Super cheap LoRa node with PCB antenna

Finally I finished my LoRa node PCB layout. It’s simple, very small size and very cheap, with PCB antenna on 868 MHz. Compatible with FT232RL FTDI USB To TTL Serial Converter. There is the I2C pin header to.

LoRaNode-View

Schematic can be found here

All source files here:

I will be happy If you have any suggestions.

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see also the solar version :wink:

Yep, that one needs little bit more components and it’s larger, but you can benefits from all-in-one solution. This one is more versatile…

tnx, do you sell the complete boards or PCB 's ?

Sorry but no. I realized that my soldering skills degraded very rapidly during few years. So I’m happy when I can finished my few PCB. But especially this PCB is easy to solder, so you can definitely manage this alone :slight_smile:

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S11 Measurement shows that antenna is pretty good even without any matching circuit…
LoRaNode-S11

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How effective is the PCB antenna as a radiator though, in terms of radiated power how does it compare with a standard 1/4 wave vertical with radials ?

I thing in theory there is no big difference between this and 1/4 lamda wire antenna. But simple wire antenna can change its parameters very dramatically according to size of grounding plane, antenna position and encapsulation. Another big question is repeatability in manufacturing process. PCB antennas have smaller dimensions, are much more stable during the time and are very low cost.

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Very cool @riske! Nice job.

In real world tested performance (RSSI / dropped packets at distance) have you found this antenna comparable with a 1/4 lambda wire antenna? What resources did you use to come to this design? I’m looking to create something for 915Mhz.

For 915 Mhz you need only to shorten the last antenna segment to 1mm :wink: :
http://www.ti.com/lit/an/swra228c/swra228c.pdf

Great! And how have you found the range performance (compared to a wire antenna or another familiar design) in a real world scenario?


The maximum gain of monopole antenna is 2 dB. But this value can be achieved only with infinite grounding surface. Very small surface decreasing gain and most important the resonance frequency. So in best case scenario you can achieve 0 dB gain without resonance frequency shift. PCB antenna counting with finite grounding plane, so i have much better and repeatable results.
But it’s true that I doesn’t test it, so when somebody can achieve better results with wire antenna I will apologize him :wink:

My first comment, and first project viewed.
Are you planning on creating a PCB with the option of an SMA/MMCX/IPX connector for the antenna?

Welcome moonlit :wink:
Actually no. I think for you perfectly fits hallard’s PCB:

I just added 5 more GPIO’s and push button:

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Simply great, thanks! It might be nice to make an identical, larger version with only through hole components. That would make it really accessible to a large group.

I was afraid of doing SMD, but now that I’ve tried I find it actually easier than PTH – at least up to 0805 (I’m too old for 0603 and smaller :wink: )

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I added LED and mounting holes. I’m pretty happy with this configuration so i don’t plan to improve this design anytime soon. But good ideas are always welcome.