RE: [digitalradio] Re: Operating ROS In USA
Actually, the Nazi's did obey the law. (That is not a defense of their actions.) They just changed the law to make whatever they wanted to do legal, or did it outside of Germany where the law did not apply. - 73 - Rud Merriam K5RUD http://mysticlakesoftware.com/ > -Original Message- > From: Thomas F. Giella NZ4O [mailto:n...@tampabay.rr.com] > Sent: Tuesday, July 20, 2010 8:48 AM > To: digital radio eGroup > Subject: [digitalradio] Re: Operating ROS In USA > > > Garrett /AA0OI said Spoken like a good Nazi > > NZ4O says it's all about obeying the law. The Nazi's did not > obey the law > and it was their downfall. > > > > 73 & GUD DX, > Thomas F. Giella, NZ4O > Lakeland, FL, USA > n...@tampabay.rr.com >
RE: [digitalradio] ROS are sending data from your PC
Could this ROS discussion be taken offline or elsewhere? I expect others, like I, are sick of the rehashing. (And if you are sick please don't reply in support of this message - that would be as bad as the rehashing.) Andy?? - 73 - Rud Merriam K5RUD http://mysticlakesoftware.com/ > -Original Message- > From: rein...@ix.netcom.com [mailto:rein...@ix.netcom.com] > Sent: Friday, July 09, 2010 12:43 PM > To: digitalradio@yahoogroups.com > Subject: Re: [digitalradio] ROS are sending data from your PC > > > OK John. > > Understood. > > Did it work on your computer? > Did it work on the xyl's computer? > > ( I like to know whether there is such a list in the program.) > > If there is, then I think it is a hopeless case. And NOBODY should > use ROS. NOBODY, foreign or domestic. > > > 73 Rein W6SZ > > > > -Original Message- > >From: "John Becker, WØJAB" > >Sent: Jul 9, 2010 1:14 PM > >To: digitalradio@yahoogroups.com > >Subject: Re: [digitalradio] ROS are sending data from your PC > > > >Sorry Rein - > > > >Please forgive as that was about the time I was having big time > >computer problems. Lost a bunch of emails. > > > >what was that my "final question" again. > > > >John, W0JAB > > > > > > > > > > > >http://www.obriensweb.com/digispotter.html > >Chat, Skeds, and "Spots" all in one (resize to suit) > > > >Facebook= http://www.facebook.com/pages/digitalradio/123270301037522 > > > >Yahoo! Groups Links > > > > > > > > > > > > http://www.obriensweb.com/digispotter.html > Chat, Skeds, and "Spots" all in one (resize to suit) > > Facebook= http://www.facebook.com/pages/digitalradio/123270301037522 > > Yahoo! Groups Links > > > >
RE: [digitalradio] The first "official" release of SDR-Radio Console
Hi Andy, Are you near Ripley? I'm in Houston know but grew up just east of Buffalo in East Amherst. My father is from Westfield and had a lot of family there so we used to drive down once a month of so. Of course we went through Ripley to get there. - 73 - Rud Merriam K5RUD http://mysticlakesoftware.com/ > -Original Message- > From: Andy obrien [mailto:k3uka...@gmail.com] > Sent: Tuesday, May 04, 2010 8:20 PM > To: digitalradio; alleghenyvalleyra...@yahoogroups.com; > wn...@yahoogroups.com > Subject: [digitalradio] The first "official" release of > SDR-Radio Console > > > http://www.sdr-radio.com/LinkClick.aspx?fileticket=NSl58870YzQ > %3d&tabid=319&mid=1287 > > The first "official" release of SDR-Radio Console, released May 2nd. > > > As demonstrated by K3UK at the Allegheny Valley Radio > Association Ripley , NY hamfest May 2nd. > > Too bad I did not have a few SDR-IQ's to sell, quite a bit of > interest in both the SDR-IQ and the software. > > > Andy K3UK >
RE: [digitalradio] Re: 1976 FCC - Delete all Emission Types from Part 97
But Two points: IARU / ARRL band plan to manage the frequencies, allocating areas for unattended, digital, analog, etc signals. The underlying regulation of "good amateur practice" as the stick for enforcing the band plan. If you operate unattended in the analog band plan section the OO would get onto you, and so would the FCC eventually. Same for operating analog in the digital section. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://mysticlakesoftware.com/ -Original Message- From: KH6TY [mailto:kh...@comcast.net] Sent: Tuesday, March 09, 2010 2:20 AM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: 1976 FCC - Delete all Emission Types from Part 97 Paul, it works, at least in part, because the huge numbers of US amateurs in proportion across the border are regulated both by mode and by bandwidth. Radio does not stop at borders, of course, so what makes it work for the US helps make it work for Canada. Imagine what it would be like if there were no US regulations on unattended operations. Those automatic messaging systems would be covering the phone bands as well as everywhere else. They don't currently, only because they are not allowed to, but they would expand to cover the phone bands if there were regulation only by bandwidth so they could escape QRM by others like themselves. The bandwidth of Pactor-III is roughly the same as a phone signal, and unattended stations cannot QSY even if requested to do so. Imagine also if spread spectrum were allowed anywhere in the current phone and upper data segments. The complaints about NCDXF and Olivia QRM from ROS would be nothing compared to what it is already if spread spectrum were allowed anywhere in the same bandwidth as phone, and hordes of operators wanted to use ROS, and not just a relative few. This is another US regulation that is helping to limit the number of stations using a very wide bandwidth (i.e. to 222 MHz and above) when a more narrow bandwidth mode like Olivia or PSK31 can do the same, or almost the same, job in one fifth the space or less. If there were unlimited room on HF, regulation by bandwidth would work, as it already basically does at VHF frequencies and up, even under US regulations. Your question is a valid one, but the subject was hotly debated several years ago, resulting in no change to the status quo, because, although imperfect, it seems to work for the huge majority of amateurs all trying to use a very limited amount of spectrum on HF. Regulation by bandwidth would work if everyone were fair, but everyone is not fair, so there must be regulation by mode to protect the small or weak from the big and powerful, and to protect phone operators from QRM from wideband digital operations. Phone is wide and digital is usually more narrow, so regulation by bandwidth keeps phone out of the data segments, but would not keep wide data out of the phone segments. Once you make exceptions to regulation by bandwidth to exclude certain modes in a space, you no longer have regulation by bandwidth, but a combination of regulation by bandwidth and regulation by mode, which is what we have now in the US. 73 - Skip KH6TY
[digitalradio] Spectrum Spreading
I avoided most of the discussion in the last week or so but finally decided to see what the ARRL Handbook had to say. At first I thought it was totally unhelpful but after it sank in a bit found it some help. What I gleaned is that many digital modes use spectrum spreading techniques. The handbook seemed quite clear on this point. I am still trying to understand what spectrum spreading means. There is an implication in there of using more spectrum than. something. For analog, i.e. voice, this is somewhat clear. If you are sending voice up to 2.5kz then the spectrum 'something' is around 2.5 kHz SSB, or double that for AM. Spectrum spreading would utilize some additional spectrum. Consider a hypothetical mode where you took the voice signal, spread the audio by 4 times to generate a 10 kHz signal, and used that audio to modulate the RF. That would be a spectrum spreading technique. I simply cannot get a handle on what spreading means for a digital signal. Is the base 'something' CW and PSK31? >From the Handbook, and I gather from the discussion here, there is another aspect which concerns the way in which the signal is encoded. In my hypothetical analog mode you might somehow invert or fold the frequency spectrum. The reverse technique would be required to decode the signal. It is my sense that some types of encoding are not allowed, while others would be acceptable. Not trying to start the entire debate but hoping to get a better understanding of the meaning of all this. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://mysticlakesoftware.com/
