February 2013 - PSDR - mailman.hamwan.org

Traffic protection without encryption
by Benjamin Krueger 23 Feb '13

23 Feb '13

I think we can solve a lot of our crypto-regulation problems if we explore IPSec in Authentication Header Transport mode. This signs every IP packet which gets us connection integrity, origin authentication, and replay protection without encrypting anything. Then we only have to take very basic measures to ensure folks don't intentionally or unintentionally make encrypted connections (over SSL, SSH, or other commonly encrypted protocols). The only outstanding question then is how to handle IKE (key exchange) in an automated way with certificates. I'm going to speak to some infosec geeks about this tonight NB: This doesn't handle initial network access authentication. That's still a problem to be solved, possibly with 802.1X, though that has its own problem since RouterOS only supports TLS-EAP which incorporates crypto. -- Benjamin

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Holy smokes - we really need to update some of these subject lines!
by Rob Salsgiver 22 Feb '13

22 Feb '13

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Re: [HamWAN PSDR] Holy smokes, we have Internet address space!
by KL7WM＠aol.com 22 Feb '13

22 Feb '13

I don't understand why you don't get it. It is LEGAL TO ORDER PIZZA ON HAM RADIO unless you own or work for the pizza business. PERIOD. If you are a pizza delivery driver you can't use amateur radio to get direction to a customer. We have swap net on amateur radio. We talk about money on the air. This is OK TOO! Daniel Stevens, KL7WM In a message dated 2/20/2013 11:38:40 P.M. Pacific Standard Time, cory(a)nq1e.hm writes: It appears that we're getting our layers mixed up. Phone patches to the pizza place are legitimate because the patching system itself is run by a licensed control operator. In this case, the RF link is layer 1 and the phone call is at least layer 3. The rules are for governing who gets to use layer 1 and for what purpose. It would be totally inappropriate for a pizza place to get a radio and camp on a frequency for the purpose of accepting orders. However, contacting another ham and asking them to order a pizza for you on their phone (or giving you an auto patch to do it yourself) is appropriate because the RF portion is still ham-to-ham, even if the message being relayed is not. The same goes for "broadcasting". Your transmission must be intended for one or more hams, even if the message must be relayed by them to reach its final destination. If you knew the general public all had scanners tuned to a ham frequency, it would not be appropriate to create your own radio show meant for them. Regarding AAA, I think we were also thinking about different layers. Securing the configuration of a network device and providing "security" for a network service (think SSL/TLS) is quite a bit different. I was referring to the latter. Using IPSec(AH) is a very good idea. I have high hopes that this will all work out. It sounds like so much fun, I can't contain myself! ;) -Cory On Wed, Feb 20, 2013 at 9:55 PM, Bart Kus <_me(a)bartk.us_ (mailto:me@bartk.us) > wrote: First of all, +1, Informative. On 2/20/2013 11:22 AM, Cory (NQ1E) wrote: It's not just optimization. We have serious restrictions on what type of content can be moved over our RF links. Everyone who runs a device that transmits is responsible for its operation. Luckily there is precedent here since each node can be considered the same as a "digital packet repeater" in historical context. In those cases, the repeater operator is not held liable for illegal content relayed through them as long as they take "reasonable measures" to limit it and when discovered, stop it. While it's not preferable to get into the distributed firewall business, it may be necessary if this network carries traffic to or from the internet. If we had another "reasonable" way to make sure only licensed hams were able to originate content on the network, firewalls likely wouldn't be needed. I think of the case of an audio repeater phone patch. A ham can call someone via hammy spectrum, but the return voice traffic may not belong to a ham. This has been allowed in the past as fair use. Now if we tweak the scenario and say the phone call is originally inbound from the repeater to the ham by a non-ham, but consists of content which the ham (in control of hanging up) considers appropriate as per the hammy rules of airwave content, should the conversation be allowed to continue? :) My read on this is yes. 99% of the airtime will be the bidirectional content of the conversation, just as it is in the outbound case. As long as this content is in compliance with ham law, it ought not matter who sent the original ring. The next step in this line of thinking is to translate the concepts of the analog telephone call to that of opening a digital inbound TCP session to a ham server. It's up to the ham who is hosting the server to ensure that the content of such conversations complies with ham rules. Hang up (TCP RST) the session if the content goes outside the law. The role of HamWAN is simply to facilitate the exchange of signals, and we're not held responsible (as per voice repeater rules) should hams decide to break the rules of content. There is of course that little lingering issue of the initial unsolicited ring in the analog world, or TCP SYN in the digital world