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GRJ, I'll make this comment now just so I can say "I told you so".   If you go direct to an Arduino A/D pin for your transponder you've probably seen the application notes about having a low source impedance.  51k Ohms is not a low source impedance!  The A/D sub-system in the Arduino microcontroller is not hi-impedance relative to an instrumentation voltmeter.   Anyone wondering what the heck I'm talking about, don't worry about it.  GRJ knows what I'm talking about...

Attached are the plans for the 455kHZ earth ground signal car meter.  The signal car meter consists of a 51K resistor, .1uf cap & a R2LC radio board which I mounted on an old dummy engine with pickups.  Also used a Harbor Freight free-be meter on the 200 u amp range.  The trickiest part of this build, was to solder a wire to pin 13 of the MC3372IC, which is located on the R2LC board.   See the attachments for the schematic, R2LC board pin assignments, MC3372IN spec sheet.

Also attached a summary sheet that Chris Lord of our team but together, on all the items we learned from talking to Lionel's CTO group when we were doing our testing of the TMCC/Legacy signal.

Thanks to OGR forum member Gary Emmich for investigating on how to use the R2LC radio board to measure signal strength.

Hope this helps,

Bob D

NJ-HI Railers

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Last edited by rad400

Thank you Bob! That's everything I need. Looks like the worst is behind me on this already. I got the lead soldered to pin 13. That was tricky, not used to work that small.

For anyone else attempting this, take a short length of small gauge wire and tin the end. Get a small bead of solder on the tip of your iron, and very carefully touch them all together on the pin.

Dale:  I'm constantly concerned with errant noises generated by faulty or unfiltered products when Shortwave listening.  There seems to be no end to them in today's appliances and lighting.  Dimmers tend to be the worst offenders if not of the proper kind.  This was the reason I commented on Elliot's lighting much earlier on in this topic.

Elliot:  The Legacy and stereo are connected to 2 different breakers.  I installed a sub panel with 4 breakers in the train room to handle lighting, outlets, switched outlets and extras.  Powering up 3 ZW's has no effect on the radio, but add Legacy and it sets up a buzzing.  You got me thinking that if it isn't the Legacy itself, maybe it's the Legacy power supply...that gigantic wall wort could be suspect.  I noticed one other noisy appliance in the room as of late is my digital soldering station.  To complicate matters, I just added DCS to the layout...but we won't go there.

BobD:  Thanks for the sniffer car info.

Bruce

 

Bob, one more time!  Please send out correct information.  The outside row of pins on the R2LC is the odd row- Pins 1-23, not as your diagram shows.  The square pad for pin 1 is at the corner, and the antenna pin is at the other corner.

We don't need a bunch of guys trying to build this up incorrectly.  Your diagram would have them putting their antenna on the Serial Data Out pin.

Nick12DMC posted:
BobbyD posted:
Big_Boy_4005 posted:

"Thank you Nick. Patience and persistence are the words of the day. There were those who just said send it in. I'm glad I toughed it out a bit. If you look back on page 4, near the middle, that's where the diagnosis came together. After that, the surgery was easy. This has been a fun topic, getting a lot of people involved, and thinking out in the open."

Now that the legacy base is fixed, I think I'll change the topic title one last time, to something we can run with...

Adventures in TMCC & Legacy

Curious, would this have been solved much sooner if a known good Legacy base was substituted since the TMCC base functioned? Nice layout and construction thread.

While this makes sense and I do agree. Sometimes it's just not that easy. I have my Legacy set away for repair at the moment. My issue was LCS operations so different from Elliot's problem.  It could have been quickly diagnosed with a spare Legacy set. However I only know of around 6 Legacy sets in the whole UK! Arranging to borrow one would have been a bit tricky.

I guess I could spend $300 and have a spare sitting in a drawer. But I have a spare TMCC base for a backup. 

I would like to see a diagnostic utility built in to the LSU software. So you attach your base to the serial/USB lead and your PC and it automatically checks everything is within operating limits. Might need some sort of special lead so it could check the output on the terminal so it could diagnose an issue like Elliot had. 

