MU locomotive to locomotive range issue with LM-3S-G ?

[JRad]

I may have discovered a range limitation when MUing large scale locomotives in split configurations.


Yesterday I set up a 16 car train with a lead locomotive, a mid train helper after car 8 and a pusher on the rear.  Once all coupled together MU set up went as planned and loco directions were confirmed. Attempting to move the train, the pusher was not responding and ended up being dragged. I checked my setup and tried again with the same result. Breaking up the link, uncoupling the trailing locomotive and serting up again with only two locomotives functioned as expected.  Moving the third locomotive to the mid-train position also worked as expected so I can rule out an MU response problem with locomotive #3.

My best guess as to what the problem was is that the trailing locomotive was not communicating with the lead locomotive due to distance which was  about 21 feet from the lead to the pusher.

I have other range issues that have me considering adding a repeater, even though I only use on-board battery power.  Would a repeater help with loco-to-loco communication or only handheld-to-loco ?  Just wish Ring would come out with a dedicated repeater module without the power supply.

[Josephbw]

Make sure that all of your locos are set to go in the same direction. If the first 2 are going forward and the last one is in reverse, it will look like it is sliding, but it is trying to go backward.

Joe

[JRad]

Thanks Joe, but if you read my post I checked that twice. All were running the correct direction.

[William Brillinger]

Very interesting. I think you'd have to ask Ring to know if the repeater in a PWR-56 will help this issue.

Regarding asking for a dedicated repeater, The PWR-56 sells for a lot less than the cost of an LM-3SG and not much more than the AM-1 Assuming your suggestion of a stand alone repeater is based on an expected cost savings, I doubt there would be one. However, you might consider asking Ring (directly) to make a Repeater Program that could be loaded on an LM-3 which is the least expensive radio equipped part that Ring offers with any onboard processing. The CI-1 is cheaper, but requires a PC to drive it.

[JRad]

Thanks William -

I guess I should be more clear of my want for a stand-alone repeater.  What I am after is a PWR-56 without the AC to DC supply. Like you say,  a true dedicated module would be nearly identical except without the wire terminals, so there would be no cost savings.

One day when I have time during office hours I'll give Tim a call about this. He would probably sell me just the PWR-56 module without the AC/DC supply.  I would be powering it with a 14.5VDC Lion battery.  I'll be powering with battery because where I need repeaters is a long way from AC power.

[William Brillinger]

I can sell you a PWR-56 without the power adapter. The price is $75 including shipping in the USA.
Feel free to contact me to order one. my email address is billy@pdc.ca

[JRad]

Thanks Bill -

I'll let you know.  Not quite ready to go there, I still have modules yet to be installed!

[Bruce Shanks]

I too am interested in this issue.  I'm dealing with a club layout that will be all dead rail.  About 300 x 50 feet. Some mountains made from chicken-wire reinforced concrete. Range and reliability are concerns.

We have 120 VAC outlets scattered around, so could power repeaters, but don't need the 12 VDC power supplies.  Presumably a wall wart would be sufficient to power the radio. 

From the discussion so far, it appears that the loco modules don't have the transmitter power or receiver sensitivity that the repeaters have. Which leads to the question, how far can the loco get before reliable control is lost?  Are we looking at 3 repeaters to cover our 300 foot length?

[G8B4Life]

...how far can the loco get before reliable control is lost?

That's a good question, and not one that I think anyone here has pushed the boundaries of. This is what Rings FAQ has to say about it.

How far does the Direct Radio signal reach?
You can control locomotives on huge HO scale layouts with outstanding control using Direct Radio.  The Direct Radio signal can reach over 100ft in an open environment.  When properly setup, you can achieve fast and dependable control that has the feel of being directly wired to your locomotives.
If you want to control your trains from the far side of your layout, we recommend a repeater every 15 ft for areas divided into small rooms.  Our power supply has Direct Radio built in and can be used as a repeater.  With one PWR-56 in the middle of the layout, you can expect outstanding coverage for a 30 ft x 30 ft layout while transmitting through multiple walls. If the room is open, it may work well for 50 ft x 50 ft or even larger areas with only one repeater.  The current program in the handheld controller lets you use up to 4 repeaters for outstanding coverage on huge layouts.
You can run RailPro without a repeater.  For example using only a handheld and locomotive equipped with a RailPro module.  If you follow your trains (staying within 15-20 feet) you will not need a repeater and you can expect fast and dependable control.  However, if transmitting through multiple walls, you might find that at some angles you will loose communication at 40 feet away.  By adding repeaters as necessary, you can get fast and dependable control from over 40 feet away through multiple walls.

The PWR-56 and HC manuals have sections on repeaters. What it appears though, is that only the HC can use repeaters (LM's can not) and 4 repeaters is the hard limit with the current HC program. My suspicion is that when a HC is using repeaters it's not a broadcast to any repeater that's listening but rather the HC sends out to each specific repeater that it has loaded.

