Uplink, downlink rssi

part of my gw config file about tx_lut is below.
my network server gives downlink telling gateway to use 23dBm.
with below config, my gateway could transmit packet with 23dB right?
Or am i do something wrong?

“tx_lut_0”: {
“desc”: “TX gain table, index 0”,
“pa_gain”: 0,
“mix_gain”: 8,
“rf_power”: -6,
“dig_gain”: 0
},
“tx_lut_1”: {
“desc”: “TX gain table, index 1”,
“pa_gain”: 0,
“mix_gain”: 10,
“rf_power”: -3,
“dig_gain”: 0
},
“tx_lut_2”: {
“desc”: “TX gain table, index 2”,
“pa_gain”: 0,
“mix_gain”: 12,
“rf_power”: 0,
“dig_gain”: 0
},
“tx_lut_3”: {
“desc”: “TX gain table, index 3”,
“pa_gain”: 1,
“mix_gain”: 8,
“rf_power”: 3,
“dig_gain”: 0
},
“tx_lut_4”: {
“desc”: “TX gain table, index 4”,
“pa_gain”: 1,
“mix_gain”: 10,
“rf_power”: 6,
“dig_gain”: 0
},
“tx_lut_5”: {
“desc”: “TX gain table, index 5”,
“pa_gain”: 1,
“mix_gain”: 12,
“rf_power”: 10,
“dig_gain”: 0
},
“tx_lut_6”: {
“desc”: “TX gain table, index 6”,
“pa_gain”: 1,
“mix_gain”: 13,
“rf_power”: 11,
“dig_gain”: 0
},
“tx_lut_7”: {
“desc”: “TX gain table, index 7”,
“pa_gain”: 2,
“mix_gain”: 9,
“rf_power”: 12,
“dig_gain”: 0
},
“tx_lut_8”: {
“desc”: “TX gain table, index 8”,
“pa_gain”: 1,
“mix_gain”: 15,
“rf_power”: 13,
“dig_gain”: 0
},
“tx_lut_9”: {
“desc”: “TX gain table, index 9”,
“pa_gain”: 2,
“mix_gain”: 10,
“rf_power”: 14,
“dig_gain”: 0
},
“tx_lut_10”: {
“desc”: “TX gain table, index 10”,
“pa_gain”: 2,
“mix_gain”: 11,
“rf_power”: 16,
“dig_gain”: 0
},
“tx_lut_11”: {
“desc”: “TX gain table, index 11”,
“pa_gain”: 3,
“mix_gain”: 9,
“rf_power”: 20,
“dig_gain”: 0
},
“tx_lut_12”: {
“desc”: “TX gain table, index 12”,
“pa_gain”: 3,
“mix_gain”: 10,
“rf_power”: 23,
“dig_gain”: 0
},
“tx_lut_13”: {
“desc”: “TX gain table, index 13”,
“pa_gain”: 3,
“mix_gain”: 11,
“rf_power”: 25,
“dig_gain”: 0
},
“tx_lut_14”: {
“desc”: “TX gain table, index 14”,
“pa_gain”: 3,
“mix_gain”: 12,
“rf_power”: 26,
“dig_gain”: 0
},
“tx_lut_15”: {
“desc”: “TX gain table, index 15”,
“pa_gain”: 3,
“mix_gain”: 14,
“rf_power”: 27,
“dig_gain”: 0
}

why are you looking at the gateway side and not at the node ?
did you try a different node ?

@LoRaTracker
what do you mean by this??

:rofl:

you really don’t understand ?

From your previous comments you seem to know what an antenna is, so have your operated (or switched on) either unit without an antenna connected ?

I’m quite confused. when i test uplink and downlink of node and gateway, i always operate them with antenna attached. (why should i do without antenna?)

what i mentioned above is wired attenuator which emulate no path loss between node and gateway. when i connect RF sides with wired attenuator, the low RSSI problem on downlink still occurred. (although gateway emits downlink packet with 23dBm).

Because people do, accidently say while they are fiddling around or testing, power a unit on , when there is no antenna on the gateway or node. I have done it.

This can (but not always) damage the device when it attempts to transmit with no antenna. The symptoms of such damage are as mentioned earlier, extremly low power output.

You reported the node displaying -90dBm RSSI from the Gateway packets, suggesting the Gateway has extremly low power output…

what i mentioned above is wired attenuator which emulate no path loss between node and gateway. when i connect RF sides with wired attenuator,

Um, you direct connected the gateway and node RF sides, with what value of attenuator ?

