Yavuz Mert <yavuzmertt <at> gmail.com> writes:
>
> Hi,
> I have a problem setting tx power in osmo-trx. I debugged and found
that
> correct gain value is passed to uhd_device::setTxGain. But whatever
value is
> set to usrp_dev->set_tx_gain, usrp_dev->get_tx_gain(chan) returns -28
db.
> In uhd_device::setTxGain(double db, size_t chan) I put a printf to
see
> values.
>
> usrp_dev->set_tx_gain(db, chan);
> tx_gains[chan] = usrp_dev->get_tx_gain(chan);
> printf("Written %f, read %f\n",
db,tx_gains[chan]);fflush(stdout);
>
> Written 21.000000, read -28.000000
> Written 11.000000, read -28.000000
> Written -35.000000, read -28.000000
>
> But despite the read values, actually the power is somewhat changed. I
plugged
> TX1 to spectrum analyzer and set TX gain from -35 to 21 in 2 db steps.
Until
> -5 db the signal gradually increases, but from -5db to -3db it drops
down to
> lowest. Is there something I should pay attention while using higher
gain
> values. Meanwhile I do not play with RX gain or noise level, leave
them at
> default values.
>
> thanks
> yavuz
>
>
Hi,
i am facing the same issue, and have spend the whole day to find that
tx_gain value is not set no matter what. the output signal only
registers maximum of 1.6 dBm on watt-meter.
Temperature is not high so i doubt temperature is a problem. may be its
related to uhd driver? or tx_gain values not written to eeprom.
i might be missing some configuration option or trick. any help is much
appreciated,
thanks,
arif
