Re: Radar Project - BladeRF2.0
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 > >
Re: Radar Project - BladeRF2.0
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
Re: Radar Project - BladeRF2.0
SDR based RADAR will be discussed at 6:30 PM European time as announced at https://2020.sdra.io/pages/programme.html The slides are at http://jmfriedt.free.fr/sdra_radar.pdf RThe reference on slide 17 explains how to switch LO frequency without stopping the data stream when using osmosdr. Not sure how it is applicable to the BladeRF. JM -- JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 26 rue de l'Epitaphe, 25000 Besancon, France June 24, 2020 3:04 PM, "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
Re: Radar Project - BladeRF2.0
Hi Dionisio, probably gr-radar [1] is a good starting point for that. Based on Ettus USRP though. [1] https://github.com/kit-cel/gr-radar Mit freundlichen Grüßen/Kind regards Sebastian Müller On Jun 24 2020, at 3:03 pm, 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 theFrequency 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 > >