RE: [digitalradio] Consensus? Is ROS Legal in US?`
Jose, If anyone knows about RF protocols it is John KD6OZH. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://mysticlakesoftware.com/ -Original Message- From: jose alberto nieto ros [mailto:nietoro...@yahoo.es] Sent: Wednesday, February 24, 2010 4:03 AM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Consensus? Is ROS Legal in US?` I see you have not idea waht is the meaning of Spread spectrum. Spread spectrum reduce energy density. _ De: John B. Stephensen Para: digitalradio@yahoogroups.com Enviado: mié,24 febrero, 2010 03:55 Asunto: Re: [digitalradio] Consensus? Is ROS Legal in US?` Convolutional coding and Viterbi decoding may increase the occupied bandwidth but they also decrease the amount of power required to communicate. In some cases, like trellis-coded modulation, the bandwidth stays the same even though the power required decreases by a factor of 2-4. Spread spectrum increases the occupied bandwidth without the decrease in power. 73, John KD6OZH - Original Message - From: W2XJ <mailto:w...@w2xj.net> To: digitalradio@ yahoogroups. <mailto:digitalradio@yahoogroups.com> com Sent: Wednesday, February 24, 2010 01:24 UTC Subject: Re: [digitalradio] Consensus? Is ROS Legal in US?` I have a different take on this. There are a number of modes that uses vertebrae coding which could be mis-described as spread spectrum by some. The problem with part 97 is that it tries to be as broad as possible where technical parameters are concerned. In this case it causes things to be vague. There are many things that can be described as spread spectrum that are not by definition in part 97. FM would be one of them. Anytime information is transmitted in a wider bandwidth than necessary it could be described as spread spectrum. This would include some low noise modes. The problem is that we petitioned the FCC to loosen SS rules and the more vague those rules are made the more open to debate they are. The worst that can happen under the rules if one would be operating ROS in the phone segment would be an order to cease such operation if the comish so ordered. _ From: KH6TY Reply-To: Date: Tue, 23 Feb 2010 19:53:53 -0500 To: Subject: Re: [digitalradio] Consensus? Is ROS Legal in US?` I am for whatever will succeed, but do not underestimate how difficult it is to convincingly reverse oneself after first originally being so convincing. For myself, even from the beginning, I could not understand how the spreading was accomplished by a code that everyone else automatically had, but that was the claim, so I accepted it. Perhaps there is no spreading code independent of the data, but if so, it must now be proven thus, and not just claimed in what might be seen as an attempt to have something approved that has already been disapproved. Just because I might possess the necessary technical skills does not mean I can individually overrule the FCC with my actions. Even opposing technical experts are called by both parties in a legal argument, and the "judge" to decide who is correct in this case is the FCC, which has already issued an opinion, even if it may be wrong if given new information, but just "saying it is so does not make it so". I believe some concrete proof is required now, and maybe your spectrum analyzer display can be part of such proof. Other's opinions may vary... 73 - Skip KH6TY W2XJ wrote: Skip You are over thinking this. The FCC said as they always do that you as a licensee must possess the technical skill to evaluate whether or not a particular mode meets the rules. On Joses part a better technical description and some clarification would be very helpful to this end. I think just looking at the output on a spectrum analyzer would also be quite revealing. _ From: KH6TY Reply-To: Date: Tue, 23 Feb 2010 19:03:06 -0500 To: Subject: Re: [digitalradio] Consensus? Is ROS Legal in US?` Jose, I am only trying to suggest whatever ideas I can to get ROS declared to be legal. You have made such a strong case for FHSS already, that only "saying" you were mistaken probably will not convince the FCC. They will assume you are only changing the description so ROS appears to be legal and will demand proof that it is not FHSS to change their minds. This is only my personal, unbiased, opinion, as I would like very much for you to succeed. Essentially, you must PROVE that, spreading is NOT accomplished by means of a spreading signal, often called a code signal, which is independent of the data. How do you do that without disclosing the code? At this point, I doubt that the FCC will believe mere words, because there is so much pressure to allow ROS in HF in this country. Keep in mind the mess that Toyota finds itself by previously denying there is any substantial problem with unattended acceleration
RE: [digitalradio] Why would anyone
No, Packet can't operate at more than 300 baud. Nothing on HF can exceed 300 baud. I didn't argue this implicitly or explicitly. You made the argument implicitly. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://mysticlakesoftware.com/ -Original Message- From: Charles Brabham [mailto:n5...@uspacket.org] Sent: Thursday, October 29, 2009 11:51 AM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Why would anyone Rud: Note that I didn't make an arguement, I asked a question. By your arguement, Packet should be allowed to operate at 600 baud - but guess what? 73 DE Charles Brabham, N5PVL Prefer to use radio for your amateur radio communications? - Stop by at HamRadioNet.Org ! http://www.hamradionet.org - Original Message ----- From: Rud Merriam <mailto:k5...@arrl.net> To: digitalradio@yahoogroups.com Sent: Thursday, October 29, 2009 9:36 AM Subject: RE: [digitalradio] Why would anyone Baud rate is baud rate, i.e. symbol change. There is nothing in the regulations about how much the symbol can change. Packet and RTTY uses two tones. PKS31 uses one. By your argument Packet and RTTY should be banned because their symbol change is larger than PSK31s. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://mysticlakeso <http://mysticlakesoftware.com/> ftware.com/ -Original Message- From: Charles Brabham [mailto:n5...@uspacket.org] Sent: Thursday, October 29, 2009 8:03 AM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Why would anyone John: Do the rules specify that there is no baudrate limit upon FDM modes? The fact that they are mentioned does not necessarily imply that they are not intended to fall under the 300 baud restriction.
RE: [digitalradio] Why would anyone
Baud rate is baud rate, i.e. symbol change. There is nothing in the regulations about how much the symbol can change. Packet and RTTY uses two tones. PKS31 uses one. By your argument Packet and RTTY should be banned because their symbol change is larger than PSK31s. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://mysticlakesoftware.com/ -Original Message- From: Charles Brabham [mailto:n5...@uspacket.org] Sent: Thursday, October 29, 2009 8:03 AM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Why would anyone John: Do the rules specify that there is no baudrate limit upon FDM modes? The fact that they are mentioned does not necessarily imply that they are not intended to fall under the 300 baud restriction.