@LoRaTracker
Hi, I tried another end node, however, the problem occurs again.
it seems gateway has some problem.

Below is the log of downlink packet (JOIN_ACCPET). it seems gateway transmit the packet with 23 dBm. I changed gateway board attached to raspberry pi, but same problem occurred.

JSON down: {“txpk”:{“powe”:23,“imme”:false,“tmst”:1128609155,“codr”:“4/5”,“datr”:“SF7BW125”,“freq”:922.5,“modu”:“LORA”,“rfch”:0,“ipol”:true,“size”:17,“data”:“IB1JQeZQg7GSF1647Yi3LDU=”}}
src/jitqueue.c:140:jit_enqueue(): Current concentrator time is 1123764767, pkt_type=0
src/jitqueue.c:117:jit_sort_queue(): sorting queue in ascending order packet timestamp - queue size:1
src/jitqueue.c:119:jit_sort_queue(): sorting queue done - swapped:0
src/jitqueue.c:452:jit_print_queue(): INFO: [jit] queue contains 1 packets:
src/jitqueue.c:453:jit_print_queue(): INFO: [jit] queue contains 0 beacons:
src/jitqueue.c:459:jit_print_queue(): - node[0]: count_us=1128609155 - type=0
src/jitqueue.c:318:jit_enqueue(): enqueued packet with count_us=1128609155 (size=17 bytes, toa=51000 us, type=0)
src/jitqueue.c:433:jit_peek(): peek packet with count_us=1128609155 at index 0
src/jitqueue.c:448:jit_print_queue(): INFO: [jit] queue is empty
src/jitqueue.c:362:jit_dequeue(): dequeued packet with count_us=1128609155 from index 0
INFO: tx_start_delay=1495 (1495.500000) - (1497, bw_delay=1.500000, notch_delay=0.000000)
INFO: Enabling TX notch filter
66.a0.0.43.45.2f.ac.c.0.97.11.10.0.8.0.0.20.1d.49.41.e6.50.83.b1.92.17.5e.b8.ed.88.b7.2c.35.end
INFO: [down] PULL_ACK received in 0 ms
lgw_receive:1155: FIFO content: 1 49 1 5 17
lgw_receive:1174: [2 17]
Note: LoRa packet

What was the answer to the question I asked earlier ?

the attenuator experiment is another thing.

in that experiment, problem still occurs.

attenuator can adjust path loss from -60dBm ~ 0dBm.

when i changing value of attenuator, uplink rssi seems reasonable, however downlkink rssi range is strange. (-130dBm ~ -90dBm)

So you connected the gateway and the node antennas together with a 0dB attenuator in place ?

hmmmmmmm … try reinstalling the gw software , I’ve read somewhere that you seems to have your own loraserver

  • I changed gateway board attached to raspberry pi, but same problem occurred.
  • Hi, I tried another end node, however, the problem occurs again.

strange and not very logical

i mean i changed gateway board with the same new device(RAK831).
i tried reinstalling gw software, however, not effective…

and i think lora server is not the problem as you see my gw transmit log above. it seems gw transmits a packet with no problem. (23dBm, SF7)

Have you ever checked downlink rssi from RAK831?
everyone has experience about uplinks, however, i guess they didn’t check downlinks.

how did you measure that on the RPI ?

why didn’t you try another node and repeat the same experiment ?

Whilst the software might claim to be transmitting 23dBm, you really need to know how much power is actually being sent.

indeed, that’s why I asked ’ how did you measure ’ that

downlink rssi could not be checked on the RPI side. it’s gateway side which sends downlink packet directly.

i measure downlink rssi from the node which receives the packet.

and i told you that i tried with another type of node which has sx1276, however, the problem still happened.

and if above happened, it should’ve shown different result when i changed gateway board with a new one, isn’t it?

Not necessarily.

You dont know for sure whether your seeing a hardware or a software problem.

but when i checked the quality of transmitter between two gateway device (RAK 831) (using util_tx_test), rssi value of received packet is good enough.

then it’s not cause of gateway device itself right?

uhm, guys… i don’t know why…

it just worked. I do not change anything but,
downlink rssi seems reasonable right now (-60~-80)

I did experiment for about 1 month, however, this problem was not configured.

But, today it seems fine. uhm, really strange.