Popular Posts

Wednesday, December 23, 2009

Monday, December 14, 2009

Goofs For Die Hard 4 (Live Free Or Die Hard)

  1. Factual errors: The "police radio" in McClane's NYPD car (and a few other official vehicles in the film) was actually a ham radio. It was an ADI model AR-147 FM transceiver. It was tuned to 144.330 MHz which is an amateur radio frequency in the two meter band. Except for extraordinary emergencies, that band is not used for law enforcement communication.
  2. Factual errors: The frequency seen programmed into the NYPD unmarked cruiser police radio is 144.33 mhz. That frequency is assigned by the FCC to ham radio operators.
  3. Factual errors: The CB radio frequency is 66.6 but CB radio is in the 27MHz frequency. 66.6 would be in the broadcast TV portion of the spectrum.
  4. Factual errors: Downloading 500 Terabyte of data via USB connection would take at least 100 days, but in the film it takes less than 2 days.



Wednesday, December 9, 2009

How To Jailbreak iPhone 3GS

Geohot has released blackra1n. This is a 3.1.2 jailbreak for all devices: iphone 2g, iphone 3g, iphone 3gs, ipodtouch 1, 2, 3 (note: ipod touch 3 8gb users say this isnt working). It’s pretty easy. You just load the app and click the “make it ra1n” button and follow the prompts. Unfortunately, the ipod 3 and any iphone 3gs after week 41 is tethered which means if you reboot you have to run blackra1n again. (Note for iphone 3gs owners, check your week by looking at the 4 and 5th digits of your serial number).
As of RC3 you can now unlock your 3.1.2 iPhone with the sn0w option!
From geohot: So, what is blackra1n? blackra1n is a 30 second ALL device 3.1.2 jailbreak. Even the ipt3, but the ipt3 is tethered. In order to boot it, just rerun blackra1n. As far as donations go, they are much appreciated, but not until after blackra1n works for you.
To use: load the app and follow the prompts. It’s pretty simple. If you have problems, see troubleshooting section below the last step of the tutorial.

Step 1) Install blackra1n and iTunes 9 or newer.
Step 2) Close itunes and kill iTunesHelper.exe in taskmanager.
Step 3) Attach your device to your computer using the cable, and run blackra1n. You see this:




Step 4a) Hit the “make it ra1n” button. You will see this:



and this



and finally this. This step should only take a couple seconds. If it hangs on running you have itunes helper still running.



Step 4b) Now, watch your iPhone. It will soon show this. When it reboots it is done:



Step 5) Now the jailbreak is done, it’s time to install cydia.
Note: There is plenty of discussion on whats better between cydia, icy, and rock app. I can tell you that Cydia is strongly recommended even if you don’t want to use it. It does everything right and installs a proper BSD base. Rock app is flashy and cool also. The jailbreak install of Rock does not install rock extensions so it is ok to install. The icy install is broken on this jailbreak (version RC1). At this time, I recommend not installing it. It does not get installed with super user permissions and cannot install software properly.

EDIT: ABSOLUTELY DO NOT INSTALL Icy. (Icy removed from RC3 so RC3 users can ignore this). It overwrites dpkg especially if you install it last. Result will be you cannot install mobilesubstrate or anything that depends on it (libhide, sbsettings, categories, etc). This is because a bad Icy bundle was used.
On your device you now have a new icon:


Load this app and select your installer preferences. Remember, we are not skipping cydia,  install Rock App if you want also. If you need to unlock, select Sn0w. If you do not need to unlock do not select sn0w.
Note: If you have not activated your device in iTunes, blackra1n will hactivate it for you. If you have a contract carrier, this will not work unless you also unlock. Unlock and hactivation must go together or you will get no service. Here are some rules:
  • If you have activated in iTunes before running blackra1n and have service, you should not select sn0w.
  • If you did not activate in iTunes, blackra1n will hactivate for you. You will not get service via a contract carrier or not without unlocking at this stage. Select Sn0w.
  • If you have a 3g (not a 3gs, but a 3g): If you do not need to unlock now but think you may travel and want to unlock “next month” or something, you should hactivate and unlock by installing sn0w.  If you have already activated in iTunes (you have your carrier signal and icons in springboard) you probably need to restore and start over without your sim card inserted. Restore in iTunes, run blackra1n, and select sn0w and let it do the hactivation and unlock. Then insert your carrier sim card.
  • 3gs owners can ignore the previous bullet. You can swap sim cards later once you activate in iTunes normally.