RE: [digitalradio] OT WEB HOSTING QUESTION
Check out Google Apps at http://www.google.com/apps/intl/en/group/index.html. You get a lot of capability for free. You can register a domain name for them ($10 / year) which is the only cost. There is not a site builder but you can build pages with a WYSIWYG online editor. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://mysticlakesoftware.com/ > -Original Message- > From: Bert Morton [mailto:hamradio...@vermontel.net] > Sent: Saturday, October 24, 2009 1:42 PM > To: ubuntuli...@yahoogroups.com; s...@yahoogroups.com; > rigblas...@yahoogroups.com; Andy obrien; > digitalradio@yahoogroups.com; > digitalradio-ow...@yahoogroups.com; > forsale-s...@mailman.qth.net; ham-radio-del...@yahoogroups.com > Subject: [digitalradio] OT WEB HOSTING QUESTION > > > I am looking for suggestions for a reliable and reasonable > web hosting > company to host a simple website for me. > > It would have to include a site builder option as well. > > Thanks, Bert W1DFU >
RE: [digitalradio] Re: Puppy Mail
Been to Scotland but not that a far north. The wife of an associate is from north of Aberdeen. He is from Aberdeen. I could barely understand him when he was speaking English. I had no hope of understanding her - speaking English. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://mysticlakesoftware.com/ -Original Message- From: Toby Burnett [mailto:ruff...@hebrides.net] Sent: Thursday, October 22, 2009 6:43 AM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Puppy Mail You should come up here to the Outer Hebrides NW Scotland, where every second person speaks Gaelic! I know a little tiny bit but these guys will talk in their native tongue just to Pi*s you off so you don't understand what they are saying about you! Be glad that Generally English is the international Ham radio language or we'd really have a problem. ---Original Message--- From: DANNY DOUGLAS <mailto:n...@comcast.net> Date: 22/10/2009 12:33:46 To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Puppy Mail Ive just gotta comment on your English comment. Did you know that modern day American English is considered (by experts - in the know) that American English is more akin to Olde English, than is British English of today? We have a couple of small valleys, here in Virginia, where the old time populations speak a very-near, old time English, and experts often come here to talk to them, in their studies of the language. Danny Douglas N7DC ex WN5QMX ET2US WA5UKR ET3USA SV0WPP VS6DD N7DC/YV5 G5CTB All 2 years or more (except Novice) short stints at: DA/PA/SU/HZ/7X/DU CR9/7Y/KH7/5A Pls QSL direct, buro, or LOTW preferred, I Do not use, but as a courtesy do upload to eQSL for those who do. Moderator DXandTALK http://groups. <http://groups.yahoo.com/group/DXandTalk> yahoo.com/group/DXandTalk dxandt...@yahoogrou <mailto:dxandt...@yahoogroups.com> PS.COM Moderator Digital_modes http://groups. <http://groups.yahoo.com/group/digital_modes/?yguid=341090159> yahoo.com/group/digital_modes/?yguid=341090159 - Original Message - From: obrienaj <mailto:aobri...@stny.rr.com> To: digitalradio@ <mailto:digitalradio@yahoogroups.com> yahoogroups.com Sent: Wednesday, October 21, 2009 11:06 PM Subject: [digitalradio] Re: Puppy Mail burn another CD Russell, perhaps you have a bad burn. If you have a good burn, you simply load the CD from a system -reboot and then Puppy will begin to load. It will set up basic drivers (mouse, keyboard, video card, etc) automatically. It will give you a choice of display resolution to use (I just opt for the default) and the language. I choose US English despite it not being real English :>) As you are probably aware from your other server install, the software uses the Internet to connect to a APRS server in the Nederlands. So you would need to activate the network/internet settings on the Puppy. That is fairly easy to do. With FLdigi you will also have to set it up for your sound devices. The Puppy should detect them for you and display them in the fldigi configure soundcard area. If it does not, you would need to run the soundcard setup from the Puppy, that is fairly easy to do too. Andy K3UK --- In digitalradio@ <mailto:digitalradio%40yahoogroups.com> yahoogroups.com, Russell Blair wrote: > > Andy, I cant get the Puppy to load from CD, I put the CD in the drive and reboot, the monitor just goes blank.�Did you have to do anything other than just put the CD in the drive and reboot. I download the ISO�(PSKmail-Puppy-412.iso). Well I will keep trying to get it to work.. > Thanks Russell > �1- Whoever said nothing is impossible never tried slamming a revolving door! > 2- A government big enough to give you everything you want, is strong enough to take everything you have. > - Thomas Jefferson > > > " IN GOD WE TRUST " > > > Russell Blair (NC5O) > Skype-Russell.Blair > Hell Field #300 > DRCC #55 > 30m Dig-group #693 > > > > > > From: obrienaj > To: digitalradio@ <mailto:digitalradio%40yahoogroups.com> yahoogroups.com > Sent: Wed, October 21, 2009 8:52:42 PM > Subject: [digitalradio] Re: Puppy Mail > > � > Windows on the HD and Puppy Linux on the CD ROM > > Andy. > > --- In digitalradio@ yahoogroups. com, Russell Blair wrote: > > > > Andy, The PC you have Puppy on is it a windows PC, or does it have Linux on it. > > > > Russell > > 1- Whoever said nothing is impossible never tried slamming a revolving door! > > 2- A government big enough to give you everything you want, is strong enough to take everything you have. > > - Thomas Jefferson > > > > > > " IN GOD WE TRUST " > > > > > > Rus
RE: [digitalradio] Provisional article on RS ID on Wikipedia
I went into Wikipedia and removed the deletion notice. I added a comment that this is a good article for the world-wide amateur radio community and it should remain. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://mysticlakesoftware.com/ -Original Message- From: Patrick Lindecker [mailto:f6...@free.fr] Sent: Tuesday, September 15, 2009 1:05 PM To: multi...@yahoogroups.com; multipsk_t...@yahoogroups.com; alera...@yahoogroups.com; digitalradio@yahoogroups.com Subject: [digitalradio] Provisional article on RS ID on Wikipedia Hello to all, For the ones interessed by RS ID (and Video ID), I have put an article on Wikipedia about this subject. http://en.wikipedia.org/wiki/Reed_Solomon_Identifier_(RSID) This article is going to be deleted from Wikipedia the 19/09/2009, so... The original article (with two pictures but not updated) is on my WEB site: http://f6cte.free.fr/PAPERS.ZIP 73 Patrick
RE: [digitalradio] Fldigi Linux CD
I just downloaded and used ImgBurn in the last couple days to create a Win 7 RC DVD. It worked fine. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://mysticlakesoftware.blogspot.com/ > -Original Message- > From: Andrew O'Brien [mailto:andrewob...@gmail.com] > Sent: Thursday, July 23, 2009 12:17 AM > To: digitalradio@yahoogroups.com > Subject: [digitalradio] Fldigi Linux CD > > > Can someone point me to a free ISO burner and also a current > link for a ISO file so that I can burn a new bootable Linus > FL-digi? Thanks > > > > > > Announce your digital presence via our Interactive Sked Pages > at http://www.obriensweb.com/sked > > Recommended digital mode software: Winwarbler, FLDIGI, > DM780, or Multipsk Logging Software: DXKeeper or Ham Radio Deluxe. > > > > Yahoo! Groups Links > > > >
RE: [digitalradio] QST article about RS-ID
QEX might be interested in an in-depth technical article. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net > -Original Message- > From: Andy obrien [mailto:k3uka...@gmail.com] > Sent: Saturday, July 11, 2009 6:34 AM > To: digitalradio; wn...@yahoogroups.com > Subject: [digitalradio] QST article about RS-ID > > > I have composed article for Steve Ford at ARRL/QST about > RS-ID. Due to the heavy load at QST ( many feature articles > in the pipe-line ) and advice from Steve, I wrote the article > for inclusion in his column, Eclectic Technology. This > limits the submission to 700 words. Accordingly, I have > focused on the utility of RS-ID rather than the technical > details. The article will reference additional reading on > the technical details and also provides reference to current > applications that implemented RS-ID. Am I correct in listing > the following > > Pocketdigi > Multipsk > Fldigi > DM780 > > Did I miss any applications ? > > > Acknowledgement is given to Patrick for his pioneering work, > and Vojtech, Dave/Skip, and Simon for their collaboration. I > will also reference Tony's you tube video and include some > pictures for Steve to consider. > > The article should meet the August 1st deadline for November QST. > > Andy K3UK > > > > > Announce your digital presence via our Interactive Sked Pages > at http://www.obriensweb.com/sked > > Recommended digital mode software: Winwarbler, FLDIGI, > DM780, or Multipsk Logging Software: DXKeeper or Ham Radio Deluxe. > > > > Yahoo! Groups Links > > > >
RE: [digitalradio] Outdoor screen viewing?
