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Cake day: March 31st, 2025

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  • the theoretical reason for doing that is that if you have to split jamming power over broader frequency range, then for every n^2 times increase in bandwidth, here number of channels, range decreases n times. however gnss signals are so weak, it probably doesn’t matter, and if you’re adding extra power per channel, then it doesn’t apply

    now if missile detects that gnss is fucked with (signal too strong, wrong direction, physically impossible location), the correct thing to do would be to fallback to inertial navigation while accepting that accuracy decreases until gnss can be received again, if at all, and acted upon. theoretically speaking, it’s a matter of software update, better hardware also can help with that, so idk why would they release this. maybe there’s something that prevents this












  • here if you need anything over certain power (6kW; depends on country i guess) you need a three phase installation, and even if you get single phase, it’s really handled as three phase split between single phase customers (a block gets three phase supply, then splits flats in three groups, each group gets connected to one phase). this gets supplied by a distribution transformer that might serve somewhere around 200 people per (in residential areas)

    i understand that sometimes americans also get distribution like this, with 208/120 three phase coming from substation, without 240v available









  • transformers are not the only way to do this, and some other circuits can be used instead. if you take a transformer with 1:2 winding ratio, then if on one side current is 1 and voltage is 1, then on the other current will be 0.5 and voltage 2, which means that impedance increases 4x. in EFHW, it’s 1:7 winding ratio and impedance ratio is 49x, which works for end-feeding a half-wave dipole, just as expected (from 50 ohm to ~2500 ohm). that transformer is a limitation on power usable in this antenna and main reason to use this type of antenna is mechanical

    most importantly, transformers work nicely only if you have real impedances, so your antenna has to be resonant anyway. l- or pi-network tuner will also handle complex impedances so doublet or random wire will work nicely with it, as long as you can accept weight and losses in tuner