TMCC: Can there be TOO MUCH added antenna/ground plane wire?

Phil, I think the answer to your question is yes, but it's not a function of antenna or ground plane. My layout has over 3000 feet of track, and I was having terrible signal issues. I worked with Dale Manquen, and he sent me one of his signal boosters, which cleared up most of the problems. There are still a few stubborn spots where some engines don't want to run, but most make it around the layout. Unfortunately, with Dale's passing, I don't know if anyone can supply such a signal booster.

GunrunnerJohn may be able to pick up the ball on this.

Dale's signal booster performed very well at the P & P club layout in Scottsdale, AZ.  We hope someone can duplicate Dale's work and produce a signal booster for sale.

If you go the LCS way, the SER2 is a booster

"If you go the LCS way, the SER2 is a booster"   Chuck:  'Sorry for being a bit dense, but i don't know what these 2 abbreviations mean....Is it something I could try?

It's the new Legacy with the options to control the Legacy with an iPad or iPhone which has modules for different purposes that are daisy chained together. One is a module that runs serial port connected devices and is Lionel's answer to driving more serial devices when using the Legacy base and system.

I have a prototype booster in hand, but I haven't tried to reverse-engineer it yet.  I was actually working with Dale, and he was going to send me the documentation, schematics, BOM, etc. and I was going to lay out the PCB.  Sadly, that never happened, I was in touch with him a few weeks before his passing to make the arrangements but I never heard from him again, obviously we all know why now.

I also had to ask a fellow club member what LCS and SER2 were.  I was informed "installation and testing on our layout is ongoing in multiple areas".  I get the sense that LCS / SER2 may improve signal performance if we are using a phone or tablet only.   I happen to like my Legacy controller.

John, is Dale's booster the only current way we know of to boost the signal for Legacy controller use?

Thanks,  Dave

John I would be very interested if you could reverse  engineer the module that Dale was working on, since I have a few bad areas on my layout.  Would you expect communication to be better using wifi and phone?  The signal still has to go through the command base.

Thanks Marty

Using LCS or a WiFi app will not improve the signal between the base and engine.  You also will not have any better Cab2 to base communication.     You will have good communication between the app and the base especially when connected via a decent router. That of course is base on your signal. 

Like Marty says, there is nothing other than the command base involved in the track signal generation, so none of those other factors will have any effect on the track signal.

The way the prototype is wired, it's going to take a little time to unwind, and I haven't allocated the time yet.  I was anticipating just taking a schematic and parts list and doing a PCB, I wasn't counting on having to reverse engineer the buffer. 

It's going to end up being a multi-step process.

Once I have a schematic and parts list, I'm going to have to order boards and hand build a prototype.  Only after the prototype is tested will I be able to go to a larger build.

GRJ,

I would be in for one of these if you can reverse engineer it......  Please keep us posted...

Thanks,

Me, too, GRJ....Naturally!           Also, what's your opinion re:  My original Q:  Can there be too many 'ground wires'?  If so, I guess there must be a layout-dependent optimum.

Hey #DaveOlson is Lionel still thinking about a signal test car?  It was mentioned at a few Legacy meetings ago. 

I suppose there "could" be too much ground plane, but I haven't heard of anyone going that far.

I would suspect that the determining factor would be the capacitance between the ground plane (pin 5 on the base, I believe) and the outside rail (binding post on the base.) When the connected capacitance becomes too great excessive current would flow, causing a voltage drop through the source impedance of the base. If the output circuit of the base is some sort of L-C filter I suppose excessive capacitance could detune it but I don't have any factual information about the design of the base circuitry.

I only have a Base-1L, but if I get bored later in the weekend I may see what happens to the signal voltage as I apply various values of capacitance to the output. 

Edit 9:30 AM EDT

I was just poking around Dale Manquen's Trainfacts website. If you search for "Troubleshooting at the Dumont Museum," Dale offers a few comments about having indeed found excessive ground plane and the effects thereof.

YIKES!  It just dawned on me that there are 'miles' of wire that [can] carry the CB output with or without extra added ground wire on the layout.  ALL of the ground & neutral wires in the entire house [and train room building in my case]  are carrying  [or trying to carry] the CB's output.   This seems to reduce the relevance of my original Q!!

