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Multipath is covered in the first slides. Co-channel interference, Spatial Diversity and Diversity combining multiple antennas. But combining antennas also amplifies interference.
Equal Gain Combining (EGC) adds linerally. Phased Array's focus the beam - dynamically.
|Multipath is covered in the first slides. Phased Array's focus the beam - dynamically. Co-channel interference, Spatial Diversity and Diversity combining multiple antennas are some of the techniques. But combining antennas also amplifies interference. Equal Gain Combining (EGC) adds linerally.|
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|Jim explains that phased array with lots of active antennas elements is hard. The gain is not always uniform over the field. The more elements you have, the trickier it is. But it is effective. Generating nulls from interfering signals sources is also an advantage of phased arrays.||Jim explains that engineering a phased array with lots of active antennas elements is hard. The gain is not always uniform over the field. The more elements you have, the trickier it is. But it can work. Generating nulls from interfering signals sources is also an advantage of phased arrays.|
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|Jim also mentioned the Nomadix patent for captive portal. Jim thinks it's (mostly) bullshit. He worked at Waveport and thinks there's prior art. Jim is not sold on captive portal "splash" pages but thinks that the Nomadix patent is unlikely to fly.||Jim also mentioned the Nomadix patent for captive portal. Jim is extremely skeptical. He thinks there's prior art. Jim thinks that the Nomadix patent is unlikely to fly.|
When and Where
Urban Grind Coffee 2214 NE Oregon St. (take 22nd Ave. 2 blocks North of Sandy Blvd.)
Wednesday, January 28th, 6pm-9pm
Scribe: Sam Churchill
JimThompson and GlennFleishman will be presenting tonight. JimThompson will talk about Phased Array Antennas and Glenn Fleishman's presentation will be "The Future is Free - But It'll cost you $20/month". Glenn was originally going to drive down to Portland from Seattle but couldn't make it due to car problems. No problem. Glenn is on-line via iChat for all to see and hear.
Jim works for [http://www.netgate.com Netgate.com], one of the most popluar wifi gear sales sites on the internet. He has extensive experience with engineering wireless equipment and networks. He'd like you to know that he bakes a mean croissant and that he's trapped in Spokane, longing for the Parisian-lite appeal of Portland.
Glenn Fleishman claims to spend most of his waking hours thinking about technology, mostly wireless, and how it all fits together with Jim's croissants. He has written two editions of The Wireless Networking Starter Kit, a book for intermediate users and small offices. Among Glenn's press credits is the Mac column in the Seattle Times, which makes him an expert on the way radio waves traverse pastel lucite.
Topics will be offered at the monthly, or divined using a new Wireless-Pundit Presentation Topic Detector from Belkin.
Special thanks to both our speakers for allowing me to abuse their bios.
Recordings of past meetings are archived: http://ptp.thebasement.org/meetings/
- 6:00PM - Introduction to Personal Telco for new comers
- 6:30PM - Speaker #1
- 7:15PM - Speaker #2
- 8:00PM - Business
6:15: Nigel has taken the stage and is starting the meeting.
Jim Thompson has an iChat camera on this meeting. There are actually 3 separate iChat cameras in Portland. Don't know where you might see the live feed, however. You'd need an Apple, of course. About 70 people are gathered in the Urban Grind Coffee Shop in Portland where this meeting is taking place.
- Introductions: New people are introducing themselves. A variety of backgrounds and interests. [Glenn is holding up "Bender", the robot from Futurerama. Laughs around.
- New Access Point: The Ugly Mug is Sellwood will be on-line shortly. First in Sellwood (SE Portland).
- Nigel's involvement in the Portland Telecom group would involve rooftops owned by the city. Four buildings have been chosen. Has permission to put in gear. It would "shut off" public access in the event of an emergency and be available for emergency use.
Nigel says proprietary WiMax gear WILL be installed. Funding for 4, fault tolerant nodes with free wifi access will be used. Emergency use will be available for public services.
- 6:45pm: Darren Eden, president of Personal Telco, has taken the stage and explains the goals and mission of PersonalTelco. "Most importantly it's about you." Hands out the PersonalTelco contact sheet with the most active users who are installing nodes and making it work. Keegan Quin is the "chief engineer" while Don Park has the final word on what's deployed. Other members, too fast to transcribe, are on the contact sheet.
- Michael Weinburg is introducing Glenn Fleishman. Glenn,in Seattle, is coming through loud and clear and his picture is being projected on a large projection screen. Looks like about 15 fps. Nice.
Glenn explains his background and his interest in WiFi. Glenn says the topic is "The Future is Free - But It'll cost you $20/month".
Jim Thompson, locally in Portland is running Glenn's PowerPoint presentation. Hey, this is working great! Glenn Operates probably the most popular and well read Wi Fi Blog, [http://www.wifinetnews.com WiFiNetNews]
[http://www.wifinetnews.com Glenn] is contrasting T-Mobile's Starbucks with Barnes and Noble locations. B&N locations are bigger. Often an entire building is dedicated to BN. That means a captive venue.
Other captive ventues: Hotels, Conference centers, Airports.
Hotels are becoming increasingly free; Best Western, Holiday Innn, Marriot budget hotels, Wyndham. Now cell phones are destroying room revenue. So packaging access + phone may be the future. Convention Centers, says Glenn, have taken advantage of their captive audience, charging as much as $1000/week for T-1 access.
At this point, Darren got up and said that too many people were using their laptops and causing bandwidth problems. The audio was really pretty good and (almost) completely understandable. Darren has opened it up for q&a.
Other Q&A....not many notes...
Next UP: Jim Thompson.
Jim Thompson was CTO for [http://www.wayport.net Wayport], pioneering some of the first "hot spots" anywhere, many in airports. He left Wayport to found a company called Musenki. The Musenki Box, was a ground-breaking, one-piece Linux-based access point. After Musenki, he worked at Vivato. Jim left Vivato earlier this week to devote full-time to his first love, economical, Community LAN gear, and has developed a follow-on to the Musenki Box. This one-piece box will use Atheros chips with Sam Laffer's MadWiFi drivers. Thompson's company, [http://www.netgate.com Netgate] hopes to sell it for $99!
Jim's speech in on phased array antennas. He says he cannot answer questions or address issues that involve specific Vivato technology. So he's going to do a generic presentation.
Vivato was founded by Skip Crilley. Vivato uses phased array antennas to focus dynamic WiFi beams on individual users. It can use FCC point to point rules for a higher EIRP. Vivato's antenna uses beams with the equivalent of about +25db gain, concentrating the signal for both sending and receiving. Vivato has about 120 individual antenna elements. Vivato has 13 radios simultaneously running.
Multipath is covered in the first slides. Phased Array's focus the beam - dynamically. Co-channel interference, Spatial Diversity and Diversity combining multiple antennas are some of the techniques. But combining antennas also amplifies interference. Equal Gain Combining (EGC) adds linerally.
Jim explains that engineering a phased array with lots of active antennas elements is hard. The gain is not always uniform over the field. The more elements you have, the trickier it is. But it can work. Generating nulls from interfering signals sources is also an advantage of phased arrays.
The presentation is pretty technical with lots of math on how phased arrays work. Your scribe is not going to try to paraphrase.
Jim brought up Motia, the new phased array chip people. They do "blind beam forming" in the analog world. Jim appears somewhat skeptical about Motia but thinks it would be great if it works. Their chips should be out in a few weeks.
What is Jim's personal choice for WiFi chipsets? His personal favorite is Atheros due to cost and performance. It's in CMOS.
Jim also mentioned the Nomadix patent for captive portal. Jim is extremely skeptical. He thinks there's prior art. Jim thinks that the Nomadix patent is unlikely to fly.
Jim like Mesh Networking (OLSR) is an algorhytm he likes.
