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    Drones, RF, Robotic, Electronic, Programming, Networking and Forensic...

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madhak's Achievements


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  1. lol, sorry about that read too fast, just going trought tons unread post since my last visit try this command: modprobe usb-storage did you tried booting with the key in? also try reformatting the key, I know it should detect it regardless of formatting but sometime that help on some usb key
  2. Every BIOS is different, its usually in the advanced tab, google is your friend: "how to enable usb legacy support in bios" will get you going, if it doesn't work add your bios version to the querry.
  3. Try to set your BIOS usb mode to legacy
  4. Hi again, About the antenna separation distance well the further they are the better but its really just a matter of how precisely you can calculate the angle, for example, our eye are capable of evaluating the distance of anything at lest than 100m yet they are spaced less than 10mm, everything further are difficult to assess the distance, if you increase the separation distance you can calculate further distance. Regarding 3D map, I plan to use google map, most of the building in Montreal are mapped in 3D but for my application i'm only interested in the 2D plot. Cables is the biggest killer here, keep them short, put the receiver unit as close as possible to the antenna and run USB cable instead of Coax... I usually put a 10" patch from the antenna to the RX or DX then I run longer cable from the processed signal to the computer. I like this one: http://www.dpcav.com/xcart/SMA-to-SMA-Patch-Cable-Semi-Rigid-RG-402-Coax.html Regarding my own project well it started with this, cost me about 2K... http://madhak.com/?p=499 I abandoned the project after testing the 1st units I was getting good result but its very complicated, bulky, heavy and expensive so I went an other route http://madhak.com/?p=931 This one cost about 500$ and I can make 4 for the price of a tracker. My main goal is to plot a heat-map of the RF spectrum across different band and time to find path where I can maximize the operation of drone. I found that my range vary greatly depending of the location an time of day so with this tool i'll be able to plan my path in order to maximize the RF range while staying at low energy RF, I do have huge booster that can go hundred of kilometer but I have a feeling that the CRTC (Canadian equivalent of FCC) will be knocking at my door soon, so staying at 100mW is my goal, to do that I need distributed relay and RF site survey.
  5. One of the tool I mentionned decrypt the .jar .APK =>APKTool => DEX2JAR => jd_gui(JAR Decrypt) => SRC I've done it a few time, at first I was frustrated the .xml file in the src tree would not decrypt but In was doing it wrong ;)
  6. Hi, using the drone batterie would introduce a lot of electrical noise in the Pineapple and the SDR which is really bad for RF application. Since drone flight time is pretty limited, pretty mutch any battery size will do, look for a Lipo 3S 300mAh~1000mAh http://www.hobbyking.com/hobbyking/store/uh_listCategoriesAndProducts.asp?idCategory=86&LiPoConfig=3&sortlist=&CatSortOrder=desc
  7. Android APP can easily be decompiled, modified and recompiled, although it wont be seen as a trusted app but you can disable the trusted app check, not sure about the other platform... not an iFan and I ditched blackberry before the APP revolution... For android, you need those tools: - apktool - dex2jar - jd-gui You will find the instruction as you search for those term... You can also interact with most APP from your own APP, in android each screen is called an activity, you can call other app activity from your app and get them to return you some data but as for modifying existing app you can also override their code base too by creating an @override class of the same name as the class of the APP you want to modify... check the tutorial on android, not that hard and really worthwile today...https://developer.android.com/training/basics/firstapp/index.html?hl=it I guess other platform are similar since they all use Java but I never needed to work on these yet.