In windows there is a screen setup where you have a black background with white letter, etc. This works okay but requires the program to follow the Windows display setup instead of hard coding the colors. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: Briggs Longbothum [mailto:bru...@verizon.net] Sent: Friday, July 03, 2009 9:49 PM To: digitalradio@yahoogroups.com Subject: [digitalradio] Outdoor screen viewing? What has anyone found to be handy and effective to enable good screen viewing outdoors, in daylight, etc?? Has anyone tried any versions of those "wide screen goggles" (I know you might need a pc to TV adapter). I like to play "/p" but digimodes are difficult in daylight with a regular pc/laptop. And good ideas that work? I'd be willing to invest in googles if they work but need to know what does and what doesn't first. All replies graciously received with thanks in advance. Briggs, ab2nj in Gloucester, Ma. Announce your digital presence via our Interactive Sked Pages at http://www.obriensweb.com/sked Recommended digital mode software: Winwarbler, FLDIGI, DM780, or Multipsk Logging Software: DXKeeper or Ham Radio Deluxe. Yahoo! Groups Links
RE: [digitalradio] The ARQ Advantage?
Ah, AX.25 is an ARQ mode. How is it different from other ARQ modes vis-a-vis "evaluation"? - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net <http://thehamnetwork.net/> -Original Message- From: Charles Brabham [mailto:n5...@uspacket.org] Sent: Thursday, June 25, 2009 10:24 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] The ARQ Advantage? Hello, Tony! The advantage you mention for ARQ modes is in fact their primary drawback in the environment we inhabit as amateur radio operators, which is shared spectrum. In commercial or government channelized spectrum, ARQ does in fact have some edge. Our amateur radio HF spectrum however, with the single exception of sixty meters is not channelized, There is no such thing as a distributed HF channel within our range, and attempts to operate as if such a channelized environment exists invariably leads to interference of legitimate, legal QSOs that are operating within the shared spectrum environment as it is intendfed to be utilized. When that happens, it is the operator trying to pretend that they are in a channelized environment who is at fault, not the operators who are operating as the regulations specify. It's one of those 'square peg in a round hole' deals where the harder you try to force it, the more difficulties you end up generating. International agreements specify that amateur radio's bit of HF spectrum ( with the single exception noted ) is all shared spectrum, and it is our duty to respect those agreements, operating within both the letter and spirit of the law. In this light, it should be obvious that digital modes that are tailored for utilization within our shared spectrum will of course be better performers - for hams - than digital modes that are designed and optimised for a channelized environment. Evaluating ARQ modes for amateur radio use then must take this fact of life into account. That is to say that as an amateur radio digital mode, an ARQ mode must be evaluated in light of how well it fits in a shared environment. - How good a nieghbor it is within the amateur radio bands is most significant, not its behavior in an idealized, channelized commercial or government slice of spectrum it may be optimised and intended for. Poor old Bill Vodall was here not long ago, trying to gin up interest in the hinternet paradigm one more time, despite the well-known fact that amateurs prefer to go to the internet for thier internet, and consistently show zero interest in raking PART97 over the coals so that we can have a slower, less useful and rather pointless version of the internet running over the ham bands. Once again, the square peg is being pounded with gusto, but it just doesn't fit into the round hole. The harder it gets pounded, the more difficulties are sure to arise. My point here should be obvious by now... Sure, ARQ modes are better in a channelized environment - but that's not what we are working with, as amateur radio operators. Responsible hams would be more interested in how well it fits in as an amateur radio digital mode. Anyone can see where ARQ can be useful for one-on-one QSO's - but trying to utilize it within an amateur radio network, or trying to simulate a channelized environment within shared spectrum is sure to be problematical. The more stations you have trying to do this, the more problems you will generate for the hobby. As amateur radio innovators, our job is to to innovate within the environment we inhabit. Emulating systems designed for different operating environments can hardly be characterized as a step forward, or as an advancement of the art. - When 'the art' is amateur radio. ARQ enthusiasts are trying to emulate commercial and government operation within a channelized environment... Hinternetters are trying to emulate the internet. - Niether one of these though is amateur radio, and this is why they just do not fit very well and are highly unlikely to ever do so. These efforts are wasting time and effort, misdirecting talent that could and should be channelled into advancing the art. Innovation is several orders of magnitude above emulation - most particularly when emulating something that does not fit your working environment. 73 DE Charles, N5PVL - Original Message - From: Tony <mailto:d...@optonline.net> To: digitalradio@yahoogroups.com Sent: Thursday, June 25, 2009 4:56 PM Subject: [digitalradio] The ARQ Advantage? All, It would seem that ARQ modes would have some advantage on a disturbed HF channel since the data is checked and repeated in an attempt to achieve error-free throughput. In theory, the non-ARQ mode will lose data when the channel fades below threshold where the ARQ mode should detect the fade and recover the data. This is probably an oversimplification, but it would seem to be the case if both modes were equa
RE: [digitalradio] The best of all features - SdR
I have been watching, and commenting at times, on a VHF/UHF SDR transceiver. Something with I/Q I/O and RF. Nothing so far has appeared. I keep toying with the idea of building something but in all honesty it exceeds my capability and energy level. I am getting more hopeful because a recent QEX article had a DDS board that handled the VHF (maybe UHF, I don't recall) frequencies. That is a key component that has been missing. All the previous DDS boards handled only HF and maybe 6m. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: Bill V WA7NWP [mailto:wa7...@gmail.com] Sent: Monday, June 22, 2009 6:45 PM To: digitalradio@yahoogroups.com Cc: All things digital and fun Subject: Re: [digitalradio] The best of all features - SdR > For information, with the last version of Multipsk (4.14), you can > decode 48 KHz (for standard sound cards) up to 192 KHz (with specific > sound cards) if you have a SdR. If we could get access to 192 KHz with a special sound card and some minimal hardware - couldn't we really open up the high speed data possibilities. Something simple to get on any band from 10 through 220 MHz would be way cool! Bill - WA7NWP Announce your digital presence via our Interactive Sked Pages at http://www.obriensweb.com/sked Recommended digital mode software: Winwarbler, FLDIGI, DM780, or Multipsk Logging Software: DXKeeper or Ham Radio Deluxe. Yahoo! Groups Links
RE: [digitalradio] Boot discs for emcomm/ham radio
Actually, I find recovering from a crash with a bare install to be beneficial. It gets rid of all the junk that builds up over a year or so. One thing that helps is I copy all install CDs to a hard drive. (Actually they are in a version control system - Subversion - if you know what one of those is.) With them on a hard drive the install goes faster and I don't have to get everything installed all at once. I just add things back as I need them. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net <http://thehamnetwork.net/> -Original Message- From: Toby Burnett [mailto:ruff...@hebrides.net] Sent: Thursday, June 11, 2009 8:29 AM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Boot discs for emcomm/ham radio I also would be interested as to booting windoze from a memory stick like a live cd of Linux. It takes so long for me to re install everything should I have a system wide crash. Just to get back back onto win XP pro I have to load XP home first and then all of XP Pro. With that and all the driver disks etc and whatever else you loose in the process it can take a good day at least just to get back to a blank windoze system with everything working. My Laptop which I just got (Vista) gave the option to make a recovery disk set (4 DVD's!) which took the best part of 4 - 5 hours to create. That's a lot of data even for a memory stick and I dread the day I have to use them. ---Original Message--- From: Simon \(HB9DRV\) <mailto:simon.br...@kns.ch> Date: 11/06/2009 14:18:21 To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Boot discs for emcomm/ham radio Just keep a memory stick with a Windows installation. These are now so cheap they make a good solution for netbook-portable. Simon Brown, HB9DRV www.ham-radio-deluxe.com - Original Message - From: "Andrew O'Brien" mailto:k3ukandy%40gmail.com> com> >I had a PC problem last night and Windows would not load. I was able to >get on the Internet and active in digital modes within a few short minutes >by booting a CD that contained Fldigi via Linux. This simple way of >getting on the air when a HD crashes of Windows fails made me wonder if >there is a Windows CD somewhere that we can boot and it also contains a >browser, digital mode software, etc? <>
RE: [digitalradio] Pskmail Server in U.S.