Phil, that's one of the underpinnings of the TMCC design.  The original intent was that the house ground wiring would be the radiator for the over-the-air part of the TMCC signal.

Understood, John.  But my point is that MOST of the wires doing the radiating are NOT in the train room.  The added ground wires in the train room are probably just a fraction of the total....

MartyE posted:

Hey #DaveOlson is Lionel still thinking about a signal test car?  It was mentioned at a few Legacy meetings ago. 

 

Marty, I'm not sure how much of a market there would be for such a car. It really only comes into play with large or complicated layouts. With the help and instructions of people here on the forum, I built such a test car using an R2LC, a cheap multi meter, and a couple electronic components, total cost: about $50, 40 of which was the R2LC.

The conversation gets a little lengthy, but all the info starts here.

gunrunnerjohn posted:

Phil, that's one of the underpinnings of the TMCC design.  The original intent was that the house ground wiring would be the radiator for the over-the-air part of the TMCC signal.

What would be the result of  that TMCC ground plane/antenna extension/etc have if it terminated into a metal rod in the ground outside the building instead of to the building ground wiring?  Enhance/degrade/no effect/unknown?

Is there such a thing here as signal overdrive?  If there are thin black TMCC ground plane wires strung all over the place, could it be providing too much signals, too many signal umbrellas mixing with each other?  Long enough wire could the signals get out of phase due to millisecond delay between one end and the others, of which there would be many dead-ends?

Squelch knob on a CB receiver or scanner... doesn't it work to prevent signal overdrive reception?  Don't know, just asking.

phil gresho posted:

Understood, John.  But my point is that MOST of the wires doing the radiating are NOT in the train room.  The added ground wires in the train room are probably just a fraction of the total....=

In free air, the signal strength decreases in inverse proportion to the distance away from the transmitter antenna.  Obviously, with walls, furniture, etc. in the way, the picture becomes more muddled.  However, in general terms, the ground plane a foot from the locomotive antenna will be a LOT more effective than the wiring in your attic.

gunrunnerjohn posted:

phil gresho posted:

Understood, John.  But my point is that MOST of the wires doing the radiating are NOT in the train room.  The added ground wires in the train room are probably just a fraction of the total....=

In free air, the signal strength decreases in inverse proportion to the distance away from the transmitter antenna.  Obviously, with walls, furniture, etc. in the way, the picture becomes more muddled.  However, in general terms, the ground plane a foot from the locomotive antenna will be a LOT more effective than the wiring in your attic.

What would impact the signal on a layout to the point a TMCC ground plane wire would be needed next to every foot of trackage for all the locomotives to work well on TMCC control?  I installed it slightly below track level, glued to the side of the sub-roadbed, around the upper level and that's it on the whole setup.  Works great.  Engines passing below it don't blink the lights or lose control.

Kerrigan, can you please be more specific (pictures, arrows up close, etc) where you located the ground plane wires?  Your solution is very important to my layout.

LionelAG posted:

Kerrigan, can you please be more specific (pictures, arrows up close, etc) where you located the ground plane wires?  Your solution is very important to my layout.

The little black wire you see hot-glued to the side of the subroadbed (the plywood) along the edge of the upper level trackage ONLY.  Not needed anywhere else on the layout.  Don't have the tool for putting in arrows etc (still old school).  You can see it in the above photo.

It is one continuous wire plugged into the wall outlet ground plug hole, and no connection at the other end to anything.

Works great.  But caution here: stuff works on the CL&W which doesn't on a lot of other layouts ... I know little about electrical/electronic theory, so it's all wired in the simplest manner possible.  And it all works together no problems: DCS/TMCC/Conventional .. take your pick.

  by Kerrigan:  "What would be the result of  that TMCC ground plane/antenna extension/etc have if it terminated into a metal rod in the ground outside the building instead of to the building ground wiring?  Enhance/degrade/no effect/unknown?" 

This is a good Q, but needs a small correction:  It's not "instead of";  rather,  "in addition to".  The signal ALWAYS also goes to outside ground via the house power panel, where the neutral & ground wires are truly connected by a 'rod' to the earth.

I'll admit that I don't understand how the signal could get from earth-ground at the house to earth-ground at the train room.....All I can say for my case is that,  in addition to the many added 'antenna-wires around the layout,  connection to earth ground just outside my train room (which is 50 feet from the house) definitely HELPS TMCC communication!

