No... the original WR1000 was largely an analog radio. That's not SDR. The real novelty of the original WinRadio models was computer control - tune to a particular frequency - check received signal strength - select mode like AM vs. FM or SSB. You could write software to do automated sweeps of spectrum and log the results but the actual signal path was mostly analog.
One more thing - the PC internal version was an ISA card - NOT PCI.
WinRadio finally introduced a PCI version about a month ago (not ten years ago).
Most secretive organizations use a cell structure. If one cell is compromised, the others continue on undetected. However, someone somewhere has to provide information and funding. It's conceivable that the NSA is using the tree patterns from the call records to identify who that someone might be.
However - I really don't give a shit. People who sacrifice liberty for safety deserve neither. [ Hmmm... who said that? ] What's the point of living in the supposedly freest nation in the world if we (or our government) has to stoop to this?
FWIW, Adobe's PDF includes embedded images using DCT or discrete cosine transform for compression. If you extract the image sections from the document, you end up with a JPEG file.
"The server system sends to the client system the assigned client identifier and an HTML,XML,PDF, or ASCII document or other document format known to the art identifying the item and including an order button."
Here's a piece of the Texas Criminal Code as an example. See part (B) below:
33A.03. MANUFACTURE, POSSESSION, OR DELIVERY OF UNLAWFUL TELECOMMUNICATIONS DEVICE. (a) A person commits an offense if the person manufactures, possesses, delivers, offers to deliver, or advertises:
(1) a counterfeit telecommunications device; or
(2) a telecommunications device that is intended to be used to:
(A) commit an offense under Section 33A.04; or (B) conceal the existence or place of origin or destination of a telecommunications service.
(b) A person commits an offense if the person delivers, offers to deliver, or advertises plans, instructions, or materials for manufacture of:
(1) a counterfeit telecommunications device; or
(2) a telecommunications device that is intended to be used to commit an offense under Subsection (a).
(c) An offense under this section is a felony of the third degree.
(d) It is a defense to prosecution under this section that the person was an officer, agent, or employee of a telecommunications service provider who engaged in the conduct for the purpose of gathering information for a law enforcement investigation related to an offense under this chapter.
You need a central certificate authority to validate the autheticity of users. And, that is a big no-no in P2P systems.
Actually, you don't need a central CA - a distributed one will do. In other words, every peer implements their own "buddy list". The buddy list includes positives (confirmed trustworthy) and negatives (confirmed un-trustworthy). Instead of distrusting every peer, you can choose a list of peers from one peer you already trust, and build from there.
When performing a search, your P2P software might color code the results based on this list. Green for known good peers, red for bad peers/spammers/etc., and yellow for unlisted, unknown peers.
Actually there are two openings under legal eavesdropping. There is the "readily accessible to the general public" clause you already mentioned. The 802.11X standards are certainly "readily accessible".
The second opening is another clause that deals with interference.
(iv) to intercept any wire or electronic communication the transmission of which is causing harmful interference to any lawfully operating station or consumer electronic equipment, to the extent necessary to identify the source of such interference;
Regardless of whether the eavesdropping is legal, common sense says to encrypt any sensitive data.
In addition to MZ's comments on reliability/redundancy... the issue of latency in digital systems is significant.
Try this with two digital mode cell phones: set both to full volume, have one phone call the other. Now listen to your voice echo from the second phone as you speak into the first one. That's quite a delay from message sent to message received. Let's suppose that time is 300 to 400 milliseconds - yeah, that's like 3 or 4 tenths of a second.
That's 3 to 4 tenths of a second lost when someone yells into their radio "Get out NOW!"
With some level shifting circuitry you can turn any common RS232 serial port into a 4 channel logic analyzer. It you've got +5 volt TTL levels, you can probably get away without any extra circuitry.
Say what?!
Yep. Most anyone can do this. In my case, I went so far as to write a device driver that makes it work under Windows NT/2K/XP. It hooks the serial ports interrupt service routine and logs the state of the UART's modem status register or MSR. Four bits from the MSR tell us the state of the CTS, DCD, DST, and RI input pins. I use the RDTSC instruction which offers ridiculous accuracy (theoretically, it's the CPU's clock speed) compared to most other software based solutions - even betten than some coarse-grained hardware solutions.
