minus-squaresketchyenchantment@sh.itjust.workstoAmateur Radio@lemmy.radio•[Question] Metal Sign on Railroad Says "790Hz"linkfedilinkarrow-up14·3 months agoYou should check out this patent. When the train goes over a special section of track, it will trigger the signal at the nearby crossing linkfedilink
You should check out this patent. When the train goes over a special section of track, it will trigger the signal at the nearby crossing