I'll have to agree with Russell that I have not seen hostility here toward packet. If I may offer some constructive criticism, not meant as an attack. When you start a message with "what you have is nice but WE have..." you are likely to engender a defensive reaction. Addressing the issue of packet, you certainly are aware that better protocols exist for use on HF. That is one of the goals of ham radio to experiment and develop new technologies. PSKMail is a very positive illustration of this. They created one means of providing a messaging capability that has evolved to utilize new capabilities as they became available. The NBEMS is similarly positioned to lever new developments. Packet has technical shortcomings that have been addressed by other protocols. Why not take advantage of the newer capabilities? - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net <http://thehamnetwork.net/> -Original Message- From: Charles Brabham [mailto:n5...@uspacket.org] Sent: Sunday, May 17, 2009 3:45 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Pskmail Server in U.S. Group members will have to forgive a few members here who appear to harbor some personal hostility regarding the SkipNets, and Packet radio in general. To find out more about the SkipNets without getting flames stirred up here, please contact me off-list for details. As it stands today, the Skipnets transport miscellaneous bulletin traffic to keep the system exercised. There is some personal messaging, but there is a great deal of underutilized capacity for more point-to-point messaging between amateurs. No non-ham or 3rd-party traffic is transported by the Skipnets, but ham-to-ham communications are definately encouraged. A new HF network roughly modeled on the SkipNets is currently under development, but the first servers will probably not appear for some months yet. There are still numerous issues to resolve. In the mean-time, participation in the SkipNets are a good way to get up to speed on the basic concepts behind a global, independent, all-ham radio communications network. Again, due to the hostility here, please take all comments and questions off-list. Contact me personally at: n5...@uspacket.org - Or stop by at http://www.uspacket.org where there is a forum. 73 DE Charles, N5PVL
RE: [digitalradio] Re: Mode of the Day? RS ID on SdR bandwidth
The RSID is good but is it overly complicated? What if a pilot tone or tones were sent indicating the mode? Maybe 25 msecs of tones with changes at 5 msecs. These tones would also establish the center (or edge) frequency for the mode so auto-tuning might be possible. A pattern might be 1k and 1.2k for 5 msecs, then 1k and 1.4k, then 1.2k and 1.4k ... Some modes like PSK31 might not need a dedicated tone since the idle patter is unique. The drawback to RSID is you have to get a good decode. Something simpler like a set of relatively long durations tones might be more robust. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net > -Original Message- > From: Simon (HB9DRV) [mailto:simon.br...@kns.ch] > Sent: Saturday, May 02, 2009 9:50 AM > To: digitalradio@yahoogroups.com > Subject: Re: [digitalradio] Re: Mode of the Day? RS ID on SdR > bandwidth > > > I've just looked at Vojtech's code, it seems reasonable *and* he's > resampling from 8kHz up to 11.025kHz. > > If I can get this working (and why not!) then I suggest we > attempt to for a > standard for the RSID codes similar to the SSTV VIS codes, maybe even > storing the standard in this forum. > > This will really help when not using a 'standard' mode such > as PSK31, 63 or > RTTY. > > Simon Brown, HB9DRV > www.ham-radio-deluxe.com > > - Original Message - > From: "Vojtech Bubnik" > > > > My code is derived from Patrick's, only I heavily optimized it to be > > executed on a less powerful fixed point arithmetics CPU. I > am obsessed > > with optimization to increase battery life of the Pocket PC device. > > > > > > Announce your digital presence via our Interactive Sked Pages at > http://www.obriensweb.com/sked > > Recommended digital mode software: Winwarbler, FLDIGI, > DM780, or Multipsk > Logging Software: DXKeeper or Ham Radio Deluxe. > > > > Yahoo! Groups Links > > >
RE: [digitalradio] Question about mail servers on HF
On article about HF email in Africa is at http://www.linuxjournal.com/article/6299. I remembered it but not the details so Google "africa hf email". There are some other search results you might want to read. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net > -Original Message- > From: Kristoff Bonne [mailto:kristoff.bo...@skypro.be] > Sent: Tuesday, March 31, 2009 2:52 PM > To: digitalradio@yahoogroups.com > Subject: Re: [digitalradio] Question about mail servers on HF > > > Hi All, > > > Russell Blair schreef: > > We'er going out in the RV for about two weeks, and would > like to check > > my mail on yahoo.com: Question is there nay mail servers on > the HF that I can check into and get my mail, and what > program would I need for this to happen, any help ? > > > You know. I once saw a TV-documentory on this, and more > particular on communication and life for people living on the > small poor islands-nations of the pacific ocean. > > They used some kind of HF-radio based system to sent messages > from "post-offices" located on certain islands to other > Islands. I never found what system they where actually using. > All information I found on the net is either aimed at hams or > emergency communications, or for > (rich) owners of yachts. > > Does anybody know if these systems are used by "PTT"s in the world? > > > > BTW. According the documantory, the main problem for these > island-nations was not really the technology and equipement, > but find a good secure electricity-system which -by > preference- is not dependent on (to be imported, so very > expensive) petroleum. > > > Cheerio! Kr. Bonne. > > -- > jabber/gtalk: krist...@krbonne.net > >
RE: [digitalradio] Re: Unable to set clock
It looks like your firewall or router is block the time service port. That is the ntp service on port 123. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net > -Original Message- > From: Kim [mailto:kimme...@yahoo.com] > Sent: Thursday, March 19, 2009 3:48 PM > To: digitalradio@yahoogroups.com > Subject: [digitalradio] Re: Unable to set clock > > > Thanks for the suggestions. Yeah I've downloaded half a dozen > softwares that claim to access servers to update my computer > clock. None work because there is something in Windows > configuration that blocks this process. About three computers > back I had the same problem. Trouble is I can't remember what > the solution is. > > I was hoping someone familiar with Windows configuration > would respond. > > Kim AB7JK > > > --- In digitalradio@yahoogroups.com, "Patrick Lindecker" > wrote: > > > > Hello Kim, > > > > You can try: > > * the Internet time with Clock.exe (in the Multipsk package), > > * AboutTime.exe soft. > > > > Of course you can get time from Radio-clock transmitters > (with Clock), > > but > > the most simple is to get time from Internet. > > > > 73 > > Patrick > > > > - Original Message - > > From: "Kim" > > To: > > Sent: Thursday, March 19, 2009 5:39 PM > > Subject: [digitalradio] Unable to set clock > > > > > > > I'm trying to use JT65A but I'm unable to set my computer > clock. All > > > attempts to contact time set sites results in error > messages or unable to > > > connect messages. > > > > > > Can anyone assist or tell me how to fix this problem? > > > > > > Kim AB7JK > > > > > > > > > > > > > > > > > > Announce your digital presence via our Interactive Sked Page at > > > http://www.obriensweb.com/sked > > > > > > > > > Recommended software: Winwarbler, FLDIGI, DM780, or Multipsk > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > > > > > > > > > > > > > Announce your digital presence via our Interactive Sked Page > at http://www.obriensweb.com/sked > > > Recommended software: Winwarbler, FLDIGI, DM780, or Multipsk > > > > Yahoo! Groups Links > > >
RE: [digitalradio] on another note
