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Hello Everyone;

My mainlines have been operational for several weeks now and decided it was time to check DCS Signal Strength. But I'm really, REALLY confused in regard to the results I got!

I'm hoping more experienced DCS users will shed some light as to why this happening.

The following is the process I used to check signal strength:
1. My layout consists of all Lionel tubular track.
2. Pin tightness/cleanliness was checked during track assembly.
3. Because of engine length (longer than standard Lionel 10 inch length), two track sections were checked at a time.
4. Engine was moved to each 2-track section and stopped.
5. Track Signal was selected for that engine from the DCS remote.
6. 25 "samples" for each 2-track section was viewed; with "samples" meaning the refresh of the DCS remote screen was monitored (the Track signal screen was allowed to refresh 25 times).
7. During this process it was noted that DCS signal strength would start at Level 10 for several "samples", then immediately drop to "Out of RF Range" for several samples; then immediately go back to 10's!
8. The reverse is true also; where signal strength for a 2-track section would start at "Out of RF Range" for several "samples", jump to 10 for several "samples" and back to "Out of RF Range".
9. Steps 4 thru 8 are repeated for the entire layout.
10. No "lighted" cars were on the layout and no other engines were on the layout either.

These are results I did not expect. Several 2-track sections provided constant Level 10 signal strength for all 25 "samplings". But quite a few track sections were "10-to-Out of RF Range".

Are these typical results when checking signal strength? If so, how can a Level 10 signal immediately drop to "Out of RF Range"....or vice versa?

Heres some background info about my layout wiring:
1. 2 TIUs are used; where both Fixed channels are connected to their own PW ZWs (ZW x 4).
2. One TIU is Rev. I, the other has NO Rev. label and no internal circuit breakers! Both are running software version 5.0.
3. Foam was put into both TIUs and the remote to make sure the radio boards would not work loose.
4. Fixed outputs are wired to their own terminal blocks (a total of 4).
5. Each terminal block has an 18v bulb wired to the INPUT of the terminal block (from the output wire of the TIU attaches).
6. Each of the terminal blocks have 10 or less track blocks connected to them.
7. Number of track sections per track block are 11 or less.
8. Each "terminal block-to-track block" wiring path passes through a relay; so that each track block can be switched On or Off. The connection is wired through the "Normally Closed" side of the relay. That way power from the terminal block to the track blocks is always "available" without the relay being "active".
9. All wiring is 14 gauge "sheathed" wire and none of the wire lengths exceed 10 feet.
10. Because PW ZWs are used, the layout is wired using the Power District approach (as defined in Barry's DCS Companion book). This approach shares the power load; putting a lot less strain on the ole ZWs.
11. Because I'm using the Power District approach, I'm running both TIUs in Super TIU mode.
12. One TIU is named TIU1, the other is named TIU2.

I'm hoping someone might have some insight as to why I'm getting such weird signal strength results? Or maybe my testing process is totally wrong? Or this is SOP for DCS?

I hope someone can help!

Original Post

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After testing a section of track that your getting this weird behavior on, run the engine around the layout and park it on that same section and see if you get the same exact reading. If the reading changed it could be your pick-up rollers.  Buff the pick-up rollers with some Scotch Bright then flush them out with a few drops of rubbing alcohol while spinning them. After they dry, apply some good conductive oil, like Bachmann EZ Conductive Lube, to the pick-up axles and spring loaded hinges. Then test again and see if that helped.

Personally, I would not use sheathed cable, to avoid possible capacitance-effect diminution of signal.  But Barry's first sentence is good advice.

I'll throw out another question for the electrical engineers to ponder:  If one uses an AC-coil relay to turn a block on or off, energizing the relay to turn power on, can inductance from the coil near the contacts, when the coil is powered, have an effect on the DCS signal????

"sheathed" wire - is the wire solid wire, two wires similar to household installation wire?

If so - it will not transmit the digital signal well at all.  You need stranded, twisted pair wire.  OGR sells it in 250' lengths.  DCS runs on packet switching, individual digital packages, sent on the outer surface of the wire.  The more outer surface the better.

bruce

Last edited by bruce benzie

Hi All.....

Thank you all so much for helping with this question and what I'm seeing. I'm responding to each of you here. Since there haven't been any comments/questions about my testing process, I'm guessing it is solid.