The same could easily be done under Linux or anything with a serial port and Pentium compatible processor.
I never thought anyone would be interested so no website or anything. Interested persons can send me an email...
I will place 2 or 3 AP's on different channels with the power turned all of the way down so it will balance the user load between the them.
This is a great example of an intelligent use of the 802.11X protocols. Use only as much power as you need, and only where needed. As opposed to the usual (and wrong) tactic of using full-power in an attempt to squash a neighboring access point's signal.
Your nyquist analogy assumes a simple binary symbol set (ie. "1" and "0"). The signal bandwidth is a function of the symbol rate. If your symbol set is larger than just two symbols (say 8, or 16, or...), then you can deliver more bits per symbol. That's why "G" delivers more data bandwidth than "B" in the confines of the same channel signal bandwidth.
The emergency equipment should just as well be running off of cellular equipment, as should any other communications equipment.
Ewww... yuck. Folks need to understand that the two main communications modes used by public safety: dispatch and tactical. For dispatch you can use a cellular network. Examples of tactical comms are SWAT/hostage type situations or on-scene fire control. For tactical communications what you really want is direct peer-to-peer. You don't want to depend on your signal travelling all the way to a tower a half-mile away - and back again - just to talk to someone 100 feet away. This is critical when trying to talk from inside a burning building.
Digital channels take up less bandwidth than analog channels, is clearer, and is secure.
Less bandwidth? Not necessarily, ACSSB (amplitude compandored single side-band) fits inside a 5 khz wide channel.
Is clearer? Nope - the digital systems all use some form of speech compression which sacrifices sound fidelity for narrower bandwidth.
Is secure? No... digital does not equal encryption. It's easier to encrypt once it's digital but requires key management. It's not a given.
Also, for public safety... encryption is of little value... reliability and interoperability among different agencies are more important. For most agencies, encrypting voice comms for surveillance activity and encrypting data terminal access is more than sufficient.
[ecode]How is the 1.9GHz band "more valuable" than the 800MHz band? Especially as Nextel are running their own protocols rather than an off-the-shelf standard (so even the "it's in common use therefore there are cost savings with the hardware" argument doesn't work)?[/ecode]
Well... the 1.9Ghz spectrum being discussed is contiguous, nationwide spectrum compared to the disjoint patchwork of channels that Nextel currently owns.
Nextel also operates on 900 Mhz in South America. Some of the models offered by Motorola are dual band. You can even get a dual mode phone that will use Nextel iDEN in the US and GSM in europe.
-rick
Getting a license from the FCC is like buying a house. It's in your interest to know your neighbors and to make an effort to be a good neighbor. With that in mind, here's a few notes on what this whole fuss over interference is really about.
1. direct interference - someone transmits on someone else's frequency. This happens occassionally by accident and usually gets fixed quick. Nextel was once fined for doing this unintentionally a few years ago near New Orleans, LA.
2. co-channel interference - two entities each have a license to use the same frequency in geographically overlapping areas. The two parties
are mutually responsible for making equipment and operating adjustments to eliminate interference.
3. equipment mis-configuration (including co-located equipment) - different companies often share the same tower sites and often the signal from one company's transmitter will "leak" into another causing mixed products and emissions outside licensed frequencies.
4. receiver desensitivity caused by proximity to low elevation, high power transmitter sites (ie. cell towers).
Nextel is causing problems for other 800Mhz licensees mostly as a result of items 3 and 4. Non-Nextel cell towers (like Verizon, Sprint, and AT&T) also cause #4 above but the problem is more severe when near a Nextel tower site because the transmissions are in the same band as the other non-Nextel users' equipment.
They should have seen this comming before selling that spectrum to Nextel.
Nextel purchased existing licenses as well as "new" licenses from the FCC. The pre-existing licenses were converted for use in Nextel's cellular network.
In both cases (pre-existing and new), Nextel agreed to operate the licenses in a responsible manner. That's part of the license - like using your driver's license to operate automobile in a responsible manner.
Slashdot Mirror
Where there's a good margin, competition will follow.
