FM wireless mounted at loco is working! must see..stans video!

Did you try a 1uf non-polarized cap across each of the motors?

no.. do you prefer across the 2 terminals or a cap each from the terminal to motor case?

Your first photo is hilarious - a true LOL.

What exactly does the noise sound like, does it change with speed?  Can you post an audio recording?

I'd start try smaller caps across the motors - say 0.01uF if you have them.  The PS motor drive electronics uses high-frequency pulses to drive the motors and a 1uF capacitor would appear as a relatively low impedance shunting the drive current.  Put them across the motor terminals.  The motor case is electrically connected to the frame/chassis which connects to the noisy outer-rail. So putting a capacitor to the motor case would create a round-about current return path back to the motor drive circuit which I don't think is what you want.

So you're going to place the transmitter back in a dummy unit?  How will you access the battery and on/off switch? 

Presumably you're running wires from speaker to a dummy.  Neither of the PS2 speaker outputs are "ground" and there are endless stories of mis-haps where a speaker wire touches the frame and poof...there goes your audio amp.  So I suggest you add, say, a 1000 ohm resistor (any wattage) to each speaker terminal, then run the wires back to the dummy.  If one or both tether wires get pinched and touch the frame or whatever, the current will be limited and you should not pop the amp.  Then on the dummy side, put a 0.1uF cap across the two wires before going into the transmitter.  So in addition to gaining protection, you have a simple R-C low-pass filter of about 800 Hz which should adequately pass diesel rumble.

Does your stereo tuner have a "MONO" button to disable FM stereo?  This is far-fetched but FM stereo encodes left-and-right using sub-carriers that might interact with the high frequencies generated by the PS2 motor drive...in your photo the transmitter is sitting on top of a motor!  Putting the receiver into MONO mode disables the circuitry which looks for these sub-carriers which might eliminate the noise IF that's what it's from.  Again, it's a long-shot but it only takes a single button press.

I'll bet you'll never see someone try that with a legacy loco

I'm pretty sure you would loose that bet. FM shows the idea could work. I think today Bluetooth would be a better choice to avoid brush and pickup roller noise.

Pete

with remote vol all the way down and i move engine ahead i hear the best described as a low frequency scratchy noise through my stereo.turn up the vol at my remote to normal level and i can barely hear the noise but i know it is there. with engine sitting in neutral and i raise labor rev up i dont get the noise. i did install caps[from a spare computer board laying around that said 104/ .1uf maybe? on them] from each motor terminal to motor case but still have the noise. even with all this a great pleasure to listen to. i will try the mono mode next.

Roller Pickup noise is a problem with FM, likely a higher amplitude than motor noise. Try drop of WD 40 or better yet Atlas Conducta Lube on the rollers and try and get the track as clean as possible. Its diificult to eliminate completely though. Its more obvious when using a video camera that transmits to a TV.

Pete

i am 2 rail...cant lube the track..pulling to heavy..wheels would slip.

Sorry, I missed the 2 rail part. 

Pete

 i see the confusion on noise. prior i had the treble @ my amp up and it enhanced the the noise from the tweeter. the adjustments now are with the treble off and bass full on. i reinstalled the tweeter and used the same settings and it now the tweeter has very little effect. the noise is best described as listening to an AM station but nearby lightning causes static...i will ck my pile for an audio transformer..plenty of room in the loco for one.

Well, curiosity got the better of me so I found a FM transmitter module probably similar to what you have and wired it up to a PS2 diesel that happened to be opened up. 

I simply attached the speaker terminals using alligator jumpers directly to the transmitter 1/8" connector and put the transmitter in a gondola as shown in the video.  I had to turn down the volume of the engine to "50" since anything above that seemed to clip at the receiver.  This makes sense since the PS2 audio uses 5V and audio devices often want "line-level" signals which is typically 2V.  The video starts out with "just" the PS2 engine speaker...then at a few seconds in I turn on the FM receiver with amplifier.  The video does NOT reflect the room-shaking volume of this method. I could not detect any noise when the engine started moving forward or reverse.  I turn off the amp again a few seconds before the end of the video.

People casually throw around terms like "awesome" but I must say the effect is indeed awesome!  

