February 2013 - PSDR - mailman.hamwan.org

Testing performance of OFDM systems / radios
by Bart Kus 18 Feb '13

18 Feb '13

Does anyone know how to do this? I have a bunch of ideas written down at the Radio Analysis <https://www.hamwan.org/t/tiki-index.php?page=Radio+Analysis&structure=HamWAN> page, but honestly it feels like stabs in the dark. I don't have any true noise generators with adjustable bandwidth (donate! :)), so my simulated wideband interference signal consists of a bunch of peaks instead (FM'ing a carrier with a sine wave). Any tips or help appreciated. Also seeking 1W+ 20dB+ 6GHz+ attenuators, and splitters/combiners (with good isolation) that can work @ 6GHz+. I'd like to simulate a full cell site (3 PtMP sectors + some PtP links) within a totally confined coaxial system, and inject arbitrary noise into it. Given the cost of these microwave attenuators + splitters, it might be easier to set it up with real antennas instead. But that has problems of environmental noise and multipath / echoes. Linked from the Radio Analysis page is the RouterBoard Metal 5SHPn <https://www.hamwan.org/t/tiki-index.php?page=RouterBoard+Metal+5SHPn&struct…> page. It has the result of 1 performance test so far, dealing with amplifier clipping leading to increased sideband energy. This is of great importance in designing sectorized systems. When these unexpected sideband emissions leak into adjacent antennas, you can shoot yourself in the foot. So I'm trying to characterize the tolerance of the radios to nearby or in-band interference. Doing this in TDMA/OFDM space is not trivial. --Bart

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Antenna Shootout results are published
by Bart Kus 18 Feb '13

18 Feb '13

Hello, Last night I took the microwave test lab mobile (what a complicated thing to do, btw). I was able to test all the candidate antennas over a 100m span in an obstruction-free environment. So now we've finally got comparable gain results between antennas over non-trivial distances which allow proper focusing of signals. The details of the whole setup and the results are available at the Antenna Shootout <https://www.hamwan.org/t/tiki-index.php?page=Antenna+Shootout&structure=Ham…> page. I'll have to do this type of measurement again though, since 2 new sectors just came in, and I have 1 more on the way. Die Antwoord is still lookin like a great antenna. :) --Bart

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More sector antenna results, and high gain antenna battle heats up!
by Bart Kus 17 Feb '13

