With some metal dipsticks, for example, disposable dry cleaning hangers, you can build for free a Yagi antenna to receive UHF signals.
UHF Yagi antennas are the most common antennas... the roof TV antennas. Taking a look in an store you can find them with prizes from 15€. The problem is the frequency they are designed. Starting at 470 Mhz up to 862 Mhz. A little bit high for our purposes. If you want to buy an specific UHF 433 Mhz antenna then the prize increase to 50€ a 3 directors one, and the interesting for us, 5 or more directors are around 75€ to more than a hundred.
Now it's time to assemble and fix the Balun. In our cas the balun calculated by John Drew's software is a 4:1 with 228 mm distance.
And next step is to connect to the SDR and check it!