RC Submarine 5.0 – radio (6/10)

Now we need a radio control for the submarine. This is a challenging task because today everything uses 2.4GHz, which doesn’t penetrate water at all. My previous submarines used low-frequency radio boards cannibalized from Chinese toys. This time, I’ll try a more professional solution – old equipment from the 2000s, back when low-frequency radios were still used. Transmitter I bought a Graupner X-412 radio transmitter on Ebay. It cost 35 EUR. The main selection criteria in buying this transmitter was the 40 MHz frequency which should penetrate fresh water well (a few meters at least). Another possibility would have been 27 MHz, but those are harder to find. Note that 35 MHz is illegal in Finland for anything other than rc aircraft, so I couldn’t use that. The transmitter has 6 channels: 4 proportional sticks, an on/off switch, and a turning knob. That is more than enough for my submarine. The switch and knob will come in handy for controlling depth. The transmitter also looks really…