  8. Yep. that's why I have implemented WPA2 with Radius auth for my Hotspot AP... I was getting a lot of complain about user not being able to login while our system said they were loged in and being charged for... Now they login to WPA2 as guest, purchase internet access using encrypted channel, then the portal send a WISPr message to the device which contain their personal WPA2 credential,... please hack that guy, you are the reason I have a job lol ;)
  9. Hehe, good one Sebkinne, I just found how you knew yet didn't watched lol
  10. Here's the test flight of a miniature Predator Drone, very impressive! https://www.youtube.com/watch?v=I8s2J4CMQYw
  11. LOL, my advise, NEVER use IE hehehe
  12. Hi Swaggie, that's an interesting link you got there. Sorry if I kept insisting about the Dual WiFi antenna setup, I assumed you focused on the end result more than the learning experiment itself... If you want to learn RF please do, its a fascinating world but I feel you still have a lot to learn before tackling such project. First you have to understand how radio frequency work, a good analogy I like to use is water wave, RF are essentially wave so once you understand that concept you will be able to visualize the type of antenna you need. the way a parabolic antenna work can be easily visualized in a pool, then you hit the water, it will make wave, when wave hit the curved side of the pool they will bounce and the wave will converge at a specific point, at the convergence point the wave will be higher then anywhere else, that's what parabolic antenna do, they take a faint wave and focus it in a narrow point so its easier to extract the information the wave contain because it stand out more than the background noise, which can be visualized as all the little random wave that wander around the pool... So essentially you want to have a dish as big as possible to capture as much of faint signal as possible, larger the better. The reason grid antenna work is because radio frequency have much larger wave length than visible light, while visible light can pass trough the space between the grid, RF frequency cant and as far as they are concerned its a solid surface as long as the spacing between the mesh is inferior than the wave length. Wavelength; the lower the frequency, the longer the wavelength, this is also why a FM Radio antenna is much longer than a WiFi antenna. wavelength is the distance between each peak of the wave, you can only carry information on those peak so the more peak you have the more bandwidth you have, higher frequency = more bandwidth = more information. So for each different frequency you will want to monitor you will need a different antenna, if you go to higher frequency like 5.8GHz and above your dish reflector will need to be more opaque, because your are getting closer to visible light, for example a satelite TV dish is solid, because it work at 20GHz, if it was a grid the hole would need to be very small, the only reason they use grid antenna when possible is because if has better resistance to wind. You can use a 20GHz parabolic dish to capture lower frequency but not the inverse. Now about distance, there's no such thing as a distance in RF, only dB, because the distance will depend on the transmitting power, attenuation (mountain, building, fresnel), background noise (interference). In the best case scenario, distance is equal to the square root of the ERP (effective radiated power) which is a composite of power and gain, that's why its much easier to talk in dB where for every 3 dB you double the distance... But again, that distance is relative here, not absolute so we cant talk in meter, just in dB... dBi are different than dB, dB is how strong the signal is, dBi is how much the signal is focused... Note that strong (dB) is not equal to loud (W), W make it loud, but just because you turn the volume up doesn't always mean you will hear better, just like speakerphone doesn't make the conversation better, even sometime worst, that's why booster are not so effective. I could probably go on forever and end up writing a book lol but here's a few link to get you going; First, study the HAM resources: http://www.qsl.net/aa0ni/toc.html Also, understand the spectrum: http://en.wikipedia.org/wiki/Electromagnetic_spectrum Then antenna theory: http://www.antenna-theory.com/ More RF stuff: https://www.youtube.com/results?search_query=how+radio+wave+work Understand what is a Photon: https://www.youtube.com/watch?v=aAcDM2ypBfE After that maybe a bit of quantum physic, at least the basic stuff, what is a field, photon, electron, youtube have a lot of visual explanation If you have any specific question I will be happy to help you.
  13. The reason the quadrifilar work so well with satellite is because of the polarization, non geosynchronous satellite rotate on themselves in space, if you have a linearly polarized antenna, like ALL wifi antenna then you get 100% polarization match 1/4 of the time, and 50 % 1/2 of the time and 0% 1/4 of the time. Also this effectively mitigate multipath problem as the reflected signal reflected from a mountain will arrive out of phase but also out of polarization, so it negative effect will be lowered. To efficiently communicate with satellite, circular polarization is required, but if you listen to a wifi signal with a circularly polarized antenna then the same limitation apply as above so you wont get good signal http://sv1bsx.50webs.com/antenna-pol/polarization.html http://en.wikipedia.org/wiki/Circular_polarization
  14. - Any parabolic shaped metalic structure with gap between element less than 1cm will work, bigger overall shape the better, make it a 25m large dish and reach the moon, literally - Down-converter use active component in the process, they always require some sort of power, for MMDS they get their power from the receiver STB unit when normally used for digital TV - Servo, hum what to say, you don't really need a tutorial on that, with a USB servo driver you just have to tell the position that the servo should move to the desired position, a 180 degree servo will be at 0 degree with value of 0 and 180 degree with value of 1024... How they work doesn't mater, lest assume its magic for now. - Regarding bandwidth well a downconverter will not loose information, its just the carrier that change so instead of having your signal traveling a 2.4GHz carrier it travel a 900mhz carrier, however to represent the same information on a 900mhz carrier you need more bandwidth so a 20MHz bandwidth on a 2.4GHz carrier will take about 60MHz on a 900MHz carrier. The biggest problem is the SDR that is capable of tuning to only 2.5MHz of bandwitdh at a time, but thats enought to grab a mac address of the header of a frame but not a full frame. Again if your goal is truly to sniff WiFi devices then a dual WiFi radio with directional antenna is WAY WAY WAY more simpler and cheaper...
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