Guess I'll never grasp what makes some layouts of similar size TMCC-equipped, work with no, or few, ground/plane-antenna extension, wires while others literally need a dozen of them all over the place, to make it work.  I remember a big modular layout at a state fair, which was in a building with a very high ceiling ... where the "house wiring" was located.  Must have been 30 feet above them.  Nothing but problems with their TMCC, hardly worked at all.  One guy was trying to get a switcher to behave laying the hand unit antenna right on the tender.

Also seen a couple of rather large layouts without any TMCC ground plane wiring at all, and it worked fine everywhere on the layout.

Just another one of The Mysteries Of Toy Trains.

phil gresho posted:

  by Kerrigan:  "What would be the result of  that TMCC ground plane/antenna extension/etc have if it terminated into a metal rod in the ground outside the building instead of to the building ground wiring?  Enhance/degrade/no effect/unknown?" 

This is a good Q, but needs a small correction:  It's not "instead of";  rather,  "in addition to".  The signal ALWAYS also goes to outside ground via the house power panel, where the neutral & ground wires are truly connected by a 'rod' to the earth.

I'll admit that I don't understand how the signal could get from earth-ground at the house to earth-ground at the train room.....All I can say for my case is that,  in addition to the many added 'antenna-wires around the layout,  connection to earth ground just outside my train room (which is 50 feet from the house) definitely HELPS TMCC communication!

Electrons which are asked to travel long distances through the ground get very tired and sometimes just can't make the grade ;-)

Kerrigan posted:

Guess I'll never grasp what makes some layouts of similar size TMCC-equipped, work with no, or few, ground/plane-antenna extension, wires while others literally need a dozen of them all over the place, to make it work.  I remember a big modular layout at a state fair, which was in a building with a very high ceiling ... where the "house wiring" was located.  Must have been 30 feet above them.  Nothing but problems with their TMCC, hardly worked at all.  One guy was trying to get a switcher to behave laying the hand unit antenna right on the tender.

Also seen a couple of rather large layouts without any TMCC ground plane wiring at all, and it worked fine everywhere on the layout.

Just another one of The Mysteries Of Toy Trains.

There are a lot of misconceptions about the TMCC and Legacy systems. The handheld communicates with the Base, not the engine directly. The TMCC handheld frequency is in the range of CB radio (about 27 MHz) and transmits directly to the base. The Legacy handheld is in the wifi frequency and about 2.6 GHz I think and communicates directly to it's base. Both kinds of bases transmit on about 455 KHz directly to the track and the overhead antenna which is the ground wires in the house wiring. That signal is picked up by the antenna in the top of the engine, while the "common" for the signal is the engines wheels on the track outside rail. The common inside the base is connected to the outside rails. Usually troublesome layouts can benefit from additional ground wires which radiate thru the air to the antenna in the top of the engines. Things like track directly over the engine below can mask the airborne signal. In those cases, a ground system wire directly below that overhead track, while above the engine below can help. Different lengths of additional ground wires has been mentioned as a possible phase difference problem. The wave length of the 455 KHz signal is over 2100 feet. So the phase difference idea is just not true. The data traveling along this signal thru the ground wires is traveling at near the speed of light...186,000 feet per second. The information gets to all parts of the layout at virtually the same time.

There is no other mystery about it except that you cannot see the patterns of the 455 KHz signal and determine if an additional ground wire can help or not. Trial and error is the procedure here. One thing, grounding the already grounded ground wire system in the house (already grounded at the entry panel for the house power) is not necessary and is against the electrical code for house wiring. An ground stake in addition to the one single required one can be problematic in terms of AC currents in the ground outside the house and yard and detrimental in case of lightning storms. If you have an additional power panel in the garage or addition to the house, you will find that the common and ground wires in those panels go separately directly back to the main entry panel. One poster said an additional ground stake outside the train room made a positive difference. It may have by skewing the airborne signal pattern, but it's not recommended.

One thing I would recommend when working on signal coverage is to try a run of ground wire, if it helps, leave it in place. If it does not help, remove it and try another different run. I don't believe in running ground foil or wires routinely except under over head track and possibly in metal tunnels or bridges. It's really simple, there is the common side of the signal, the outside rail the engine sits on. And there is the ground wire system in the house which radiates the signal to the antenna in the top of the engine. If the ground wire can visually see the engine, it will work.

