Post by thread:[OT]: RFID & Spectrum Management (was: Self-serve

> The problem I see is the DSP algorithms needed to overcome all the > effects of metal and other RF changing fields in the basket (cans, foil, > liquids, etc). > > RFID isn't going to come for quite some time. > > -Adam Not to mention the inevitable interference complaints from other licensed users of all the bands they've decided to use in the so-called "unlicensed" spectrum. (I love it when manufacturers make it out like they're using this wide open spectrum that no one else is licensed in. Example, I got a flyer for a broadband Internet company moving into my neighborhood using the "unlicensed portion of 900 MHz". I went to the device manufacturer's site, and they say they're going to cover large areas with indoor non-line-of-sight antennas and total output power of 320 or so mW. Obviously to do that their recievers are going to be very sensitive. And they're probably not going to spend much money making them super-selective, plus they won't want the resulting loss in sensitivity... so they'll build broad-door wide front-ends that are highly pre-amplified -- and then they're going to have a really hard time figuring out why their devices front-ends are blown away when I fire up a fully licensed, 11W 900 MHz FM repeater at 921.2 in my backyard... and the entire broadband provider in the neighborhood goes dead. Oh well... you're unlicensed... and your recievers are too broad... sorry.) At least here in the U.S. the FCC seems bent on offering up spectrum for use without licensing for these types of applications but then they shirk their old more "traditional" responsibility of mediation of interference -- stepping back and allowing the unlicensed spectrum users duke it out on their own -- no longer are they interested in supporting the spectrum use plans with the teeth of enforcement like they used to. Or creating reasonable plans to keep incompatible services from interfereing with each other. The only folks that they do that for is public safety systems, really. It comes across as amazingly lazy. Of course, when they do offer up real licensed spectrum they auction it off for millions and millions of dollars. When did spectrum management become a revenue source for the Feds? (And then they learned that a bunch of these companies went under, the spectrum is unused, and the bills are not paid. Ahh... surprise surprise. And they even got their arse's handed to them on a platter by a Federal Court when they tried to re-auction off spectrum of a company in bankruptcy protection -- oops -- you're no longer in charge of that bandwidth Mr. FCC, because the company's "assets" are protected from you as their "creditor" while they're in bankruptcy. Smooth move that one was!) With cordless phones, baby monitors, and stuff -- 900 MHz here in the U.S. is already a mess -- but now higher power systems like the 900 MHz tags for motorists driving on a local toll-road and these broadband data systems are already throwing crud all over the band through transmitters that have gone a little... uhh... let's just say they're broken and it shows up nicely on a spectrum analyzer... Here locally there's at least two Internet bandwidth providers fighting over 900 MHz with others duking it out in 2.4 and 5.8 GHz. And guess where the newest batch of cordless phones is already at? Ha... this is laughable spectrum management! Governmental spectrum managers are taking the easy way out allowing this "everyone dogpile on"-mentality to reign in these bands... it *will* come back to bite them. And they're encouraging it by making the "cost of entry" to licensed spectrum impossible for anyone smaller than a multi-national conglomerate corporation to afford. In light of all that, I think RFID is slated to just be more noise... literally. It'll also be interesting to see some anti-social young person create the first "supermarket jammer" device just to create havok when RFID starts to get widespread deployment. I'll be watching for it as a cheesy "hax0r Walmart's checkstands and be a l33t d00d!" article in publications like 2600 magazine... as I'm sure it'll be there, eventually. And I'm sure lots of kids will build them just to be annoying. Nate Duehr, spam_OUTnateTakeThisOuTnatetech.com - WY0X -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

These tags operate with inductive coupling, narrow band, on relatively low frequencies. Check the microchip RFID docs. There are other players, but they are all similar in this regard. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> These tags operate with inductive coupling, narrow band, on relatively low frequencies. Check the microchip RFID docs. There are other players, but they are all similar in this regard. Yes, but the manufacturers of these devices have repeatedly asked for spectrum in the 430 MHz range, which is chock full of licensed users. It's been blocked at the Request for Comment stage at least once now, but they'll keep asking... Nate Duehr, .....nateKILLspam@spam@natetech.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> > These tags operate with inductive coupling, narrow band, on > relatively low > frequencies. Check the microchip RFID docs. There are other players, but > they are all similar in this regard. > > Yes, but the manufacturers of these devices have repeatedly asked for > spectrum in the 430 MHz range, which is chock full of licensed > users. It's > been blocked at the Request for Comment stage at least once now, > but they'll > keep asking... I don't think there are ANY plans to do RFID at that high a frequency. Remember, with RFID the carrier is supplying power as well as info, it's much easier to power a device from a 120kHz signal then one at 430MHz, cost is of upmost concern here. TTYL -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Hate to tell you but there are tags that work @ 900mhz and higher. We found them when working on a couple of RFID projects. Check out the antennae on truck scales and toll tags for bridges. Ponchartrain bridge across Lake Ponchartrain in Louisiana uses 900mhz. Herbert Graf wrote: {Quote hidden}> > > > These tags operate with inductive coupling, narrow band, on > > relatively low > > frequencies. Check the microchip RFID docs. There are other players, but > > they are all similar in this regard. > > > > Yes, but the manufacturers of these devices have repeatedly asked for > > spectrum in the 430 MHz range, which is chock full of licensed > > users. It's > > been blocked at the Request for Comment stage at least once now, > > but they'll > > keep asking... > > I don't think there are ANY plans to do RFID at that high a frequency. > Remember, with RFID the carrier is supplying power as well as info, it's > much easier to power a device from a 120kHz signal then one at 430MHz, cost > is of upmost concern here. TTYL > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> Hate to tell you but there are tags that work @ 900mhz and higher. We > found them when working on a couple of RFID projects. Check out the > antennae on truck scales and toll tags for bridges. Ponchartrain bridge > across Lake Ponchartrain in Louisiana uses 900mhz. Those are completely different apps where the cost per tag isn't supposed to be <$0.10, apples vs. oranges. We are talking about, essentially, a replacement for the UPC barcode on items. Cost per tag has to be in the "few cents" range, I just don't see higher frequency techniques getting there before lower frequency solutions. TTYL -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Herbert Graf <PICLISTKILLspammitvma.mit.edu> wrote: > We are talking about, essentially, a replacement for the UPC > barcode on items. Cost per tag has to be in the "few cents" range, > I just don't see higher frequency techniques getting there before > lower frequency solutions. Hmm, the RFID system which I helped to develop a few years ago used 5-cent tags operating in the 2.4 GHz area. It was a bit faster than the low-frequency systems, too; read speed was about a thousand tags per second in the best case, and a cart containing a few-hundred tagged items could easily be read in the time it took to pass it through a doorway. -Andy === Andrew Warren -- .....aiwKILLspam.....cypress.com === Principal Design Engineer === Cypress Semiconductor Corporation === === Opinions expressed above do not === necessarily represent those of === Cypress Semiconductor Corporation -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

{Quote hidden}> -----Original Message----- > From: pic microcontroller discussion list > [EraseMEPICLISTspam_OUTTakeThisOuTMITVMA.MIT.EDU]On Behalf Of Andrew Warren > Sent: Thursday, 19 June 2003 10:17 AM > To: PICLISTspam_OUTMITVMA.MIT.EDU > Subject: Re: [OT]: RFID & Spectrum Management (was: Self-serve checkout > lanes) > > > Herbert Graf <@spam@PICLISTKILLspammitvma.mit.edu> wrote: > > > We are talking about, essentially, a replacement for the UPC > > barcode on items. Cost per tag has to be in the "few cents" range, > > I just don't see higher frequency techniques getting there before > > lower frequency solutions. > > Hmm, the RFID system which I helped to develop a few years ago > used 5-cent tags operating in the 2.4 GHz area. It was a bit > faster than the low-frequency systems, too; read speed was about > a thousand tags per second in the best case, and a cart > containing a few-hundred tagged items could easily be read in the > time it took to pass it through a doorway. > > -Andy I remember testing these in the warehouse of a former employer, a customer wanted to see how well they worked, so a few items at a time would get added to the basket, and I had to move them through a doorway as quick as possible :o) we maxed out at about 300 tags and me running as fast as I could through the door way. I wondered why I had a nice green glow since that experiment ;o) Regards, Kat. --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.443 / Virus Database: 248 - Release Date: 10/01/2003 -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email KILLspamlistservKILLspammitvma.mit.edu with SET PICList DIGEST in the body

I don't understand something. If the range of the RFID is about 10-20cm, how can they be utilized at supermarkets, wouldn't you need thousands of readers spread around the cashiers? Or how can you use them in a warehouse, the range seems so limited, are there longer range RFIDs , maybe 10-20 meters or so? Regards, Omer {Original Message removed}