I'm calculating the link budget for a rocket communication that reaches 3km altitude.
I'm using HopeRF RFM98W for both ends of the system. Max RF output: 20dBm Antenna Gain: 3dBi 3km FSPL at 433MHz: 94,72dB
After the receiver antenna gain we get: 20+3-94,72+3 = -68,72dBm
The RFM98W has a receiver sensitivity of -148dBm. We calculate the link margin:
-68,72-(-148) = 79,28
The link margin seems a little off. In the examples I saw, they get a link margin of around 8dB
I think I'm missing the cable RF loss here. I couldn't find any datasheets for the adapter board itself. I would like to calculate cable rf loss due to a 2mm wide 10mm long 0.5mm thick copper wire on a PCB.
Thank you for reading.
datasheet for the module and antenna: rfm98w: https://www.hoperf.com/modules/lora/RFM98.html antenna: https://www.rcscomponents.kiev.ua/datasheets/hp-433-3800n-datasheet.pdf