Nick

We understand and agree with your reasoning. Got a 990 and 993. Our first 990 set had to be returned as it wouldn't power up so we could not operate Lionel then, no base. The second 990 would not charge or power down and was returned. Again we could not operate Lionel, no base. The third 990 set won't charge and the 993 has display issues. As unreliable as these are if we had to do it again we would've gotten two 990's just so we could possibly use one them when the other is in for repairs. 

BobbyD posted:

We understand and agree with your reasoning. Got a 990 and 993. Our first 990 set had to be returned as it wouldn't power up so we could not operate Lionel then, no base. The second 990 would not charge or power down and was returned. Again we could not operate Lionel, no base. The third 990 set won't charge and the 993 has display issues. As unreliable as these are if we had to do it again we would've gotten two 990's just so we could possibly use one them when the other is in for repairs. 

If it weren't for bad luck, you'd have no luck at all!

Dale Manquen posted:

Bob, one more time!  Please send out correct information.  The outside row of pins on the R2LC is the odd row- Pins 1-23, not as your diagram shows.  The square pad for pin 1 is at the corner, and the antenna pin is at the other corner.

We don't need a bunch of guys trying to build this up incorrectly.  Your diagram would have them putting their antenna on the Serial Data Out pin.

Dale

Thanks for the pick up of the reversed diagram.  Hopefully it didn't confuse anyone to much.  I have attached a revised diagram showing the back view of the R2LC board.

Bob D

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Last edited by rad400
Gregg posted:

OK guys. What's the next move? build the meter? and where do you start testing? and how?

Gregg/all

Very good question!

First, make sure your command unit (TMCC/Legacy) is providing the correct output as described earlier in this tread by using a scope or Dale’s tester. Once you know the command unit is working correctly now you can go through all of the items people have been discussing on how to improve TMCC signal. Listed below are some of the items we checks at the club:

1 )Make sure the “U” terminal connection is not run in the same bundle with earth ground wires. Try to keep earth ground and “U” terminal wires at least 2”-4”
apart. Remember all 110v AC lines have earth ground wires.
2) Make sure your track & engine wheels are clean.
3) Try connecting the command walwart into different ac outlets. NJ-HI railers are in an old commercial building and different AC outlets gave us different
readings.
4) For areas where you have low earth ground signal readings (blinking engine head lights that go solid light when you put your hand over the engine) try running over head ground wires. We ran an earth ground bus wire around 3/4 of the layout with individual leads coming off the main bus to address weak areas. We disguised the wires as wires on telephone or electric poles. You can also run the a ground wire on the top of the layout, but just keep it at least 2+” away from the outside rail.
-5) We initially years ago, installed thin copper strips under the track, which we now removed. The copper strips (earth ground) was not 2+” away from the
outside rail which carries the other part of the signal from the “U” terminal (Item 1 above)

Also, see the attached sheet that Chris Lord put together, from our discussion with Lionel on improving TMCC/Legacy.

If you have individual diesel engines which are giving you problems, you can extend the internal antenna. We have extended engine antennas by just adding additional wire to the existing antenna or you can use 1/2” copper foil to extend the antenna. I found that using the copper foil provided 30% improvements over the same length of 18 gauge wire. I took antenna readings using the signal car and attaching different types of antennas and saw what gave the best results.


For us at the NJ-Hi railers, we found readings in the 38+ ua range satisfied most diesel engines but needed readings in the low 40’s or higher for steam engines. These are the numbers for our layout, yours may differ. By experimenting, you will find the range that engines will work properly on your layout. The earth ground meter will give you real time results as you are making changes on your layout.  It is much easier than trying to figure out if the engine head light on your engine is blinking more or less after making changes.

