jst@ccnext.ucsf.edu (Joe Stong) (02/07/91)
[Apple computer petitions the FCC for 40 MHz in the area of 1.8 to 1.9 GHz for digital 10MB/s LANs, with a max of about 150 feet.] A hundred and fifty feet? What garbage! Maybe they want to sell a lot of repeaters, and keep me from doing my connection to the building across the street! I certainly wouldn't max the license out at 150 feet, 2000 feet might be more like it, with provisions for the transmitters using only as much power as necessary, like cellular systems. With the frequencies they're using, it should be easy to put a small directional antenna on it to boost the ERP. I'm sure I've seen portable telephones with 2000 foot ranges, even though a majority are probably less than this. I'd think this would give a clue for what a maximum "personal convenience" radio connection distance would be. To me, wiring between buildings is MUCH more trouble than wiring within a building. I'm pleased that somebody's introducing an FCC petition for commercial data useage, but this sounds much too restrictive! If they want to produce most of the UNITS with a 150 foot range, that's fine with me, as long as they can legally sell higher power units with somewhat greater ranges for the circumstances where they're needed. BTW, someone told me about the NCR WaveLAN product. I've asked NCR for literature and pricing. [As usual, please CC: me in mail if you post about this, I try to read telecom faithfully, but I miss things ] Joe Stong jst@cca.ucsf.edu [Moderator's Note: I'd think the risks of having your data snooped on or deliberatly messed with would be too great at 2000 feet. Some people would deliberatly park in front of your plant to mess around with you. 150 feet is more realistic from a security standpoint, although of course someone could interfere with that also, but not as easily unless they were inside your premises.
kthompso@entec.wichita.ncr.com (Ken Thompson) (02/13/91)
You are late to the party, Apple. NCR has had its WaveLan out since last year. It operates spread spectrum in the 908-928 MHz band at a 2M data rate with DES encoding for security. Rf power is two watts and with small gain antenna distances of five miles between nodes is easily attained. I think it lists for $1390 a node, installs in any IBM compatable, and is Netware compatable. Ken Thompson N0ITL NCR Corp. 3718 N. Rock Road Wichita,Ks. 67226 (316)636-8783 Ken.Thompson@wichita.ncr.com
alan@adept.uucp (Alan Ruffer) (02/16/91)
In article <74672@bu.edu.bu.edu> Ken Thompson <entec!kthompso@ uunet.uu.net> writes: X-Telecom-Digest: Volume 11, Issue 114, Message 8 of 10 > You are late to the party, Apple. > NCR has had > its WaveLan out since last year. It operates spread spectrum in the > 908-928 MHz band at a 2M data rate with DES encoding for security. > RF power is two watts and with small gain antenna distances of five > miles between nodes is easily attained. I think it lists for $1390 a > node, installs in any IBM compatable, and is Netware compatable. The REALLY sad part about all this is that 902.0 - 928.0 Mhz is the amateur radio 33 centimeter band. Devices that operate in this band are NOT guaranteed freedom from interference! There are other wireless gadgets that operate in this frequency range too. Buyers of these devices should be aware of this. While it is illegal for an amateur to intentionally interfere, these devices are subject to unintentional interference, and amateurs may ALSO be subject to interference from these transmiters. This is a bad situation that will get much worse before it gets better. Alan R. Ruffer UUCP: {csccat,chinacat!holston}!adept!alan Route 1, Box 1745 Amateur Radio Station WB5FKH Sulphur, LA 70663 BBS: (318) 527-6667, 19200(PEP)/9600(V.32)/2400/1200
meier@uunet.uu.net (Rolf Meier) (02/21/91)
In article <telecom11.119.8@eecs.nwu.edu> Alan Ruffer <alan@ adept.uucp> writes: > The REALLY sad part about all this is that 902.0 - 928.0 Mhz is the > amateur radio 33 centimeter band. Devices that operate in this band > are NOT guaranteed freedom from interference! There are other > wireless gadgets that operate in this frequency range too. Buyers of > these devices should be aware of this. While it is illegal for an > amateur to intentionally interfere, these devices are subject to > unintentional interference, and amateurs may ALSO be subject to > interference from these transmiters. In theory, narrowband transmissions in the 902-928 band should not cause interference to spread spectrum transmissions in that band, and vice versa. That is the whole purpose of allowing spread spectrum to operate in that band. Now, any band is subject to interference from transmissions which operate illegally within that band, but that is a matter of enforcement, not regulation. There are a number of spread spectrum systems operating successfully in the ISM (industrial, scientific, medical) bands, such as 902-928. According to my chart of spectrum allocations, this is a "secondary" amateur band, whatever that means. I don't believe it is encouraged for amateur usage. Rolf Meier Mitel Corporation
