RX/TX separation for x40
Posted: Mon Jan 21, 2019 1:28 pm
Hi,
is there any specification with regards to RX <-> TX separation for the x40 board?
I have a setup where LNA is into RX and the TX goes into GNSS recevier - a commercial grade GNSS receiver that claims to have -160dBm sensitivity. With active antenna and additional LNA I can have up to 50dB of gain for GPS band - that would mean signals up to -80dBm at RX port (best case open sky signal strength for GPS is -130dBm). I don't see that the gnss module is able to sync when rx/tx are off, but the reported signal strength is non-zero - thus the question.
I have seen LMS FAQ p5.16 with TX -> RX separtion in terms of noise density @ TX dBms :
- from calcualtions it seems to be roughly 70db - is that correct? Would that mean that -80dbm on RX port could have -150dBm on TX? Getting more gain at RX would mean the risk of coupling the signal from RX to TX directly then?
thanks, best regards
is there any specification with regards to RX <-> TX separation for the x40 board?
I have a setup where LNA is into RX and the TX goes into GNSS recevier - a commercial grade GNSS receiver that claims to have -160dBm sensitivity. With active antenna and additional LNA I can have up to 50dB of gain for GPS band - that would mean signals up to -80dBm at RX port (best case open sky signal strength for GPS is -130dBm). I don't see that the gnss module is able to sync when rx/tx are off, but the reported signal strength is non-zero - thus the question.
I have seen LMS FAQ p5.16 with TX -> RX separtion in terms of noise density @ TX dBms :
So : -135dbm/hz @3.84Mhz -> 10^(-135/10) * 3.84e6 ->10*log10()-> -69dbm (band 1 is 2100Mhz)Band 1 -135dBm/Hz with TX output -2.2 dBm/3.84
- from calcualtions it seems to be roughly 70db - is that correct? Would that mean that -80dbm on RX port could have -150dBm on TX? Getting more gain at RX would mean the risk of coupling the signal from RX to TX directly then?
thanks, best regards