Receiving downlink packets (e.g join-accept) does not work

[dromero]

Hi all, I am trying to sniff downlink packets (e.g. join-accept) by using the FiPy device, but I am not able to receive any data.

As it is detailed here: https://www.thethingsnetwork.org/docs/lorawan/frequency-plans.html#eu863-870 I am using the "869.525 - SF9BW125 (RX2 downlink only)" frequency, SF and BW. (In order to do the tests I have another FiPy device, which connects to the TTN network (OTAA) and sends some UP packets repeatedly) - I have also tried to send some downlink packets from the TTN console.

Same tests were done with other UP frequencies such as 868100000 and it worked well. Do you know what I am doing wrong?

Thanks!

Code in use:

from network import LoRa
import binascii
import socket
import time

_frequency   = 869525000 
_tx_power    = 14
_bandwidth   = LoRa.BW_125KHZ
_sf          = 9
_preamble    = 8
_coding_rate = LoRa.CODING_4_5
_power_mode  = LoRa.ALWAYS_ON

lora = LoRa(mode=LoRa.LORA, frequency=_frequency, tx_power=_tx_power, bandwidth=_bandwidth,
    sf=_sf, preamble=_preamble, coding_rate=_coding_rate, power_mode=_power_mode)

print("[*] fq:%d sf:%d bw:%d" % (_frequency, _sf, _bandwidth))

s = socket.socket(socket.AF_LORA, socket.SOCK_RAW)
s.setblocking(False)

while True:
    response=s.recv(1024)
    if len(response) > 0:
        print("[*] Packet received: %s" % binascii.hexlify(response))
        response = ""