Augustus Caesar Posted February 12, 2017 Share Posted February 12, 2017 This isn't a question per say but more of a curiosity but here goes... When I received my eLink many moons ago the USB cable that was supplied was fitted with a ferrite bead. I'm curious to see how many actually weren't supplied with the bead fitted... or, indeed, how many members on here have replaced the supplied cable with an ordinary or even longer cable with no ferrite fitted. A ferrite bead, for those who don't know, is fitted to many cables such as coaxial, USB and laptop chargers plus more. It is there to attempt to stop interference from and to the cable as the cable itself can be seen as both a transmitter and receiver of signals. This is its simplest form and if you need to know more then check it out. So, who has eliminated the original and is using an ordinary USB cable with their eLink and did you replace it without noticing any extra 'noise' or interference?As my box transmits a very high pitch tone when on (and I know some do and some don't - I'm not overly bothered by this) I am curious to see what others have done to change things or swapped cables over... Link to comment Share on other sites More sharing options...
96RAF Posted February 12, 2017 Share Posted February 12, 2017 Once again I defy the odds and use any old kit and my RM works without any of the frequently seen problems. I use a pair of 1.5 metre long flat section USB cables from our equivalent of Poundland. Available in black or white - mine are the white ones so I can write on them with a black marker which port and which controller they are for. These only cost a couple of euros so are obviously of no great quality and they are plugged into a pci card outputting USB3.0, not a native port on my HP i5 win10 tower pc.Rob Link to comment Share on other sites More sharing options...
Chrissaf Posted February 12, 2017 Share Posted February 12, 2017 In normal use, my Elite sits right next to my Laptop. Thus I use my own cable (without beads) that is 500mm long. For the testing I recently did for Ray (detailed in another recent post) I needed to move my RM Laptop away from the layout to place it next to my home office desktop PC. To do so, I used a 5 metre USB cable extended a further 2 metres with a shop bought USB extender cable. I know this exceeds the USB specification as written for non active USB cables, but it worked just fine for the temporary purpose I needed it for. Again, no beads were part of this 'Heath Robinson' lash up..PS - Unlike the eLink, the Elite doesn't come with a Hornby provided USB cable, so it has to be ones own that gets used and typically won't have beads. Link to comment Share on other sites More sharing options...
Augustus Caesar Posted February 12, 2017 Author Share Posted February 12, 2017 Am I correct that both of you have noted no interference from any cable used without the ferrites fitted?I would assume there would be either no or very little difference as modern cables are shielded anyway.The ferrites are there on some USB cables but can be removed easily if not required as they just snap shut and can be prised open.The reason I thought about this is because I have a ferrite bead on my original cable but it is only 1 metre in length and I need a two metre cable. I have plenty here at home both with and without ferrites but just wondered about the necessity for having one supplied with eLink units when purchased. I think, however, that they were just supplied as is and not for any specific purpose of signal reduction although no harm can be done with them added of course.I am still curious though to see if all eLinks were supplied with these things on them... /media/tinymce_upload/6175c2a57ba24504e7718ae4188bec94.png /media/tinymce_upload/906c65ef71179cc384541a44b90702d5.png The first image, for the folk who want to know what a ferrite looks like, shows the inner ring made up from rust and other metals (forming the ferrite ring) with its plastic outer case open... the second image shows the ferrite bead (or ferrite choke) in situ on a USB cable. Link to comment Share on other sites More sharing options...
Chrissaf Posted February 12, 2017 Share Posted February 12, 2017 Am I correct that both of you have noted no interference from any cable used without the ferrites fitted?.Not that I am aware of. Link to comment Share on other sites More sharing options...
96RAF Posted February 12, 2017 Share Posted February 12, 2017 No noticeable adverse effects on Hornby or other attached or integral kit, not that I would recognise it other than as a freeze up or flashing on screen. Link to comment Share on other sites More sharing options...
Augustus Caesar Posted February 12, 2017 Author Share Posted February 12, 2017 Thanks guys... my thoughts would be that if any interference was noted at all it would be through a freeze of the communication to and from the eLink via the PC or laptop and, of course, via that cable.In other words the signal would be 'scrambled' going through the USB cable because of that interference.I would doubt that any such break would happen simply because it would have been noted by now as a spurious connection error by someone somewhere down the line.As said though this was only a curiosity thing to see if anyone had noted anything and about whether or not the cables were supplied with or without the chokes fitted.Thanks for the feedback Rob and Chris and if anyone can add anything I'll look it over. I'll also keep my ears open for any 'noise' and eyes for any drops of signal causing a break in communication... though I don't expect anything at all really. Link to comment Share on other sites More sharing options...
St1ngr4y Posted February 13, 2017 Share Posted February 13, 2017 Hi AC,Can this interference be cumulative? By this I mean is it more likely to occur the longer the cable is in use i.e. the longer a Railmaster session?Ray Link to comment Share on other sites More sharing options...
