[Discuss-gnuradio] powerline PHYs?
I am curious if/how folks are attaching SDRs to household electrical outlets for data networking experiments. Are there any kits or off-the-shelf components that adapt from 120 VAC to a form more suitable for SDR I/O? Dave -- David Young OJC Technologies [EMAIL PROTECTED] Urbana, IL * (217) 278-3933 ext 24 ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Deeper story on FCC versus open source SDR
On Mon, Jul 23, 2007 at 04:05:07PM -0700, John Clark wrote: , but because of the FCC's paranoia (and other regulatory agencies around the world...), John, Does any written statement from the FCC give credence to the regulatory excuse for keeping the Atheros HAL closed? Atheros cites the FCC's SDR NPRM, which doesn't really apply. Dave -- David Young OJC Technologies [EMAIL PROTECTED] Urbana, IL * (217) 278-3933 ext 24 ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] FCC creates obstacles for Open Source software radio
On Sat, Jul 07, 2007 at 09:29:37AM -0400, Lamar Owen wrote: On Friday 06 July 2007, Philip Balister wrote: Found on /. I wonder how much Cisco paid for the words http://news.com.com/Feds+snub+open+source+for+smart+radios/2100-1041_3-6195 102.html?tag=nefd.lede Well, quite honestly, Cisco's only costs would have been the lawyer time and the filing of the petition. This action to me seems rather reasonable. The only software that the FCC is worried about is that which sets the radio's operating mode, emission mask, and transmit power. Given the FCC's well-known reticence to radio anarchy this is as much of a concession as could be expected at this time. Do you think that the software that concerns the FCC is concerned with must reside in the radio? Sometimes the transmission parameters such as modulation, mask, and power are under control of the host computer. If the FCC's definition of software-defined radio encompasses software running on the host computer, then it seems that they have encumbered the development of open-source software for a broad category of devices, including most of the 802.11 radios on the market. I feel certain that this was not their intention, but I do not think one can tell by reading the law alone, and that is worrisome. What do you think? But is open source less secure, when the item being secured is 'how do I manipulate the operating frequency, power, and mode of this radio?' Discussion, anyone? I do not think open source is less secure. Commercial software is developed under enormous time pressure for very narrow purposes by teams of developers that are oftentimes insulated from outside ideas and criticism by corporate secrecy, IP paranoia, and the not invented here syndrome. The narrow purposes of commercial development do include best performance for the price on the market; they do not include show how our security measures can be defeated and our equipment exploited to interfere with television broadcast. There is less time, and there are fewer persons for finding defects in a commercial development than in open-source development. Developing out in the open exposes your security measures to the diverse purposes of a wider segment of companies, of hobbyists, of academic researchers, and---let us admit---of bad guys. In this way, I believe an open-source community will detect more security problems in a product before a firm sends it to market than if the product had survived the scrutiny of one firm's developers alone. Dave -- David Young OJC Technologies [EMAIL PROTECTED] Urbana, IL * (217) 278-3933 ext 24 ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Modem and/or ADSL Daughter card
On Wed, May 10, 2006 at 07:24:07PM -0700, Eric Blossom wrote: On Thu, May 04, 2006 at 02:01:31PM -0400, Michael Milner wrote: Hello, I was just wondering if anyone has used GNURadio for any non-radio applications, specifically phone line modulation/demodulation. It shouldn't be too difficult to design a daughter board for the USRP to sample phone line voltage (with an appropriate line interface circuit of course). After that it should be rather easy in GNURadio to generate DTMF tones for dialing, and modem tones for data communication. Any thoughts? Mike A simple DAA (Data Access Arrangement) plus the LF daughterboard would probably work. There are two chip DAA's available. Been a while since I looked, but I think that Crystal Semiconductor used to make them. Google solid state daa There's also the classic Midcom transformer plus a couple of other discretes. These things are tricky to get right. You definitely want to find somebody's reference design and use that. Or use the pre-approved chipset. The USRP is pretty much thermonuclear overkill for this application. You could just use a sound card with a DAA. That's how all the soft-modems work. IIRC some of the the AC97 codecs support a second channel for telecom (modem) apps. Here is an example that uses a sound card, http://www.araneus.fi/audsl/. idle-musing It would be neat if there were the PC audio-out equivalents of the iGo iTips power adapter plugs, with plugs that adapt audio-out to media such as AC powerline, phone wire, Cat5, and television cable. A suitable software modem would adapt to whatever medium was on hand, adding a new dimension to ad hoc networking. /idle-musing Dave -- David Young OJC Technologies [EMAIL PROTECTED] Urbana, IL * (217) 278-3933 ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Re: Cellular relay
On Mon, Sep 19, 2005 at 04:54:35PM -0400, Aaditeshwar Seth wrote: Hi This is a follow-up on a mail I had sent out earlier to the list but didn't get a reply. I found something interesting that I thought of sharing with you guys. And it'll be great if you can tell me about some public CDMA SDR implementations, and whether the people on this list are thinking of doing anything about it in the future. Ok, so making this kind of a relay is indeed possible. And the kind of applications it opens up are quite interesting. Have a look at http://blizzard.cs.uwaterloo.ca/keshav/mediawiki-1.4.7/index.php/Recycling_a_billion_cell_phones which is my PhD supervisor's idea on reusing old cellphones. Now, when you have this kind of a low-bandwidth cellular relay, you can have all your old cellphones plugged in different rooms as security cameras (all cellphones have cameras already!), or for medical survelliance, or just to do some cool digital-home kind of stuff. So, it is indeed useful to have something like this. And to do it, here is a small email exchange I had with people working at a leading cellular provider. Aaditeshwar, It is a shame if I have to buy or build a basestation to get any use out of old cell phones in my home, even if I can use a USRP and GNU Radio to do it. :-) Are any cellular modes more symmetric than CDMA? Is direct phone-to-phone communication possible, even without WiFi? Do you know whether or not it is possible to get instructions for re-programming the old phones? Dave -- David Young OJC Technologies [EMAIL PROTECTED] Urbana, IL * (217) 278-3933 ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: GigE (was Re: [Discuss-gnuradio] DSP based SDR)
On Wed, Jun 22, 2005 at 12:40:06PM +0200, Harald Welte wrote: On Tue, Jun 21, 2005 at 04:10:35PM -0700, John Gilmore wrote: What thruput do YOU see using a good GigE card under Linux? Can you move 100 Mbytes/sec from user process to user process with TCP, across two GigE interfaces and a GigE switch? If so, it's doing much better than USB2 ever will, and much better than any version of FireWire. I'm usually not doing client-to-server TCP benchmarks over my test networks, since I'm more interested in small-packet forwarding performance. I'm sure with the right tuning (and probably some of the recent work on TCP BIC etc.) you can saturate a 1000-base-tx link with a single tcp flow, no question on that. But at what expense? you copy data back and forth between different address spaces (kernel/user), you have lots of complex code that deals with retransmissions, protocol demultiplex, ... that is totally unneccessarry for the gnuradio/USRP kind of application. Systems like NetBSD have moved to zero-copy TCP. I am surprised if Linux has not done the same. Perhaps more important is that I do not see any reason, in principle, that you cannot do the same for UDP+RTP. (API adaptations may be necessary.) Dave -- David Young OJC Technologies [EMAIL PROTECTED] Urbana, IL * (217) 278-3933 ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