First, I would not dismiss sound card modes. I think there is much more that can be done with them. One of the main issues IMO is that they don't (1) adapt to changing band conditions, and (2) don't utilize FEC as much as is possible. (We also might need much better sound cards. The study reported at <http://www.baudline.com/solutions/full_duplex/imic_v0.06/index.html> http://www.baudline.com/solutions/full_duplex/imic_v0.06/index.html is pretty grim.) Second, further gains could be made using external DSP boards. These are not that expensive today. I have explored some of this in the past but got seriously distracted a year or so ago with a broken arm, some surgery and other issues. Nothing serious but just a pain in the eh, shoulder and other places. I will be turning my attention to either digital communications or robotics now that all that distraction is finished. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net <http://thehamnetwork.net/> -Original Message- From: John Bradley [mailto:jbrad...@sasktel.net] Sent: Monday, February 23, 2009 2:48 PM To: digitalradio@yahoogroups.com; hfl...@yahoogroups.com Cc: multi...@yahoogroups.com Subject: [digitalradio] on another note As many of you know, I have been very active with digital communications over the past number of years, eagerly testing the latest and greatest, and was honored when Andy gave me recognition last year in with his digital awards. I have been and continue to be a strong proponent of digital communications within the emergency services field, have worked in emergency services as a planner, communicator, trainer and consultant. This, as well as a passion for Search and Rescue is a summary of most of my ham radio activities over the past 20 years. I have been known to be somewhat outspoken at times, I have locked horns with Bonnie more than once, I have had interesting off post political commentaries with Roger the lawyer, and from time to time, been called anti American, anti Canadian, Anti Ham, anti pactor, and anti auntie, even. I have gleefully participated in some of the lively debates on these posts and have come awfully close to being punted by moderator Andy. So you are asking yourself by now, where is this crazy Cannuck going with all this?? Simply put, ladies and gentlemen, I have seen the light ( actually a whole mess of little ones but who is counting) Over the past couple of weeks I have been testing a SCS PTC2 usb modem with a pactor3 license, and have come away amazed and humbled by what this thing can do. It is faster than ANYTHING else I have tried, including RFSM8000, and works further into the weeds than anything else I have tried. I have connected to a RMS station midday close to 1000 miles away on what I would call a "dead" band. I have connected to RMS stations at least 500 miles from me on 80M well into mid morning, and resumed these connections by about 3PM , still when nothing else could be heard on the band. I had in the past heard the claims that this modem would work 10db into the noise. At the time my reactions was "yah,right!!!" but it really does. If you have a chance, try it out . So my thinking has undergone an abrupt change of direction, from using soundcard modes with internet access, to using P3 for primary links and sound card modes for the last mile or so.. and would like to hear other opinions. we all know the givens about pactor: the modems are expensive, the operators insensitive, proprietary hardware and software etc etc. but how could this mode be incorporated with current soundcard software? John VE5MU
RE: [digitalradio] Modes - What are they and What about New Developement??
There are three characteristics you can change on an RF signal: amplitude (CW, AM, SSB, etc), phase, and frequency. Even then if you squint a little phase and frequency modulation become basically the same. So the fundamental methods of modulating a signal are all known and used. Nothing new there. Mixing those in various ways gives all the different digital modes of operation. What has been realized in with the advent of digital signal processing (DSP) is all the modulation and modes are mathematically related using sine and cosine functions that are mixed to provide the final signal. The real unknown is how to maximize throughput to approach the Shannon Limit. An open question is whether deciphering such a message can be done in a reasonable time frame. We currently have digital techniques which are efficient but are only suitable for message passing, not chatting or voice, since the latency is on the order of seconds. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net <http://thehamnetwork.net/> -Original Message- From: Gmail - Kevin, Natalia, Stacey & Rochelle [mailto:spar...@gmail.com] Sent: Sunday, February 22, 2009 5:30 PM To: digitalradio@yahoogroups.com Subject: [digitalradio] Modes - What are they and What about New Developement?? Hi All, I am hoping with the number of members in this group that someone might be able to answer my question. Many years ago, as we know radio started off with CW, then AM was developed, with an improvement to only use one part of the AM carrier to produce SSB with carrier or SSB suppressed carrier. Then somebody developed FM. Now in my view this gives 4 actual modes? But I see you say (Maybe), we have all the digital modes. But are these actually modes? Why I ask and the reason for the question, is these are still using one of the current 4 above, over a SSB carrier for the likes of PSK-31, SSTV etc, or FM for the likes of Packet. So will the future be able to bring us anything new that will improve the usablility of radio? Doing a search on Google brings up thousands of hits, but none actually answer the questions, most also class each digital type as a mode. Would be very interested in your thoughts. If you do not feel this is the fourm to reply, a direct email to sparcnz(nospam)@gmail.com will be fine. (please remove the (nospam) before sending, I am trying to limit the amount of spam) Regards and thanks for looking at this thread. Kevin, ZL1KFM. My status Get Skype <http://www.skype.com/go/download> and call me for free. sparc_nz Description: Binary data
[digitalradio] Skip - Quad detials?
Could you provide sufficient details on the quad to allow building it? Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net
RE: [digitalradio] Suggestions for cheap Packet 2m rig
I have used a couple of Icom IC-25A rigs for packet. I think they are 25w. The drawback with them is they do not come with memory that holds across a power failure. But there is a connection point for adding a battery backup for the memory. Last I looked they were about $40 on Ebay. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net > -Original Message- > From: Sholto Fisher [mailto:[EMAIL PROTECTED] > Sent: Thursday, November 06, 2008 4:07 PM > To: digitalradio@yahoogroups.com > Subject: [digitalradio] Suggestions for cheap Packet 2m rig > > > Hi All, > > Can anyone recommend a brand/model of an older cheap 2m rig which is > simple to hook up to a TNC for VHF packet only. I don't > really want to > buy a new rig just for this use so am looking at older "workhorses". > Power needs to be around 35W but would prefer a rig that can do a low > power setting too. > > Tnx es 73. > > Sholto > KE7HPV > > > > > Announce your digital presence via our Interactive Sked Page > at http://www.obriensweb.com/sked > > 30M digital activity at http://www.projectsandparts.com/30m > > Recommended software : DM780, Multipsk, FLDIGI, Winwarbler > ,MMVARI. Yahoo! Groups Links > > >
RE: [digitalradio] Fast ARQ Hardware
How come you are discussing a topic the moderator asked us to drop? I will repeat my assertion that VOX operation can be done without any changes to the protocol. All that is needed is for the IMPLEMENTATION that supports the protocol, i.e. the software, to generate a tone. The tone triggers the VOX either in the rig interface or the transmitter. During the keying period of the transmitter the tone continues. After the keying delay expires the IMPLEMENTATION starts sending the actual protocol. The receive might hear some milliseconds of the tone before it begins to hear the protocol. No changes needed there, either. Nothing changes in the protocol. Nothing is required of the protocol. Nothing of the protocol is damaged. Nothing of the protocol is thrown away. Actually the tone could be useful as a marker. The receiver could use it to tune into the transmitted signal. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of expeditionradio Sent: Friday, August 29, 2008 2:06 AM To: digitalradio@yahoogroups.com Subject: [digitalradio] Fast ARQ Hardware It has been argued by several in this group that the first part of a digital mode transmission may be deleted by faulty transmit hardware without any problems in the reception on the other end. In other words, the first part of a transmission may be thrown away or discarded, and the message will still get through. 73 Bonnie VR2/KQ6XA