making its way onto hammy spectrum. I like to think HamWAN could even set some useful precedent here, by delivering worthy use-cases, and perhaps cause an eventual tweak to the official rules to allow for short control messages ("I would like to talk") to be sent over hammy spectrum by non-hammies. Another way of thinking about this inbound ring from non-hams is that while the actual ring is received by ham equipment (repeater / digital microwave router) on a non-hammy medium (telco / ISP network), the hammy RF spectrum transmission from the repeater or digital microwave router is not a signal relay, but rather a whole new communication, initiated by a ham-licensed station (the repeater and its owner) to inform the target ham of the presence of an inbound message on the non-hammy medium, and is therefore ham2ham traffic after all! We can do these legal mental gymnastics for a long time, but the bottom line is unless someone actually complains and the FCC decides to care, we should just go on and operate instead of shying away in fear. If the practices are eventually ruled as illegal, we can cease such operations easily by applying new firewall rules. I hope it does not come to that as it would greatly stall the progress of digital ham radio. In a somewhat related issue, there is also precedent for hams using encrypted WiFi links with part 97 rules. Supposedly, it's only acceptable to encrypt when the purpose is not to hide the content of your message. This means that it's okay to run encryption as long you publish the decryption keys so that they could be found by the public (negating the point of using encryption in most cases). Agreed, and I know of people who do this with P25 gear. But I don't see any useful cases in which HamWAN could make use of encryption while publishing the keys. The frequencies that we're allowed to use as licensed radio amateurs belong to the public and we're allowed to use them for the purposes of experimentation and communication with other amateurs. In order to assure the fair use of such a valuable resource, we have to follow strict rules that prevent commercial interests from taking over. That's why we're not allowed to conduct business on the air or communicate with the general public (broadcast). That's also why it's important that anything transmitted is not intentionally obfuscated from anyone else's ability to view it. I see the _definition of broadcast_ (http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&SID=ad552c047464dd8e611924492c5… .6&idno=47#47:5.0.1.1.6.1.157.2) you cite there, and boy is that a weird one. I'd counter this with my phone patch example, and cite the _ARRL guidance_ (http://www.arrl.org/phone-patch-guidelines) on the matter, which allow communication with non-amateur third parties (is that the same as "general public"?). In fact, the ARRL guidance counters what has been said about commercial communications in a previous thread: Calls to place an order for a commercial product may be made such as the proverbial call to the pizza restaurant to order food, but not calls to one's office to receive or to leave business messages since communications on behalf of ones employer are not permitted. The ARRL guidance on reverse autopatch (inbound TCP) actually runs counter to my views on the subject. In part, it states: Incoming calls to an autopatch must be answered and screened off the air by the control operator to ensure rule compliance. If an incoming call automatically causes the repeater to transmit, even if it's just a signal tone or notification message, then it is possible for an unlicensed person to initiate a transmission without the control operator's knowledge or approval, which is not permitted. This to me sounds like we absolutely need a ham-controlled edge firewall mechanism to "screen the calls off the air" as per the individual hams' specifications. One thing is for sure: we're in brand new territory. We need to tread with the utmost character so we set a good example for others who follow us. As a long-time computer engineer with a strong emphasis on security, the idea of having such an open network is very scary to me. However, it's also why I'm excited about the challenge. When most people think about security, they only think about secrecy (hiding your messages). However, security also includes authentication (making sure messages really come from the intended sender) and integrity (has this message been altered in transit). With those two aspects and a lot of help from public key cryptography, my hope is to contribute to making a network that is both open *and* secure. I've already made some strides in this area for other ham-related projects of mine, and now I'm hoping to translate that to the needs of the overall network. This is exactly right. Well, almost. :) Cisco's thinking gets it right when they refer to AAA: Authentication, Authorization and Accounting. For anyone unfamiliar with what these concepts mean exactly, can _refer to this page_ (http://www.cisco.com/en/US/docs/ios/12_2/security/configuration/guide/scfaa…) . Also Wikipedia has a _page on AAA_ (http://en.wikipedia.org/wiki/AAA_protocol) . The additional point you make about Integrity may not necessarily fall under the "Authentication" concept, since that deals more with actors in a network rather than the non-molestation of their messages, but can be served nicely by an implementation of _IPSec in AH mode_ (http://en.wikipedia.org/wiki/Ipsec#Authentication_Header) . Tons of work here for sure, after the lower layers of the network (RF) are up and running. --Bart On Wed, Feb 20, 2013 at 12:16 AM, Bart Kus <_me(a)bartk.us_ (mailto:me@bartk.us) > wrote: It's just a little more efficient to stop unwanted traffic early, before it takes up a bunch of airtime. Just an optimization, which may not be worth the complexity right up front. Your suggestion works too. --Bart On 2/19/2013 8:46 PM, Benjamin Krueger wrote: Just saw this, "just needs to push an ACL update". Why can't we just route all traffic and let the client nodes run their own firewalls? We *really* don't want to be in the distributed firewall business. :) On Wed, Feb 13, 2013 at 4:04 PM, Bart Kus <_me(a)bartk.us_ (mailto:me@bartk.us) > wrote: Global reachability is not in conflict with autonomy. Achieving both simultaneously just requires careful design of HamWAN network services. If the HamWAN internet feed drops off, the routing, DNS and other services need to continue working. The first word in ASN is Autonomous after all. :) I consider NAT and Proxies as old crusty hacks from the age of ISPs giving out just 1 IP/customer. It's time to put these ideas to rest. IPv6 will do this on the commercial internet in the coming years, and AMPRnet will allow us to do it immediately here. For the cases where communication is to be restricted due to user preference, we can push filtering rules to firewalls at the edges of the network, and at the HamWAN <-> user site interface. In short, firewalls: yes, nat+gateways: no. If a user wants to make a service running on one of his servers public, he just needs to push an ACL update to HamWAN and it'll be opened up. No need to re-IP, update DNS, change NICs, whatever else. And most importantly, it makes everyone equal. Your subnet allocation has the same powers as mine. There is no special ground to fight over, such as space on a public subnet, or access to some officially sanctioned gateway servers that are allowed to do special things. If you want though, you can of course live in the world of private IPs and NAT. Just configure your LAN router that way. Complete freedom of configuration. This is the way the internet should have evolved for geeks! --Bart On 2/13/2013 8:30 AM, Cory (NQ1E) wrote: Unless I've misunderstood the point of this network all together, there shouldn't be a case where we want the entire network address space to be reachable from the global internet. It's much more likely that the network will remain as autonomous as possible and any connections to the internet will be for connecting specific services through a gateway of some sort. A subnet of at least /23 (typical minimum for global BGP announcements) should be reserved for the purpose of being globally routable in the future, if/when HamWAN decides to peer with one or more ISPs. An address in the /23 can be given to each service gateway for connecting to the internet. The rest of the 44-net allocation can be treated as private address space, except that it's essentially guaranteed not to cause conflicts with the user-level networks since it's still globally unique. On Wed, Feb 13, 2013 at 2:28 AM, Bart Kus <_me(a)bartk.us_ (mailto:me@bartk.us) > wrote: Clever ;) What if HamWAN switches ISPs? All that IPv6 space would need to be given up. It can't follow you AFAIK. Or the ISP may charge whatever they feel like to let you take it with you. Also bad. The fees for IPv6 are not as low as I had hoped, but not as high as you think either! There's a 25% discount in effect for "extra-small" allocations (which are still larger than the entire IPv4 internet). The cost looks to be $937.50/yr. Not sure it's worth the cost, given the IPv4 AMPRnet situation. We can very likely just expand our AMPRnet allocation if we out-grow the /20. --Bart On 2/13/2013 1:10 AM, Cory (NQ1E) wrote: Here's an IPv6 allocation for you ;) ::ffff:_44.24.240.0/116_ (http://44.24.240.0/116) With the obvious exception of AMPRNet addresses for amateur radio use, IP allocations should come from an ISP. Obtaining a direct allocation from ARIN would cost around a couple grand per year. On Wed, Feb 13, 2013 at 12:46 AM, Bart Kus <_me(a)bartk.us_ (mailto:me@bartk.us) > wrote: Result: APPROVED Your allocated subnet is: _44.24.240.0 / 20_ (tel:44.24.240.0%20/%2020) _https://portal.ampr.org/networks.php?a=region&id=191_ (https://portal.ampr.org/networks.php?a=region&id=191) HamWAN now has 4096 real Internet IPs to play with. Next up: we gotta crack the mystery of getting IPv6 net space. Any volunteers? :) What an incredibly productive day, --Bart _______________________________________________ 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_ (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_ (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_ (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_ (mailto:PSDR@hamwan.org) _http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org_ (http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org) -- Benjamin _______________________________________________ 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_ (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_ (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_ (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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Sector self-interference rough results
by Bart Kus 21 Feb '13

