax using the DP44 Power Inserter? Any issues expected from adding more receivers / extra DiSEqC signal losses on a multiport splitter?

 

[zamar23]

Best of the crop

Need high quality signal distribution components? Introducing a splitter heavy weight MCR Group:

"MCR Broadband’s EDIP series Diplexers are designed for use with Direct TV (EDIP-1) and all Dish Network Satellite Installations (EDIP-2D). Their frequency range (40-2450 MHz) is greater than legacy diplexers which have a frequency range of only 5-2050 MHz. They have a lower insertion loss, filter harmonics in the off-air spectrum from satellite conversion, and allow 2000 mA power passing as required for newer installations."

 

[zamar23]

Power Blocking & Passing Components

Voltage from your receivers do not "add together" to create a higher voltage than the LNBF can accept. You could potentially damage one of the receivers by back feeding a voltage, but this is also unlikely.

A DC block could be used in place of turning OFF the LNB power in the receiver's menu if one of the receiver's is to be assigned as the master or controlling unit. Otherwise, the LNBF polarity will be set by the highest voltage. Example: if receiver "A" is set to vertical (13vdc) and receiver "B" is set to horizontal (18vdc), the LNBF will be set by the higher voltage outputted by receiver "B" and only tune horizontal polarity.

Are there DC Blocks that can pass 22KHz pulses in both directions? What makes & models?

If one can potentially damage a receiver by back feeding voltage, does it mean that a receiver would not usually have internal DC Blocks on neither LNB IN no Loop OUT ports?

If a typical in Sat TV installations Power Passing Diplexer, Directional Tap or Splitter is used, will it pass power in one direction only (i.e. it has a DC Block incorporated) or in both? I.e. will it pass power in opposite direction, if an in-line Power Inserter without an internal DC Block is connected after it on a coax line running towards a DiSEqC switch, motor or LNB?

If LNB lines from several receivers are combined via a Power Passing Splitter with line from its IN port running towards an LNB, can these receivers potentially damage each other by back feeding voltages?

Brian, pls answer when you're back from the Expo, if no-one else knows.

 

[pendragon]

Are there DC Blocks that can pass 22KHz pulses in both directions? What makes & models?

Not that I know of. You would have to fabricate such a thing. The real question is why you would need one for any typical FTA application.

If one can potentially damage a receiver by back feeding voltage, does it mean that a receiver would not usually have internal DC Blocks on neither LNB IN no Loop OUT ports?

Ideally they incorporate some protection for the power supply that supplies the LNB. In most cases I would expect the receiver front-end itself to have a DC block.

If a typical in Sat TV installations Power Passing Diplexer, Directional Tap or Splitter is used, will it pass power in one direction only (i.e. it has a DC Block incorporated) or in both? I.e. will it pass power in opposite direction, if an in-line Power Inserter without an internal DC Block is connected after it on a coax line running towards a DiSEqC switch, motor or LNB?

Power passing devices such as you indicate normally employ a diode so power can be passed in only one direction, but not the other. This is normally not referred to as a DC block however.

If LNB lines from several receivers are combined via a Power Passing Splitter with line from its IN port running towards an LNB, can these receivers potentially damage each other by back feeding voltages?

In every case I've seen, power passing splitters incorporate diodes for each "output" port so the voltage from any receiver will not back feed into another. Hypothetically if one of these diodes were to short (one possible failure mode), then it could back feed.

 

[Mr Tony]

DC blocks block everything going through it. Its the same thing as turning off the LNB power on a receiver

If you hook a DC block to a receiver's LNB input there is no power being sent to the LNB even if you have the receiver LNB power turned on.

no diseqc commands go through it
no 22k commands go through it

 

[Mr Tony]

pendragon
I moved your post form the other thread (that zamar apparently deleted his post after you responded ) then double posted

 

[Mr Tony]

The real question is why you would need one for any typical FTA application.

because he is playing in fantasy land

 

[zamar23]

Iceberg

Wow - 3 posts at once! I thought, it would be logical to move it here, if you don't mind. This is not a fantasy game, but "knowledge is power" game, explaining how basic components work together, again if you don't mind.

 

[zamar23]

Finalizing Motor Control Mod with Power Inserter

Pendragon

I haven't seen your post before moving mine. The immediate prompt to ask these questions was to finalize the solution on controlling a single motor from several receivers without modding the motor. We already discussed that a special DPP44 Power Inserter can be used for this, since it passes DiSEqC 2.0 and below commands.

However, I still had some reservations. The Motor is controlled by DiSEqC 1.2 and 1.3 commands requiring no backwards communication towards the receiver to confirm commands execution. However, if the Power Inserter doesn't have a DC Block, can it damage the receivers below the line by backwards voltage? You said, diodes in diplexers and splitters will prevent that unless damaged. It was missing peace of the puzzle.

Again, another missing peace was, if several receivers connected via a splitter to a single Motor power line can damage each other by supplying voltage in reverse. And this concern was largely removed due to diodes employed by the diplexer and splitter to block power in reverse.

Also, if several receivers connected via a power passing splitter can mess up each others brain while sending DiSEqC commands to LNBs, switches and motor. Apparently not because of the above diodes.

Would DC Blocks be helpful in any way to add on any of the lines in the schematics attached?

Another peace is will the motor still draw power from the connected via a splitter receivers, as the Power Inserter appears to act merely as a Voltage Stabilizer having presumably no pass through DC Block? If the motor still draws power from the receiver(s), in what proportion from each?

Did you modify your motor such a way that physically cuts power supply from the receiver on its command port? A weak point to recommend others such mod would be not only the warranty loss, but also that various motor makes have different PCBs, so an average FTA fan would rather damage the motor trying to copy someone else's solution, no matter how good the solution is.

Anyway, if you're familiar with Six Sigma quality assurance approach, you know what I mean by all these scenarios. I'm sure, DN and DTV engineers are pretty good at it looking at complex signal delivery systems they created.