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Cake day: March 31st, 2025

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  • Mate do i have just the right thing for you, but it requires some soldering. It’s also probably cheapest solution working over longer range than you need

    First you need two directional antennas. Use this https://lea.hamradio.si/~s53mv/wumca/cup.html the 13cm design specifically. Design of the dipole element is on another page https://lea.hamradio.si/~s53mv/wumca/sbfa.html They’re using hard to get semirigid coax but you can really just use common RG178 with braid tinned to make it stiff. This way you don’t have to leave D section they way they did, you can just solder core to the shield at the end while preserving total length (or ~1-2 mm less, because wifi is slightly higher frequency; 53-52 mm total). That dummy cable thing can be just any stiff piece of wire. Good way to get this would be getting a pack of u.fl-SMA pigtails, which you can also use for connection.

    You also don’t need special aluminum housing like they do, cookie tin of the right size would be sufficient, or any other container of similar nature. If you can’t weatherproof it, putting it inside on windowsill is also fine

    Then, plug TL-WN722N into it, or some other single-antenna thing, and you’re set. This one connects over USB and has removable RPSMA antenna, so you can connect it easily with correct cable (SMA plug - RPSMA plug)

    to your new directional antenna. This thing works well over 200m distance, provided clear line of sight, and probably more than that



  • 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