44net

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3196 discussions

Re: [44net] OFDM Modem
by Rob Janssen 02 Sep '17

02 Sep '17

> Just remember, in the US, that 70cm data must fit in 100 kHz and be 56 > kbauds (Same on the 219 Mhz band), but this is interesting work. 97.305(c) > and 97.307(f)6 We don't have such blanket restrictions here. Operating under the amateur radio regulations for individuals, you can do whatever you like within the limits of the band and conforming to established bandplans and social behaviour. With a special permit for unattended or automatic operation (required e.g. for a repeater) you get a frequency and bandwidth assigned, no technical details like a baudrate. Rob

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OFDM Modem
by Ron Economos 01 Sep '17

01 Sep '17

Hopefully this isn't too far off topic. I've just completed testing of an OFDM modem using IP over DVB-T2. It uses an SDR transmitter and a commercial DVB-T2 receiver to implement the RFC 4326 Unidirectional Lightweight Encapsulation (ULE) for Transmission of IP Datagrams over an MPEG-2 Transport Stream (TS). ULE is supported in the Linux kernel for DVB receivers. https://tools.ietf.org/html/rfc4326 It's a full-duplex modem capable of up to 50 Mbps (in both directions) in an 8 MHz bandwidth. The current test bed consists of an Ettus B200 SDR transmitter, PCTV 292e DVB-T2 USB receiver, Kuhne down converters for 13cm and 9cm, Microlab BK-26N diplexer and RFSpace TSA600 Vivaldi antenna. http://www.w6rz.net/IMG_0119.jpg http://www.w6rz.net/traceroute.png The transmitter is based on the DVB-T2 transmitter in GNU Radio and uses this OOT module for the ULE protocol. https://github.com/drmpeg/gr-ule To reduce the latency, I've merged the DVB-T2 blocks to avoid having so many buffers between blocks. https://github.com/drmpeg/gr-dvbt2ll Current test frequencies are 2305 and 3429 MHz with an 8 MHz bandwidth. The bit-rate is 28.6 Mbps (symmetrical). It's intended to replace commercial WiFi equipment for amateur WAN interlinks. Advantages: 1) Full-duplex. Adding power amplifiers, preamps, diplexers/duplexers is easy. 2) Frequency agile. Can work on any band above 420 MHz. 70cm through 5cm direct TX from the SDR and millimeter frequencies with an up-converter. 3) Bandwidth agile. 5, 6 ,7 and 8 MHz bandwidths. 4) May be legal on 70cm. Although I haven't implemented it yet, a small portion of the bandwidth can be used to send a low-rate video stream (for example, a still picture of your call sign for ID). This would classify the emission as digital ATV, not data. Disadvantages: 1) Latency is a bit high. It's currently 100 ms (200 ms round trip). This is a function of buffering in GNU Radio and the USB 3.0 connection to the SDR. An FPGA implementation of DVB-T2 and a different SDR architecture could solve this. 2) Cost. It's difficult to compete with commercial WiFi equipment. However, lower cost components can be used instead of the "Cadillac" test bed I constructed. For example, a ADALM-PLUTO at $99 could be used instead of the Ettus B200 for transmit. Two antennas instead of a diplexer and lower cost down-converters than the Kuhne units. 3) Requires a Linux computer to run it. An Odroid XU4 may be adequate, but I haven't tested it. 73, Ron W6RZ

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Re: [44net] OFDM Modem
by Steve L 01 Sep '17

01 Sep '17

John, I was hesitant at first. Mostly because I think you are an okay guy. While my message might seem poor in taste, I stand by it. I feel if you are going to play the arm chair lawyer part, then you should be more transparent with your role with NW Digital. I don't see you pointing out other rules issues, just things in those two areas, which ironically are directly related to NWdigital. I do applaud your recent AMBE effort, offering a discount on the xlxd list to aide development efforts, rather than the usual approach. Moving forward I'd like to see less poo-pooing, and more doing not just on this list, but though out the hobby. Folks are expected to know the rules are part of their entrance test into the hobby. I am not an official observer, nor a lawyer, and suspect the same is with you. We have no obligation to remind others that obligation is on each operators shoulders alone. If you want to do things that help NWdigital, I don't have a problem with you becoming the person to spear-head a more aggressive data rules overhaul proposal to the FCC. This is because its not just beneficial to NWDigital, but to amateur radio as a whole. I can't speak for others on this however, as I am sure operators of other modes may feel differently. I do encourage you to survey the odds and consider working in this positive manner to have these modernized, over the "old-man get off my lawn approach" that I have seen. Now on to a new subject that is more productive please. 73 Steve, KB9MWR

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ampr.org and 44.in-addr.arpa nameservice
by Brian Kantor 29 Aug '17

