4 ms·
Steel is bad as an electrical conductor as its much higher than copper internal resistance would waste a lot of power. I don't know if the military still use wi
by squarefoot 4y ago
Steel is bad as an electrical conductor as its much higher than copper internal resistance would waste a lot of power. I don't know if the military still use wired field telephones, but in case they do, the field phone wire is excellent. It won't sustain lots of current, but if you're OK with a few amps, then that cable is sturdy, water and oil resistant and it has both copper and steel core, the former working as good electrical conductors and the latter making it extremely hard to break. It's also very good for building low cost emergency long wire antennas, dipoles, etc.
- sa46 4y agoAround 2014 or so, we (light infantry) had field telephones on the books, but we only used them once for a field exercise to practice assuming all modern tech was down.
- H8crilA 4y agoWW2 stories of diversions to enemy communications: put small needles through the cable. At first you'd think you just have to cut the cable, but that actually makes it very easy to find and fix the problem. Small needles that short the wires are very difficult to locate. Unless you have a fast device that measures return latency on the shorted circuit, but that wasn't available in the 1940s.
- bradknowles 4y agoIt's called a Time Domain Reflectometer. They're pretty cheap. For RG-58 style coax, you can get hand-held VeEX CX41 units for a few hundred dollars. I'm sure that TDRs for other types of cables shouldn't be too much more expensive.
- jutrewag 4y agoPerfect time to use a pin nailer.
- tonyarkles 4y agoCustomers used to do this unintentionally with staples, and my boss was too cheap to buy a TDR tester for a long time
- tialaramex 4y agoHowever "a fast device that measures return latency on the shorted circuit" is presumably very cheap today. 20+ years ago, rewiring buildings for 1000baseT the Cisco switches (3650s maybe? 3750s? I know they had IPv6 multicast acceleration in the switch fabric because that's why we had them) would do this for any circuit on command, OK, 18 metres from here there's a fault, pace, pace, pace, I reckon it'll be up on this cable tray... yup, some fool tried to "repair" a broken Cat5 cable, we'll just rip it out, meanwhile patch to a different circuit.
- sandos 4y agoI believe I even had a BIOS in a PC that did this in some way.... Actually, I think it wasn't detecting faults but rather the length of cable connected.
- jmole 4y agoTime Domain Reflectometry - https://community.cisco.com/t5/networking-knowledge-base/how-to-use-time-domain-reflectometer-tdr/ta-p/3119327 https://community.cisco.com/t5/networking-knowledge-base/how...
- cjbgkagh 4y agoYou can use binary search to find the pin. Unless two or more pins are used.
- UncleEntity 4y agoWe used field phones all the time when I was in light infantry (82nd Airborne). Pretty much any time we were in a fixed position out would come the commo wire so as to not give our position away. They even went as far as having us string wire out to our ambush sites when we were on the Iraqi border during the first gulf war and reel it back up when we came in. Zero radio signals out there because they didn’t want them to know that a whole division plus French armor was there. Modern tech is good and all unless you have some dumb Joe that keeps erasing the codes out of the radio by turning on the truck without putting it on standby or something…never quite figured that one out.
- sa46 4y agoAll the way! I was 1-505 PIR. > dumb Joe that keeps erasing the codes out of the radio by turning on the truck without putting it on standby Oh man, I have nightmares about comms. Juggling frequencies while traversing areas of operation, trying to get satcom working in mountainous terrain with jammers, and depending on the finicky windows-tablet encryption device, was not a fun time.
- noduerme 4y agoFrom the fact that the writer said his concrete house was not meant to be habitable without power, I suspect he means to run an air conditioner.