Loco detection

[PJ_model_trains]

[quote] [quote]Since I installed my "mains" Local Area Network (!!) I've often wondered if someone else in my street has these gadgets installed in their house, will both our networks be joined together ? :-) I think we've wandered off "loco detection" because until something is released by Hornby, there isn't much new to say about it !! :-) Oops - I did an edit and it turned into a new post, I think! Ray[/quote] [/quote] I haven't wandered off the subject, I just can't find it, I have lost the 'Loco' My wife calls my loco 'the plot'

[Fishmanoz]

[quote] [quote] [quote]Since I installed my "mains" Local Area Network (!!) I've often wondered if someone else in my street has these gadgets installed in their house, will both our networks be joined together ? :-) Ray[/quote] Why stop at the same street Ray?[/quote] Quite so - it might go as far as the sub-station!! :-)[/quote] Yes, it will go as far as the first transformer it comes to, at least in theory. So it will be all down the street to 1 in 3 houses on the same phase as you. However, given we are talking about pretty high frequencies and mains cable isn't shielded, the stray impedances in the cable are going to limit the distance it travels In practice before it is attenuated to the extent it can't be detected.

[Fishmanoz]

[quote]I have just googled it and depending which of the two wires on your land line is disconnected your broadband will work on the one wire. Regarding using the mains, I can connect a BT FREEVIEW box downstairs to my broadband router upstairs via the mains. The BT box plugs into the mains via a special adapter and the server is plugged in the same way upstairs. The box gets TV progs from the Internet along the mains cable. Scary.[/quote] The clue is in the "depending which of the two wires". You can think of it a little like your mains wiring where you have an active wire where the potential is varying positive to negative and the neutral return part of the circuit which is sitting at earth potential all the time. Break the active and your signal is gone. Break the neutral and there is a "virtual" return via earth potential such that the signal still thinks there are 2 wires and continues to flow.

[walkingthedog]

That's what my friend said and that's what good old Google said as well. That's why it depends which wire. Not the 1st April after all eh fishy.

[Fishmanoz]

Back to LD. Each detector will need 2 wires, although one will be common to all of them, just like the blue common wire in your loco decoder function outputs. At least common to all of them going to the same controller. And that leads me to a slight complication on my common bus theory. You can have 2 LD controllers and, if they were to work exactly the same way, you couldn't have the 2 on the same bus or they would interfere with each other. Just like you can't have 2 DCC controllers on the same bus. It is possible to overcome this but it may mean modulating the outputs of all 48 detectors on each controller onto their own separate carrier frequency. But that is getting pretty complicated so chances are we will have at least one DCC bus (remember some run 2 of these, one for locos and one for accessories) and possibly 2 LD buses. Note I said may mean above as there is still the issue of how each of those sensors is going to identify itself and I'm not about to try to hypothesise a solution to that here.

[Fishmanoz]

[quote]That's what my friend said and that's what good old Google said as well. That's why it depends which wire. Not the 1st April after all eh fishy.[/quote] Yes, I'll give you that much WTD, this stuff can fool you any day of the year.

[walkingthedog]

I know fishy, I couldn't get my head around it when it was explained to me. If it hadn't actually happened I'd had thought the same as you. Maybe layouts with LD will need a large earth spike driven into the ground.

[Fishmanoz]

Good idea WTD, it will stop the table floating all around the house too.

[walkingthedog]

Think I'll buy as many as I can, I might corner the market.

[Fishmanoz]

I think I'd stick to model rsilway. Barriers to entry in the spike market will be low so you'd spend all your time looking over your shoulder for the new entrants. Someone may even come up with one you can drive into a ping pong table without any noticeable damage to the table.

[PJ_model_trains]

[quote]Back to LD. Each detector will need 2 wires, although one will be common to all of them, just like the blue common wire in your loco decoder function outputs. At least common to all of them going to the same controller. And that leads me to a slight complication on my common bus theory. You can have 2 LD controllers and, if they were to work exactly the same way, you couldn't have the 2 on the same bus or they would interfere with each other. Just like you can't have 2 DCC controllers on the same bus. It is possible to overcome this but it may mean modulating the outputs of all 48 detectors on each controller onto their own separate carrier frequency. But that is getting pretty complicated so chances are we will have at least one DCC bus (remember some run 2 of these, one for locos and one for accessories) and possibly 2 LD buses. Note I said may mean above as there is still the issue of how each of those sensors is going to identify itself and I'm not about to try to hypothesise a solution to that here.[/quote] Thanks Fishy But of all you have written above I pick up on... Note I said may mean above as there is still the issue of how each of those sensors is going to identify itself. That was why initially it was discussed every wire back to the LD controller to a separate port, a decoder does this for the signals and points. Each has a port. PJ

[PJ_model_trains]

[quote]I think you guys are on the wrong train , all the dectotors will connect to a box like a accessories decoder and then back to the pc via USB bus. You can have two of these boxes connected via Railmaster. Each box is suppose to handle many detectors (some say 56). Please correct me if I am wrong. I dont have money but I will put someone elses money of first quarter next year when LD comes out.[/quote] Hi Phul007 The LD box, I think, I may be wrong, is a decoder and controller. As mentioned earlier, I can see why initially it seemed every sensor is wired back to the controller to its own port. So why didn't Hornby make a controller and a decoder plate? Probably because by keeping them as one it keeps it Hornby, if they had made a separate decoder others would make one as well. Good thinking by Hornby, possibly, probably. So does this bring us back to one wire to the decoder/contoller LD Box, sending back small packets of information to decoded and the other to a common which all can link to and one goes back? A common bus? ;o) Just my thoughts, I may be wrong, as someone says, I may be talking out of my hat, probably ;o) PJ