Are you spacing these on a motorized dish and expecting to hit multiple satellites at different positions? Unfortunately the spacings will not be constant for different positions on the arc. Get a toroid if you want to do this and are limited to one dish.
Sat System Structure Optimization
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Are you spacing these on a motorized dish and expecting to hit multiple satellites at different positions? Unfortunately the spacings will not be constant for different positions on the arc. Get a toroid if you want to do this and are limited to one dish.
On the LNB side: use 4x4 (unpowered) or 4x8 (powered and recommended) switches. Each will take two LNBs, both polarities.
On the receiver side: use one 4x1 DiSEqC switch per receiver.
This will get you to 8 LNBs that output both polarizations.
I do know that, but the above examples of LNB spacing might work in several dish positions despite minor variations in sat spacing due to strong signal and wider misalignment tolerances of chosen sats. The rest of the Arc can be hit by the central Invacom via turning the dish. Now I'm thinking on replacing a 39" dish with a 4-footer, adding C-band LNB at the focal point, and 3 Ku-band LNBs: Invacom Quad adjacent to the focal point, as you kindly suggested, another Twin Ku-band LNB to the left of C-band one, and one more Twin Ku-band LBN to the right of Invacom on a magic bracket - to test posibility of watching multisat in some positions on a motorized dish, including C-band. Not sure, if currently sold Toroidal dish can deliver C-band at all, and I already have a motor and Invacom Quad anyway. I do understand limitations of such setup, but on the other hand it might offer a much broader clear programming choice than majority of pizza dish viewers can ever imagine. And it offers a lot broader functionality even without C-band than a traditional motorized dish can deliver.
Could you list suggested switches makes & models on LNB side? How would motor control fit into this? How to connect 3 STB Sat receivers to this matrix: I assume, only one will control the motor, so is it just adding the motor btw one DiSEqC switch and the main receiver? Will adding a C-band LNB affect this setup in any way? Will other 2 receivers be able to change polarization of LNBs not active at the moment on the motor controlling receiver? If 3 receivers switch to reception of the same sat on a Twin LNB - which receiver will control polarity selection? Or do I need to use Quad Ku-band LNBs instead with 3 receivers?
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That's a good reason why you go with multiswitches and dual LNBs, or band stacked LNBs. That way, any receiver can see any polarity.
Offset dishes lose gain very quickly off-axis. If you're 9-10 degrees off-axis on a 1.2m offset, you're talking pretty close to only a pizza dish's gain. If you're going to put up only one antenna like this, you might consider something like a 1.8m Fortec prime-focus. It's bigger than a 1.2m, but more width-wise than height-wise. It will work much better for multisatellite and C-band, too, as the gain falls off more slowly on a prime-focus dish. When you figure in shipping, the bottom-line cost of the 1.8m prime focus is in the same ballpark as a 1.2m offset because the 1.8m package is much smaller and doesn't get hit with a dimensional weight.
I am biased at the moment towards the WNC SWA-48 powered 4x8. Often under $10 on eBay and it can pass a bandstacked and/or universal LNB. It can also be modified to power C-band LNBs at 18V on any port.
Yes, one receiver pretty much has to control the motor unless you want to get fancy. As guapoharry said, if you use dual polarization or bandstacked LNBs on the 4x8s, any receiver can select any LNB and any polarization. Is your Invacom a quad output (circular and linear)? If so it can be wired to one 4x8 and you're set. If you have an ortho C-band feed, each LNB goes to one input on a 4x8 in the same manner.
Thanks. The dishes choice is plentiful around here, no shipping required. I wish I had space to put a 6-footer, and in that case I would go for a multi-dish setup anyway. On top, I can't seems to find any analogs on the web to the proposed setup - that's encouraging, as it can be quite convenient for FTA fans in urbanized multi-storey single dish settings (given above mentioned gain limits of course). Btw, Mike Kohl mentioned limitation of +/- 15 deg. off center on a 36" offset round dish with special care given to aim the LNBs.
Does WNC SWA-48 pass OTA signals (even if not in spec - you seems to mention 250 MHz)? Is there a spec for it posted anywhere, what are signal losses? So, for a 4 LNB setup (2 Twin Ku, 1 Quad Ku Invacom, 1 C- band) and 2 OTA inputs I'd need 3 SWA-48 and 3 DiSEqC switches? What's the best way to supply power to SWA-48(s) in this setup? Would you advice to replace this matrix with a single Multi-switch within the same total price range - which make and model?