Anyway, this transmitter only has 4 frequency choices and even without the transmitter on the stereo light came on in the receiver presumably from local FM radio stations.  But there was one instance where it appeared the "Stereo" light was the result of the tiny transmitter and I think I heard a scratchy sound...pressing the "MONO" button and the noise went away.  I couldn't duplicate this so it may be a false sighting but give it a try.

Again, this was PS2 diesel and I don't have a PS3 to try it on but I must say it's worth the effort if you want to re-create that visceral sensation of a diesel prime mover rolling by.  Wow!

and sitting idling...like being in the switching yard..i now leave my enhanced sound on much longer..very soothing...

THIS IS AN IDEA IVE BEEN TOYING AROUND WITH, I WILL BUY A TRANSMITTER MONDAY AND INSTALL IT THIS WEEK. KUDOS TO YOU, WOW! I HAVE A SURROUND SYSTEM THAT WILL ADD SIGNIFICANT REALISM TO RUNNING TRAINS.  CLIFFORD

the one in the picture came from the auto section at wal mart/ 13.97..got good reviews..part of my noise issue might be a 30 year old pioneer receiver.

I realize there's some logistics to getting it installed and wired-up.  And, yes, what if you have multiple engines etc. etc.  But now that I've heard it for myself, I guarantee that if you have a visitor who typically nods (yawns) politely when you show them your layout, this will blow their socks off and they will wonder when they get home why their socks are missing! 

IIRC I got my transmitter for less than $5 on eBay several years ago.  This is the best bang-for-the-buck enhancement I've seen in quite a while!

I was waiting to hear the horn blow.

 stan asks So you're going to place the transmitter back in a dummy unit?  How will you access the battery and on/off switch?

the transmitter has a slide switch but with the unit in the dummy the switch will be inaccessible. i may interrupt the battery pack[2 aaa cells] and use a small on/off switch. my dummy has constant voltage lamps...any ideas where to tap into to charge a pair of 1.2 v ni-mh batteries?

Why not just use track power with a DC power supply and a supercap to ride out the power interruptions?  Why fool around with batteries at all?

that is what i am thinking as well...my dummy unit has constant voltage lights..2 large heat inks w/ caps and circuitry as well..is there a clean dc 3 volts there someplace?

Well, A diode, a cap, an LM317, and two resistors and you can have clean DC of any voltage desired from track voltage.

Generating 3V DC from your existing DC supply in the dummy is simple.  "Just" add a 3.3V regulator IC such as the 78L33 (50 cents on eBay) to the dummy's DC supply output.  But this opens a small can-of-worms.

When the FM transmitter operates on battery (2 x AAA) it is electrically floating... meaning it's "ground" reference can take on the reference of the incoming audio signal.  This allows you to directly tie one speaker wire from the PS electronics to the FM transmitter "ground" which in this case is the common or sleeve pin (vs. the outer tip or center ring pins) on the 3-pin 1/8" connector. 

By powering the FM transmitter with a derivative of track voltage, you are breaking this isolation so you can no longer directly tie one PS speaker wire to the transmitter's ground.  That is, the PS board is also powered by track voltage.

There are work-arounds such as re-inserting the isolation using, say, an audio transformer between the PS speaker and the FM transmitter input.  Or you could generate a floating 3V DC supply using a DC-to-DC isolated converter module.  Or you could electrically reference the 2-wire PS speaker output to the transmitter's ground using a so-called differential-to-single-ended op-amp IC circuit.  Etc. Etc. Unfortunately, all this gets tedious and the devil's in the details.  For example, in your specific case I'd want any battery replacement circuit to address your noise problem.

I of course see the benefit of eliminating the battery.  But I wonder if we're getting too far afield from the simplicity of your original idea which is easy to replicate and has real shock-and-awe value?

I suspect you could use capacitor coupling of the audio to do the DC isolation as well.

I did as below and no change. Buttttt...i think i have a much better description of the problem. With the loco on the track just sitting sound is clean but if just wiggle the trucks on the track in neutral or force it ahead or backwards[wheels dragging]..bingo there is the noise..i am thinking has to be wheel to rail causing the static. When stan experimented he was 3 rail. I am 2 rail. Also if roll the dummy i will here a much reduced version of the same static.

I'd start try smaller caps across the motors - say 0.01uF if you have them.  The PS motor drive electronics uses high-frequency pulses to drive the motors and a 1uF capacitor would appear as a relatively low impedance shunting the drive current.  Put them across the motor terminals.

This is with nothing connected to the FM transmitter?  If so, can you get a piece of wire or whatever and wind it around the 3 pins of the plug (i.e., shorting them together) so that is no audio input?  Does the noise change?  The idea is to see if the noise is coming through the audio input wires.  If not, then could get tricky to, say, shield the FM transmitter possibly requiring opening it up and maybe running out a short antenna wire - can get messy...

with the host loco connected to the FM trans which is in the dummy but in watchdog mode or not in startup i can wiggle the trucks or move it ahead wheels dragging and the static noise come through. If i take the host loco completly out of the set up which leaves just the dummy and FM trans on and roll the dummy ,same noise but abated. i will try the shorted 2 pin test soon.

 I guess I can admit this now, being a decade ago. I had a similar setup with my home speaker on a flat car trailing behind. It came uncoupled for some reason, and one of the wires hit the rails. That must have sent full track voltage into the board and fried it.

 So please learn from me, connect that car with chains, or, have the wires so that if they came apart, nothing shorts!!!

to answer "This is with nothing connected to the FM transmitter?" the answer is no the transmitter was connected. i just disconnected the trans and rolled the locos...no noise. at this point do i still need to short the rings for testing?

hey joe i hear you..see photos and i will also install current limiting resistors at speaker terminals.disregard the big wire in the background..it just feeds a big speaker from under house wiring..

Well, the objective is to find how the noise is creeping into the transmitted signal.  If simply disconnecting the 1/8" plug (leaving it floating) eliminates the noise when both the main and/or dummy are powered and moving or being pushed, then clearly the wheel-track noise is enter through the plug.  Actually that's probably good news as opposed to the noise coupling through the plastic case which would become a shielding hassle.

If this were in front of me, I'd be looking as filtering/shielding the audio input.  The simplest might be to twist the speaker wires from the host and shield it.   You might even have some twisted-pair shielded wire from wherever lying around.  After that I'd try the 2 1k resistors and 0.1uF cap low-pass filter suggested earlier which is also for circuit protection for events like Joe above describes.

If simply disconnecting the 1/8" plug (leaving it floating) eliminates the noise when both the main and/or dummy are powered and moving or being pushed, then clearly the wheel-track noise is enter through the plug. < i think you nailed it.

i twisted all wires[host and dummy] as i noticed the oem mth speaker wires also twisted. not sure how to shield and also i wonder if the short pig needs something.  btw family dollar sells a transmitter like yours only black for 6.95...is yours working well?

I realize there's a logistical problem running shielded twisted-pair all the way through given the connector as shown in your last photo. Nevertheless twist the wires on both side of the connector and shield what you can (even if it's just with aluminum foil in the absence of real STP wire).  On the dummy side, I'd shield to the sleeve (transmitter's ground).  On the main side, you might need to experiment a bit as there's no convenient signal "ground" (the chassis is not a signal ground for this purpose).  By experiment, I mean trial and error will be involved - for example wrap foil around the 2-pin plug to provide a continuous shield all the way back to the 1k resistors.

I'm going down a different path as I want to put the transmitter completely in the main as I don't run MUs - so I will be ripping it apart.  And of course I'm 3-rail though I don't think that's the issue but who knows.  Yes, I see the white transmitter I have on eBay for $3 shipped but it's from Asia.  But I'll first run some experiments later with your configuration maybe using a lighted caboose as a "powered" slave and getting up to mainline speeds etc..

rewiring will be easy..i will use the 2 strand STP wire.

 I have had this train running all afternoon, idling or rolling...before these mods the sound used to get to me after 1/2 hour or so...very pleasant background ambiance now.

Well for one you guys aren't on the same page 

Willygee is using a PS3 equipped loco.

Stan2004 is using a PS2 equipped loco.

2 very different animals.

Willygee, Did you happen to test the resistance in ohm's of your setup?? I have no idea what "load" your FM transmitter is but you basically paralled it with a 4 ohm speaker which may have dropped the impedance way down...possibly enough to wipe out the PS3 board. 

