While it may be "l33t" to hack old primestar gear to make a shot, you're not coming up with anything new..
OK, it may not be NEW, but it is cool. And it is new to most readers.
Some radio standards have concrete distance limits. For instance, the GSM cellular standard works on time division multiplexing. If your station is over 22 miles away, it simply won't work. Your "packets" will arrive at the base station too late, and they will clobber the guy in the next time slot (speed of light, and all that).
My point is that it's sometimes cool to understand a little bit about 802.11 RF standard, so we know its limitations and "fringe uses".
To go much farther you either need more power (which may tick off our friends at the FCC) or directional antennas, like Cringely used, with clear line-of-sight.
Any ham will tell you that it's not the power... it's the proper matching of the antenna.
I have a friend here in Singapore who uses 10 watts to talk to his buddies in East Coast USA!
Does this mean you have to have everything from your Mother's maiden name to your pet's favorite food in there? NO.
However, when you go to order your pet's favorite
food from www.alpo.com, the dog food company will force you to log in via your Passport account, because their servers run.NET. You get the convenience of one password, right? Your dog food purchase will be correlated with your previous purchases and preferences. Pretty soon, Microsoft will know everything about you.
There are some compelling reasons to register a real name and address sometimes. This is what people are worried about.
When I worked for
[large un-named Candian Telecom giant], our management was
convinced that unix workstations automatically
shared their processor loads. So each manager
had a nice workstation running nothing but a
screen saver.
If you want to experiment with the GSM codec, try the "Windows Sound Recorder" that is included as
a standard accessory program in Windows 95/98/NT distributions. By default it saves WAV files, but it
can be persuaded to use a different encoder. GSM 6.10 is one of the encoders that is supported. I
have a 6.5 minute GSM recording that is only 650 kbytes in size.
The size/quality trade-off for MP3's varies widely with different encoders. I use a CD-ripper program
called "CD Copy". By default this ripper uses the "Blade" encoder, which is free but sounds pretty bad
unless the bit rate is as high as 128 kbps. If you plug in a different encoder, such as the "Lame"
encoder, you can get much higher quality sound with lower bit rates. After I got the LAME_ENC.DLL
and plugged it into CD Copy, I started encoding music at 64 kbps!! And it still sounds fairly good
(subjective, sure). If you would like to give this encoder a try, and you need help setting up CD Copy
for this type of WAV-to-MP3 conversion, drop me a line.
I work for a mobile phone company, so I've had to learn all of the in's and out's of the modern cellular protocols. This is my (somewhat technical) take on it.
The public land mobile network (PLMN) was developed for LAND use, and a few assumptions were made in the process. Making the system available for a few (airborne) customers would simply make it less efficient for the rest. As with all engineering, the designs involve several trade-offs. The entire system was designed around keeping the mobile terminals cheap and mass-producable, so everyone can buy a cheap phone and use it 99% of the time. We do not have unlimited hardware budgets, and we are not trying to make the phones universally usable (under water, tunnels, on planes, at sea, etc).
The GSM standard assumes that the mobile station is moving at less than about 300 miles per hour. At higher speeds, the doppler shift becomes very significant. You do the math. This becomes a very hard (expensive) spatial geometry problem to solve for a simple 8-bit processor in a phone (that is already loaded down with a lot of protocol tasks).
The standards also assume that you're near the ground level. Sure, when you transmit, you'll light up several cells from a plane (typical PCS-band cell radius on the order of a mile or two, with a maximum radius of 22 miles). Likewise, you're hearing several base stations at once. Again, a hard problem to solve.
For more info on how it all works, see "The Mobile Telephony Primer" at http://alanporter.com. If you still have questions, send me an email.
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OK, it may not be NEW, but it is cool. And it is new to most readers.
Some radio standards have concrete distance limits. For instance, the GSM cellular standard works on time division multiplexing. If your station is over 22 miles away, it simply won't work. Your "packets" will arrive at the base station too late, and they will clobber the guy in the next time slot (speed of light, and all that).
My point is that it's sometimes cool to understand a little bit about 802.11 RF standard, so we know its limitations and "fringe uses".
Any ham will tell you that it's not the power... it's the proper matching of the antenna.
I have a friend here in Singapore who uses 10 watts to talk to his buddies in East Coast USA!
However, when you go to order your pet's favorite food from www.alpo.com, the dog food company will force you to log in via your Passport account, because their servers run .NET. You get the convenience of one password, right? Your dog food purchase will be correlated with your previous purchases and preferences. Pretty soon, Microsoft will know everything about you.
There are some compelling reasons to register a real name and address sometimes. This is what people are worried about.
When I worked for [large un-named Candian Telecom giant], our management was convinced that unix workstations automatically shared their processor loads. So each manager had a nice workstation running nothing but a screen saver.
I'm not sure if it's commercial or demo-ware or what, but you might want to check it out at www.icusurf.com.
The size/quality trade-off for MP3's varies widely with different encoders. I use a CD-ripper program called "CD Copy". By default this ripper uses the "Blade" encoder, which is free but sounds pretty bad unless the bit rate is as high as 128 kbps. If you plug in a different encoder, such as the "Lame" encoder, you can get much higher quality sound with lower bit rates. After I got the LAME_ENC.DLL and plugged it into CD Copy, I started encoding music at 64 kbps!! And it still sounds fairly good (subjective, sure). If you would like to give this encoder a try, and you need help setting up CD Copy for this type of WAV-to-MP3 conversion, drop me a line.
The public land mobile network (PLMN) was developed for LAND use, and a few assumptions were made in the process. Making the system available for a few (airborne) customers would simply make it less efficient for the rest. As with all engineering, the designs involve several trade-offs. The entire system was designed around keeping the mobile terminals cheap and mass-producable, so everyone can buy a cheap phone and use it 99% of the time. We do not have unlimited hardware budgets, and we are not trying to make the phones universally usable (under water, tunnels, on planes, at sea, etc).
The GSM standard assumes that the mobile station is moving at less than about 300 miles per hour. At higher speeds, the doppler shift becomes very significant. You do the math. This becomes a very hard (expensive) spatial geometry problem to solve for a simple 8-bit processor in a phone (that is already loaded down with a lot of protocol tasks).
The standards also assume that you're near the ground level. Sure, when you transmit, you'll light up several cells from a plane (typical PCS-band cell radius on the order of a mile or two, with a maximum radius of 22 miles). Likewise, you're hearing several base stations at once. Again, a hard problem to solve.
For more info on how it all works, see "The Mobile Telephony Primer" at http://alanporter.com. If you still have questions, send me an email.