17 Feb '13

Hello, Did some more antenna measurements tonight. The Ubiquiti sectors were the new contenders for the "official sector" title. The 5G-16-120 <https://www.hamwan.org/t/tiki-index.php?page=Ubiquiti+5G-16-120&structure=H…> didn't do so well. Gain is dreadful and the radiation pattern is nearly omnidirectional. Blah! The 5G-19-120 <https://www.hamwan.org/t/tiki-index.php?page=Ubiquiti+5G-19-120&structure=H…> did a lot better. It looks to be a 90 degree sector though, if we're honest. -3dB points were measured just 81 degrees apart. The +/- 60 degree points look to be -8dB, not the -6dB I've come to expect from some manufacturer beamwidth claims. The radiation pattern is also a bit weird in its shape, but not awful. The frequency response is pretty good though. The final drawback of this sector is price. It's about $150 a piece. Although that is cheaper than the Laird sector which is $180 a piece. This Ubiquiti sector is also dual polarity, so if we ever do MIMO, antennas won't have to change. More contenders have arrived though! I'll get them tested soon. Hopefully they blow all these expensive sectors out of the water. :) Now, on the "official high gain antenna" front, I've measured two new contenders as well. The ARC-DA5834SD1 <https://www.hamwan.org/t/tiki-index.php?page=ARC+ARC-DA5834SD1&structure=Ha…> does not disappoint. It is well constructed and weighs less than you'd think. The frequency response is the flattest of ANY of the antennas tested so far. The radiation pattern is THE most directional of any of the antennas tested so far as well. Just look at that gorgeous rejection, all at least -30dB down. This is the #1 choice if you've got the $300 (shipped) to spend on it. It is also a dual polarity antenna with a fair amount of isolation between the polarities. On the rear are N-connector to waveguide adapters. They combine to feed one solid circular waveguide that protrudes from the center of the dish. At the end of the waveguide structure the metal turns to plastic and the waves are allowed to radiate through the plastic shield/support onto the subreflector at the very tip. This subreflector has a really cool wavey pattern milled into it on the underneath to collimate all the waves properly to/from the main reflector dish. I found the N connectors somewhat hard to start threading for whatever reason. Was not getting alignment. The mounting system is well thought out and a pleasure to use, especially to adjust the tilt of the antenna! You just turn one nut to raise/lower the tilt. To rotate you can loosen both U-bolts. Now, normally this would make the antenna slide down. But they're thought of that and provide you with a stopper you install on the mast before hand. The weight of the antenna rotates on this base. When angled right, you just tighten the antenna's u-bolts. There's also a built-in mini-mast section to bolt a radio to. Very well thought out. A very nice antenna. But still, $300 shipped from Streakwave isn't cheap. WLANmall looks to have it <http://www.wlanmall.com/arc-34dbi-dual-pol-4-94-5875ghz-dp-dish.html> for much less shipping. Streakwave tried to jack the shipping on this antenna by another $50 *after* I placed the order. It would have been $350 if I let them have their way. The Poynting K-GRID-003-06 <https://www.hamwan.org/t/tiki-index.php?page=Poynting+K-GRID-003-06&structu…>, henceforth known as "Die Antwoord <http://en.wikipedia.org/wiki/Die_Antwoord>", is a surprisingly well performing high gain antenna. It is designed and manufactured in South Africa <https://maps.google.com/maps?hl=en&ll=-26.10403,28.079563&spn=0.012689,0.00…>, just like its musical namesake. It may indeed be "the answer" for HamWAN's directional antenna needs. While I do not have official trustworthy absolute gain comparison figures yet for any of the antennas, the preliminary numbers make it look like Die Antwoord gets about 5dB over its similar-in-size cousin, the Laird GD5W-28P <https://www.hamwan.org/t/tiki-index.php?page=Laird+GD5W-28P&structure=HamWAN>. It also looks like the $300 dish is only 1dB better. Die Antwoord also features a much flatter frequency response, and a far better radiation pattern than the Laird. You know you're doing something right when the manufacturer's published H-plane pattern <http://cdn.entelectonline.co.za/wm-43814-cmsimages/A-K-GD-003-06%20Datashee…> strongly resembles your own results. Notice the distinctive side-lobes touching -20dB on either side of the main lobe. Notice the containment of all other lobes within the -30dB limits. This is a FINE antenna! And for not lying about the patterns like so many others do, Poynting gets my "fine manufacturer" seal of approval. Poynting and I disagree on the frequency response, but the difference is 1dB, so I'll let it go. :) The gain is really quite flat. A surprising achievement for such a broadband antenna. In fact, the gain flatness is only bested by the $300 ARC dish mentioned in the previous paragraph. What does all this wonderful performance cost? Would you believe a mere $95 shipped <http://www.titanwirelessonline.com/Poynting-5-8GHz-31dBi-Grid-p/at-30gr-58.…>? NOTE: Do *NOT* follow the advice of the one gentleman who commented on this product at the link I just gave you. The man is a fool who ruined his antenna. :) The radiating element is meant to be unconventionally oriented. Follow the assembly instructions. The physical size difference between the $95 Die Antwoord (bottom) and the $300 ARC dish (top) is small. Here they are both enjoying my couch, just yearning to RF @ each other: To truly measure the real long distance gain of these antennas, I've got to test them over a longer range. Something like 100m should be enough to make the EM waves mostly perpendicular to the DUT antennas instead of hitting them at weird angles. This straightening of geometry should allow for real-world gain measurements and comparison of absolute gain performance. A 3ft dish on a 20ft range may not get the chance to focus correctly, and it may be losing gain because of this. I've taken steps so that I can take the measurement lab mobile and deploy in a large field. I also screwed up the measurement process enough times that I finally sat down and documented it, step-by-step, at the bottom of the Antenna Analysis <https://www.hamwan.org/t/tiki-index.php?page=Antenna+Analysis&structure=Ham…> page. Who could possibly screw up executing a 57 step sequence from memory? :) Finally, I also had a discussion with a microwave antenna measuring friend of mine, and figured out how to measure the absolute gain of each antenna. This is different from measuring "comparison of absolute gain", aka "absolute gain delta between antennas". This would be deriving that actual dBi you'd print on a box of a product and you'd have to stand by it. I'm not sure if the process is worth it though, since it's only the deltas which lead to antenna selection decisions. We'll see. Now, where are those new sectors ... --Bart

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34dBi 3ft dish is here
by Bart Kus 14 Feb '13

14 Feb '13

Seems legit.... --Bart

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Ubiquiti sectors are here
by Bart Kus 14 Feb '13

14 Feb '13

From left->right we have: Ubiquiti AirMax 5G-19-120, Ubiquiti AirMax 5G-16-120, ARC Wireless ARC-VS5818SD1. Then laying on the bottom we have the Laird SAH58-120-16-WB, shown without radome cover. The Ubiquiti antennas will go on the antenna test range shortly. Just an interesting size comparison. --Bart