Your selections will now install:



Step 6) When you are all done, load up blackr1n again and use the uninstall blackra1n to remove the blackra1n icon. It’s not needed any longer.

Step 7) Load Cydia, let it reorganize your apps, do the upgrades, and install your software!

Troubleshooting:
1) Blackra1n just crashes - You don’t have itunes 9 installed or your apple mobile device service is not running. Install itunes 9 or reboot to solve.
2) Blackra1n says it’s missing QTCF.dll. Put QTCF.dll into the same folder with blackra1n.exe and run it again.
3) Blackra1n hangs on running… - You need to kill iTunes and iTunesHelper.exe. This step should only take a couple seconds and something should happen.

Sunday, December 6, 2009

FireFound And Prey - Locate Your Stolen Laptop

FireFound

FireFound is an add-on for Firefox and Fennec (mobile Firefox) that helps your find your computer (or mobile phone, in the case of Fennec) if it is lost or stolen. Every time your computer's location changes, FireFound sends a secure message to a central server with its current location. You can then log into the server and see your computer's current location.
All of the location data is encrypted, so no one can find out where your computer is without your password.
If you lose your computer, you can tell FireFound to clear your personal data (saved passwords, browsing history, etc.) if anyone starts your browser before you can retrieve it.
You can even run your own FireFound server; all of the code is open-source.

Note: All geolocation data is approximate, and should only be used as a guideline. If your computer has been stolen, do not try to retrieve it yourself - alert the police.



Download

You can download the FireFound browser add-on from Mozilla Add-ons. The next time you restart your browser, you'll be asked to choose a username and password for your account. You can use that username and password to log in at this website and view the latest locations of your computer.


Prey is a lightweight application that will help you track and find your laptop if it ever gets stolen. It works in all operating systems and not only is it Open Source but also completely free. 

 

Saturday, December 5, 2009

Basic Electronics For The New Ham Slide




Becoming ham radio operator or amateur radio operator ?
First of all, we need to know a lil bit about electrics and electronics.
Get a slide from ARRL

Between Amateur Radio Of Malaysia And United States

Technician Class License. You can get an entry level Amateur Radio Technician license by passing a 35-question multiple-choice examination. No Morse code test is required. The exam covers basic regulations, operating practices, and electronics theory, with a focus on VHF and UHF applications.
Technician Class operators are authorized to use all amateur VHF and UHF frequencies (all frequencies above 50 MHz). Technicians also may operate on the 80, 40, and 15 meter HF bands using Morse code, and on the 10 meter band using Morse code, voice, and digital modes.  No Morse code test is required.

General Class License. The General Class license offers a giant step up in operating privileges. The high-power HF privileges granted to General licensees allow for cross-country and worldwide communication.
Technicians may upgrade to General by passing a 35-question multiple-choice examination. The written exam covers intermediate regulations, operating practices, and electronics theory, with a focus on HF applications. You must successfully pass the Technician exam to be eligible to sit for the General class exam. No Morse code test is required.
In addition to the Technician privileges, General Class operators are authorized to operate on any frequency in the 160, 30, 17, 12, and 10 meter bands. They may also use significant segments of the 80, 40, 20, and 15 meter bands.

Amateur Extra Class License. The HF bands can be awfully crowded, particularly at the top of the solar cycle. Once you earn HF privileges, you may quickly yearn for more room. The Extra Class license is the answer. Extra Class licensees are authorized to operate on all frequencies allocated to the Amateur Service.
General licensees may upgrade to Extra Class by passing a 50-question multiple-choice examination. No Morse code test is required. In addition to some of the more obscure regulations, the test covers specialized operating practices, advanced electronics theory, and radio equipment design.

From http://www.arrl.org/FandES/ead/classes.html

Here in Malaysia, we need to pass 100 questions to get B license ( UHF, VHF and only 10 meter on HF ) and need to sit for CW test to get A class ( Can working on any amateur bands ).

Malaysia Boleh!

p/s: im not hating morse code, im loving it. i have my own training keyer, but sometimes we need to see on other side too. just keep moving forward.