No ... the original WR1000 was largely an analog radio. That's not SDR. The real novelty of the original WinRadio models was computer control - tune to a particular frequency - check received signal strength - select mode like AM vs. FM or SSB. You could write software to do automated sweeps of spectrum and log the results but the actual signal path was mostly analog.
One more thing - the PC internal version was an ISA card - NOT PCI.
WinRadio finally introduced a PCI version about a month ago (not ten years ago).
-rfmobile
Most secretive organizations use a cell structure. If one cell is compromised, the others continue on undetected. However, someone somewhere has to provide information and funding. It's conceivable that the NSA is using the tree patterns from the call records to identify who that someone might be.
However - I really don't give a shit. People who sacrifice liberty for safety deserve neither. [ Hmmm ... who said that? ] What's the point of living in the supposedly freest nation in the world if we (or our government) has to stoop to this?
FWIW, Adobe's PDF includes embedded images using DCT or discrete cosine transform for compression. If you extract the image sections from the document, you end up with a JPEG file.
Oh year? Well, my patent reads ...
"The server system sends to the client system the assigned client identifier and an HTML,XML,PDF, or ASCII document or other document format known to the art identifying the item and including an order button."
Guess someone owes me some big bucks.
Here's a piece of the Texas Criminal Code as an example. See part (B) below:
33A.03. MANUFACTURE, POSSESSION, OR DELIVERY OF
UNLAWFUL TELECOMMUNICATIONS DEVICE. (a) A person commits an
offense if the person manufactures, possesses, delivers, offers to
deliver, or advertises:
(1) a counterfeit telecommunications device; or
(2) a telecommunications device that is intended to be
used to:
(A) commit an offense under Section 33A.04; or
(B) conceal the existence or place of origin or
destination of a telecommunications service.
(b) A person commits an offense if the person delivers,
offers to deliver, or advertises plans, instructions, or materials
for manufacture of:
(1) a counterfeit telecommunications device; or
(2) a telecommunications device that is intended to be
used to commit an offense under Subsection (a).
(c) An offense under this section is a felony of the third
degree.
(d) It is a defense to prosecution under this section that
the person was an officer, agent, or employee of a
telecommunications service provider who engaged in the conduct for
the purpose of gathering information for a law enforcement
investigation related to an offense under this chapter.
-rick
Actually, you don't need a central CA - a distributed one will do. In other words, every peer implements their own "buddy list". The buddy list includes positives (confirmed trustworthy) and negatives (confirmed un-trustworthy). Instead of distrusting every peer, you can choose a list of peers from one peer you already trust, and build from there.
When performing a search, your P2P software might color code the results based on this list. Green for known good peers, red for bad peers/spammers/etc., and yellow for unlisted, unknown peers.
-rickActually there are two openings under legal eavesdropping. There is the "readily accessible to the general public" clause you already mentioned. The 802.11X standards are certainly "readily accessible".
The second opening is another clause that deals with interference.
Regardless of whether the eavesdropping is legal, common sense says to encrypt any sensitive data.
-rickIn addition to MZ's comments on reliability/redundancy ... the issue of latency in digital systems is significant.
Try this with two digital mode cell phones: set both to full volume, have one phone call the other. Now listen to your voice echo from the second phone as you speak into the first one. That's quite a delay from message sent to message received. Let's suppose that time is 300 to 400 milliseconds - yeah, that's like 3 or 4 tenths of a second.
That's 3 to 4 tenths of a second lost when someone yells into their radio "Get out NOW!"
-rick*sigh* Typo ... sorry, that's the CTS, DCD, DSR, and RI input pins.
-rickWith some level shifting circuitry you can turn any common RS232 serial port into a 4 channel logic analyzer. It you've got +5 volt TTL levels, you can probably get away without any extra circuitry.
Say what?!
Yep. Most anyone can do this. In my case, I went so far as to write a device driver that makes it work under Windows NT/2K/XP. It hooks the serial ports interrupt service routine and logs the state of the UART's modem status register or MSR. Four bits from the MSR tell us the state of the CTS, DCD, DST, and RI input pins. I use the RDTSC instruction which offers ridiculous accuracy (theoretically, it's the CPU's clock speed) compared to most other software based solutions - even betten than some coarse-grained hardware solutions.