We are definitely on the same page. This experimentation is into its 29th hour of operation...PS3 board is 100 percent.

I can't even imagine a little FM transmitter with an input impedance so low as to endanger the audio amp on the engine.  Are you personally familiar with such a setup?  I confess that I wouldn't have even considered that when connecting across a 4 ohm speaker.

So I found a lighted passenger car in my stash that hasn't been converted to LEDs so it draws good current and conveniently had noisy rollers/wheels so it flickered when moving.  I attached my white FM transmitter as shown with both L and R inputs going directly to the PS2-3V speaker.

With track powered to full DCS voltage with the engine at idle and the passenger car nice and bright, I pushed/dragged both cars back and forth many times quickly, slowly, etc..  NO NOISE even as the passenger car flickered madly.

I ran the assembly under DCS at various speeds both F and R.  If you can play the attached recording, you can hear a burst of static-like noise at about 4, 6, and 10 sec into the recording.  The engine is running at 50 MPH and obviously the sound has fallen into the clickety-clacking.  But this noise would occur at the same point in the layout at any speed.  So I'd move the receiver around the room going to a different AC outlets for the receiver and the locations of these static-noise would change and again always occur when the engine passed the same points around the layout.  My conclusion is this is FM transmission noise given a relatively weak transmitted signal and reflections/ghosting/whatever given an FM wavelength of about 10 feet (100 MHz).  Is this what your noise sounds like?

So I could not get any "noise" pushing/dragging the powered main unit and/or slave (lighted passenger car).

I also now recall that the reason these gadgets do not have an antenna wire is they assume you are hooking this up via a "long" cable to a CD player or whatever.  So they couple the RF signal onto the "ground" wire of the audio input and let that be the antenna.  After all, you only need to transmit from your front seat to your car radio...which is different that running a train around a basement or larger.  And of course these widgets presumably were tested to pass FCC power limitations.  This can devolve into a very nerdy discussion so I'll just leave it at that but jot this down almost as a note to myself as I need to keep the antenna issue in mind if I am able to cram the components into just the main unit.

That's the noise but through my small amplified 2.1 sub and satelites of course a little more accentuated. The noise also shows behind a vented lazer heater and behind my couch consistantly for a couple of seconds but basicaly a very acceptable broadcast most of the time. Also if i stand between the loco and my stereo[signal interference?] there is the noise.

Now this AM very little if any noise from wheels but i also went 88.1 to 106.7 last night. It seems the freq with some weak station broadcast do better than the no audible broadcast frequencies.I am still unshielded and no res or cap at t

he speaker terminals but i did leave the .01uf caps across the motors. Also the batteries are 1.2v ni-mh and have at least 10 hrs on them.

 this listening experience has steered me away from my 3 inch only speaker days..and i have 4 PS2 just "jonesin" to be converted.

If this is what you're hearing it's the "picket-fencing" effect when an FM radio bounces around trying to decide what signal to lock-on to (a real FM station, your FM transmitter, or nothing at all).  Another clue is, as you say, you can walk around the room and induce the effect as that obviously has no correlation to what the engine's electronics, motor brushes, or wheels are doing.

I suppose there are dozens of options but practically speaking the easiest is first to boost the transmitted signal level by using an alkaline batteries vs. a 2.4V source.  That will give you about 2-3 dB additional RF power.  You could experiment with the audio shield (sleeve) ground wire which I believe has the transmitted signal coupled to it.  That is, make it longer which seems counter-intuitive in terms of picking up local motor brush noise or whatever but that doesn't seem to be the problem.   That can give you another boost in effective radiated power probably in the couple of dB range.  You can mess with receiver antenna placement or antenna type though of course this simultaneously improves reception of interfering stations...but some combo of the right frequency and antenna placement could help.

More involved alternatives might be to experiment with using one rail as part of the antenna whether it be the transmitting or receiving side...sort of like TMCC.  Or see if you can turn a blind eye to FCC regulations and boost transmitter power if the circuit can take, say, 5V instead of just 3V - or build a simple RF booster.  And so on...

 Urrgg. You guys are dragging me back into doing this! That rig sounds great to me Stan. I did it with a G gauge Challenger. The digital sounds were amazing to my ear. It sounded like a real Challenger was in the basement!