Multiple motorized dishes from the same receiver?

[geekt]

For more than the last week I keep wondering if it's possible to hook up two or more motorized dishes to be controlled by one receiver, or would you need each additional motorized setup to be controlled manually?
I know you can access the multiple LNB's from multiple receivers through switching, but I was just wondering for such cases as when you have multiple birds across the arc that you want to access, but don't wish to be limited one to a fixed position on one of them.

 

[brentb636]

At the moment, I'm running a USALS hh-motor for my Ku band and a Diseqc 1.2 G-box off of a single receiver, successfully. All the Ku band stuff is USALS and all the C-band stuff Diseqc 1.2.
An Ecoda 22khz switch does the switching between the two devices.

 

[brentb636]

In the past, I tried tying two motorized Ku systems together with a network of Diseqc switches and 3x4 switches, so that only one receiver would drive one dish, but ALL receivers could monitor any dish. That was unsuccessful. I found it impossible to tie these things together and yet prevent the USALS commands from occasionally getting through to the wrong motor ( as well as the right motor ). I don't think the Diseqc switches provide "perfect " isolation" from signals coming thru the lnbf from another receiver. Sometimes they do, sometimes they don't .
You have a chance of getting your system to work using Diseqc switches in conjunction with an ecoda 22 khz switch, but the chance of problems is high, to include burning out your Diseqc switches with motor current. I think it might be more of a headache than it's worth.

 

[Arion]

A 22khz switch to select between two motorized systems is the ticket.

 

[brentb636]

The problem with using JUST an Ecoda 22khz switch is that Diseqc commands go thru both ports, regardless of which is selected. A standard 22khz switch passes NO Diseqc commands . Perhaps using an Ecoda 22khz switch with a Diseqc switch for each motor would isolate the commands so that ONLY one motor could receive the USALS Disecq commands.
I still think it's a headache.

 

[Vorg]

But isn't there a problem of putting switches ahead of motors because they can't pass the needed current to run the motor? Unless you do the motor mod

 

[brentb636]

There is always the chance that motor current will burn out a switch. I've never had it happen with an Ecoda 22khz switch, but the Diseqc switches are even more "iffy". Personally, I've tried to simplify my life, go to a minimum of switches, and move all of them inside the house.
If you look at the current rating of a particular switch , it may say "300 ma" . That can support an HH motor , BUT who know if the "300 ma" is a true number for that switch? I don't really believe what the specs are , on these cheap devices, but only believe the results as I see them. Experimenting is fun, but sometimes the solution we desire is not possible with the hardware that we bought .
Maybe it'll work. Maybe not. There are too many variables to predict the outcome. Personally , I'd keep it simple.

 

[geekt]

Glad to see that my question wasn't a dumb one.

Considering the problem of moving a dish during recording, I wish there were a way to lock out movement of a dish during recording, and still have the freedom of a motorized setup. Maybe eventually I'll choose to have two motorized dishes, and one on manual, so I can move the manual one to my latest dish addiction, and wherever I'd recording from.

I think part of the problem these days seems to be old tech running into new tech. Old tech is to use these simple cables for everything, and tones and voltage for controlling. It doesn't even make sense though anymore, because everything from the sats is data packets. For me it'd be simpler if I just had an ethernet cable from each LNB, and motor, the signal was sent through the LAN as data, and the motor had a seperate power source. That way I wouldn't have to deal with the motor going faster depending on V vs H polorization, the signal didn't have time to degrade since the LNB does the receiving, and every device gets it's own unique IP.

 

[Vorg]

I think you would be talking fiber for ethernet to handle the data from an LNB. That said there are LNB's now that are connected by fiber instead of cable. But you would still need to run copper to power the lnb.

 

[geekt]

Standard Cat5e/6 can handle over a gig/sec, with duplexing. That should be more than enough for even the largest HD streams.

But I'm sure eventually the setups will start to switch to some new tech in the next 20 years or so. Though you should never underestimate the lack of innovation by common man.

 

[pendragon]

If you want to run motors for multiple dishes, simply feed them from the different ports of a DiSEqC switch. Contrary to prevailing myths, DiSEqC switches and motors are designed to be compatible with one another and are intended to work in this configuration. There may be poor quality switches that cannot handle a motor load, but I've picked up ones for $3-5 that have no problems. I've also measured the instantaneous current from several motors under a variety of conditions and none exceeded DiSEqC limits.

It may be fun to dream about connecting Ethernet cables to a LNB, but this only demonstrates thinking in a very small box. The de facto design standards for FTA and DBS provide an IF bandwidth up to 1.1 GHz. With current technology one can easily route from an enormous number of LNBs through switches to an almost unlimited number of receivers with negligible losses in CNR. There are some products that can pass this through fibre instead of coax, but the concept is still the same.

GbE Ethernet bandwidth would be woefully inadequate to carry this as digital data, as one would need say 22X more than its peak (never obtainable) rate. One could put tuner(s) and possibly demod(s) in a LNB to accomplish what you want, but there would be even more problems with that, including the lack of scalability, vulnerability to technical improvements, power, reliability, cost, etc. While the current architecture may seem dated and is definitely mature, be assured there are very good reasons why it has not been supplanted.

 

[geekt]

Oh, no, you're right, I just get annoyed by the complications caused by the simplicity of the one line approach. Such as planning setups with multiple LNB's with universal vs standard, multiple motors, multiple receivers, etc. I get the basic concepts, but in practice it's probably easier and yet more complicated. People who have worked with these systems for years could probably setup a system with 16 LNB's without any planning, but everyone else has to think about it and wonder if the system will work right.