"the "common" for the signal is the engines wheels on the track outside rail."

This is one of the misconceptions.  TMCC reception is not reliant on the engine's wheels making contact with the outside rail.  The outside rail is just a handy antenna that Lionel chose to use.

I think that YOU are wrong, Bob:  The outside rails + wheels + frame  form the circuit that conducts the other half of the signal to the R2LC radio.

To Chuck:  Thx for the nice summary review.  I have some Q's and a minor comment:  The speed of light is 186,282 miles per SECOND; in vacuo.  In wires, it's maybe 80% of this.

Q1.  What exactly can go wrong with a second ground rod?  AC currents?  Lightening?

Q2.  What exactly does this mean:  "....skewing the airborne signal pattern,..."?

"I think that YOU are wrong, Bob:  The outside rails + wheels + frame  form the circuit that conducts the other half of the signal to the R2LC radio."

Try this experiment.  Put a section or two of Gargraves track on the floor.  Connect a transformer to it via alligator clips or other method.  Put a TMCC Command Base on the floor.  Connect a 3 or 4 foot length of wire to it and lay the wire on the floor, parallel to the track but 6 inches or so away.  Put a TMCC locomotive on the track.  Plug in the Command Base, then plug in the transformer.  Run the locomotive under full TMCC control.  The house wiring is one side of the broadcast antenna and the wire laying on the floor is the other side.  Like I said, the outside rail of the track was just "handy" to be used as an antenna.

I routinely run locomotives on my work bench or in my paint booth (powered by alligator clips to a small transformer) under TMCC control with my Cab-1.  I just make sure the layout is powered on and transmitting the signal.  The bench and booth are at least 6 feet from the closest part of the layout.

to Kerrigan:  Electrons do NOT travel long distances.  They push & pull  (AC) or just push (DC); but in both cases, they 'flow' like an incompressible fluid.  The 'speed' of a single electron is VERY LOW [millimeters/sec],  but the speed of their associated electricity is 'lightening-fast'!

phil gresho posted:

To Chuck:  Thx for the nice summary review.  I have some Q's and a minor comment:  The speed of light is 186,282 miles per SECOND; in vacuo.  In wires, it's maybe 80% of this.

Q1.  What exactly can go wrong with a second ground rod?  AC currents?  Lightening?

Q2.  What exactly does this mean:  "....skewing the airborne signal pattern,..."?

Oh sorry, I meant to write miles. AC currents in the ground soil and in the case of lightning, a potential difference between the ground wires in the house. Changing the ground connections can cause the signal to get stronger in weak areas and weak in strong areas. It's difficult to predict.

As to the common rails, I too can get TMCC to work on a test track not even connected to the layout where the base is. That doesn't mean that the track isn't the common side of the signal the base is putting out on the ground wires. It's not reliable, but happens probably through the wiring of the house, transformers, etc. Again I don't try to draw a schematic for it, but the signal propagates. I don't think it would work say in the next door house to your house.

Bob:  Good point.  In fact, I, like you, run TMCC locos on my work bench in complete isolation from the  TMCC-powered RR.  What seems to be happening here is that BOTH halves of the signal are radiated to the engine's radio.... the 1st half in the usual way [via house wiring] and the other half via radiation from the TMCC-powered outside rails to the outside rails on my work bench.  Strange, what?  [When I run an engine upside down in a cradle in TMCC,  I connect 1 wire from my local track [ which itself is powered by a Lionel 1033 tranny] to a roller and the other,  from the outside rail on my bench, to a ground/common on the engine.]

Addendum to Bob B:  I can also run in the cradle simply by 2 wires directly from the 1033 to the engine....No track needed.  Thus, the engine-in-cradle picks up both halves from the air!

I have found that adding metal truss bridges to the ground plane works.   That's means the ground plane signal envelopes the locomotive when it's within the bridge, so too much ground plane may be a non issue.  (Tinplate track has to be isolated from the bridge).

I'm sticking with our one 24ga TMCC antenna extension wire, continuous from the wall ground plug to the end of it's 120' length, along the elevated roadbed only, with no others.   Leaving the TIUs and TMCC brick buried under the 6-track freight yard, because IT ALL WORKS. 

Like Pappy said "If it ain't broke, don't go a-fixing it!!"