The same could easily be done under Linux or anything with a serial port and Pentium compatible processor.
I never thought anyone would be interested so no website or anything. Interested persons can send me an email ...
mailto:rfmobile@swbell.net
-rickThis is a great example of an intelligent use of the 802.11X protocols. Use only as much power as you need, and only where needed. As opposed to the usual (and wrong) tactic of using full-power in an attempt to squash a neighboring access point's signal.
-rickYour nyquist analogy assumes a simple binary symbol set (ie. "1" and "0"). The signal bandwidth is a function of the symbol rate. If your symbol set is larger than just two symbols (say 8, or 16, or ...), then you can deliver more bits per symbol. That's why "G" delivers more data bandwidth than "B" in the confines of the same channel signal bandwidth.
-rickEwww ... yuck. Folks need to understand that the two main communications modes used by public safety: dispatch and tactical. For dispatch you can use a cellular network. Examples of tactical comms are SWAT/hostage type situations or on-scene fire control. For tactical communications what you really want is direct peer-to-peer. You don't want to depend on your signal travelling all the way to a tower a half-mile away - and back again - just to talk to someone 100 feet away. This is critical when trying to talk from inside a burning building.
Less bandwidth? Not necessarily, ACSSB (amplitude compandored single side-band) fits inside a 5 khz wide channel.
Is clearer? Nope - the digital systems all use some form of speech compression which sacrifices sound fidelity for narrower bandwidth.
Is secure? No ... digital does not equal encryption. It's easier to encrypt once it's digital but requires key management. It's not a given.
Also, for public safety ... encryption is of little value ... reliability and interoperability among different agencies are more important. For most agencies, encrypting voice comms for surveillance activity and encrypting data terminal access is more than sufficient.
-rickWell ... the 1.9Ghz spectrum being discussed is contiguous, nationwide spectrum compared to the disjoint patchwork of channels that Nextel currently owns.
-rickiDEN is also used by Southern Linc - a competitor to Nextel that uses the same Motorola equipment.
-rickNextel also operates on 900 Mhz in South America. Some of the models offered by Motorola are dual band. You can even get a dual mode phone that will use Nextel iDEN in the US and GSM in europe. -rick
Getting a license from the FCC is like buying a house. It's in your interest to know your neighbors and to make an effort to be a good neighbor. With that in mind, here's a few notes on what this whole fuss over interference is really about.
1. direct interference - someone transmits on someone else's frequency. This happens occassionally by accident and usually gets fixed quick. Nextel was once fined for doing this unintentionally a few years ago near New Orleans, LA.
2. co-channel interference - two entities each have a license to use the same frequency in geographically overlapping areas. The two parties are mutually responsible for making equipment and operating adjustments to eliminate interference.
3. equipment mis-configuration (including co-located equipment) - different companies often share the same tower sites and often the signal from one company's transmitter will "leak" into another causing mixed products and emissions outside licensed frequencies.
4. receiver desensitivity caused by proximity to low elevation, high power transmitter sites (ie. cell towers).
Nextel is causing problems for other 800Mhz licensees mostly as a result of items 3 and 4. Non-Nextel cell towers (like Verizon, Sprint, and AT&T) also cause #4 above but the problem is more severe when near a Nextel tower site because the transmissions are in the same band as the other non-Nextel users' equipment.
-rickNextel purchased existing licenses as well as "new" licenses from the FCC. The pre-existing licenses were converted for use in Nextel's cellular network.
In both cases (pre-existing and new), Nextel agreed to operate the licenses in a responsible manner. That's part of the license - like using your driver's license to operate automobile in a responsible manner.
-rickTime for RoboCob!
-rick[01-03-04 19:32:12] Beer Location: Outside customers mouth. [01-03-04 19:32:13] Beer Location: On the ground.
One whole second before it hit the ground? Must have been Lite beer.
-rickOne if you want to access SVN over a network. You don't need Apache if the repository is local.
-rick
a 255-byte range from address $00-$FF
Um, that's 256 bytes. Hey, on the 6502 and zero page memory, every byte counts!
-rickuh huh.
-rick
My personal favorite ...
Sam Spade
-rick