I suppose your measurement is

I suppose your measurement is on the base station disconnected from the track. According the  https://www.nmra.org/sites/default/files/standards/sandrp/pdf/s-9.1_electrical_standards_2006.pdf
the lowest frequency of the DCC is 1000/(61us+64us)=8kHZ with max 9.3kHz. I don't know if this is the cause. 

About spikes  In the first

About spikes 
In the first link exist a suggestion of back to back zeners to cut the spikes ----

https://www.dccguy.com/?p=311

https://sites.google.com/site/markgurries/home/dcc-general-best-practices/wiring-planing/wire-properties/track-wire-voltage-ringing

.

i believe the spikes indicated on the scope trace is an artifact of the scope probe or bandwidth

This is the reading of the

This is the reading of the base station disconnected form the bus.  

Same reading as OP but this is at the rails 

Thank you for the Reference documents ill read thought them soon.

Snubbers

Dear Ryan,

From your fault symtom descriptions, I can't help but feel there may be some track-buss snubbers in your future...

https://ncedcc.zendesk.com/hc/en-us/articles/204128735-Snubber-RC-Filter

https://sites.google.com/site/markgurries/home/dcc-general-best-practices/wiring-planing/snubbers-rc-filter

Happy Modelling,
Aim to Improve,
Prof Klyzlr

About spikes  In the

transmission line model

the trace measured at the base station with the track disconnected should convince you there is nothing wrong with the base station.   The fact that the waveform is not flat on top is because the probe is not adjusted.

now consider what the track looks like, long lengths of parallel wire, a transmission line, with an adjoining segmented transmission line (i.e. track), with no termination or twist.    Transmission line models include lots of non resistive elements resulting in damped oscillations (i.e. ringing)

might be interesting to compare the scope trace with a locomotive running.

A decoder losing it's

A decoder losing it's configuration is one of the symptoms of a degraded DCC signal.  One of the fixes, as the Prof says, is adding snubbers at the end of the bus.  He's given you the pertinent links.

I wouldn't spend a lot of time with measurements and theory.  I would add the snubbers and see if the problem disappears.  Then I'd read the recommendations about wiring best practices and see if you need to start re-wiring the rat's nest that may be under the layout.

gs

And if snubbers don't help...

The other cause of scrambled decoders I've seen is shorts with auto resetting boosters, which try to reset about once a second while there is a short until the short is removed.  That can result in a lot of weird noise on the track depending on the nature of the short and the wiring involved.  Some decoders seem to be more prone to getting scrambled by that than others.  If you suspect this is your problem, the fix is just to turn off the auto reset on the booster or breaker (assuming that's possible - it is on the ones I've used) and use a manual reset button.  That gives you time to look around and find and fix the likely cause of the short before pushing the button.

degraded DCC signal

can you explain why?   not disagreeing, trying to understand.

i thought messages to change CV values were repeated.   So I am wondering how a corrupted DCC signal during normal operation could cause a decoder configuration to be screwed up.

@gregc - my wording a

@gregc - my wording a "degraded" may not have been the best choice.  In the two links to Gurries' web site he discusses how spikes caused by shorts or other problems cause problems with decoders. 

gs

@Ryan R, please give us a

@Ryan R,
please give us a feedback how you solved this. I would appreciate some info about the wire gauge, stranded or solid, approx. length of the longest wire from the booster, feeders gauge, booster's amps and if you use block detectors.

Wondering on paper if

a transient suppression diode like a P6KE33CA across the tracks might help at the dead ends as the snubber.  It would be one piece.  The eBay price is right too.

Nick

I will give feedback as soon

I will give feedback as soon as I have it.  

some more information this is club layout that layout room is in 80ft by 70ft room. we have one command station w/o booster running 12 booster with Circuit breakers.  I know that there are snubbers at the end of the bus lines.  and we do have amp block detectors what are Tower Controller Mark II LocoNet.  I remember looking at the wire and the gage was right with NEC manual I don't remember the exact gauge off the top of my head.  I look tomorrow.  

the last two time the decoders lost the programing there was no short on the layout.  

my to do Lists

Test with oscilloscope with load on the rails 

Snubbers 

moving booster closer 

Update with testing

Unloaded track!

Loaded track with 10k ohm resistor and LED! 

Loaded track with 10k ohm resistor and LED With one Snubber!

My conclusion is it we going need more than one snubber per Block

Before I'd start sowing

Before I'd start sowing filters everywhere:
Try to isolate the problem
Did I make any change(s) recently?
Short sircuit?  Loose wires?
The problem appears on every booster district?
I would check if I missed something 
https://sites.google.com/site/markgurries/home/dcc-general-best-practices/booster-connections-power
https://sites.google.com/site/markgurries/home/dcc-general-best-practices/booster-connections-power/multiple-booster-wiring

An update on what we have

An update on what we have been working. After years of talking and board change at the club.  We are making some changes to the wiring.

We have talked to NCE and Ph.D. in Electrical engineer.  We have installed Snubbers with little change +-2v at the most.  
 We found that when wiring for DCC they wire this home run with wire two blocks that are next to two bus lines.  We now are working on daisy chain together blocks and remove extra wiring.  On one booster we have removed more the 700ft of bus lines.   We are still removing wiring and the Bus lines are running next to each other so we did not see a drop yet.  A lot of work still needs to happen to see if this works. 

We also found that the breaker was set at 6.3amp of trip current.  we have brought that down to 5.08Amps.  we have not lost the decoders since then.  

We found that when wiring for

can you explain?   what does "wire this home run with wire two blocks" mean?

how were things wired?

 home run  look like

 home run  look like this 

daisy chain together

Sounds nasty

Might be a good idea to take the command station and hook up one pair of new track wires to an isolated section of track approximating your longest leg and establish what a baseline trace looks like.  If it’s clean, then bring blocks back on one at a time until you see the errant trace show up.

Could this be a feedback loop perhaps caused by a failed/failing component. If you watch the scope over a period of time do things change?  Does that flutter amplify?  Are there diagnostics available for your various components to test them one at a time?  As someone else pointed out depending on the scope itself, it might be introducing something into the circuit.
 

Bugger to trace, and for all you know someone tapped into a bus wire with some wee building sound or lighting  circuit or something and didn’t think it mattered and didn’t ask/tell anyone.   
 

Club could pretend it’s Division had a monster storm and it is getting Track back online one section at a time.  

never heard the terms "home

never heard the terms "home run" or "daisy chain" regarding DCC

seems like there are several common approaches

• common bus (top)
• separate buses perhaps for isolating power districts or from multiple boosters (middle)
• multiple boosters with separate power districts (bottom)

obviously, a common bus snaking around a layout may be very long while a more centrally located booster or separated boosters with separate buses radiating (star) would have sorter buses

Hello your common bus (top) =

Hello

your common bus (top) = daisy chain

your separate buses perhaps for isolating power districts = home run

and I’m talking about off the breakers, not the booster. The booster that I’m working on have 10 breakers home run on with about 5-6 block on them.  On this booster, I have done 6 to daisy chain and I have 4 more to go on this booster.

With the 6 breakers are done we got 700ft of bus lines removed. we are talking about adding a booster and have 5 breakers per booster but that is later.