High Speed Amateur Packet Radio Using Part 15 Wireless Ethernet Devices Ham Radio Ethernet - High Speed Amateur Packet Radio Using Part 15 Wireless Ethernet Devices For Amateur Radio Background: In 1989 Al Broscius, N3FCT suggested the use of Part 15 Spread Spectrum wireless ethernet devices that were becoming available for amateur packet radio use. Implications for the Radio Amateur- an excerpt from "License-Free Spread Spectrum Packet Radio" by N3FCT in 1989 There are numerous manufactures of these devices. They operate on the shared 900 MHz, 2.4 and 5.7 GHz bands with speeds between 1 and 54 Mbps. Wireless LAN product/feature comparison- by Barry McLarnon, VE3JF (slightly dated) (410 Kb PDF -mirror) Amateur Band Allocations- for the 900 MHz, 2.4 & 5.7 GHz bands In early 1997 TAPR began development of a 1 watt, 128 Kbps 900 MHz FHSS radio, suggesting this is the future for amateur packet radio. In late 1999 the FCC relaxed Amateur Spread Spectrum rules. Now allowing any commercially available Part 15 SS device to be reclassified under Part 97. (Prior only certain spreading codes where allowed) Part 97.311- current Amateur spread spectrum rules Today: We know it is possible as unlicensed Part 15 devices to obtain omnidirectional ranges up to about 5 miles and directional ranges up to about 17 miles using high gain antennas. We should also realize that greater communication ranges are possible (if necessary) by reclassifing these devices under Part 97. We are then allowed to modify them using pre-amps, RF amplifiers and high gain antennas. Then by placing a central routing node in the middle of town on top a tall building/tower or hill they can serve as a inexpensive high speed supplement/alternative to existing packet radio systems. Part 97 vs Part 15 & Permissible Power Comparison - and clarification http://www.qsl.net/kb9mwr/projects/wireless/plan.html (1 of 3) [3/31/2003 12:10:18 AM] High Speed Amateur Packet Radio Using Part 15 Wireless Ethernet Devices Price comparison- between a conventional packet setup and a Symphony setup Misc. Part 97 clarifications- pertaining to this application True some urban areas may be very infested with Part 15 devices already. But you have 3 bands to choose from, and you shouldn't have any problems if you use FHSS, with one watt amplifiers before your antenna polarized the opposite of everyone else. My Experiences: I have experimented with Proxim's Symphony 1.6 Mbps Frequency Hopping Spread Spectrum 2.4 GHz network card. It was only $130 and as a Part 15 device coupled with an old 24 dB MMDS 2.5 GHz partial screen parabolic antenna (previously used for receiving rural wireless cable) you could easily obtain ranges up to 6 miles line of sight. Low Cost Wireless Network How-To- our abundance of documented, experiences, work and research (which includes homebrew bi-directional amplifier designs and path-loss calculators) Other Peoples Experiences: During my Proxim Symphony experimentation I sought out reports from other hams who had attempted long distance communications paths: Symphony based links: KE6WED, VE3JF, K5OKC, and 4Z4ZQ Other hams exploring and using this technology using different hardware: KO6YQ, N3WFI, KG6DFV Re-classifying: All commercially available wireless ethernet devices are suitable for Amateur use. However there are 3 things you may need to pay attention to when re-classifying. 1. You need to identify your station every 10 minutes by transmitting your callsign in ASCII or by some other method that is publicly documented. I suggest having a script send out a ping every 10 minutes with your callsign embedded in it. (more info) 2. You will need to keep your operations within the 2400-2450 MHz amateur overlap if you plan to re-classify under Part 97. (this is only an issue on the 2.4 GHz band with FHSS, all other bands http://www.qsl.net/kb9mwr/projects/wireless/plan.html (2 of 3) [3/31/2003 12:10:19 AM] High Speed Amateur Packet Radio Using Part 15 Wireless Ethernet Devices have full overlap & DSSS systems can be set by user for center freq below 2.45) Order your Symphony directly from Proxim and send a copy of your license and they will change your cards country code shifting operation below 2450. (more info) 3. If you need to amplify your spread spectrum signal over 1 watt PEP you will need to incorporate automatic transmitter power control. You may need to buy a expensive commercial amplifier (such as Teletronics Bi-directional SmartAmp) to accomplish this. (more info) If your like me and are seeking a simple way to build a high speed, affordable, RF network, where you mimic the internet and have