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Re: [HamWAN PSDR] system usage
by KL7WM＠aol.com 13 Feb '13

13 Feb '13

But we can order pizza on our amateur radios. I wouldn't go much farther then that though. Daniel Stevens KL7WM In a message dated 2/13/2013 7:57:32 A.M. Pacific Standard Time, rob(a)quailsoftltd.net writes: Short answer – I did read the mission <g>. In this instance I had no knowledge of Seattle vs NW Mesh and looked up the wrong one. There are will still be the need to make ongoing distinctions though, and your long answer even can create some situations where the line would be blurred. As an example – using hamWAN as an Internet survival backup for amateur purposes is one thing – i.e. – during a disaster contacting another ham or looking up information on a website. Shopping via hamWAN on the other hand, crosses the commerce line – i.e. – you can’t order a pizza on ham radio. I see this as one of those ongoing conversations that will probably be more of an issue as we get started than once things “firm up”. Once we start having some demonstrated amateur uses it will help illustrate the drawn lines. Rob From: PSDR [mailto:psdr-bounces@hamwan.org] On Behalf Of Bart Kus Sent: Wednesday, February 13, 2013 12:06 AM To: Puget Sound Data Ring Subject: Re: [HamWAN PSDR] system usage An excellent point to bring up, and one I've struggled with in the past as well. Short answer: read _Article 0_ (https://www.hamwan.org/t/tiki-index.php?page=Constitution&structure=HamWAN#…) of the _Constitution_ (https://www.hamwan.org/t/tiki-index.php?page=Constitution&structure=HamWAN) . It describes HamWAN's mission. Longer answer with rationale for HamWAN's mission: A useful and vibrant computer network is one that allows like-minded people to communicate together. In the case of the Internet, we have the ultimate wide deployment across geographical regions and social groups. It is everywhere and provided to everyone. From there, you see communities forming around their collective commonalities. Topic-specific message boards, mailing lists, IRC channels, web sites/apps, etc. We cannot hope to compete with the speed of terabit fiber-optics, or the budgets of global ISPs to be all things to all people. I, however, am a nerd. And I enjoy the company of my fellow nerds. It is these nerds that I would like to exchange data with. I believe that passing a basic amateur radio license exam is a good filter for the quality of nerd that I'd like to see on the network. Such a requirement also broadens the adoption of amateur radio itself in our society filled with computer nerds, who would love to play with digital networks, but don't have a ham license. This is a good thing. The compu-nerds might learn new things in the realm of radio along the way. Voice net check-ins burn at my computer-literate soul, and the injection of computer-savvy nerds into the amateur radio hobby will fix these archaic procedures. So there you have (part of) the rationale for requiring all participants to be licensed radio amateur operators. I'm also a bit of an independent. Why should I put my communications needs solely in the hands of large corporations and the Internet? Most of my communication is local. I would be very happy to achieve independence from the corporate teat for at least my local communications needs. On this kind of independent network, WE define the rules. Comcast wants to charge $200/mo for a 50Mbit downlink feed. I think we can beat that if we build it ourselves. And make it symmetrical at the same time, so none of this 10Mbit uplink limit. Nerds are not just consumers, they're also providers of data services. The common Internet services target your typical mom & pop audience, who are dominantly consumers of data. I'd love to live in a world where I can carry around a _ham-phone_ (http://en.wikipedia.org/wiki/NinjaTel_Van) , my car is a mobile ham-hotspot, and my house is tied into the HamWAN, all at a significantly lower cost than the for-profit commercial offerings, while being tailored to my nerdy needs. And there you have some rationale for "free digital communication" as a goal. I can go on for quite a while on this subject. :) I'm also a bit of a survivalist. I like knowing exactly how my communications facilities work and how to fix them. Should my Internet or cell service go down, I like knowing I have another completely independent system of communication. The other emergency communications groups share this attitude, and it makes them great partners in building this network. These are the driving forces behind the emergency communications part of HamWAN's mission. Did I mention I'm a nerd? :) Doing the R&D to bring this type of network to life is great fun. A long focused effort by a group of nerds will (and already has) produced valuable results. These need to be published so that others may benefit from our experience in building their own networks of this kind. And there you have mission point #2, about conducting and publishing R&D. The publication of this knowledge also ties in with point #4, of educating and spreading knowledge. Point #4 is also supported by requiring participants to pass ham exams. Lastly, I realize HamWAN will not be in control of all such like-minded networks. These types of ideas (both technical and organizational/social) can spread like wildfire, and independent groups are sure to spring up. When groups' networks grow and start touching each other, I want to be sure they are compatible. For this reason the last sentence of the mission statement is that HamWAN will act as a coordinator of interoperability. The recent decision to go with AMPRnet block registration solves a large part of the interoperability problem. But there are other considerations, such as the universal adoption of the NV2 protocol which would make a roaming ham's equipment compatible with other groups' networks. We may also have to implement an inter-network registration system for roaming hams. There are analogous systems in the cellular telco world. If we develop & establish a universal system of digital ham identity at least, that would go a long way even if we fail on the protocol adoption front. Someone suggested using the LoTW client certificate, which is not a bad idea at all. ARRL provides a rigorous identity verification system in LoTW signup, although I'm not sure how good they are at expiring said certs in a timely manner should the registration lapse or be revoked by the FCC. Phew! I'm out of words. There's so much work ahead it's scary. _Recruiting recruiting recruiting recruiting_ (http://www.youtube.com/watch?v=KMU0tzLwhbE) ! There's no way I can implement the entirety of this vision for the future alone. --Bart On 2/12/2013 9:16 PM, Rob Salsgiver wrote: Ok….. time for more questions, now that the marathon meeting is over <g>. A number of times I’ve heard potential uses that seem to blur the line between amateur and commercial, so my question is – how do we draw the line? As an example – connecting to the Seattle MeshNet. As I read it, the MeshNet is non-amateur. Are we looking to be a generic carrier grade ISP? If so, then this will work, but we won’t be able to use amateur frequencies to do it. Similar question for connecting firehalls down south – if we are sticking to strictly amateur uses, then the usage by laptops and other devices at a firehall would be limited to amateur related uses – i.e. – no non-hams using it. It may be that I’m just missing a big concept here, but I see a lot of blurring of the lines in conversation, and I think it needs to be better spelled out before we get in front of too many folks. I’ll stop with this one for now, rather than continue to show my ignorance and unfamiliarity <g>. Rob _______________________________________________ PSDR mailing list _PSDR(a)hamwan.org_ (mailto:PSDR@hamwan.org) _http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org_ (http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org) _______________________________________________ PSDR mailing list PSDR(a)hamwan.org http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org

