Re: [Discuss-gnuradio] Variation in Tx power across USRPs

[Marcus D. Leech]

On 07/12/2016 06:15 PM, Pavan Yedavalli wrote:
> Hi,
>
> I was doing a quick test to see whether all of the USRPs are 
> transmitting at the same level, so I did a single setup where I 
> connected each USRP's Tx/Rx output to a spectrum analyzer (with 
> attenuations). After sequentially doing it, I am getting up to 5 dB of 
> variation across different USRPs. Is this expected?
>
> For instance:
>
> USRP1: -16.x dB
> USRP2: -19.x dB
> USRP3: -14.x dB
> USRP4: -16.x dB
>
> Note that I'm disconnecting the same cable and reconnecting to each 
> USRP, so that is constant, as well as the exact same code (with just 
> changing the address of each USRP). Should I double check some 
> connections or is this variation expected? It seems too high for it to 
> be expected. Please keep me posted. Thanks.
>
>
> --
> Pavan
Variability of a few dB is normal in RF gear, particularly as you go up 
in frequency.

Are these all the same types of USRP, with the same types of 
daughtercard, at the same frequency?