Barry - I've actively been in the process of doing what you suggest. My "enjoyment factor" is diminished because of dreaded Out of RF Range messages I get when running my trains. All my track is flat and screwed down (layout pic below). The upper loop track was just laid and has no power to it yet. I'm not going any further until debugging the track on the lower level loops and sidings is done.
20170817_084152

RJR - the relays are DC coil relays mounted in a socket that will be powered by their own wall-wort. They are not wired to any power yet. That's another reason why I chose to use the NC side of the contacts. And I just thought of this while responding to you....I'm running BOTH the Red (Hot) and Black (Ground) wires through the relays! I'm wondering if I should only run the Red through the relays and have the Black bypass them? 
20170817_084101

Dave - I will clean the pickup roller as suggested and retest the querky areas of track.

RJR and Bruce - I'm guessing I used the wrong terminology to describe the wire I used. This is the stranded 14ga oxygen-free copper wire I used....
20170817_082857

Matt - I will check all my wiring connections. I'm thinking I will also test track signal one TIU channel at a time to see if these signal gremlins go away or hone in on the offending channel/TIU.

Gregg - I have not done testing via a tethered remote and I will try that as well. Stupid question Gregg....what does testing via a tethered remote buy me? I'm guessing this would indicate a communications issue between the remote and the TIU??

All - I'm using 18v 1A AC power supplies (2) to power the TIUs. Is that enough "Oompf" to provide a reliable radio signal??

Thank again for all your suggestions/help.

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Gregg - I have not done testing via a tethered remote and I will try that as well. Stupid question Gregg....what does testing via a tethered remote buy me? I'm guessing this would indicate a communications issue between the remote and the TIU??

Yes .

 

    Our layout  is very similar to yours, PW Zws . 4 tiu in super. 8 remotes however we have used all 4 channels on each tiu. The var channels are set to fixed mode and operate just like fixed 1 & fixed 2. Since each channel has it's own signal generator, this gives you  the option of  less track  to feed the dcs signal. You can use the same power supply but now have 2 signal generators instead of 1. Yep still have to separate each channels track with a center rail insulated joint.

Before too much further I would test each channel's dcs signal with a small test track and one engine... you should be able to get a perfect 10 on every channel.  

Barry - Thanks....I'll make that change.

Gregg - Here's my test setup. I connected 2 072 curve together (the track joint is very tight) and I soldered leads to one curve as close to the end (center of both) as I could. The transformer is old so I used my test meter at the rails to make sure I get at least 18v....

20170817_112310

I don't believe my eyes! After running 30 refreshes on each TIU/channel....I got the following signal strength test results....

TIU1 (Left TIU)
Var1 - all 10s
Fix1 - all 10s
Fix2 - 11 Out of RF Range occurrences, 19 10s
Var2 - 6 Out of RF Range occurrences, 24 10s

TIU2
Var1 - 3 & 4, never higher
Fix1 - 4 & 5, never higher
Fix2 - 3 & 4, 1 Out of RF Range occurrence
Var2 - 4 & 5, never higher.

Holy Crap.....time for new TIUs??

BTW.....I was sitting right in front to the engine holding the remote.

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Last edited by Junior

Tethering may eliminate the out of range messages but it seems tiu #2 maybe in need of repair, That's really low for a small test track.. Don't give up just yet.   Does the "read" find both tiu? 

Does the   red led on Tiu number 1 blinks once  and   blink twice    for tiu #2  on power up  and both have been set to super.... right?

 

 

Hi Gregg....

1. The left TIU red light blinks once, the right TIU red lights blinks twice.
2. Both TIUs are set in Super mode for un-tethered and tethered tests.
3. Pressing "Read" in wireless (un-tethered) finds both TIUs; 1 and 2.
4. Below are the signal test results with the remote tethered....
TIU1 (Left TIU)
Var1 - 10s
Fix1 - 9 & 10
Fix2 -  10s
Var2 - 10s

TIU2
Var1 - 3, 4 &5
Fix1 - 3, 4 & 5
Fix2 - 4 & 5
Var2 - 4, 5 & 6

Hmmmm . Hopefully one of the  MTH repair guys might explain  the low dcs signal with tiu #2... The only thing I can come up with is.... Perhaps the transceiver board is loose...  6 screws to get it apart however I doubt it...

I'm looking at the layout and wondering if you actually need 2 tius . Anyway good luck & hopefully someone can come up with an answer for the low dcs signal with tiu#2. I bet it's  repairable.(GGG)

Hi Gregg.....I cracked the cases on both TIUs and the remote and put in foam after reseating the transceiver boards early on to make sure I didn't run into that problem.

Yeah....this is pretty depressing......any thoughts about the Out of RF Range messages on TIU1? I'm holding the remote about 18 inches from the TIUs when I run these tests......

Hi Casey.....you're right.....I didn't run any of these tests with light bulbs attached to the TIU outputs. I figured I didn't need to considering the proximity of everything to each other (everything is "inches" away from each other). I'll go back and do them again with light bulbs on the TIU outputs.

