Absolute limit RF input power for Enterprise Gateway / Outdoor Gateway RAK7249

(Markus K.) #1

Dear RAK team,

I have a question for “DIY Enterprise Gateway / Outdoor Gateway RAK7249”.

What is the maximum allowed RX input power (dbm) to the gateway from the LoRA antenna?

Does it depend on module used? We need to make sure the gateway is protected from excess energy of nearby senders.

Thanks in advance!

(Vladislav Yordanov) #2

I can not give you a precise number, but I would be very surprised if you manage to overload it.
Considering it can output 27dBm and normally you have somewhere around -100 dBm RSSI, I would say you will need to have all the LoRa nodes in the world in a box on top of the gateway :slight_smile:
Jokes aside, how many nodes are you considering of deploying and how close ?

(Markus K.) #3

Hi Hobo,

thank you. Yes that’s exactly the problem, mostly you have an RSSI of -100dBm or less. But if you have a nearby (5m distance = 45 dB path loss) device transmitting at +22dBm, you could easily overload your receiver with -23dBm of power! And that is without any antenna gain. I have seen a gateway from an other vendor damaged in practice already. So we need to protect our gateways from accidental or malicious damage.
I have already contacted RAK, and they will respond in this forum thread what the receiver limits are so we know what steps to take for the gateways.

(Vladislav Yordanov) #4

Hi @kwinz,

This is indeed very good to know. Still I am curious what is your setup, that you have so many devices so close. I have had nodes literally sitting on the gateways with no issues by the way.

(Markus K.) #5

Ah that’s a good point that you have done that already and nothing happend to your gateway.
Well as I said it’s either from accidental damage (you have a higher power transmitter on you and you walk directly at the antenna) like when you do maintenance or demo. Or someone bad purposely sabotaging your gateway. I really need an official answer from RAK with the exact data and not anecdotal evidence. Thank you though for trying to help.

(Jeff.Wang) #6

Dear Kwinz,

The maximum allowed RX input power (dbm) is about -7dBm which will damage the device.Usually, you can’t get so large RX input power at antenna port unless you connect sender by RF cable directly without attenuators.

(Markus K.) #7

Dear Jeff,

understood. Thank you very much for that information. Very helpful!