I’m absolutely sure there are topics already posted about this, but I’m either really bad at searching or really bad at spelling. I have a NExT in L0 and an xMagic in R0, and I’m getting a NExTv2 installed in a few days. Is it a bad idea to put the v2 at L1 if they’d end up being ~10mm apart? The issue I’m foreseeing with other locations on my left hand is that I can clearly see a vein under the skin at L2 and it may be difficult to tent the skin at L3.
Also, I’m sure I’ve seen posts about this before, and I suspect there is no guarantee of any particular orientation, but would you normally expect the LED in the NExTv2 to be at the pokey end or the plunger end of the injector?
The locations post should have some directions regarding this…
TL;DR 10mm is very close for two HF transponders to be next to each other, but it could work depending on the readers you’re using. You would just need to be very specific about how you presented your hand for specific readers.
I read through the locations post but somehow found myself still confused - if I can work out exactly why, I’ll post in there too but this helps a ton and I appreciate your patience for silly questions. At least I’m not posting stuff that belongs in “that” thread, I guess?
The major concerns putting two implants near each other are physical proximity increasing risk of breaking, and RF interference / compatibility issues.
Putting two x-series 10mm apart is fine to alleviate the risk of breaking. However 10mm isn’t enough to generally provide enough space between transponders that will have interference problems. Putting a 125khz transponder 10mm from a 13.56mhz transponder is fine, but putting a NExT v2 that near a NExT or xMagic will be an interference / usability issue.
Do you think a flex near an x-series would have more or less interference problems than say an x-series by another x-series?
On the one hand, I’d imagine the greater range on the flexes could increase the interference, but I also know antenna shape is important, so perhaps two similar implants would sort of cross-connect and interfere that way?
I think I should quantify interference better. Almost every high frequency transponder is capable of anti-collision. That means they will never actually interfere with each other, by design these types of transponders can all exist in a reader field at the same time. There is much bellyaching by me on this forum about how applications never take advantage of this feature and this is what causes the problem for high frequency transponders. A reader that reads both transponders will pass one ID and then the other to the application layer and typically the application will only care about the first. Because of this, transponders that are read basically simultaneously will randomly get picked as the first, resulting in inconsistent performance.
Low frequency transponders rarely support anti-collision and will actually interfere with each other because they are both trying to “talk” at the same time and this will cause data collision errors and nothing will get through.
So to answer your question, if you put a flexEM near an x-series with a T5577 for example, chances are pretty good that a reader could read both and cause collision errors. The same would be true for two high frequency devices but performance would be impacted for a different reason (poor application support for multiple transponders in the field at the same time)
Basically yes In theory you could detune implants by placing them too close together such that communication of any kind with the reader would be impossible, but that would actually require placement that would basically cause them to overlap… and even then the impact would be pretty negligible unless you got it just perfectly aligned.
So not too derail the main topic about collisions with x-series but I remember an ages old thread about interference with x-series and magnets like the Xg3 nearby but I can’t remember if it helped or hindered and what the rule was with that.
I imagine two magnets need even more room to prevent pulling each other closer… 5 cm may have been mentioned before? I might be imagining that…
I also vaguely remember someone theorizing that a magnetic implant could saturate the ferrite core on an x-series if it was too close, lowering performance…
That was @Satur9 who tested and saturating the ferrite rod, effectively magnetizing it, results in poor performance. The reason is that you want a magnetically neutral conductor of flux inside the coil antenna. Otherwise the magnetic field of the ferrite rod “will push against” (for lack of a better term) the flux coming from the reader while current is flowing in one direction, then pull the flux while the current is flowing in the other direction. Basically it kind of lopsides the field and you don’t get good performance. Thankfully it is very temporary because the ferrite rod does not hold it’s domains for very long.
Did some testing for another member who wanted to put an xG3 next to an Apex flex. It didn’t impact that implant. Not exactly sure how much it would impact an x-series, but yeah it would have to be right next to it to matter.
I ended up getting the NExTv2 in L3 and it didn’t suck anywhere near as much as I thought it would. Kudos (as always) to Patrick at Bound by Design in Denver.
I have a NExT in L0 and an xMagic in R0, and I’m getting a NExTv2 installed in a few days. Is it a bad idea to put the v2 at L1 if they’d end up being ~10mm apart? The issue I’m foreseeing with other locations on my left hand is that I can clearly see a vein under the skin at L2 and it may be difficult to tent the skin at L3.