The right TIU (#2) is the old, old one that has no Rev label and no internal fuses. AndI cracked the case. Nothing is loose at all. All the wires to the terminal are soldered and do not move. Nothing else on the motherboard appears loose either.

Junior posted:

Hi Gregg....the Out of RF Range messages have disappeared while the remote was tethered (tethered test results are in an earlier post above). Adding the bulbs as we speak (or key).....

I hate to mention it but... You may have to reseat the transceiver board in the remote . I hate taking the remote apart  but  it can be done.  I see you have Barry's book so that will help. Did the bulbs make a difference?

I seated and added foam to the remote's transceiver board when I seated the transceiver boards in the TIUs. Did all the before I ever hooked the TIUs up to the layout.

Here my results running the TIUs using an un-tethered remote with an 18V bulb attached to the TIU outputs. To be clear, when I run these tests I am moving the transformer power wires and track output wires from channel to channel on the TIUS (in other words, they are NOT all connected at the same time). I joined the bulb leads to the Red/Black wires using wire nuts. I guess the wire nuts are acting as terminal blocks ....
20170817_161529

Again, I'm watching the remote screen refresh 30 times.

TIU1 (Left TIU)

Var1 - 10s = 9, Out of RF Range = 21 occurrences, I reran this test 5 times with crap results like this.....
Fix1 - 10s = 30
Fix2 - 10s = 30
Var2 - 10s = 30

TIU2 (Right, old TIU with no Rev and no internal fuses)
Var1 - 5, 6 & 7s
Fix1 -  5, 6 &7s
Fix2 - 4, 5 & 6s
Var2 - 4, 5 & 6s

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I read some, but not all of these post.  What engine are you using...PS-3 or PS-2?  The older TIU is one of the first (No fuses).  Not a rev I which would have an identification sticker.

Some older TIU do not work well with PS-3 engines with out chip modification.  So if using PS-3, try a PS-2 3V engine with TIU 2.  It may work better.

In the end, I would replace it with a Rev L and yes remote is universal to TIUs.

You can then relegate the old TIU to small temporary layouts or conventional control, etc...  G

Last edited by GGG

Hello GGG;

Sigh.....I ran all the test using a FP45 Model #30-20154-1. The box label says it's a PS 3.0 engine. I will rerun the tests with a PS 2.0 engine.

Also....referencing the pictures and posts above; from the picture the LEFT TIU which is the first TIU in the list of signal test results is the Rev. I TIU. That's the one that produces the 9 - 10 signal levels and Out of RF Range messages.

The RIGHT TIU (from the picture) which is the second TIU in the signal test results list is the OLD TIU without internal fuses. That's the one that produces the 3 - 6 signal levels.

GGG - I ran signal tests using a 4-6-2 Forty-Niner Model # 30-1440-1. The box label says this engine has PS 2.0. Again, I would watch the remote's display screen refresh 30 times to watch for variances in the signal strength.

I ran multiple tests on the Rev. I TIU and got a mixed bag of result on ALL channels. On some tests I was able to get through a channel with all 30 refreshes displaying all 10s. On other tests, I would get Out of RF Range messages interspersed with 10s. On one test, the Track Signal Quality screen displayed for a LONG time (7 - 10 seconds) before I got and Out of RF Range message. That test displayed way more Out of RF Range message that signal strength messages. I would guesstimate that when I started getting Out of RF Range messages, they would display 2/3rds of the time on this TIU.

The OLD non-fused TIU provided a whole different set of results. This TIU displayed signal level 10s across every channel for multiple test sessions (using the PS 2.0 engine). One time did I received Out of RF Range message....once on VAR1 and twice on FIX1. Otherwise signal strengths were 10s again, using a PS 2.0 engine! I put the FP45 back on the test track to prove to myself that PS 3.0 can impact signal strength that much.....and it does. Signal strength drops back down to 4 - 6 on THIS TIU! This seems to indicate a hardware change between this TIU and the Rev. I TIU.

As I'm documenting these tests, I'm beginning to realize that there appear to be TWO distinct problems that may or may not be related (I'm hoping you can clarify that with your repair experience). There is an Out of RF Range problem; indicating there's a TIU-to-Remote communications issue. And there's a signal level issue; where the TIU's signal generator is not putting out a constant signal strength. But the signal strength issue could be compounded by the Out of RF Range issue......correct??

Gregg - I will rerun the tests with the TIUs in "normal" mode to see what happens. Oh....almost forgot....I'm running software v5.0 on all components.

Last edited by Junior

Gregg - just finished doing signal strength testing with both TIUs in Normal mode. I have to share....I was testing a VAR channel and some how the engine got into "conventional" mode and took off! It scared the crap out of me! But I caught it before it reached the end of the test track! I laughed so hard! Boy....THAT woke me up!

Anyway, the Rev I TIU:
VAR1 - started at level 3 then jumped to level 10 and stayed there.
FIX1 - same....started at level 3 then jumped to level 10 and stayed.
FIX2  started and stayed at level 10
VAR2 - same....started and stayed at level 10.

I did notice throughout all this testing that when a signal test is being done, a loud click comes from the engines speaker and typically occurs at a pretty constant pace; about every second. This was not the case with this TIU. It almost sounded like the TIU was really working to push out the signal. The clicking was not constant at all. In many instances, there was as much as a 2 second delay between clicks. And this occurred on all channels.

The OLD un-fused TIU provided level 10 signals on all channels. And the pace of this TIUs clicking was very consistent; every second.

So sorry about doing testing earlier with a PS 3.0 engine.....I didn't even notice it. I just crabbed one and started testing. Had no idea it would have such a dramatic affect on signal testing.....sorry.

I would place no reliance on a signal test showing variations.  I have always found that normal.  To me, if trains do what I want them to do, signal is adequate.  10s are my normal.  I have two original issue TIUs, and have had no problems with them and any loco.  10+ years ago, I thought a signal generator was failing, and it turned out to be a failing ground connection out on the layout.

Gregg....you spent a lot of time with me and I greatly appreciate it. And I appreciate all who responded with helpful questions and suggestions...you all make such a difference...

I'm going to order a Rev. L TIU today and use it to replace the Rev. I TIU. I'm very suspicious of the signal generator and the many Out of RF Range messages it's been issuing.

I think I can temporarily use the OLD un-fused TIU. It appears to have a more consistent signal generator and issued very few (if any....the tests are running together) Out of RF Range messages. I can use this one to begin debugging my track. It'll be fine as long as I run PS 2.0 engines.

Once the Rev. L comes in, I'll probably send the Rev. I out for repair to MTH. 

And trust me.....I will do a bench test of the Rev. L. I've gotten pretty good with those :-) .

I will then retire the OLD un-fused TIU. With the advent of PS 3.0 engines....it just won't cut it.

Finally.....I'm waiting for GGG to respond to my questions in an earlier post. Hopefully he will.

What did we ever do before the Internet.....seriously!

Junior, finding a bad connection, or a wiring short, is a long slog.  Experience helps, as does a knowledge of the wiring and circuits, but nothing, absolutely nothing, beats being dumb and lucky.  Just came across the connection by chance.  Years ago, I had an intermittent short (the worst kind) and after searching for months, found a file cabinet under the train table had knocked the tape off of a splice.

Let me give you a hint regarding the Rev I TIU.  The best source for any DCS repairs is GGG.  He is reasonably priced, and the only person I would trust with repairing anything regarding DCS electronics.

The clicking during signal testing is normal.  FYI, often after terminating the test, the volume will be reset to 0; hit up volume a dozen or so times to bring it back up.

I would not break the black (outside rail) circuits to blocks.  Only the red (center rail).

I haven't time to read all the posts in this thread.  Did you open the Rev I and check the nuts inside it on each terminal.  They don't stay tight without lock washers and lock nuts.  The Rev G is no problem; these were soldered.  My 2 ancient Rev G's are solid as rocks, even with PS3; I have put back them on the layout when I've had problems with later versions, and am planning to install one on a layout I'm building for some grandchildren.  If GGG says there has been an issue, then there has been an issue---I just haven't experienced it.

If you don't get Out of RF Range when tethered, you've pinpointed a problem:  a board is loose or has an intermittent internal failure.

RJR - Thanks for info about that short....I was afraid that was going to be your response :-) . I'll crack the Rev. I case and check those connects.

All - I put back the OLD non-fused TIU (TIU2) by itself on the layout, set it up in Normal mode and ran the Forty-Niner around the outer loop at a crawl with signal level check turned on and got 10s!! Woo-Hoo!

I then started checking the inner loop and sidings and found a track block that needs investigating. The remote displayed 10, dropped to a 1, then Out of RF Range, then went back to a 10 when it left that track block. Im guessing this is how the TIUs should've been working all along.

The only other Out of RF Range message I encountered was when I had to remove and re-add the engine. The remote displayed Out of RF Range (in BIG block letters) for a long time. It then issues a message saying the engine was added.....which seems to be running fine.

Thank you all again for staying with me and getting these issues identified. I now have several courses of action.....

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