Dear USRP users, I wonder that how long a length of VERT2450 antenna inside plastic cover is. Currently, I am trying to measure channel matrix, channel state information (magnitude and phase of each OFDM subcarrier) of Wi-Fi. And also I am curious whether a length of VERT2450 antenna has an impact of measuring magnitude and phase of each OFDM subcarrier. (e.g., incorrect antenna length results in incorrect channel state information.) Frankly speaking, I am using not USRP, but only VERT2450 antenna. I am using it with connected to Atheros 802.11n Wi-Fi card. (ath9k series; AR9580, etc.) The last small question is,does a length of a cable, and shielding connecting VERT2450 and Wi-Fi card (or duaghterboard) have an impact on channel matrix? Regards, Jeon.

Good places to start reading and learning would be http://www.arrl.org/antennas <http://www.arrl.org/antennas> http://www.arrl.org/arrl-antenna-book <http://www.arrl.org/arrl-antenna-book> and there may be some good starting points here http://www.antenna-theory.com/ <http://www.antenna-theory.com/> For your particular topic, I’d start by reading IEEE journals as much work has been published on channel characterization. There you will find the answer to your last question is “yes”. Finally, it’s likely worth searching for theses and dissertations on the topic. I remember a few published back in the late 90s early 2000s by students at my university. Good luck. Steven Knudsen, Ph.D., P.Eng. www. techconficio.ca www.linkedin.com/in/knudstevenknudsen Der entscheidende Augenblick der menschlichen Entwicklung ist immerwährend. Darum sind die revolutionären geistigen Bewegungen, welche alles Frühere für nichtig erklären, im Recht, denn es ist noch nichts geschehen. - Franz Kafka > On Jun 14, 2016, at 06:43, Jeon via USRP-users <usrp-users@lists.ettus.com> wrote: > > Dear USRP users, > > I wonder that how long a length of VERT2450 antenna inside plastic cover is. > > Currently, I am trying to measure channel matrix, channel state information (magnitude and phase of each OFDM subcarrier) of Wi-Fi. > > And also I am curious whether a length of VERT2450 antenna has an impact of measuring magnitude and phase of each OFDM subcarrier. (e.g., incorrect antenna length results in incorrect channel state information.) > > Frankly speaking, I am using not USRP, but only VERT2450 antenna. I am using it with connected to Atheros 802.11n Wi-Fi card. (ath9k series; AR9580, etc.) > > The last small question is,does a length of a cable, and shielding connecting VERT2450 and Wi-Fi card (or duaghterboard) have an impact on channel matrix? > > Regards, > Jeon. > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

In addition to Steven's references, I'd like to add that yes, VERT2450 is really just a monopole. It *is* a good 2.4GHz WiFi antenna, but if you're looking for measurement antennas, it's definitely not the product of choice. Other than that: WiFi cards equalize heavily. I don't believe that even a very narrowband antenna would pose a significant problem for that. But yes, *everything*, including temperature, air moisture and connector pressure influence the channel matrix. The question is how you would measure that with something like a WiFi card, which is by no means a device meant for measurements, or with something as varying, fading, selective as the typical WiFi channel, short of using an anechoic chamber. Best regards, Marcus On 06/14/2016 03:14 PM, Steven Knudsen via USRP-users wrote: > Good places to start reading and learning would be > > http://www.arrl.org/antennas > > http://www.arrl.org/arrl-antenna-book > > and there may be some good starting points here > > http://www.antenna-theory.com/ > > For your particular topic, I’d start by reading IEEE journals as much > work has been published on channel characterization. There you will > find the answer to your last question is “yes”. > > Finally, it’s likely worth searching for theses and dissertations on > the topic. I remember a few published back in the late 90s early 2000s > by students at my university. > > > Good luck. > > > Steven Knudsen, Ph.D., P.Eng. > www. techconficio.ca <http://techconficio.ca> > www.linkedin.com/in/knudstevenknudsen > <http://www.linkedin.com/in/knudstevenknudsen> > > /Der entscheidende Augenblick der menschlichen Entwicklung > ist immerwährend. Darum sind die revolutionären geistigen Bewegungen, > welche alles Frühere für nichtig erklären, im Recht, denn es ist > noch nichts geschehen. - Franz Kafka/ > >> On Jun 14, 2016, at 06:43, Jeon via USRP-users >> <usrp-users@lists.ettus.com <mailto:usrp-users@lists.ettus.com>> wrote: >> >> Dear USRP users, >> >> I wonder that how long a length of VERT2450 antenna inside plastic >> cover is. >> >> Currently, I am trying to measure channel matrix, channel state >> information (magnitude and phase of each OFDM subcarrier) of Wi-Fi. >> >> And also I am curious whether a length of VERT2450 antenna has an >> impact of measuring magnitude and phase of each OFDM subcarrier. >> (e.g., incorrect antenna length results in incorrect channel state >> information.) >> >> Frankly speaking, I am using not USRP, but only VERT2450 antenna. I >> am using it with connected to Atheros 802.11n Wi-Fi card. (ath9k >> series; AR9580, etc.) >> >> The last small question is,does a length of a cable, and shielding >> connecting VERT2450 and Wi-Fi card (or duaghterboard) have an impact >> on channel matrix? >> >> Regards, >> Jeon. >> _______________________________________________ >> USRP-users mailing list >> USRP-users@lists.ettus.com <mailto:USRP-users@lists.ettus.com> >> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