Does WNC SWA-48 pass OTA signals (even if not in spec - you seems to mention 250 MHz)? Is there a spec for it posted anywhere, what are signal losses? So, for a 4 LNB setup (2 Twin Ku, 1 Quad Ku Invacom, 1 C- band) and 2 OTA inputs I'd need 3 SWA-48 and 3 DiSEqC switches? What's the best way to supply power to SWA-48(s) in this setup? Would you advice to replace this matrix with a single Multi-switch within the same total price range - which make and model?
Can you elaborate on that fancy thing a bit? I do have a DVB-S2 Sat PC Card - if you mean PC control is required and the motor mod for a separate drive power? But it wouldn't allow to control it from STBs...
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If you can find a 'wide' offset dish like Mike Kohl prefers, if you use top-flight LNBFs matched to the dish, if you can find helpful sidelobes and if you have the instrumentation he employs for optimization, you might squeak a little extra gain out of such a setup. However even commercial prime focus dishes are down 8-10 dB when 15 degrees off-axis and offset dishes are generally worse. These data are published and available. I can buy Mike's results for the 1.8m dishes, but I'm reaching to accept some of the 90cm claims. I'm not saying it can't be done, but in the absence of any technical substantiation and with third party measurements to the contrary, I can only wish you well.
I haven't seen any useful specs for these or pretty much any other switch. I came across the WNCs while reading in DTV forums how some people were passing WB signals through them. That suggested 950-2150 was possible and a few posters were claiming to get channels, from my understanding, that would have been passed between 250-750 MHz. I purchased a few as a gamble and confirmed 950-2150, which is all I care about. I noticed signals on my spectrum analyzer well below 950 MHz from my Ku LNBs and verified these were known feeds. None of my DVB receivers work at those frequencies and therefore this is useless for my purposes. I have NOT measured passbands below 950 MHz, and there is no guarantee that any SWA-48 you buy will even go above 1450 MHz. Mine all did.
I'm not sure what you mean by 'signal losses'. Are you referring to a gain loss, which is immaterial in a well-implemented FTA system, or a high NF? One of the reasons I went to these units was the mediocre performance of the unpowered switches I tested. My conjecture was DTV wouldn't be using switches that significantly degraded their signals, and that turned out to be correct.
Correct on the counts. The WNC switches are provided power with coax lines. Given this should all cost under $50, I would be surprised to find a better or equivalent for the same or lower price. If you find such a solution, I'm sure many would be delighted to hear about it.
Do you want to position the dish from more than one receiver? If so, please describe. If you're only using one receiver for control, it can be either a STB or PC receiver. The motor mod isn't necessary, but in my mind is a good idea. I don't even like powering switches or LNBs from receivers, but put up with DiSEqC switches as there isn't much I can do about that.
Yes, but the OP is talking about doing this with subscription channels. (With TPs that are much higher power) From one of pendragon's excellent threads, wasn't the loss 4-5 dB with a 9º off-axis spread?
I guess that made sense after reading from Mike Kohl's website that DBS birds are typically separated by 9º
It's too bad that subscription channel receivers won't control a motor...
Finally catch you on the 9 deg slippery slop!
Just kidding, of course, you're correct (to some degree, in general) big times. :up Yes, it's desirable to control the motor from any receiver in use at the moment (of course after asking family members for a quick break, if there's some redundancy in a multi-LNB setup in several dish positions. I guess, its all about compromise...). I kind of bought into your suggested setup altogether (you know, one starts falling for something, and end up falling for everything, if sold by a pro ). Understood, switch power is delivered by coax, what I was asking, how to minimize count of coax runs into the house? Btw, is that a useful spec for a multiswitch - there're more there.That's why I'm outerly confused with the whole motor control thing.
bow Besides, these spacing examples you mentioned are just it - general examples of some possible combos. On top, FTA fans often report satisfaction with watching clear only channels like NASA, Ion, etc on cir. sats, as there're a lot more clear channels to watch on other sats. However, my question is: how to control the motor from any FTA receiver, while watching Ku-multisat that way, say via any combo of FTA receivers and a PC Sat Card - is such (low cost) setup possible?
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Not to quibble, but Mike Kohl's website says +/-15 degrees worked for him on FTA Ku satellites on a 90cm dish. That's where my published 10ish dB loss came into play. I'm not the only one who has measured this and posted data on the Internet. Mike also claimed +/-25 degrees for subscription satellites. If he can do this and have margin, all the more power to him. I'm not disputing his claims at all, but frankly the data he offered wasn't enough to verify anything independently.