Jim "thinks 16a will fail." You'd be fighting too much interference. Drive up in a truck by the transmitter, transmit between two laptops, and you are going to cause havoc because the nearby signals will overwhelm weaker signals.
And with that, Jim finished his talk.
Michael Weinburg announced the Capital Campaign. He wants to raise $3000. There will be 50% matching from the principals behind PersonalTelco. He explains that PTP has no money. It needs money to build stuff and create networks and pay lawyers (if needed). You can donate at PersonalTelco with a PayPal account and the web site. Provide internet access to events, etc. Michael also created a brochure for potential ptp node operators.
Show and Tell
Darren shows a SIP VoIP phone. Costs about $65 and plug it into you DSL (Ethernet). Have a WiFi model coming out. Also a board that does software defined radio.
Keegan showed off a 4 port (4 radio) outdoor access point from Latvia. The Mikrotik board has four mini PCI slots and a PC card. Has usb, and other items. Costs $200. Similar to Soekris but a little cheaper.
Tom Higgins displayed a 15db cookie can antenna he made himself for $15. Tom will have a workshop to build dish antenna using PrimeStar satellite dish. Go. Next month.
Darren says PTP will be involved in a July 3th project to link to Port Angeles, Washington. It will link to Victoria, BC. All will party that night. Maybe a video channel across the channel. It will be a permanent link about 30 miles. We've got a bet - $50 for 5mbps.
I (SamChurchill) mentioned tomorrows meeting at the [http://www.mhcrc.org/grant/ApplicationRelease2004.htm Mount Hood Cable Office] which has $700k available for community projects. Can include the I-Net, the city-run coax system.
PTP President Darrin Eden will be giving away a new Linksys WRT54G to one lucky attendee. Entries can be made with a business card or a sheet of paper upon arrival at the meeting, and the drawing will be held at the end of new business. Good luck! And the winners are -- Jeff Willard, Joe McCain, Arason, Mac (of Urban Grind), Ross Olson, Irving, Bert French, and others. Nigel brought the "stuff". The Linksys WRT54G donated by ?, is Troy something or other. Congratulations! An unnamed black box from Netgate was also won, donated by Jim Thompson.
And that's the meeting! It ajourned about 8pm.
After the meeting, informal discussion extended for some 45 mintues. Some members left for Rose and Raindrop Tavern.
Weekly Structure Motion
- Weeklies continue to be run in an "adhoc" fashion.
- One officer will be assigned to attend each weekly. If no officer is available, it will be announced prior to the meeting that none will be in attendance.
- The officer present will take down a list of all points that are brought up that require a board decision. These minutes will be approved by a quorum of attendees prior to the end of the meeting.
- Points needing executive decisions will be addressed by the officers and board members at biweekly meetings. These will be scheduled by the officers and board members based on their schedules, and may vary in time from meeting to meeting. There must be enough people in attendance for a quorum.
- Executive decisions will be announced at monthlies, and then archived in the minutes of those meetings. Individual decisions may be announced by other means if they are time-sensitive.
Weekly Meeting Structure Alternation Motion
Weeklies are held informally every week, the day to be announced on the general mailinglist at some point before it is to happen. Propose amendment to announce meetings on announce mailinglist as opposed to general exclusively. AaronJohnson
- Members, Board and/or Executives may or may not show up.
- At said meetings Items are raised for Discussion and possibly to be moved to Action
- Items resolved to be done at said meetings are done so under the aegis of the "Just Do It" policy. Resloution comes about if a Member or Members deem to take on the Action or Actions.
- The notes of the weeklies are posted to the list and to the wiki, as they have been done, wherein the Membership, Board and Executives can discuss, disuade, disavow, approve, accelerate, aid or ignore the Discussion and Actions.
- The Monthly Meetings will be the time to review and re-evaluate any Discussions or Actions the Members, Board or Executives so desire. This can include some, none or all of the Discusions and or Actions from the weeklies.