Thanks to both of you for responses. I'll study and investigate on antenna theories. Regards, Jeon. 2016-06-16 3:05 GMT+09:00 Marcus Müller <usrp-users@lists.ettus.com>: > In addition to Steven's references, I'd like to add that yes, VERT2450 is > really just a monopole. It *is* a good 2.4GHz WiFi antenna, but if you're > looking for measurement antennas, it's definitely not the product of choice. > > Other than that: WiFi cards equalize heavily. I don't believe that even a > very narrowband antenna would pose a significant problem for that. > But yes, *everything*, including temperature, air moisture and connector > pressure influence the channel matrix. The question is how you would > measure that with something like a WiFi card, which is by no means a device > meant for measurements, or with something as varying, fading, selective as > the typical WiFi channel, short of using an anechoic chamber. > > Best regards, > Marcus > > > On 06/14/2016 03:14 PM, Steven Knudsen via USRP-users wrote: > > Good places to start reading and learning would be > > http://www.arrl.org/antennas > > http://www.arrl.org/arrl-antenna-book > > and there may be some good starting points here > > http://www.antenna-theory.com/ > > For your particular topic, I’d start by reading IEEE journals as much work > has been published on channel characterization. There you will find the > answer to your last question is “yes”. > > Finally, it’s likely worth searching for theses and dissertations on the > topic. I remember a few published back in the late 90s early 2000s by > students at my university. > > > Good luck. > > > Steven Knudsen, Ph.D., P.Eng. > www. techconficio.ca > www.linkedin.com/in/knudstevenknudsen > > *Der entscheidende Augenblick der menschlichen Entwicklung > ist immerwährend. Darum sind die revolutionären geistigen Bewegungen, > welche alles Frühere für nichtig erklären, im Recht, denn es ist > noch nichts geschehen. - Franz Kafka* > > On Jun 14, 2016, at 06:43, Jeon via USRP-users <usrp-users@lists.ettus.com> > wrote: > > Dear USRP users, > > I wonder that how long a length of VERT2450 antenna inside plastic cover > is. > > Currently, I am trying to measure channel matrix, channel state > information (magnitude and phase of each OFDM subcarrier) of Wi-Fi. > > And also I am curious whether a length of VERT2450 antenna has an impact > of measuring magnitude and phase of each OFDM subcarrier. (e.g., incorrect > antenna length results in incorrect channel state information.) > > Frankly speaking, I am using not USRP, but only VERT2450 antenna. I am > using it with connected to Atheros 802.11n Wi-Fi card. (ath9k series; > AR9580, etc.) > > The last small question is,does a length of a cable, and shielding > connecting VERT2450 and Wi-Fi card (or duaghterboard) have an impact on > channel matrix? > > Regards, > Jeon. > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > > > > _______________________________________________ > USRP-users mailing listUSRP-users@lists.ettus.comhttp://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > >