Microwave Plasma Chamber – Part 2 – RF Energy Shielding Primer

RF Shielding Primer

There’s a lot of in-depth overview random basic RF information. With that said I don’t mind getting into the details because this information will help keep me safe while I perform experiments in the future.

Magnetron
Magnetron

A magnetron generates large amounts of RF energy and emits that energy as an antenna pumped through a wave guide. Most microwaves transmit/operate at 2.45GHz. Unless something is wrong with your microwave or you have taken it apart like I will be doing the RF energy, 2.45GHz, transmission is contained within your microwave using a Faraday cage. On your right is an example of a crude Faraday cage. While crude this mesh size would probably be safe to use for 2.4GHz.

Photo from www.physics.montana.edu
Radio in a Faraday Cage photo from http://www.physics.montana.edu/demonstrations/video/5_electricityandmagnetism/demos/radioinfaradaycage.html

A microwave oven works by pumping a lot of RF energy into an enclosure where it bombards the molecules of food or whatever you have put in your microwave. This RF energy is not in a straight line but is guided through a wave guide then and then bounced off the metal walls of the inside of the microwave. The RF energy then vibrates the molecules which creates heat. This is like when you rub your hands together (friction) and they get warm but on a molecular level. What I don’t want is my molecules to get vibrated.

The Faraday cage is made up of the mesh in the window as well as the metal case which share a chassis ground. The mesh in the window blocks the the RF because the mesh size is smaller than the wavelength of 2.45GHz/2450MHz/2450000000Hz. If the mesh size is lower than the nominal wavelength the mesh should be effective. Look at the list below to see what the wavelengths in size is. For this project I plan on using the RF blocking glass that I obtained samples of from Viracon which is way different than a Faraday cage but same principle. You can see the article I linked to but I also included an image here.

  • Full Wavelength = 12.23643cm/122.3643mm = 0.1223643m
  • Half Wavelength = 6.118215cm/61.18215mm
  • Quarter Wavelength = 3.0591cm/30.591075mm

You can calculate the wavelength using the formula 𝜆 = c/𝑓 or 0.1223640816326531 = 299792000/2450000000

𝑓 = frequency in hz, = speed of light in mps 299792000, 𝜆 = Wavelength in meters

N5JLC is my math right?

So basically if my mesh is smaller than 30mm, if I’m right, I should be protected. I plan to use the glass but if needed I will use hardware cloth.

RF Meters

In order to protect myself and nearby electronics I want to monitor external and internal RF to ensure there is not leakage. RF Meters in general are not that difficult to build but ones that cover the 2.4GHz range require a bit more than a germanium diode and multimeter. In short you’ll probably see a 2.4GHz RF Meter project coming soon. Below are some RF Meter projects but if you know of any please let me know.

Frequency Spectrum Chart

Frequency Spectrum

Symbols and Values

  • 𝑓 = frequency in hz
  • c = speed of light in meters per second (mps) 299792000
  • 𝜆 = Wavelength in meters

Microwave Plasma Chamber – Part 1 – The Plan

 

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Sony Google TV Box Hack Research

Sony NSZ GT1
Sony NSZ GT1

This project is still in the first stages of research.

After waiting forever for Google to make negotiations successful and continue to workout bugs some media sources still do not work such as Hulu.

I have a Sony Google TV box model NSZ-GT1. My box has the 20120917 update installed which may not be possible to downgrade.

Hack process involves downgrading and installing modified update files.

Notes

Looks like someone leaked HC for the Sony NSZ-GT1

Quote:
This is a HC update with root for the NSZ-GT1 GoogleTV Bluray Player
http://www.multiupload.com/1SU4ZPXQP5

from: http://www.reddit.com/r/GoogleTV/comments/lilis/hc_update/

This build works great and contains root (if you remount adb).

Install Instructions:
1.) Download update and place on a thumb drive (at least 512MB capacity) in the root directory of the device.
2.) Plug thumb drive into NSZ-GT1.
3.) Enter Sony Recovery by first unplugging the power from the box, then while holding the power button plug in the power cable. Continue to hold the power button until the Sony Recovery menu displays.
4.) Choose “System update with USB” option (option #3).
5.) The device will ask you if you would like to upgrade, choose 1 for yes.
6.) The device will present a progress bar and will reboot when completed. (Do not turn off the box during this period)
7.) Enjoy HC on the sony NSZ-GT1

Thanks,
Zenofex

http://forum.gtvhacker.com/nsz-gt1/topic278.html?sid=de3418e15a95628fb2d66eb23d05bbaa

 

 

 

Turns out there is a check in place to limit browser and flash from accessing Hulu/CBS/NBC/ABC. (1)

Update.zip exploit (1)

package_list_;cd tmp; cd mnt; cd diskb1; sh t.sh; .zip
/package-updater.sh -l 0 -p /tmp/mnt/diskb1/package_list_;cd /tmp;cd /mnt;cd /diskb1;sh t.sh;.zip

“The command above involved a t.sh bash script (to meet filename size limitations) which spawned a shell over UART and telnetd. From there we proceeded to dump the recovery file system.”

Unfortunately this exploit was patched in the 7/2011 update

 

Reboot
Apply Update from USB (update.zip)
Wipe data/factory reset
Wipe cache partition
All update files provided are RSA verified before the box attempts installation

 

  1. DEFCON Xenofex Panel Hacking the GoogleTV