Bob D

NJ-Hi Railers

Attachments

rad400 posted:

Attached are the plans for the 455kHZ earth ground signal car meter.  The signal car meter consists of a 51K resistor, .1uf cap & a R2LC radio board which I mounted on an old dummy engine with pickups.  Also used a Harbor Freight free-be meter on the 200 u amp range.  The trickiest part of this build, was to solder a wire to pin 13 of the MC3372IC, which is located on the R2LC board.   See the attachments for the schematic, R2LC board pin assignments, MC3372IN spec sheet.

Also attached a summary sheet that Chris Lord of our team but together, on all the items we learned from talking to Lionel's CTO group when we were doing our testing of the TMCC/Legacy signal.

Thanks to OGR forum member Gary Emmich for investigating on how to use the R2LC radio board to measure signal strength.

Hope this helps,

Bob D

NJ-HI Railers

Adding additional information: 

The red connector next to the meter is a connection point to test  different types of antennas which could be used in your engines to improve signal strength.  I used the four wooden poles at the corners of the engine, to wrap wire/foil around during testing.

The second photo provides a top view of the connections to the R2LC board

Bob D

NJ-HI Railers

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Images (2)
  • blobid0
  • IMG_2707: Top side view of R2LC board mounted on engine
Last edited by rad400

First, I ran TMCC for several years with just a few signal issues on select engines. I addressed those issues with ground plane wires on a couple of areas of the layout that were problematic.  I then added Legacy to the mix and signal issues cropped up everywhere.  

I sent the Legacy base back to Lionel, they upgraded it to 1.3, fixed the early charging issues and returned it to me.  Once again the same signal issues appeared.  I have two separate loops and several blocks which helped in isolating problems.  What I finally found was that two of my PW cars with vibratory motors were playing havoc with the Legacy signal.  These were a searchlight car and the GM generator car.  Once I removed these cars from the various consists the Legacy signal was as good as the TMCC signal.  I solved the problem by adding diodes to the vibratory cars.  However the signal still was not perfect.

Second, I have two 200 amp services coming into my  home.  Each feeds a 200 amp panel for the various power needs.  I had an electrician out to add transfer switches to the panels so I could hook up an emergency generator to one spot and not have to drag extension cords all over the house in the event of power outage (we have a lot of ice storms in North Georgia).  While doing the work he casually mentioned that the current code for our county now required two earth grounds for each incoming service and suggested we bring things up to code.  I agreed and he added the second ground.  All of a sudden all of my signal issues with command control went away. Obviously this makes no sense, but it worked for me and might work for others.

So to sum it up I had an interference problem and apparently some sort of earth ground issue that a second grounding point cured.  While this may not help at all with your problem it may help others along the way.  Good luck!

Bruce

Thank you for joining the conversation Bruce, that's interesting to know.

Personally, I don't think I have the grounding problem, because I wired my entire house, and the inspector made me drive a ground stake for each of my two 150 amp panels as well as bonding them both to the water pipe. I have no water meter to bypass, because I have well and septic out here. I think I had to run #4 copper about 30' to reach from the panels to the water entrance.

There are no accessories, post war or modern on my layout. All I have beside track is Tortoise switch machines. And that may very well be all I ever have.

I didn't think I was having any additional problems with Legacy connected than with just TMCC, but now that you mention it, a couple of engines did make noise when they shouldn't have.

stan2004 posted:
stan2004 posted:
...

Yes, resistors in series add.  Or, equal resistors in parallel divide by 2 - you may have 2 100k resistors which in parallel would make a 50k

From what I can see, it looks like this is what the NJ-HR group did.  2 100k resistors in parallel (50k) in lieu of a 51k.

Untitled

 

That is correct.  Radio Shack didn't have a 51K, so I used two 100Ks in parallel 

Bob D

 

Was just reading the following thread about a train mount-able tiny video camera for only $21.  I think the wireless ones are maybe $100 or so? 

https://ogrforum.ogaugerr.com/t...y-layout-for-just-21

If the video electronics doesn't interfere with the signal-strength meter this might be a way to record the signal-strength readings on a route so you don't have to follow the train around.  The video itself could be saved for later comparison or sharing via youtube or whatever to get opinions.  If the camera captured both the changing meter display and the layout in the background perhaps additional eyes can uncover some correlation - maybe a small mirror if the meter lies flat on a flat-car.  Of course there are smaller meters than the Harbor Freight freebie but then the "system" would cost more than 10 cents!

 

I was thinking some kind of mylar sheet (craft stores) or the like angled so the meter can lie flat on its back.  The camera could then capture the meter reading (albeit upside down) and the moving layout in the background.  If going thru a tunnel (if it's wide enough to handle the meter) you'll need a light since the Harbor Freight meter does not have a backlight for its LCD - but then again what do you expect for FREE?   Upon reflection (!) Harbor Freight also has freebie LED mini-flashlights which you could mount.  So since it appears you already have the video device the budget under a dollar!

IMG_0536

 

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OK guys, I built the car... Time to figure out why it's not working

 

Here we have the R2LC with the lead soldered to pin 13. Seems to be a good joint, not touching adjacent pins.

IMG_6301

Here we have the donor chassis, a bay window caboose with a light. I folded the original light bracket down flat, and clipped the light to the body mounting bracket.

IMG_6302

This is the resistor & capacitor part of the circuit. I didn't have a 51KΩ either, but I had a 47K and a couple 2200's, so 51,400 it is. The resistors are in series with each other and the capacitor is in parallel with them.

IMG_6303

I scratched the black finish off a spot on the chassis and soldered on the ground wire.

IMG_6304

I cut a block of wood to size, put in the antenna posts, then hot glued the block to the chassis. I also hot glued the two components to the wood block.

IMG_6305

I added the ground leg to the resistor cap unit.

IMG_6306

There are 3 white wires and one black one tied together here. The ground source soldered to the chassis, the lead from the resistor cap unit, a loose lead which will connect to the R2LC, and the black one is the lead to the meter.

IMG_6307

I soldered on a piece of brass wire the correct size to fit the board socket. This black wire comes direct from the pickup rollers.

IMG_6308

The white wires are all track ground.

IMG_6311

This junction connects the pin 13 lead (black), the resistor cap combo and the other meter lead.

IMG_6312

Because the pin diagrams are mirror image, I hope I got this right. I based the placement off the photo of NJ club's unit. The black and white pair are hot and ground. The orange is my antenna, and the odd black wire in the middle is supposed to be the light.

IMG_6310

I have the meter set to 200μ DCA.

IMG_6313

Any ideas where I went wrong?

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  • IMG_6306
  • IMG_6307
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gunrunnerjohn posted:

Did you move the lead on the meter to the current hole?  You didn't provide a shot of the whole meter, so I can't tell where you've got the leads connected. 

For the low current ranges, it's the same two "holes" as for voltage measurements.  The upper "hole" is only for the 10 Amp DC current range which is not in play at this time.

IMG_0538

 

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gunrunnerjohn posted:

Did you move the lead on the meter to the current hole?  You didn't provide a shot of the whole meter, so I can't tell where you've got the leads connected.  You should program the R2LC so you can control it and turn the light on/off as Stan suggests, then you know for sure the rig is working and receiving.

What's the input impedance of these meters? It seems y'all are developing a voltage across the 50K resistor and then shunting it with an ammeter. So...if the input impedance of the meter is 10 Meg or so (typically), you can use the voltmeter. Max reading from the data sheet is 60uA or 3 vdc across the 50K.

Anyway y'all had me confused.

And y'all are making me want to build one of these...

Dale Manquen posted:

Check for voltage on the MC3372 chip - Pin 4 = +5.7V, Pin 15 = Gnd

Just did this test, 0 V. Makes me wonder if this board's no good.

I got it out of a bucket of stuff that Matt had been working on. Not sure if it came out of something or was supposed to go into something. If it came out, it could have had a problem. The only other thing I can think of is the brass pins I attached to the leads aren't making contact in the board socket, hence no juice.

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