While 1.2G video is working very well for flying around obstacles, it also has own limitations. 2.4G video is somewhere in middle – small VTX, smaller antennas and good enough penetration, but unsuitable for flying in city (WiFi everywhere) and in meetings (2.4G RC adds a lot of noise even on 2370/2510 channels).
So, i moved back to 5.8G with some of my copters. Did simple RSSI-based diversity, added RX5808 modules to my HMD… Works good enough for everyday flying, but i noticed, that my friend can fly further using FR632 RX. LOS Range is acceptable for both, but he was flying further over obstaclesÂ and in buildings.
Long story short – started with 5.8GHz on mini FPV copter (pocket rocket quad), soon got another, tried 1.2GHz (see earlier videos here) and finally picked 2.4GHz for my video.
Things change with time, Lithuania now has #1 Wi-Fi coverage/speed in the world and now i found that 2.4GHz for video usually has lower range than old 5.8GHz setup. It still works fine in forests or far far away from populated places, but flying in city is next to impossible (for example, Vilnius Old Town, near UÅ¾upio KÅ«drÅ³ parkas – loosing video in 20m away from me, using 2370MHz or 2510MHz which should be away from common Wi-Fi range).
I had several RF heads – based on AD8317 (and working from PC), also based on AD8313 (you can get entire RF head assembled for ~20$ or so at https://www.sv1afn.com/projects.html) and decided that i need portable box for measuring signal levels and VTX power.
Did that, working well:
it’s actually very simple and entire box costs ~35$ or so (if you have basic parts and attenuators already). Accuracy is acceptable (+/- 1.5dBm in -10 … -40dBm range).
And no, it won’t work better than other tools (even RF explorer is much better with it’s -105dB+ range); it won’t do correct math for frequency (MCU is too weak to do proper calculations). So, if you need serious tool – go look for other solutions. If you need something cheap and working well enough to test antennas/TX/RX – it works good enough.
Got one CPATCH12… Looks OK, but pricey – i want to do large phased array, so i measured dimensions and will try to make it on other materials (original material – black FR4, probably requires some modifications if dielectric material changes).
Anyway, pics (with active part visible – i put microcontrast at max), dimensions (active part) and 3D drawing below.