RE: [digitalradio] Re: Signalink No Good for ARQ Modes
Bluntly, you are ignoring the reality of trends in computer hardware. Further, my suggestion does not impact any protocol. The protocols require no changes. What could be changed is the way a protocol __implementation__ signals that it ready to transmit. A simple check box on the screen that defines the radio interface and sending an audio tone, possibly sub audible, is all that needs to change. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net > -Original Message- > From: expeditionradio [mailto:[EMAIL PROTECTED] > Sent: Tuesday, August 26, 2008 11:17 PM > To: digitalradio@yahoogroups.com > Subject: [digitalradio] Re: Signalink No Good for ARQ Modes > > > IMHO, it is ridiculous to suggest that > the "protocol implementers" should change > the protocol to add overhead to accept > cheapo bogus hardware. In many cases, the > excellent worldwide standards have already > been set, and the proliferation of > sub-standard interfaces on the market is > not going to affect the protocols, like the > tail wagging the dog. > > There simply is no need to purchase a > poorly designed bogus interface that depends > on VOX, that chops off the beginning of each > transmission or received signal. > > It is up to operators themselves to select > a proper interface that conforms to the > standard of digital protocols they intend to > operate. The trend is for more ARQ protocols > being used in ham radio. > > There are many excellent interfaces on the > market that function properly. Why bother > with the junk ones? > > It is also very easy to homebrew an interface. > I've built several of them in a few hours of > work, and put the plans for them on the web: > http://hflink.com/interface/ > > Bonnie VR2/KQ6XA > > > > Rud Merriam" wrote: > > > > Or the protocol implementers need to recognize > > the need to generate a tone to trigger the VOX. > > This would be analogous to the delay they provide for > > transmitter keying. > > > > > Announce your digital presence via our Interactive Sked Page at > http://www.obriensweb.com/sked > > Check our other Yahoo Groups > http://groups.yahoo.com/group/dxlist/ > http://groups.yahoo.com/group/contesting > http://groups.yahoo.com/group/themixwgroup > Yahoo! Groups Links > > >
RE: [digitalradio] New Digital Mode Winmor
If the protocol is used on ham frequencies it must be documented. I think for this mode a number of people would raise a stink if it is not documented sufficiently to implement. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net > -Original Message- > From: digitalradio@yahoogroups.com > [mailto:[EMAIL PROTECTED] On Behalf Of "John > Becker, WØJAB" > Sent: Tuesday, August 26, 2008 6:25 PM > To: digitalradio@yahoogroups.com > Subject: Re: [digitalradio] New Digital Mode Winmor > > > Licensing helps pay for all that R&D (research and > development) that could very well run into the millions. > doing otherwise would not be good for any business. > > At 12:37 PM 8/26/2008, you wrote: > >I really hope the code or at least a DLL is made available. > Anything to > >get > >rid of PACTOR III has my vote (I do not like the licencing > issues involved). > > > > > > > > > > > > > > > > > Announce your digital presence via our Interactive Sked Page > at http://www.obriensweb.com/sked > > Check our other Yahoo Groups http://groups.yahoo.com/group/dxlist/ > http://groups.yahoo.com/group/contesting > http://groups.yahoo.com/group/themixwgroup > Yahoo! Groups Links > > >
RE: [digitalradio] Re: Signalink No Good for ARQ Modes
Or the protocol implementers need to recognize the need to generate a tone to trigger the VOX. This would be analogous to the delay they provide for transmitter keying. - 73 - Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net > -Original Message- > From: digitalradio@yahoogroups.com > [mailto:[EMAIL PROTECTED] On Behalf Of expeditionradio > Sent: Tuesday, August 26, 2008 1:26 PM > To: digitalradio@yahoogroups.com > Subject: [digitalradio] Re: Signalink No Good for ARQ Modes > > > > Sholto Fisher wrote: > > I can't believe it makes any significant > > difference at least for ALE400 FAE. > > Hi Sholto, > > Whether you believe it or not, that's > up to you. But the math doesn't lie, > and neither does the oscilloscope. > > IMHO, any interface that chops off part of your > transmission, for whatever mode, should > be returned to the manufacturer for refund :) > > 73 Bonnie VR2/KQ6XA > > > > > Announce your digital presence via our Interactive Sked Page > at http://www.obriensweb.com/sked > > Check our other Yahoo Groups http://groups.yahoo.com/group/dxlist/ > http://groups.yahoo.com/group/contesting > http://groups.yahoo.com/group/themixwgroup > Yahoo! Groups Links > > >
RE: [digitalradio] AX.25 vs Something New
Chuck, No problem. It may just as easily been something I missed. On the SEDSAT Wiki page they describe the "sliding window" technique used to stream packets. As I recall this was used in the Kermit protocol for PC to PC file transfers. Something similar, modified for half-duplex channels, would be an improvement to our RF digital communications. I liked the point about not needing a timer to monitor timeouts with the sliding window. AX.25 has a plethora of timers that make it a hassle to implement. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net <http://thehamnetwork.net/> -Original Message- From: Chuck Mayfield - AA5J [mailto:[EMAIL PROTECTED] Sent: Saturday, August 09, 2008 7:12 AM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] AX.25 vs Something New Rud, I said It was in the Design <http://wiki.seds.org/index.php/SEDSAT-2_Communications_Design_Notes> Notes par. 2.2.1. However, I now see that I got off the track and that page applies to Design Notes for the SEDSAT-2. Maybe the par. on fx.25 and the list of possible tnc's are not connected together. If that is the case, then Sorry for the confusion. Chuck
RE: [digitalradio] AX.25 vs Something New
Chuck, Would you point me to the claims for fx.25 TNC compatibility? I do not see any specific TNCs mentioned. I am real curious about this because 2 years or so I looked at doing some experiments with modified protocols using existing TNCs. All of them insisted, even in KISS mode, that the received packet be a valid and correct AX.25 packet. I went so far as to check the TNC-X code to see what changes would be needed to allow it to pass invalid packets but decided not to get into PIC development at that time. I like the streaming capability with multiple packets and the FEC code transmitted in one burst. The time delays waiting for TX stability have a big impact on throughput. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Chuck Mayfield - AA5J Sent: Friday, August 08, 2008 3:47 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] AX.25 vs Something New Several modems on that link claim fx.25 compatibility; TNC-X comes to mind, but they all seem to have been developed for VHF/UHF use, so YMMV on HF. Chuck AA5J
RE: [digitalradio] AX.25 vs Something New
Sorry, brain fart on my part. I should have checked the models before I wrote that. It does not matter at the levels we are discussing. I am needing to review material quickly since it has been early February since I pursued any of this. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net > -Original Message- > From: digitalradio@yahoogroups.com > [mailto:[EMAIL PROTECTED] On Behalf Of Chuck > Mayfield - AA5J > Sent: Wednesday, August 06, 2008 10:34 PM > To: digitalradio@yahoogroups.com > Subject: Re: [digitalradio] AX.25 vs Something New > > > Rud Merriam wrote: > > > > You mention protocol layers. Which model do you want to use for > > discussion, > > OSI or the Internet model? Perhaps not a big question since > layers 1 & > > 2 are > > the same but once we start moving up the stack they differ. > > > > > > > > I have a problem with the formatting on this reflector. > Please excuse > me for that. > > My question, as an unenlightened retired engineer, is "What > difference > does it make which model is used if the proposed changes are to Level > 1? Apparently I don't speak the same language ...but can the same > model(s) not be used with a differing Level 1 protocol? > > Chuck AA5J