webpages, conferencing, FTP and so on, I encourage you to look into this technology and use it. If you use this technology and would like to share your experiences, or if you have questions, you may contact me. Also feel free to link to this document and or reprint any portion of it. Steve Lampereur, KB9MWR Entire project overview- (1.12 Mb PDF) http://www.qsl.net/kb9mwr/projects/wireless/plan.html (3 of 3) [3/31/2003 12:10:19 AM] License-Free Spread Spectrum Packet Radio Excerpt from; License-Free Spread Spectrum Packet Radio By: Albert G. Broscius, N3FCT 1989 Implications for the Radio Amateur While it may be disheartening that commercial systems have become available before their amateur counterparts, it should be mentioned that these license-free systems may be used to augment or supplement our communications abilities even though they are not regulated under Part 97 of the Rules. It is also possible that a system which qualifies under 15.126 could be modified to be pursuant to Part 97 spread spectrum rules and thus allowed to operate at the higher power limit, one hundred watts, available for amateur spread spectrum as long as the control operator satisfied all appropriate requirements of the Rules. And of course, placing a 15.126 unit on a Microsat-class vehicle could pave the way for license-free space operation although there may be other restrictions which come into play in that situation. The design of a power-limited spread spectrum network with realistic inter-node distances would require substantial antenna engineering skills which could be provided by amateur operators familiar with propagation conditions on these bands. However, the resulting network would be free of Part 97 restrictions in the spirit of the pre-Commission Ham activities. Realistically, a Wild West scenario of competing BBS networks and CB- style chaos could make this non-Ham would an unpleasant environment. Unfortunately, unless a pro-active position on this technology is taken, we may see a digital CB world forming around our shared allocations. Neglecting intentional interference to amateur transmissions and power-limit abuses, there is still the issue of a high noise floor on the weak signal portions of the shared bands. Although these bands now suffer from their shared status, some fell that an influx of consumer electronics items which may each transmit up to one watt will cause unacceptable degradation on the "quite regions" of the band plan. Considering the possible density to be tens of radiators per city block, the argument of RF pollution seems credible. Recommendations To responsibly address this technology, we fell amateur operators should experiment with the commercial systems now available in establishing long distance communications paths using high-gain antenna systems coupled with the maximum legal power of one watt, determining interference levels seen by week signal receivers attributable to spread spectrum transmissions, and carefully introducing this technology to computer bulletin board operators who could financially support development of an http://www.qsl.net/kb9mwr/projects/wireless/ss_pr.html (1 of 2) [3/31/2003 12:10:33 AM] License-Free Spread Spectrum Packet Radio unlicensed computer internet. http://www.qsl.net/kb9mwr/projects/wireless/ss_pr.html (2 of 2) [3/31/2003 12:10:33 AM] Amateur Band Allocations Part 15/ISM Bands are: 902 - 928 MHz, 2400 - 2483.5 MHz, 5725 - 5875 MHz Amateur Band Allocations: 902 - 928 MHz Secondary to industrial, scientific and medical devices; location monitoring service, and government stations. 2300 - 2305 MHz Secondary - No primary 2305 - 2310 MHz Secondary to fixed, mobile and radiolocation services 2390 - 2400 MHz Primary 2400 - 2402 MHz Secondary - No primary amateur service 2402 - 2417 MHz Primary 2417 - 2450 MHz Co-secondary with government radiolocation (industrial, scientific and medical are primary) 2450 - 2483.5 MHz No amateur - Industrial, scientific and medical *** 5650 - 5725 MHz Co-secondary with space research (deep space) service 5725 - 5850 MHz Secondary - No primary 5850 - 5925 MHz Secondary to non-government fixed-satellite service You may need to use directional antennas to avoid interfering with any primary occupants such as ISM (industrial, scientific and medical) As a secondary service you you may not cause harmful interference to primary service stations that may exist in your area, nor may you claim protection from harmful interference from primary stations. Unlicensed Part 15 users may not cause harmful interference to primary or secondary services and also may not claim protection from either. *** Many 802.11 