21 Feb '13

Hello, I setup 2 similar sectors (in terms of their +/- 120 deg attenuation characteristics) on a section of Rohn 25, angled at 120 deg away from each other. The Laird and the 19dBi Ubiquiti were the specific sectors used. I was able to measure the path loss between them as -65dB. This seems pretty good! But maybe it's not enough. With +31dBm @ full power on one sector, 65dB of attenuation results in -34dBm out-of-band power at the adjacent receiver. The attenuation of this remaining -34dBm is left up to the receiver filter skirts. By transmitting low-power in-band packets into this same receiver, a throughput slow-down was observed. Shifting the interfering RF 30MHz further away from the channel being measured paradoxically resulted in a FURTHER slow-down. This is not consistent with filter skirt behavior. Something else must be at play. These are pretty rough results, since the setup is entirely in my garage and is subject to tight confinement which means lots of reflections. I need to test the path loss when the sectors are spaced further apart, to simulate a larger tower structure, or the presence of an intentional separation system. In a real-world deploy the sectors may also be staggered vertically to minimize coupling. I should also try building shields to see if that improves isolation. As Rob pointed out, gotta be really careful about destructive interference bouncing off these shields. Which means measuring FR over several angles. Good thing a 2-axis positioning rig is on the way to facilitate this kind of testing. :) RF is hard. --Bart

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toys & tennas
by Rob Salsgiver 21 Feb '13

21 Feb '13

Got 2 radios - (5SHPn's) and one of the ARC-DA5830SD1's in today from Baltic Networks. So far received 2 orders from them and they seem to be a dependable source. Got a couple of rubber ducks and some adapters to round out the package for a garage to house link so I can do some playing around with the OS and a few other things. Ordered and received a Yeasu 5500 AZ/EL rotor with a FoxDelta ST-2 PC interface (used). Had to make the cables between the rotor control box & rotor. All tested out very nicely. FoxDelta is a serial-port driven interface that can also control the rotor via front panel push-buttons. The 2 line LCD shows programmed AZ and EL, as well as current AZ/EL. Protocol for commanding it seems to be very straightforward and quite simple. Character codes followed by text or integer values, sent via serial port. Current position can be read the same way. Calibrated the unit and put it through full rotation testing via Hyperterminal <g>. Commanding and controlling the rotor should be fairly easy - going to start an application to do a predictable pattern of scanning for measuring the antenna radiation patterns. Bart - we traded a basic outline on the scan setup, but we'll need to come up with however you want to coordinate the position control with the measurement recording. Do you want to have the position sent to the test equipment, output the test equipment values to the PC to be recorded with the position, or something else? I don't know that I need the info right this second, but we can start thinking about it in the background. Sunday will be my first day to play with it, but barring Murphy it shouldn't take THAT long (famous last words..) Cheers, Rob

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Sector antenna radiation geometry and alignment procedure
by Bart Kus 21 Feb '13

21 Feb '13

Hello, I'm about to start measuring the vertical radiation patterns of the sector antennas here. But before I start that exercise, I thought it'd be good to understand the vertical radiation requirements first! To this end, I've updated the Radio Frequency Engineering <https://www.hamwan.org/t/tiki-index.php?page=Radio+Frequency+Engineering&st…> page with a semi-bogus example (does not account for ground elevation at the client side) between Cougar Mtn and Paine Field. From the example, I also outlined a procedure for sector alignment to achieve the correct radiation pattern in the real world. Any comments or suggestions for improvement? Seeing the actual geometry is kind of startling. I think it'd be helpful to translate and import the actual sector antenna radiation pattern readings being done in the lab to Radio Mobile .ant files and simulate coverage based on real topographical data. Anyone feel like writing the conversion software, or is familiar with .ant file format? I don't think it's possible to feed it 3D radiation patterns, but at least AZ/EL single polar scans should give something useful. --Bart