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Re: [HamWAN PSDR] system usage
by KL7WM＠aol.com 13 Feb '13

13 Feb '13

The NW Mesh is a yahoo groups. They have had several Mesh Day meetings and have another one scheduled on March 16th in Auburn. Register at HamShare.com Daniel Stevens KL7WM In a message dated 2/13/2013 7:51:22 A.M. Pacific Standard Time, rob(a)quailsoftltd.net writes: Ah – THAT clicked it in. I had not heard of the NW Mesh “movement” and had done a search and turned up the Seattle Mesh. Thanks, Rob From: PSDR [mailto:psdr-bounces@hamwan.org] On Behalf Of Cory (NQ1E) Sent: Wednesday, February 13, 2013 1:20 AM To: Puget Sound Data Ring Subject: Re: [HamWAN PSDR] system usage Seattle MeshNet is not an amateur radio project and is strictly part15. That network would not be a likely peer for HamWAN. You may be confusing that with NW-MESH which is a recently popular ham-based project in the Seattle area. NW-MESH would be a perfect candidate for peering with HamWAN. _http://groups.yahoo.com/group/NW-MESH/_ (http://groups.yahoo.com/group/NW-MESH/) _http://nw-mesh.wikidot.com/_ (http://nw-mesh.wikidot.com/) On Tue, Feb 12, 2013 at 9:16 PM, Rob Salsgiver <_rob(a)quailsoftltd.net_ (mailto:rob@quailsoftltd.net) > wrote: Ok….. time for more questions, now that the marathon meeting is over <g>. A number of times I’ve heard potential uses that seem to blur the line between amateur and commercial, so my question is – how do we draw the line? As an example – connecting to the Seattle MeshNet. As I read it, the MeshNet is non-amateur. Are we looking to be a generic carrier grade ISP? If so, then this will work, but we won’t be able to use amateur frequencies to do it. Similar question for connecting firehalls down south – if we are sticking to strictly amateur uses, then the usage by laptops and other devices at a firehall would be limited to amateur related uses – i.e. – no non-hams using it. It may be that I’m just missing a big concept here, but I see a lot of blurring of the lines in conversation, and I think it needs to be better spelled out before we get in front of too many folks. I’ll stop with this one for now, rather than continue to show my ignorance and unfamiliarity <g>. Rob _______________________________________________ PSDR mailing list _PSDR(a)hamwan.org_ (mailto:PSDR@hamwan.org) _http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org_ (http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org) _______________________________________________ PSDR mailing list PSDR(a)hamwan.org http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org