- Tim

[Alan]

About 300 x 50 feet. Some mountains made from chicken-wire reinforced concrete. Range and reliability are concerns.

Well, you won't get 300' range that's for sure. 

Keep in mind that issues, if they arise, will be because of what the signal passes through on a straight path from HC to LM. Not necessarily what else is in the room. The chicken wire and concrete are a problem only if the train is on one side of the mountain and you are on the other.

One would assume the person controlling the train will be somewhere near the train and most certainly have a clear line-of-sight to the train. This being the case then layout size is rendered moot. If the train is orbiting the layout then HC connection is irrelevant as the LM will retain last command. To take back control wait for the train to pass by you as it makes its very long journey around the 1500 ft² layout.

Did they really use concrete??? I can't imagine how challenging that would be to do. Concrete is way too runny for chicken wire. Perhaps you meant plaster? Otherwise, call Guinness. They may have set the world record for heaviest model train layout. 

[Bruce Shanks]

Concrete is used as a generic term.  Chicken wire is wired to half inch re-bar skeleton spaced about a foot apart.  Then covered with burlap soaked in soupy mortar mix.  Once cured it's topped with additional layer(s) of mortar, dyed with concrete colorant.  We're fighting the Phoenix sun and winning.

The general description of RailPro leads one to think that it is a peer-to-peer network with all units talking to each other, but it appears that in reality it's more of a client-server set-up with the HC in the cat-bird seat.  On a huge layout like ours, even with repeaters, running more than one consist at a time would mean that they will be out of control, unless they are close to the operator.  Which swwms to be the source of JRad's issue that started this thread. 21 feet was tooo much separation.

Am I missing something?

[Gibs]

Each LM, TALKS TO EVERY OTHER LM, or how do you think that a MPU/DPU tells each loco it needs to pull its own share of the load. It's the big selling point of the whole system. So if the LM's are talking the same language as the HC (which they do), it only stands to reason that they will use a REPEATER just as well as the HC!.
Ring does say "Network" on all RF products.

In fact you may want to go and re read this bit again : https://ringengineering.com/DirectRadio.htm

PS : The ideal location for any repeater would be suspended/ mounted ABOVE the layout so that it's line of sight TX has a far easier time of it and can cover a larger area.

[G8B4Life]

Concrete is used as a generic term.  Chicken wire is wired to half inch re-bar skeleton spaced about a foot apart.  Then covered with burlap soaked in soupy mortar mix.  Once cured it's topped with additional layer(s) of mortar, dyed with concrete colorant.  We're fighting the Phoenix sun and winning.

So that tells me we're talking about an outdoor layout then? If you have any tunnels under all that mortar, chicken mesh and rebar I can see that would pose a unique set of circumstances for communication. I would also say any other over the air system would fall into the same boat as RP in that regard.

The general description of RailPro leads one to think that it is a peer-to-peer network with all units talking to each other, but it appears that in reality it's more of a client-server set-up with the HC in the cat-bird seat.

We don't really know a lot about Rings +Net features, how it works is the sort info he guards closely as if other manufacturers are just waiting in the wings to pounce on anything for their own systems. I think what you'll find is that it's actually both, some things probably work in the client-server space and other things work in the peer to peer space, for instance Accessory Modules have no need to communicate with anything else but the handheld so they probably work in the client-server space whereas Locomotive Modules do talk to each other so they do work in the peer to peer space.

So if the LM's are talking the same language as the HC (which they do), it only stands to reason that they will use a REPEATER just as well as the HC!.

You sure about that Gibs? Nobody I know has done any analysis of the radio traffic to see what's going on. If your PWR-56 is password protected is the repeater functionality password protected too? How's an LM going to know what the password is?

- Tim

[Gibs]

Hi Tim, matey he clearly states so in that article I linked of his, so since he built it that way I'm pretty sure it does.
The clue is in the statement " it's all one code " .
If in dout ask the man 🙂.

[Gibs]

Here is another clue, all the information for each and every loco is stored and controlled by the LM's, not the HC. All the HC does is access the network of stored information on all LM's at any given point in time as well as  facilitate the loading of an LM with all of its relevant data before its first use in a loco.
Once an LM has been initialise it will access the network and Tx it's stored data onto the network. Ring clearly state that each LM is its own Transmitter, so it's the LM's doing all the heavy lifting, not the HC.
Given that, why would you not have a LM able to use a Repeater to talk to another LM since by RailPro's very own definition, it's all about radio networking using one code that is small light and fast.

As to how can a LM access a password repeater, I say the same way as it access a passworded LM. Passwords are to control HC access, not an LM's ability to do so.

Remember an HC is NOT like a server.
That's how I understand all this to work, could be wrong though. 😀.