Re: [Discuss-gnuradio] IQ imbalance...

[Matt Ettus]

On 04/11/2010 11:09 PM, Ian Holland wrote:
> Hi Matt
>
> Can you please confirm by input level you are referring to the input to
> the transceiver daughterboard? I am using the XCVR2450, for over-the-air
> reception. The input level (to the XCVR2450 at the receiver) would have
> been roughly:
>
> Tx Power (max. 20 dBm as per
> http://www.ettus.com/downloads/er_ds_transceiver_dbrds_v5b.pdf) + Tx
> Ant. Gain (3dBi) - Free Space Loss (at least 46dB for 2m separation and
> 2.4 GHz freq.) + Rx Ant. Gain (14 dBi)
>
> As far as I can tell based on the above (presuming the 20 dBm transmit
> power is based on max. gain setting for the Transmitting XCVR2450), the
> largest signal I could have at the Rx port after the Rx antenna is:
>
> 20 + 3 - 46 + 14 = -9 dBm
>
> So, if this is the case, I presume all was safe regardless of the chosen
> Rx gain setting for the receiving daughterboard.


Yes, -9 dBm is safe.

> Can you please confirm if this would be the case, as I am encountering
> inconsistent behaviour with my equipment (such as the unrepeatable error
> mentioned earlier, and occasional fails to lock at 5 GHz without first
> trying to lock to a much lower frequency).

I have not seen the problem locking without trying a lower frequency. 
What if you try 5 GHz twice in a row?

Matt