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Re: [HamWAN PSDR] system usage
by KL7WM＠aol.com 13 Feb '13

13 Feb '13

In a message dated 2/13/2013 7:51:22 A.M. Pacific Standard Time, rob(a)quailsoftltd.net writes: Ah – THAT clicked it in. I had not heard of the NW Mesh “movement” and had done a search and turned up the Seattle Mesh. Thanks, Rob From: PSDR [mailto:psdr-bounces@hamwan.org] On Behalf Of Cory (NQ1E) Sent: Wednesday, February 13, 2013 1:20 AM To: Puget Sound Data Ring Subject: Re: [HamWAN PSDR] system usage Seattle MeshNet is not an amateur radio project and is strictly part15. That network would not be a likely peer for HamWAN. You may be confusing that with NW-MESH which is a recently popular ham-based project in the Seattle area. NW-MESH would be a perfect candidate for peering with HamWAN. _http://groups.yahoo.com/group/NW-MESH/_ (http://groups.yahoo.com/group/NW-MESH/) _http://nw-mesh.wikidot.com/_ (http://nw-mesh.wikidot.com/) On Tue, Feb 12, 2013 at 9:16 PM, Rob Salsgiver <_rob(a)quailsoftltd.net_ (mailto:rob@quailsoftltd.net) > wrote: Ok….. time for more questions, now that the marathon meeting is over <g>. A number of times I’ve heard potential uses that seem to blur the line between amateur and commercial, so my question is – how do we draw the line? As an example – connecting to the Seattle MeshNet. As I read it, the MeshNet is non-amateur. Are we looking to be a generic carrier grade ISP? If so, then this will work, but we won’t be able to use amateur frequencies to do it. Similar question for connecting firehalls down south – if we are sticking to strictly amateur uses, then the usage by laptops and other devices at a firehall would be limited to amateur related uses – i.e. – no non-hams using it. It may be that I’m just missing a big concept here, but I see a lot of blurring of the lines in conversation, and I think it needs to be better spelled out before we get in front of too many folks. I’ll stop with this one for now, rather than continue to show my ignorance and unfamiliarity <g>. Rob _______________________________________________ PSDR mailing list _PSDR(a)hamwan.org_ (mailto:PSDR@hamwan.org) _http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org_ (http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org) _______________________________________________ PSDR mailing list PSDR(a)hamwan.org http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org

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system usage
by Rob Salsgiver 13 Feb '13

13 Feb '13

Ok... time for more questions, now that the marathon meeting is over <g>. A number of times I've heard potential uses that seem to blur the line between amateur and commercial, so my question is - how do we draw the line? As an example - connecting to the Seattle MeshNet. As I read it, the MeshNet is non-amateur. Are we looking to be a generic carrier grade ISP? If so, then this will work, but we won't be able to use amateur frequencies to do it. Similar question for connecting firehalls down south - if we are sticking to strictly amateur uses, then the usage by laptops and other devices at a firehall would be limited to amateur related uses - i.e. - no non-hams using it. It may be that I'm just missing a big concept here, but I see a lot of blurring of the lines in conversation, and I think it needs to be better spelled out before we get in front of too many folks. I'll stop with this one for now, rather than continue to show my ignorance and unfamiliarity <g>. Rob

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We have a Constitution!
by Bart Kus 12 Feb '13

12 Feb '13

Good Newwws, Everyone! The HamWAN board of directors cast a unanimous vote tonight accepting a slightly modified version of the proposed constitution. Our constitution has now been published at the Constitution <https://www.hamwan.org/t/tiki-index.php?page=Constitution&structure=HamWAN> page, and is in effect immediately. Why is this management overhead good news? We finally have an official process for making decisions! So if someone wants to spend HamWAN money, there's a way to go about it that's completely above board, in the light of day, using a unanimously agreed upon process, and without any ill feelings. There are plenty of other benefits, such as defining director election / removal procedures, but the biggest benefit is the ability to make official decisions in a quick and sanctioned way. Tremendous progress! Over the next few weeks the board will be working on defining our By-Laws, which will fill in the specific details of the generic language found in the constitution. We will follow Article VII of the constitution to bring the By-Laws into effect. This calls for a >=66% in-support vote, cast by HamWAN project members, not just board members. Non-voting members will not be counted as per our new constitution. In creating the constitution, I wanted to shift the power and control to those people who are actively engaged in the project. Those who are contributing. There is no concept of quorum. All voting procedures, with the exception of director removal votes, are counted based on participating member/director votes only. Abstaining from voting does not block any decisions. I won't rant about this any more. Read the Constitution page. It's really short...by design. :) --Bart

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