29 Aug '17

It's come to my attention that some of our worldwide slave nameservers are not updating when changes are made to the DNS on our master nameserver, 'ampr.org' (44.0.0.1). It will take me a while to contact the operators of those nameservers to ensure that their configurations are correct for them to get the latest changes as they occur. In the meantime, there may be differences in the answers you get regarding new entries in the DNS depending on which nameserver your query is actually made to. The way to tell if a particular nameserver is current is to examine the serial number in the ampr.org SOA record as retrieved from it and compare that with the SOA from ampr.org (44.0.0.1). I use the 'dig' tool for this purpose; there are other tools as well. - Brian

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Still re 44.177.10.254
by Libor Berka 28 Aug '17

28 Aug '17

Hi all thanks for testing ping 44.177.10.254. I apologize re 44.177.10.254 node callsign. It's OK0NMG. For Brian: ok0nmg.ampr.org (or maybe gw.ok0nmg.ampr.org) was registered for 44.177.10.254 in ampr.org DNS some monthes ago, maybe years. But disappeared. It was registered by OK2OP (Czech coordinator) who unfortunately passed away and there is no Czech callsign coordinator up to now. I asked Chris who is listed in amprnet coordinators for Czech rep. but he says he is not able to provide DNS registering. For Peter ZL2BAU: Peter 44.177.10.10 is not changed and I do not know why it is impossible to ping it from your system. It can be pinged from N1URO, VE2PKT, VK6HGR and others. Re 44.177.10.254 - it is node OK0NMG:CZGATE. I am sysop of it as well. It is of different net then 44.177.10.10. For Tom SP2L: Thanks for test/reply. 73 Dalibor

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Connecting via VPN
by Radu Draghici 28 Aug '17

28 Aug '17

Hello, I've just provisioned with a 44.182.24.0/24 subnet.I have a DD-WRT box on TP-Link TL-WDR3600 and a Ubiquiti NanoStation Loco M2.I want to interconnect with somebody via VPN for the moment. I am located in Romania and i have a static public IP from ISP. Can you please provide me a little help? Thank you in advance! Sent from my Samsung Galaxy smartphone.

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44.177.10.254 hostname problem
by Libor Berka 28 Aug '17

28 Aug '17

Gentlemen my network 44.177.10.254/32 nor showing hostname (ok20nmg.ampr.org) nor accepting pings. How to correct it? 73 Dalibor

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Hank Magnuski KA6M email address?
by Brian Kantor 21 Aug '17

21 Aug '17

Does anyone have a valid current email address for Hank Magnuski, KA6M (one of packet radio's pioneers)? The only address I have for him is decades old and doesn't work anymore. Thank you. - Brian

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What does it look like being on a mountain top engulfed by fire?
by Brian Kantor 16 Aug '17

16 Aug '17

Background: HPWREN is the High Performance Wireless Research and Education Network, implemented using commercial wireless equipment and housed on several mountaintops around southern California USA. A recent news item from them has some impressive images that you folks may find interesting. You'll need a high-performance web browser/viewer and network connection to get the most from it. - Brian ----- Forwarded message Subject: What does it look like being on a mountain top engulfed by fire? A new HPWREN update: What does it look like being on a mountain top engulfed by fire? is available at http://hpwren.ucsd.edu/news/20170815/ The article, contributed by Paul Bourke, shows an immersive time-lapse animation of a four-camera 360 degree view in high resolution of the Whittier Fire near Santa Barbara in July 2017, projected onto the inside of a sphere, within which a viewer can pan, tilt and zoom. Older HPWREN news updates can be found at http://hpwren.ucsd.edu/news/ ----- End forwarded message -----

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Re: [44net] Belgium AMPRNet coordination
by Brian Kantor 14 Aug '17

14 Aug '17

Ok, I've updated his email address in the portal to that address from the on4sax(a)on4sax.be address that it used to be, which has apparently been taken over by a domain parking service which does not deliver mail. We'll see if this address gets through. Thank you, Jan. - Brian On Mon, Aug 14, 2017 at 08:20:11AM +0200, Jan Poppeliers wrote: > robbie.delise(a)gmail.com > > 73, Jan > ON7UX > > > -----Oorspronkelijk bericht----- > Van: 44Net [mailto:44net-bounces+jan.poppeliers=online.be@hamradio.ucsd.edu] > Namens Brian Kantor > Verzonden: maandag 14 augustus 2017 7:25 > Aan: 44net(a)hamradio.ucsd.edu > Onderwerp: [44net] Belgium AMPRNet coordination > > Unless someone can supply me with a working email address for the Belgium > AMPRNet coordinator, Robbie De Lise ON4SAX, there won't be any more > allocations in the existing Belgium subnet because there is nobody to handle > them. I need a mailbox that is actually read and responded to, not just one > that doesn't bounce mail sent to it. Or if it's the case that he's turned > coordination over to someone else, I wish someone would let me know. > - Brian > > _________________________________________ > 44Net mailing list > 44Net(a)hamradio.ucsd.edu > http://hamradio.ucsd.edu/mailman/listinfo/44net > > > _________________________________________ > 44Net mailing list > 44Net(a)hamradio.ucsd.edu > http://hamradio.ucsd.edu/mailman/listinfo/44net

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