Greg Elmassian
Guest
Wow, never going to get good range at 5mW, so I don't understand the conversations about upping the voltage to the chips.
The future is a 2.4GHz frequency unit.
The idea of deadrail was (originally)to take a DCC system, and basically put the "tracks" wirelessly. What radio and what protocol is a variable, but does not affect the idea.
Now, this means no programming track in most cases, transmit from throttle to loco only, no receive.
Where it gets complicated is where you have no "system".
So, in the "beginning", you took what would go to the rails, and broadcast it. Then the locos would all have receivers. In this case the locos really have no "idea" they are wireless. (notice you can do this with battery, or track with constant power, or a combination).
So your DCC system works as before, multiple throttles all communicate to the command station, and ALL the commands for ALL the locos are put in a stream and transmitted. Therefore no limitations in the number of locos or throttles in any way different from the "normal" track powered system.
Next someone had the bright idea to have individual throttles and not use a command station. In reality, the command station was built into the throttle, it still generates DCC commands, but now there is no "SYSTEM", i.e. the throttles do not know about each other.
Here's where it gets interesting. If your throttles are all on different frequencies (like AirWire channels), no problem, they can all transmit at the same time no problem. You do lose features like "all stop" and if you have a consist made with universal consisting, the other throttles cannot "take over" that consist.
(There are some systems that can "clone" the memory of a throttle to help this a bit).
But you are still limited by the number of frequency channels, and if you want to control a different loco, you have to switch your throttle to that channel.
Enter the bright idea of sending all commands on the same frequency... now you have to solve another issue, how to keep multiple throttles from transmitting at the same time. What is usually done is different from a normal DCC system, which has commands being transmitted continuously, round robin, new commands, and what available time is left transmitting the speed commands for existing locos. (This is why you can pick a DCC loco off the track and put it back on and it resumes the speed it was at)
You need to just transmit your new command. Two large problems surface: First if you "miss" receiving a command, like stop, then you miss it, no second chance. Second, even with the short bursts of necessary commands, you still have a limitation on how many throttles you can use, and you have to randomize your transmitting. The bottom line is you lose performance and reliability to receive commands.
For my money, I would use the original concept, and if I want to take it to someone else's railroad, just buy a compact system, like the NCE PowerCab, and then add a wireless throttle to it. Granted the NCE system is 900 MHz only ok in the US, but you could change the frequency, or interface a different throttle. This can be done, and I'm working on making a small portable system, which will most likely be a powercab, and JMRI on a tiny computer and then my throttles are cell phones... all can be done cheaply and made small and compact.
Whew... just wanted to get this out in it's entirety to put things in perspective. DCC may be old, but how it works is proven and there are many features you can lose by trying to chop up the architecture to where it is no longer a system.
Greg
The future is a 2.4GHz frequency unit.
The idea of deadrail was (originally)to take a DCC system, and basically put the "tracks" wirelessly. What radio and what protocol is a variable, but does not affect the idea.
Now, this means no programming track in most cases, transmit from throttle to loco only, no receive.
Where it gets complicated is where you have no "system".
So, in the "beginning", you took what would go to the rails, and broadcast it. Then the locos would all have receivers. In this case the locos really have no "idea" they are wireless. (notice you can do this with battery, or track with constant power, or a combination).
So your DCC system works as before, multiple throttles all communicate to the command station, and ALL the commands for ALL the locos are put in a stream and transmitted. Therefore no limitations in the number of locos or throttles in any way different from the "normal" track powered system.
Next someone had the bright idea to have individual throttles and not use a command station. In reality, the command station was built into the throttle, it still generates DCC commands, but now there is no "SYSTEM", i.e. the throttles do not know about each other.
Here's where it gets interesting. If your throttles are all on different frequencies (like AirWire channels), no problem, they can all transmit at the same time no problem. You do lose features like "all stop" and if you have a consist made with universal consisting, the other throttles cannot "take over" that consist.
(There are some systems that can "clone" the memory of a throttle to help this a bit).
But you are still limited by the number of frequency channels, and if you want to control a different loco, you have to switch your throttle to that channel.
Enter the bright idea of sending all commands on the same frequency... now you have to solve another issue, how to keep multiple throttles from transmitting at the same time. What is usually done is different from a normal DCC system, which has commands being transmitted continuously, round robin, new commands, and what available time is left transmitting the speed commands for existing locos. (This is why you can pick a DCC loco off the track and put it back on and it resumes the speed it was at)
You need to just transmit your new command. Two large problems surface: First if you "miss" receiving a command, like stop, then you miss it, no second chance. Second, even with the short bursts of necessary commands, you still have a limitation on how many throttles you can use, and you have to randomize your transmitting. The bottom line is you lose performance and reliability to receive commands.
For my money, I would use the original concept, and if I want to take it to someone else's railroad, just buy a compact system, like the NCE PowerCab, and then add a wireless throttle to it. Granted the NCE system is 900 MHz only ok in the US, but you could change the frequency, or interface a different throttle. This can be done, and I'm working on making a small portable system, which will most likely be a powercab, and JMRI on a tiny computer and then my throttles are cell phones... all can be done cheaply and made small and compact.
Whew... just wanted to get this out in it's entirety to put things in perspective. DCC may be old, but how it works is proven and there are many features you can lose by trying to chop up the architecture to where it is no longer a system.
Greg
