"Impedance Matching" With Charvat And Ossmann - Recurring RF Remontados

Welcome back Michael Ossmann and Greg Charvat!

• Since we last talked to Greg, he has made many more media appearances.
• Engineering on TV shows continues to be a lame proposition. The auxiliary Mythbusters crew just got laid off. Joe Grand told us about the rigors of being on an engineering show when he was on The Amp Hour.
• Mike has started releasing videos in his SDR series. These are a supplement to the in-person 2 day classes he teaches at security conferences.
• Power and low cost requirements drove choice of no FPGA on the HackRF One (now shipping!).
• Greg has friends at the MIT Haystack observatory that have had doing similar SDR issues and don't hire FPGA programmers.
• Mike is planning to do some add-on boards for the HackRF; limpkin has already made some of these. The higher sample rates means you could see "farther" (up to 1Km) and more detail of things in the distance. This would also allow for range dopler imaging.
• Greg says that many Signal Processing PhDs talk about spacial frequency domain.
• Mike says he needs to buy Greg's book. You should too!
• Mike has been playing around with CW radar using "arduino radar" modules off eBay.
• Greg recommends instead using FMCW 24 GHz modules. One good example is RFbeam microwave K-LC1a, which cost roughly $5.
• The coffee can radar kit is currently avaiable from Quonset for $600. Lincoln Labs make one for their grad students and UC Davis are developing an Arduino shield.
• The Amp Hour (and Greg) recommend the upcoming kit of Tony Long, former guest of the show.
• Greg wrote a Circuit Cellar op ed about  the future of small radar tech.
• RADAR is seeing more use in the home. One example is a video game system shown by MIT Media Lab that can detect gestures.
• Mike gave a DEFCON talk about the NSA playset. This is the set of tools used for spying, many of which used RF retroreflectors.
• Greg recommended that Mike skips the cheap Chinese modules and instead get a surplus police radar unit. Another good choice is the hot wheels radar gun which surprisingly runs with a 10GHz chipset. Jeri did a video with the toy: https://www.youtube.com/watch?v=Dhp21FxttWM
• Mike has been trying spread spectrum for his retroreflector setup.
• There is a research paper about doing arbitrary quadrature modulations in a backscatter device. They discuss a simple passive device that is a MOSFET with an antenna. Awesome.
• Mike uses antennas from WA5VJB (Kent Britton). These are log periodic, PCB based, antennas that can go from 850 to 6500 MHz.
• Chris was embarrassed for not doing more with his USB TV tuner. Mike explained that many don't because they are lacking PAL connectors (which convert to SMA or BNC).
• Greg talks about how LabView is great for getting set up with quick experiments and validations. Chris used to use this in his FPGA DSP work.
• The HackRF will hopefully be used for derivative/add-on project.
  • Jared Boone (one of the HackRF team members) is working on the PortaPack. https://www.youtube.com/watch?v=koS-RobcKXI
  • There are people that are connecting the HackRF with the BeagleBone Black.
  • Mike is working on Filter/LNA board between HackRF and the antenna for extending filtering capabilities.
  • He also wants to possibly do a VNA board that could also do RADAR.
• Greg explains that a prior company he interned for made coversion boxes to make the HP8510 into a RADAR array.
• Mike used to get grant funding (which helped to develop the HackRF/Daisho) from the Cyber Fast Track program (which recently ended).
• Mike also used to work on the P25 digital radio at the Boulder lab of the Dept of commerce (they also do the atomic clock, wwv  & wwvb).
• All were a bit skeptical of the goTenna use cases, but were intrigued by the use of the MURS. This band is similar to the similar to FRS.
• We aren't completely sure about the goTenna but future filings about their FCC activity will be found on the FCC website.

Many thanks to Mike and Greg for returning to the show! It was great to get them together to hear brainstorming about how the coffee can radar kit and the HackRF might work together some day!

Thanks to the Poland MFA for the picture of the tower.