Allyn@uunet.uu.net (02/22/91)
>There are a number of spread spectrum systems operating successfully >in the ISM (industrial, scientific, medical) bands, such as 902-928. >According to my chart of spectrum allocations, this is a "secondary" > ^^^^^^^^^^^ >amateur band, whatever that means. I don't believe it is encouraged >for amateur usage. I believe "secondary" means that the 902-928 band is to be shared with other services. This is different from the two meter band (144-148) which is an exclusive Amateur Radio allocation. Amateur Radio isn't discouraged from 902-928 mhz. But it isn't real easy to get on it either. There is a lack of commercially available gear (available to your average ham that is). So you either have to use transverters or modify 800 mhz gear. Allyn Lai allyn@cup.portal.com
ornitz@kodak.kodak.com (Barry Ornitz) (02/22/91)
In article <telecom11.140.2@eecs.nwu.edu> Rolf Meier <mitel!Software! meier@uunet.uu.net> writes: > In article <telecom11.119.8@eecs.nwu.edu> Alan Ruffer <alan@ > adept.uucp> writes: >> The REALLY sad part about all this is that 902.0 - 928.0 Mhz is the >> amateur radio 33 centimeter band. Devices that operate in this band >> are NOT guaranteed freedom from interference! There are other >> wireless gadgets that operate in this frequency range too. Buyers of >> these devices should be aware of this. While it is illegal for an >> amateur to intentionally interfere, these devices are subject to >> unintentional interference, and amateurs may ALSO be subject to >> interference from these transmiters. Legal operation by amateurs can cause interference to these systems. Likewise amateurs can have these systems shut down if they cause interference to the amateurs. > In theory, narrowband transmissions in the 902-928 band should not > cause interference to spread spectrum transmissions in that band, and > vice versa. That is the whole purpose of allowing spread spectrum to > operate in that band. Unfortunately, many manufacturers have skimped on their designs and narrow band transmissions can cause significant interference. > Now, any band is subject to interference from transmissions which > operate illegally within that band, but that is a matter of > enforcement, not regulation. > There are a number of spread spectrum systems operating successfully > in the ISM (industrial, scientific, medical) bands, such as 902-928. > According to my chart of spectrum allocations, this is a "secondary" > amateur band, whatever that means. I don't believe it is encouraged > for amateur usage. The 902 to 928 MHz Amateur Radio band is licensed for use in ITU Region 2 on a secondary basis. This basically means that hams must not cause harmful interference to stations in the Government Radiolocation Service and they are not protected from interference from the same. There are also some special limitations in areas of Colorado, Wyoming, Texas, and New Mexico. Amateurs are not protected by ISM devices operating on these bands either. However, radio modems are not ISM devices (these are usually dielectric heaters, diathermy equipment, industrial microwave ovens, etc.). The spread spectrum devices recently allowed by the FCC on this band are Part 15 devices. According to the FCC, they must be operated on a non-interference basis to any licensed users of this band including amateurs. This means that they may not cause harmful interference to licensed operations and they must accept any interference that these systems may cause to their own operations. Some of the current spread spectrum devices for this band have virtually no tolerance for interference, and often a narrowband amateur transmission can completely lock up their system. Once again the FCC has demonstrated their lack of technical expertise in spectrum planning! :-( Finally, use of the 902 MHz band by amateurs is not discouraged. It is gaining popularity with amateurs for digital networking by packet radio. Barry L. Ornitz ornitz@kodak.com