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Ever seen an OFDM signal up close?
by Bart Kus 19 Feb '13

19 Feb '13

No? Well now you have! There's 26 of these little beauties spaced 312.5kHz apart on each side of the center marker. You can see the marker delta of 310kHz (resolution wouldn't let me be as precise as 312.5) showing the first subcarrier peak to the right of center. This one is special, in fact. It is one of 4 pilot subcarriers spread among the 52 total, leaving 48 subcarriers for data transport. This picture only shows 10MHz of the spectrum since it's hard to see the full bandwidth at this low resolution of 1001 pixels horizontal. This has been your neat fact of the day. --Bart

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Weekly meeting in 1 hour (@7PM PST)
by Bart Kus 19 Feb '13

19 Feb '13

Hello, Just a reminder that our weekly board + development team meeting will be held in 1 hour @ 7PM PST. *Meeting Details* *How* Mumble <http://mumble.sourceforge.net/> voice + text chat software *Where* Connect to server "BartK.us" *When* Tuesdays @ 7:00PM PST If you haven't installed the latest (beta) mumble client and verified you can connect and speak A-OK, this would be a good time for that. :) *Meeting Agenda* 1) Ben will give an update on insurance policy + bylaws process. I'll take over bylaws authoring if we're lagging still. 2) Curt will give a report on the publicity / recruiting / marketing / use-case research efforts. 3) Rob will give a report on use-case research for emergency response + his other work. 4) I'll give a report on the latest developments in RF lab testing. 5) We'll sync up about who will or won't be @ flea market. 6) Discussion of any other open problems. 7) Assignments for the next week. If you have any other items you'd like to discuss, please email me or mention it @ start of meeting. Apologies for late agenda, yesterday I was up till 2AM doing lab work. --Bart

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New Product... FYI
by Steve 19 Feb '13

19 Feb '13

This ran across my desk this morning. What caught my eye is it works in the 3 Ghz band. http://www.dragonwaveinc.com/products/small-cell-platforms/avenue-link-lite Steve N0FPF

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New sector antennas tested
by Bart Kus 19 Feb '13

19 Feb '13

Ran 3 new sector antennas through their paces: * ITelite Sector 50018H <https://www.hamwan.org/t/tiki-index.php?page=ITelite+Sector+50018H&structur…> * RF Elements SECM5120 <https://www.hamwan.org/t/tiki-index.php?page=RF+Elements+SECM5120&structure…> * Teletronics 15-704 <https://www.hamwan.org/t/tiki-index.php?page=Teletronics+15-704&structure=H…> The results are underwhelming. The ITelite was looking very good on FR and absolute gain, but then it totally fell apart on the radiation pattern. The RF elements has very poor gain @ the upper ham frequencies. The radiation pattern of this antenna is quite good though, if only we were using it lower down. The Teletronics has pretty low gain @ the upper ham frequencies, but more importantly, the radiation pattern is just broken. Almost a -20dB null @ 320 degrees. I've updated the Antenna Shootout <https://www.hamwan.org/t/tiki-index.php?page=Antenna+Shootout&structure=Ham…> page to add the results of these 3 new antennas. Had to normalize them to the 100m range standard levels. I also re-measured many of the other sector antennas on the 8m range and normalized their results to 100m range equivalents. Things are measuring mostly consistently. The largest delta is the 16dBi Ubiquiti sector, which lost 2dB of gain in the re-test. I re-ran the radiation pattern on it as well, since I noticed the peak gain involved adding a bit of up-tilt to compensate for the built-in electrical downtilt. The new radiation pattern is not so bad. So far the best sector is looking like that Laird I originally bought. Need to rig up vertical plane radiation pattern measurement capabilities. A narrow vertical beamwidth can kill a decent horizontally behaving sector. Unidirectional antennas are so much easier to deal with! --Bart

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