systems can be user set for frequencies centered below 2.45. (see below) 802.11 Frequency Hopping Spread Spectrum - Frequency Mapping 802.11 and other frequency hopping systems such as Proxim's Symphony generally can acheive speeds up to 2 Mbps. Most of these FHSS systems are now obsolete due to 802.11b,a,g. The problem with these under Part 97 is that thay are generally factory programmed to hop from 2400 to 2483.5 MHz usually with at least 75 hopping frequencies, separated by at least 25 kHz. In some cases vendors/manufactures such as Proxim would reprogram them if you provide a copy of your ham license. Sometimes drivers for FHSS systems let you control how/where they hop, but for the most part FHSS gear could not be easily user set for frequencies below 2.45. 802.11b Direct Sequence Spread Spectrum Channel to Frequency Mapping USA/FCC & Canada regions have 11 total user setable channels allocated. Channels are 22 MHz wide, with speeds up to 11 Mbps. There are three unique non-overlapping channels; 1, 6 & 11. Channels 1-6 land completely within the amateur overlap. Channel 11 is completely outside the amateur segment. All frequencies are in GHz. Channel Center Freq. High Freq. Low Freq. 1 2.412 2.423 2.401 2 2.417 2.428 2.404 http://www.qsl.net/kb9mwr/projects/wireless/allocations.html (1 of 2) [3/31/2003 12:10:46 AM] Amateur Band Allocations 3 2.422 2.433 2.411 4 2.427 2.438 2.416 5 2.432 2.443 2.421 6 2.437 2.448 2.426 7 2.442 2.453 2.431 8 2.447 2.458 2.436 9 2.452 2.463 2.441 10 2.457 2.468 2.446 11 2.462 2.473 2.451 802.11a Orthogonal Frequency Division Multiplexing Channel to Frequency Mapping USA/FCC & Canada regions have 12 total user setable non-overlapping channels allocated. Channels are 20 MHz wide with speeds upto 54 Mbps. The first two opperate on the (U-NII) Unlicensed - National Information Infrastructure band segments. The first is for indoor applications only and must have integrated antennas. U-NII-2 allows outdoor opperations but also has a corresponding low ERP limit. The third segment has complete amateur overlap. It also overlaps the ISM band. This segment is intended for outdoor applications with higher ERP limits under Part 15.247, however if the equipment is only 15.407 (U-NII) certified, a lower ERP limit applies. Not all 802.11a gear is capable of all three segments. It should be noted that OFDM is Not a Spread Spectrum mode per FCC definition and thus the special spread spectrum Part 97.311 rules need not apply. All frequencies below are in GHz. Band Low Freq. High Freq. 5.154 5.174 5.15-5.25 5.178 5.198 U-NII-1 5.202 5.222 Part 15.407 5.226 5.246 5.254 5.274 5.25-5.35 5.278 5.298 U-NII-2 5.302 5.322 Part 15.407 5.326 5.346 5.725-5.825 5.729 5.749 U-NII-3/ISM 5.753 5.773 Part 15.407& 5.777 5.797 Part 15.247 5.801 5.821 802.11g Orthogonal Frequency Division Multiplexing Channel to Frequency Mapping 802.11g uses the same 2.4 GHz channels as 802.11b but enables speeds upto 54 Mbps. It can co-exist and maintain backwards compatability with 802.11b. It should be noted that OFDM is Not a Spread Spectrum mode per FCC definition and thus the special spread spectrum Part 97.311 rules need not apply. http://www.qsl.net/kb9mwr/projects/wireless/allocations.html (2 of 2) [3/31/2003 12:10:46 AM] What is ISM? What is an ISM (industrial, scientific and medical) device (Part 18)? Part 18 ISM devices utilize RF energy for non-communicative purposes. They radiate only and do not receive therefore it is highly unlikely that you would ever interfere with an ISM device. See the definition of ISM equipment in 47 CFR 18.107(c). Shrink wrappers are a fine example of an ISM device. The plastic is heated and semiliquified by a very strong RF field only a few inches away. The sheet of plastic is then lowered onto the rest of the packaging, clings to the product and the cardboard, and resolidifies. Since telecommunications are precluded, and ISM signal will contain not data. The third character of the emission designator for a Part 18 device will always be N (N0N or P0N are most likely). Other ISM devices include; RF lighting systems, paint dryers, jewelry cleaners, industrial microwave ovens, and MRI equipment. Wireless ethernet cards are Part 15 devices that just happen to be operating on an older more established ISM (Part 18) band. Wireless ethernet cards are Not Part 18 devices. The prime distinction between Part 18 and Part 15 devices is that Part 18 devices use RF to do something, and Part 15 devices use RF to communicate or send a command. A recent publicized example titled: "FCC Queries Wireless 'Net Provider About Interference To Hams" Proves that Part 