(3 Reviews)
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This 433 MHz transmitter/receiver pair is a very cheap way to get packet radio data from Arduino sensors. However, the transmitter unit in the photo has a problem. There should be a three-turn wire coil soldered between the second and third pins up from the bottom left. (The hole in the lower left is for a 17.3 cm (quarter wave) wire antenna. I recently bought some of these modules from another source that had the same problem -- possibly the same offshore source.
I soldered in a three-turn coil from 26 gauge phone wire and it works fine.
Also, on the receiver module, the hole in the upper right hand corner of the module is for the 17.3 cm receiver antenna. This hole appears to be soldered over -- not an insurmountable problem, but a bit of a pain. In some of the modules I bought from other sources, the right hand end of the three-turn wire coil was soldered into this corner pin, rather than the connected adjacent pin just to the left of the corner pin. Again, not an insurmountable problem, but one that makes it much harder to properly solder the wire antenna.
These modules are widely available online for as little as $2/pair. Unless you need lots of them, $3 is an OK price, but you will have to add your own coil to the transmitter.
I'm no electronics engineer by any means and barely a hobbyist, however I make the following observations.
Regarding the "missing" coil in the first review, yes, compared to other modules of the same nature found on the Internet, it is missing a coil. However, I have found that the modules work perfectly without it. The addition of a coil as described in the review may increase range but I have not tried that.
Regarding the need for a Ham Radio license to operate these 433MHz modules, you do not. Low power 433MHz transmitters fall under under the provisions of FCC Part 15.231 for periodic transmission (which permits operations at 433MHz).
| 10 + | $0.45 each |
| 100 + | $0.40 each |
| 100 + | $0.10 each |
| 1000 + | $0.085 each |
| 10 + | $0.45 each |
| 100 + | $0.40 each |
| 20 + | $1.50 each |
| 100 + | $1.15 each |
| 25 + | $3.76 each |
| 100 + | $3.53 each |