96RAF Posted February 13, 2017 Share Posted February 13, 2017 Interference tends to be local, inductively induced by something happening close to the cable e.g. mains cable strapped in a loom with a USB cable or points motors loom fired by a CDU, etc.Rob Link to comment Share on other sites More sharing options...
Augustus Caesar Posted February 13, 2017 Author Share Posted February 13, 2017 Ray... Rob is correct where he states that the interference is generally localised (the signals aren't powerful enough to be transmitted or received to and from distance) but another scenario that may give some clue is where a USB cable without the ferrite is plugged into the rear of a PC and where the USB connection is near the PSU of that PC. Electrical interference therefore should negated at times (though the decision is personal unless a bought PC or whatever is already inclusive of cables with ferrites fitted) if something like extra noise is heard or, for example, a picture on a monitor is not static or the printer is not receiving all necessary communication to allow a print job to be completed. Reasonably extreme examples I admit but it does, sort of, put the context there. To negate those interferences then a ferrite is fitted close to the source of the potential problem. Therefore, the cable end that contains the ferrite is just about always the opposite end of the USB equipment the cable is fitted to, for example, a printer, scanner, camera or eLink unit. So if any of these are fitted to a PC then the ferrite is at the PC end generally unless the equipment itself is the source of any interference (usually printer cables) thus the following statement... Occasionally a cable is fitted with two ferrites with one at each end. These are less common and only used where there may be a little more potential for that interference to occur. I don't think there is a limit to how many that can be fitted but more than two I imagine would be a waste of time. I don't see a cumulative effect happening unless changes to the source giving out interference can change over time. I'm no electronics expert by any stretch of the imagination but wouldn't see any difference because of cable length either... one would simply fit a ferrite to each end of the cable if doubts are there about which piece of equipment is the potential source. That would do the job in my view. Over time I would say it would again make no difference as the transmissions and receiving of the source interference would not change that much at all and would have no real effect. The only issue with USB cables is that the length of the said cable should stay within its parameters for no signal degredation to occur and if extra lengths are added then a repeater/booster should be fitted. The ferrite side of this is the same no matter the length of cable. Hope that helps Ray... Link to comment Share on other sites More sharing options...
96RAF Posted February 13, 2017 Share Posted February 13, 2017 As I understand electro magnetic interference (EMI or EMC - electro magnetic compatibility) associated with PCs and other devices, it is where an unwanted signal is induced in an adjacent cable or module due to close proximity of a badly shielded cable or module broadcasting a signal which is seen by the other participant either direct or as a harmonic of the original frequency. This signal is usually seen as noise which disturbs the other equipement. The ferrite clamp-on device damps out this induced ringing in the recipient cable by absorbtion. There are other types of EMI/EMC which can be continuous, pulsed, magnetic, radiated, etc. A fix can be as simple as a bit of tin foil - e.g. look inside your TV aerial co-ax cable. I could be wrong in certain details, but that is what the old memory cells have dredged up from times past. Link to comment Share on other sites More sharing options...
St1ngr4y Posted February 13, 2017 Share Posted February 13, 2017 Hi AC & RAF,Thanks for that. My lack of electrical expertise led me to think it might have been something like a static charge which could build up over a period of time, and cause comms errors late in a RM session. I'm obviously way off course ☹️Ray Link to comment Share on other sites More sharing options...
Augustus Caesar Posted February 13, 2017 Author Share Posted February 13, 2017 I'd forgotten about the foil in those co-axial cables being used for similar dampening and absorbtion...The details you point out about EMC Rob is where I have limited knowledge. It is basic at best unfortunately.However, we all have our levels in different fields and that is a good thing...Ray... you have enough now to start digging further? 😉Myself... I am always curious about stuff like this and how it works but always stick to what I need to know otherwise it just bogs you down and creates minor explosions in the brain... :-) Link to comment Share on other sites More sharing options...
Fishmanoz Posted February 13, 2017 Share Posted February 13, 2017 Minor explosions in the brain AC? Maybe a ferrite bead on your nose might help. Or you could hide one behind an ear if people give you funny looks. The thing about co-ax cables is that they don't just have a tin foil or other shield around the signal carriers, there is only one wire down the middle and the return path is the shield so it does 2 jobs. In theory what you have is one active wire in the middle with a metal cylinder around it as the return so unwanted radiation is low (good EMC) and susceptibility to external radiation from other sources (EMI) is also low. Back in the day, that shield was relatively heavy braided wire too, not just light foil that goes and stays all the way round if you're lucky. Link to comment Share on other sites More sharing options...
Augustus Caesar Posted February 13, 2017 Author Share Posted February 13, 2017 Quite right Fishy... it is old days from when my older brother used to ask me to cut the co-axial that I remember the foil from. I don't do much with that type of cable now but when I have I can't say I have noted one way or the other what is in there. I just cut and fit because there isn't much to be concerned about. Anyway... people look funny at me all the time. Must be the ferrite ring around both ears when I'm tuned in to SETI while looking for aliens. That would explain the explosions in the brain... not blocking out the interference! New ferrites ordered... 😮 Link to comment Share on other sites More sharing options...
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