Spectrum Analyser Output from XCVR2450

GNU Radio
1

I’m doing a bunch of testing on the USRP N210 with the XCVR2450.
In particular i’m looking at areas where there is odd behaviour at
extremes
etc and at trying to put it in context.

One thing i’ve started to notice is that as I step up the uhd gain the
readings I get on the spectrum analyser do not appear to linear.
Is this correct? E.g. if I go up by 10dB, I get about 7 or 8dB increase
in
the output measured. It of course becomes non-linear as it approaches
the
maximum of 35dB.

Another odd observation i’ve made with mine is that the power I get
coming
out of my J1 port is lower then that of my J2 port! About 30dB lower!
Is this normal? I hope I haven’t damaged my device in some way… :confused:

2

my J1 port is lower then that of my J2 port! About 30dB lower!

Are you transmitting out of your J1 port? 30dB sounds like cross talk
on a non-transmitting port.

One thing i’ve started to notice is that as I step up the uhd gain the readings I
get on the spectrum analyser do not appear to linear.

I’m not sure if this is exactly right, but it has been said before,
the USRP is not testing equipment, it is a radio, so the gains and
frequencies may not be perfectly calibrated.

3

Hey Andrew, thanks for the input!
Glad to get a sanity check :slight_smile: