no data running on 433MHz

[mogyoros]

Dear Pham!

Thank you for all your efforts to share your experiences with LoRa technology. Using the provided documentation and software I managed to create a working setup on 868MHz with a RPI3+connection bridge+Libelium SX1272 module as gateway, and arduino UNO + multiprotocol shield+Libelium SX1272 module as node. Using the LM35 temp sensor I was able to send data to thinkspeak.

Now I wanted to make a trial on 433MHz with different radio modules, and followed this guide. On the gateway side I have changed the antenna, and tried to compile the lora_gateway.cpp with #define BAND433 option, but that failed. Going through the library, I see the 433MHz options are missing. I am using the RPI jessie image that is published on the webpage. So I downloaded the git version and using the gw_full_latest to run the gateway.

root@raspberrypi:/home/pi/LowCostLoRaGw/gw_full_latest# make lora_gateway_pi2 g++ -DRASPBERRY -DRASPBERRY2 -DIS_RCV_GATEWAY -c lora_gateway.cpp -o lora_gateway_pi2.o g++ -c arduPi_pi2.cpp -o arduPi_pi2.o g++ -DRASPBERRY2 -c SX1272.cpp -o SX1272_pi2.o g++ -lrt -lpthread lora_gateway_pi2.o arduPi_pi2.o SX1272_pi2.o -o lora_gateway_pi2 rm -f lora_gateway ln -s lora_gateway_pi2 ./lora_gateway root@raspberrypi:/home/pi/LowCostLoRaGw/gw_full_latest# ./lora_gateway lora_gateway lora_gateway_pi2 root@raspberrypi:/home/pi/LowCostLoRaGw/gw_full_latest# ./lora_gateway SX1272 detected, starting. ... ^$**Power ON: state 0 ^$Default sync word: 0x12 ^$LoRa mode 1 ^$Setting mode: state 0 ^$Channel CH_0_433: state 0 ^$Set LoRa power dBm to 14 ^$Power: state 0 ^$Get Preamble Length: state 0 ^$Preamble Length: 8 ^$LoRa addr 1: state 0 ^$SX1272/76 configured as LR-BS. Waiting RF input for transparent RF-serial bridge

Seems everything ok.

On the node side, I have 2 arduinos, 1 nano (SS connected to PIN D10) and 1 uno (SS connected to PIN D2) chinese clones, and SX1276 (actually 1278) LoRa modules, also from china. Using the ping-pong template (#defined BAND433) the module starts fine, but no data is received on the gateway:

Simple LoRa ping-pong with the gateway Arduino Nano detected SX1276 detected, starting SX1276 LF/HF calibration ... Setting Mode: state 0 Setting Channel: state 0 Setting Power: state 0 Setting node addr: state 0 SX1272 successfully configured --> CAD duration 550 OK1 --> waiting for 1 CAD = 62 --> CAD duration 549 OK2 --> RSSI -127 Sending Ping wait for ACK

But if I change both gateway and node side to BAND866, the communication is established! (with a very bad SNR of course, due to the transmitter module is designed to operate on 433). Also tried to run the gateway with --freq 433.3 option, but does not help. Any idea what am I missing, since I am lost a bit now? Thanks. Kind regards, Tamas

[mogyoros]

Ok. I was to lame... SX1272 operates on High Band (860 - 1020 MHz) frequencies, while SX1278 is running on Low Band (137-175 & 410-525 MHz) frequencies only! So yes, reading is always good before you buy something, SX1276/77/79 the one which is capable of running on both bands. The strange thing still about the SX1278 is that, when configuring to operate on 868 MHz, it can produce a reasonable transmit power using PA_BOOST to be able to transmit data as a node. But when operating as a receiver on this band, it really fails... Anyway, case is to be closed, solved myself

[CongducPham]

OK, great to hear that the issue was found. The design of the radio module, apart from the SX127X chip itself has great impact on the radio capabilitie as well, so issue like the one you describe may be explained by how the various amplifier lines are wired.

Wish you great success for your projects.

regards,

Le 10/02/2017 à 18:28, Tamás Mogyorósi a écrit :

Ok. I was to lame... SX1272 operates on High Band (860 - 1020 MHz) frequencies, while SX1278 is running on Low Band (137-175 & 410-525 MHz) frequencies only! So yes, reading is always good before you buy something, SX1276/77/79 the one which is capable of running on both bands. The strange thing still about the SX1278 is that, when configuring to operate on 868 MHz, it can produce a reasonable transmit power using PA_BOOST to be able to transmit data as a node. But when operating as a receiver on this band, it really fails... Anyway, case is to be closed, solved myself

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C. Pham.

--	------------ Congduc PHAM - Professor --------------------------		LIUPPA - Equipe T2I	U.P.P.A. Pau		http://liuppa.univ-pau.fr/	http://www.univ-pau.fr
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[6xdd]

Hello @CongducPham ,I use the sx1278 in the 433MHZ is ok,Now I would like to use 470MHZ how to modify the program? Thanks ～～

[CongducPham]

Just add a statement such as:

const uint32_t CH_470 = 0x758000 // 470MHz

and use this frequency for the end-device.

In the gateway, edit gateway_conf.json to have "freq" : 470.0

regards,

Le 15/05/2017 à 09:34, liuxiaodong a écrit :

Hello @CongducPham https://github.com/congducpham ,I use the sx1278 in the 433MHZ is ok,Now I would like to use 470MHZ how to modify the program? Thanks ～～

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C. Pham.

--	------------ Congduc PHAM - Professor --------------------------		LIUPPA - Equipe T2I	U.P.P.A. Pau		http://liuppa.univ-pau.fr/	http://www.univ-pau.fr
UPPA, LIUPPA laboratory, UFR Sciences et Techniques
Avenue de l'Université - BP 1155
64013 PAU CEDEX, FRANCE
phone: [33] (0) 5 59 40 75 94
fax: [33] (0) 5 59 40 76 54
Congduc.Pham@univ-pau.fr http://www.univ-pau.fr/~cpham
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[6xdd]

Thanks for your help,i can use 470MHz to send and receive data,but I have some questions，Why is communication so close？How should I adjust the parameter to a greater distance？ Thanks @CongducPham

[CongducPham]

Range depends on many factors (antenna, cables, placement,...), so hard to tell, regarding the lora parameters, so-called mode 1 with bw=125kHz and SF=12 normally provides the lowest sensibility thus the longest range.

regards,

Le 16/05/17 à 03:14, liuxiaodong a écrit :

Thanks for your help,i can use 470MHz to send and receive data,but I have some questions，Why is communication so close？How should I adjust the parameter to a greater distance？ Thanks @CongducPham https://github.com/congducpham

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C. Pham.

--	------------ Congduc PHAM - Professor --------------------------		LIUPPA - Equipe T2I	U.P.P.A. Pau		http://liuppa.univ-pau.fr/	http://www.univ-pau.fr
UPPA, LIUPPA laboratory, UFR Sciences et Techniques
Avenue de l'Université - BP 1155
64013 PAU CEDEX, FRANCE
phone: [33] (0) 5 59 40 75 94
fax: [33] (0) 5 59 40 76 54
Congduc.Pham@univ-pau.fr http://www.univ-pau.fr/~cpham
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