Good morning,
Thanks for all the information.
Regards
Dionísio
On Wed, Jun 24, 2020, 15:10 Doug wrote:
>
>
> On 6/24/2020 9:03 AM, Dionísio de Carvalho wrote:
> > hi everybody
> > This is my fisrt message here. I am pretty new in the SDR world.
> >
> > I am intended to develop a Radar with BladeRF2.0 from Nuand.
> > Is anybody in this boat?
> >
> > I have some start questions that I will be grateful for any help:
> >
> > - How can I sweep the Frequency at osmocom-sink? any idea?
> > - How can I figure out the TX power? I am trying to measure an antenna
> > S21 parameter!
> >
> > thanks for any help
> >
> > Att
> >
> > Dionisio Carvalho
> > Sao Paulo University - Brazil
>
> It is not easy to get a valid measurement of antenna gain or radiated
> power. It is easier to design the antenna according to a published
> formula (i.e., plans) and use the gain figures provided by the
> originator. Be careful to observe whether the gain figure is in
> reference to isotropic or to a dipole. A dipole has 2.1dB greater gain
> than isotropic.
>
> (An isotropic radiator is a theoretical point-source that radiates
> in all directions--all points along a sphere surrounding it.
> Professional antenna engineers use the isotropic source as a
> reference point; radio amateurs tend to use a dipole as their reference
> value.)
>
> Now, measure the power out of your transmitter, with an appropriate
> power meter--a lab meter for power levels up to about 10mW (+10dBm) or
> a Bird or other higher-power meter for levels greater than +10dBm.
> (A lab meter can be used with suitable fixed attenuators of known
> value. Be careful not to overload the lab meter!)
> Then calculate the effective radiated power: RF power from the
> transmitter times the gain of the antenna. Use the same measurement
> units (db, dbm, Watts, numerical gain or dB gain, etc.) to find the
> ERP--effective radiated power.
>
> Values in dB or dBm are ADDED, not multiplied!
>
> --doug, WA2SAY, retired RF engineer
>
>