97 has priority over Part 15, and proves that that wireless ethernet gear is indeed Part 15 and not Part 18. http://www.qsl.net/kb9mwr/projects/wireless/ism.html [3/31/2003 12:10:57 AM] Part 97.311-Spread Spectrum Rules Part 97.311 Spread Spectrum FCC Rules for Ham bands: 97.311 SS emission types (a) SS emission transmissions by an amateur station are authorized only for communications between points within areas where the amateur service is regulated by the FCC and between an area where the amateur service is regulated by the FCC and an amateur station in another country that permits such communications. SS emission transmissions must not be used for the purpose of obscuring the meaning of any communication. (b) A station transmitting SS emissions must not cause harmful interference to stations employing other authorized emissions, and must accept all interference caused by stations employing other authorized modes. (c) When deemed necessary by a District Director to assure compliance with this Part, a station licensee must: (1) Cease SS emission transmissions; (2) Restrict SS emission transmissions to the extent instructed; and (3) Maintain a record, convertible to the original information (voice, test, image, etc.) of all spread spectrum communications transmitted. (d) The transmitter power must not exceed 100 W under any circumstances. If more than 1 W is used, automatic transmitter control shall limit output power to that which is required for the communication. This shall be determined by the use of the ratio, measured at the receiver, of the received energy per user data bit (Eb) to the sum of the received power spectral densities of noise (N0) and co-channel interference (I0). Average transmitter power over 1 W shall be automatically adjusted to maintain an Eb/(N0+I0) ratio of no more than 23 dB at the intended receiver. http://www.qsl.net/kb9mwr/projects/wireless/part97.html [3/31/2003 12:11:07 AM] Part 97 vs Part 15 and Permissible Power Comparison Part 97 versus Part 15 and Permissible Power Comparison One of the main advantages to reclassifying your operations to Part 97 is interference protection from unlicensed operations (see Sec. 15.5) Licensed services have priority over unlicensed operations. Reclassifying under Part 97 also provides a way around the Part 15 certification/authorization problem. (see Sec. 15.204) Which states in short that an authorized system includes its marketed antenna and other components and must always be used in its original configuration in which it was authorized, and should not be modifed. Amateur equipment does not require certification / authorization, and hams may use equipment that has been certified for another service on amateur frequencies. [Sec. 97.315] Under Part 97 you can legally modify these devices, using (homebrew) pre-amps, RF amplifiers, and high gain antennas. Another fairly big advantage is the amount of achievable radiated power under Part 97. As you may know Part 15 operation has effective radiated power (ERP) limits. It also has different (lower) limits for omni-directional antennas. Amateur Radio has never had or has any type of ERP limits. The wording of Part 97.311(d) which regulates Amateur Spread Spectrum uses the words "transmitter power" which imply peak envelope power (PEP) or carrier power (CP) not effective radiated power (ERP). (If it said radiated power then ERP would be implied). Non-Spread Spectrum modes such as 802.11a or 802.11g have the 1500 Watt PEP limit. Note there are no ERP / EIRP limits for Part 97 operation. There is also no difference for omni- directional or directional setups. The directional antennas sited in the table below are for example purposes. And the EIRP's listed below are only limited by the gain of your antenna. So some example calculations show that the following are achievable and permissible under Part 97 if necessary (97.313): Achievable under Part 97: Max. PEP RF power Ant. gain EIRP* 1 watt w/o using automatic 900 MHz (spread spectrum) 14 dBd yagi 41.2 watts power control (per 97.311) 100 watts using automatic 900 MHz (spread spectrum) 14 dBd yagi 4,119.5 watts power control (per 97.311) 2.4 GHz (spread spectrum i.e. 1 watt w/o using automatic 24 dBi partial parabolic 252.2 watts 802.11 or 802.11b) power control (per 97.311) 2.4 GHz (spread spectrum i.e. 100 watts using automatic 24 dBi partial parabolic 25.1 Kilo-watts 802.11 or 802.11b) power control (per 97.311) 2.4 GHz (non spread spectrum 1500 watts (per 93.313) 24 dBi partial parabolic 376.8 Kilo-watts i.e. 802.11g) http://www.qsl.net/kb9mwr/projects/wireless/pwr.html (1 of 2) [3/31/2003 12:11:27 AM]