Doppler effect




The sudden change in pitch of a car horn as a car passes by (source motion) or in the pitch of a boom box on the sidewalk as you drive by in your car (observer motion) was first explained in 1842 by Christian Doppler. His Doppler Effect is the shift in frequency and wavelength of waves which results from a source moving with respect to the medium, a receiver moving with respect to the medium, or even a moving medium.
The perceived frequency (f ´) is related to the actual frequency (f0) and the relative speeds of the source (vs), observer (vo), and the speed (v) of waves in the medium by









The choice of using the plus (+) or minus (-) sign is made according to the convention that if the source and observer are moving towards each other the perceived frequency (f ´) is higher than the actual frequency (f0). Likewise, if the source and observer are moving away from each other the perceived frequency (f ´) is lower than the actual frequency (f0). Although first discovered for sound waves, the Doppler effect holds true for all types of waves including light (and other electromagnetic waves). The Doppler effect for light waves is usually described in terms of colors rather than frequency. A red shift occurs when the source and observer are moving away from eachother, and a blue shift occurs when the source and observer are moving towards eachother. The red shift of light from remote galaxies is proof that the universe is expanding.

The animations below will illustrate this phenomena for a moving source and stationary observer.


Stationary Sound Source







The movie at left shows a stationary sound source. Sound waves are produced at a constant frequency f0, and the wavefronts propagate symmetrically away from the source at a constant speed v, which is the speed of sound in the medium. The distance between wavefronts is the wavelength. All observers will hear the same frequency, which will be equal to the actual frequency of the source. For a movie showing how circular waves can be created (in terms of particle motion and wave motion) go here.


Source moving with vsource < vsound ( Mach 0.7 )


 


In the movie at left the same sound source is radiating sound waves at a constant frequency in the same medium. However, now the sound source is moving to the right with a speed vs = 0.7 v (Mach 0.7). The wavefronts are produced with the same frequency as before. However, since the source is moving, the center of each new wavefront is now slightly displaced to the right. As a result, the wavefronts begin to bunch up on the right side (in front of) and spread further apart on the left side (behind) of the source. An observer in front of the source will hear a higher frequency f ´ > f0, and an observer behind the source will hear a lower frequency f ´ < f0.


Source moving with vsource = vsound ( Mach 1 - breaking the sound barrier )


 



Now the source is moving at the speed of sound in the medium (vs = v, or Mach 1). The speed of sound in air at sea level is about 340 m/s or about 750 mph. The wave fronts in front of the source are now all bunched up at the same point. As a result, an observer in front of the source will detect nothing until the source arrives. The pressure front will be quite intense (a shock wave), due to all the wave fronts adding together, and will not be perceived as a pitch but as a "thump" of sound as the pressure wall passes by. The figure at right shows a bullet traveling at Mach 1.01. You can see the shock wave front just ahead of the bullet. Jet pilots flying at Mach 1 report that there is a noticeable "wall" or "barrier" which must be penetrated before achieving supersonic speeds. This "wall" is due to the intense pressure front, and flying within this pressure front produces a very turbulent and bouncy ride. Chuck Yeager was the first person to break the sound barrier when he flew faster than the speed of sound in the X-1 rocket-powered aircraft on October 14, 1947. Check out the movie The Right Stuff for more about this significant milestone, and the beginnings of the US space project. The figure at right shows a n F-18 at the exact instant it goes supersonic. Click on the figure to see more information and a MPEG movie of this event.

Source moving with vsource > vsound (Mach 1.4 - supersonic)






The sound source has now broken through the sound speed barrier, and is traveling at 1.4 times the speed of sound (Mach 1.4). Since the source is moving faster than the sound waves it creates, it actually leads the advancing wavefront. The sound source will pass by a stationary observer before the observer actually hears the sound it creates. As you watch the animation, notice the clear formation of the Mach cone, the angle of which depends on the ratio of source speed to sound speed. It is this intense pressure front on the Mach cone that causes the shock wave known as a sonic boom as a supersonic aircraft passes overhead. The shock wave advances at the speed of sound v, and since it is built up from all of the combined wave fronts, the sound heard by an observer will be quite intense. A supersonic aircraft usually produces two sonic booms, one from the aircraft's nose and the other from its tail, resulting in a double thump. The figure at right shows a bullet travelling at Mach 2.45. The mach cone and shock wavefronts are very noticeable.

Related Posts Plugin for WordPress, Blogger...