Great! I’m very interested how others designed & part decision & layout, please post the result if you will.
I’ve also moved to TPS62061 which is pin-to-pin compatible to ETA3410…because I’ve ran out of that chip, glad that I found replaceable parts, ETA3410 is really hard to find even on Taobao.
My previous gateway is using L80 (like L70+GPS antenna built-in), but after some testing I found that liblora uses UBX protocol, so I change to MAX-7Q. I like L70 though, it have SAW filter built-in, good for small passive antenna, but too bad that liblora doesn’t support MTK’s GPS chip…
It will be on Tindle and files on Github later, I just sent the files to PCBA and ordering parts.
I have some parts left after dev though, so might be able to put a couple boards(<5pcs) on sell later this week.
And there will be 868Mhz version
I have a LNA between my gateway and antenna, but because of that transmission in the downlink is not possible anymore. I see some improvement in reception when I use the preamp even with my short coax used in my test(-indoor)-setup. I think a (filtered) preamp near the antenna, to compensate longer coax runs, would be a good thing, but this should have a bypass option for transmitting OTAA messages.
Do you also see any improvement in reception when using your LNA? In my setup I can clearly see some specific nodes with a higher SNR. With only two nodes I receive every 10mins I don’t have any statistics… yet…
The ability to bypass LNA is quite difficult, even if I can just put only a RF switch, it still have to some how bypass LNA which is at the other end of the coex. Maybe I can do this by putting a RF Relay which turn to TX mode when no DC input from coex, and turn to LNA when there is DC power in coex. But that will definitely adding more noise to the circuit.
I think putting two antenna but able to shutdown LNA is much easier?
Since I can shutdown LNA by closing Bias-T on gateway board.
For the comparison, I did have some test with high altitude ballooning, and it doesn’t really help much with the distance, I think that might cause by the fact that LoRa is able to pickup signal under noise, which makes LNA can’t help that much, since it will raise the noise floor, reducing the sensitivity of the system.
I am quite confuse though, if LoRa can pickup signal under noise, why adding noise? But either the LoRa node chip (SX127X) and most gateway board still having LNA. Really counfused.
I have some feedback on this board. I received my order two days ago and implemented a LoraWAN gateway using the board and a Raspberry Pi 2 board. Everything works perfectly.
The Rx levels (rssi) with this board is significantly higher by about 20dBm than what was received previously from same devices on a different gateway in the same location.
The SNR on the other hand has been a bit all over the place compared to previous values, from a single channel gateway, which were more or less +/- 1 of the same value. I cannot tell why yet. Are loraserver servers able to instruct node to adjust power? Below is a screenshot of the rssi and SNR covering before and after. A marker has been placed at the point where the first transmissions were received from the new gateway.
I intend to have this installed outdoors and conduct a range test.
