Good morning, Thanks for all the information.
Regards Dionísio On Wed, Jun 24, 2020, 15:10 Doug <dmcgarr...@optonline.net> 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 > >