Huh? All I'm doing is warning you that you might end up disappointed. My measurements cast some doubt, but they don't prove anything. Nevertheless you're charting a comprehensive design that may hinge on some difficult crux moves, with goals that may be mutually exclusive. For example, a low f/D offset dish should be better for typical FTA C-band feeds, but a high f/D offset dish probably would be better for off-axis reception. You're making choices without understanding the consequences.
I can think of a spectrum of ways to do this, from manual switches to custom circuitry. It simply depends on what you want to invest in time and money and your skill level. Factor that against what you will realize in benefits.
At some point you should stop planning, jump in and start prototyping. I tend to think big sky when conceptualizing, but I've learned practical experience often trumps the best imagination. I would never start a project that is new to me with the assumption that it will turn out exactly the way it was conceived.
If anyone cares to make a distinction or quibble about something I say, please do. I might learn something. (maybe others too)
I too am interested in the possibility of using more than one receiver in a switch network to control a motorized dish, or two.
For me, it would be low to medium skill level and as much off the shelf components as feasable.
Previously, my take on it was that most switches don't handle the current a motor requires.
I too am interested in the possibility of using more than one receiver in a switch network to control a motorized dish, or two.
For me, it would be low to medium skill level and as much off the shelf components as feasable.
Previously, my take on it was that most switches don't handle the current a motor requires.
That's healthy doze of critics, I'm ready to improve on. In fact, this thread is a big step in the right direction - thanks a lot for clarifiying things! It's an amazing read for many FTA warriers. Keep in mind however, planning for some is part of their trade. You're absolutely right about a project dynamics - it's usually going on circles closer and closer to the hit mark. This thread value is in that we started discussing possible broad choices before showing a given setup photos - now everyone is free to make far better informed decisions.
What I still want to learn, if there is a way to cut on number of coax runs into the house in the proposed multi-switch setup, especially for powering switches (a power passing splitter, if all SWA-48 switches must be continuously powered?). Would a single switch power adapter deliver enough power for 3 switches via such splitter?
Of course, such desert as multi-receiver motor control schematics is a desired read. Can someone chime in with more ideas on this? Well I guess, I have one workaround in mind: use a Radio & IR Universal Remote Control to turn the motor via a designated receiver from any room. We already discussed another approach: use a LAN connected PC in any room to control a designated receiver. But its kind of not too cool - does a low cost switched solution exist?
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I am on both sides of the fence when it comes to motors and switches. If you look at motor and switch specs, you'll generally find the switches are rated to provide the motor current plus allowances for LNBs and other gadgets. But many here would caution never to put a motor on the LNB side of a switch. That makes a multi-motor setup difficult as a DiSEqC switch followed by a 4x4/4x8 for each dish is a very convenient way to set things up. When I started, I put my motors and controllers on the LNB side of DiSEqC switches and ran for months without problems.
However looking at this from a systems point of view, I decided it was better for the receivers not to power anything for a variety of reasons. Thus came mods to alter output voltages of 4x8 switches and separate LNB lines from motor commands, and both from motor power. All of this has worked well for me and likely enhanced the life of a number of my components.
I thought over the possibilities of multi-receiver controls for multi-motors, and realized that picking up another USB receiver for specific motor control was the easiest and least expensive way for my system to go. But my design is based on centralized management of pools of receivers and dishes (and their positions). That will not work for everyone.
At the simplest level, you could hook arrays of manual coax switches to get everything where you want. That may work for electron-heads, but I would be loathe to explain this to the rest of my family.
As to the challenge of using off-the-shelf parts only, I think what you fundamentally need to do is separate the switching of motor commands from the LNB access paths. That can be done with diplexers that pass power to BOTH ports or power inserters wired somewhat backwards. Once you have this done for each receiver, you could implement a separate DiSEqC switching network just for motor commands. For each motor to be controlled you could then use all port power-passing splitters to combine the commands to that motor from each receiver. There is no priority system or lockout. Whichever receiver commands a motor does the positioning.
That's all I was going to write, but I know I would invariably get a request for a diagram, so find a rough sketch attached. I've done it only for two receivers and two dishes, but it can be directly scaled to eight receivers and four dishes. By substituting DiSEqC 8x1s, we could have eight dishes. By cascading 4x1s and 8x1s you could control 32 dishes. And so forth ad nauseam. I would still suggest supplying motor power separately.
There are several issues, all of which could be solved:
1. Power passing splitters generally have blocking diodes wired the opposite direction from what you want for this purpose. But you could probably wire up a box to do this or use some F-tees in a pinch.
2. The total current draw for three 4x8s with LNBs could easily be a couple of amps or more. You would likely need a better power supply to feed this much.
3. Using a single RG-6 for this level of current is probably not the best solution. You could use a heavier gauge power cable and fashion adapters.
I sort of have a similar problem in that I have around a dozen of these switches. Instead of the above, I put them in the attic as I wired it years ago for a WiFi bridge. That keeps the wiring and switches out of the elements and gives me a more pleasant work environment when the weather is bad. It also turns out that this minimizes the cable runs because the toroid is mounted on the roof on the opposite side of the attic wall.
Just in case you looked at similar solutions in the past, do you have particular Diplexer and Power-passing Splitter models in mind to feed the motor(s)? Btw, Summit Source offers a large Multiswitch choice at various price levels.
Where the purpose is to supply power from a wall outlet via a power adapter to the powered switches? It looks like the same direction to me, as passing power from a receiver to the motor - or it isn't? Using T-type F coax cable connectors might be a good idea too. What model of a fashion adapter to connect coax to power cable do you have in mind? Here is a Cable Connector Selector if anyone needs.
The problem with urban multistorey settings often is that one can't hammer drill any holes (for several reasons) in the very thick walls to let cable in. One can probably get by with a single such hole, but to hammer a dozen of these is not rewarding at all.
Hence the task of keeping coax count down is crucial. I like your proposed setup a lot (its in part a matter of trust), but can't seems to figure out, how to keep that coax count under control - except for hammering a big hole for a large Dia. tube - assuming all switches are designed for NA outside temperature range. What is a standard solution to run multiple coax cables into a house in a weather protective way - any wall inserts for this? Any FTA dealer sells suitable large weather boxes or wall mounted switch cabinets to accommodate multiple switches outside?
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pendragon
It appears, your above posted Multimotor Control Diagram presumes for STB Sat receivers to have two independent DiSEqC Switch port selectors in Receiver Setup Menu, while many receivers offer only one such selector. Are there any receivers offering two and the way to ID the switches? Or the diagram can be refined to accomodate the issue?
It appears, your above posted Multimotor Control Diagram presumes for STB Sat receivers to have two independent DiSEqC Switch port selectors in Receiver Setup Menu, while many receivers offer only one such selector. Are there any receivers offering two and the way to ID the switches? Or the diagram can be refined to accomodate the issue?
Diplexers that pass power on both ports are not common. In fact until Anole suggested using one, I didn't even know they existed. There is the Perfect Vision PVDP-2PP that I've used successfully. A splitter for motor purposes is very non-critical. Sadoun has a number of choices and sometimes very good prices. There are many others.
Typical splitters have the diodes that run from the output (multiport) side to the input (single port) side. The anodes are on the outputs and the cathodes on the input. That means you can only pass positive voltage from output to input. If you're trying to use a splitter to feed power to multiple switches, the diodes will block.
Take a look in the electrical conduit section of your favorite big box home supply store. There are all sorts of service entrance and box solutions that are readily available. I realize the headache of pounding through a big hole for cables, but at least this is a problem that has to be solved all the time for much larger cables.
The switches we are talking about are designed for just about anything reasonable you want to throw at them, including temperature and precipitation. Make sure you use seals, however. The WNC switches are easy to open and modify because they have plates on the front and back held by screws. They do have gaskets, so if you take them apart, make sure they seal when put back together.
Actually the 4x1s for the motors have the same port configuration as the 4x1s that eventually go to the LNBs. When the receiver sends a DiSEqC switch command, it changes both switches to the same port. That's what you want.
I neglected to note one limitation of this concept that may affect your design more than people with multiple dishes. If there is more than one receiver switched to the same dish, and therefore motor, if the one commanding the motor is outputting a lower DC voltage than any other connected to the dish, the splitter will block it. I don't think this is much of a limitation for multiple dishes because if you're moving a dish that someone else is watching, bad 'people things' might happen anyway. The same thing sort of applies to one dish. In the worst case you simply turn off the receivers not in use for the move. This would be the advantage for the custom circuitry that I hinted at earlier.
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