RE: [digitalradio] AX.25 vs Something New
Here is a "presentation" by Phil with the same information: http://www.qsl.net/n9zia/newlink/page1.html The paper at a different URL: http://www.ka9q.net/papers/newlinkpaper.pdf Phil's papers: http://www.ka9q.net/papers/ Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net > -Original Message- > From: digitalradio@yahoogroups.com > [mailto:[EMAIL PROTECTED] On Behalf Of Chuck > Mayfield - AA5J > Sent: Wednesday, August 06, 2008 10:27 PM > To: digitalradio@yahoogroups.com > Subject: Re: [digitalradio] AX.25 vs Something New > > > Rud Merriam wrote: > > > > I suggest anyone interested in this topic start by reading > > > http://citeseer.ist.psu.edu/cache/papers/cs/2504/http:zSzzSzpeople.qua > > lcomm. > > > <http://citeseer.ist.psu.edu/cache/papers/cs/2504/http:zSzzSzp eople.qualcomm.> > comzSzkarnzSzpaperszSznewlinkpaper.pdf/karn94toward.pdf by Phil Karn KA9Q. > If anyone does not recognize his name or call then research him because he > is an icon in amateur packet and digital communications. One of the > "experts". > > > > I recognize him, Rud, but that link is gobbledegook to me. Can you resend it? Chuck AA5J Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/sked Check our other Yahoo Groups http://groups.yahoo.com/group/dxlist/ http://groups.yahoo.com/group/contesting http://groups.yahoo.com/group/themixwgroup Yahoo! Groups Links
[digitalradio] AX.25 vs Something New
I suggest anyone interested in this topic start by reading http://citeseer.ist.psu.edu/cache/papers/cs/2504/http:zSzzSzpeople.qualcomm. comzSzkarnzSzpaperszSznewlinkpaper.pdf/karn94toward.pdf by Phil Karn KA9Q. If anyone does not recognize his name or call then research him because he is an icon in amateur packet and digital communications. One of the "experts". Just to tease the article starts by saying that AX.25 "is widely recognized as far from optimal." There are some additional articles by Phil and others that address the issues with AX.25, including the hidden transmitter problem. You mention protocol layers. Which model do you want to use for discussion, OSI or the Internet model? Perhaps not a big question since layers 1 & 2 are the same but once we start moving up the stack they differ. I was referring to digipeating with respect to routing. Routing messages is the big problem with a ham network because the connectivity is totally dynamic and the issues with hams changing locations. Overall routing is a layer 3 protocol problem. Your perspective on the use of AX.25 hardware probably differs from mine. There is little of it in use in the US except for Winlink 2000 VHF/UHF links. Providing gateways and bridges to existing networks is problem to address. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net > -Original Message- > From: Jose A. Amador [mailto:[EMAIL PROTECTED] > Sent: Wednesday, August 06, 2008 5:59 PM > To: digitalradio@yahoogroups.com > Subject: Re: [digitalradio] Re: Has anyone looked into > FPGA-based digitalmodes? > > > > My experience has been that the weakest point on HF packet were a too > feeble modem, losing frames with just one erroneous bit and bad, > aggressive parameters. There were other reasons, like > stations not zero > beat on each other, hidden stations, etc, nothing to do with the > protocol. I have been a BBS sysop since 1992. > > I am proposing what I know that worked, is well documented > and discussed > by teams of experts, based on standards that may be > incomplete, or not > fit to the purpose. I am not sure if working from the gropund up is > going to be viable. Maybe I am a bit conservative but creating a new > wheel may never make it roll. Very likely, that was the > reason for using > a modified version of X.25, even when I know no firm details > about this > choice. I have seen discussions about all this in a QRZ disk > I gave to a > friend many years ago and never returned. I cannot remember > many details > right now. He finally quit packet and hamming... > > It would be interesting to learn in detail which are the reasons you > state that make AX.25 unsuitable. I finally dug and found > some of my old > documents. > > I am not proposing to tack some FEC to AX.25, because AX.25 > is Layer 2, > and modems belong to layer 1. > > What I am proposing is not to touch AX.25, but rather, to make the > transfers closer to the environment that X.25 expects. A more > reliable > modem can certainly help to get closer to that goal. > > Going from "simple" to complex (even when reworking the modem > may not be > too simple), I would start from what I know is wrong, the modem. > > When you refer to message routing, what do you mean? Specifying the > other end of the link, or specifying digipeaters? Digipeaters are > "wrong", inefficient, but may be useful if used conservatively, with > care, maybe one, and not more than two seems to be in the acceptable > ballpark. I have used even internally in the same PC to link two > different BBS programs, or more. Nodes are preferable, if they can be > found and used. > > Why is routing wrong, from your point of view? What would substitute > routing to reach the destination? > > I am not entrenched, but very curious, I know I do not have all the > answers, and an open discussion, some brainstorming, may > clarify ideas. > > DAMA could provide a solution to collisions, but I don't see how DAMA > would work on HF, because to keep control, routes must be > stable, and HF > isn't. And DAMA does not allow TCPIP but on connected mode, > and I prefer > to use TCPIP in datagram mode. > > Something else is the amount of equipment out there that uses > AX.25, and > trashing all that may be the final death shot. That's the reason to > strive for compatibility, because many TNC's had disconnect > headers to > use different modems and there is a lot of work done that would be > uncertain to be repeated, among them, the support for AX.25 > in the Linux > kernel. I believe that we would need very compelling reasons > to trash AX.25. > > 73, > > Jose, CO2JA >
RE: [digitalradio] Re: Has anyone looked into FPGA-based digitalmodes?
Again, AX.25 is not suitable for many reason so a new standard is needed. It is based on X.25 that assumes a reliable link which is obviously not the case with RF. Simply tacking some kind of FEC onto AX.25 will not suffice. AX.25 includes message routing which is inappropriate for that level of protocol. The URL in my signature is a place for assembling information about all of this. It has been around for awhile but nobody has taken me up on the offer to contribute. I will get back to actively working on this material but a broken arm last spring side tracked me, along with summer family visit commitments. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Jose A. Amador Sent: Wednesday, August 06, 2008 1:54 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Has anyone looked into FPGA-based digitalmodes? What I feel is needed is something based on the established technology (AX.25, BBS Spec) with a new modem more suitable for HF than the old Bell 103 modem. 73, Jose, CO2JA Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/sked Check our other Yahoo Groups http://groups.yahoo.com/group/dxlist/ http://groups.yahoo.com/group/contesting http://groups.yahoo.com/group/themixwgroup Yahoo! Groups Links
RE: [digitalradio] Re: Has anyone looked into FPGA-based digitalmodes?
For one reason because AX25 is an abomination. It packs to many protocol layers into one format and does not provide any FEC. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Graham Sent: Tuesday, August 05, 2008 7:30 PM To: digitalradio@yahoogroups.com Subject: [digitalradio] Re: Has anyone looked into FPGA-based digitalmodes? >>>>>>>>>> Packet, Pax or ARQ FAE, at least to be able to share the frequency (collisions must be managed), >>>>>>>>> Why not take the final step and code a narow band spread spectrum packet system ..using very narrow bandwith short packet bursts based on the ax25 system .enhanced by spread sprectrum . the system could fit inside the bandwith taken by one of the 'narrow' multi tone systems ? G .. --- In digitalradio@yahoogroups.com, "Patrick Lindecker" <[EMAIL PROTECTED]> wrote: > > Hello all, > > For my small experience about ARQ modes, it seems to me that: > > * a modern ARQ system does not really need a synchronous scheme as in Pactor > (with obligation to permanently exchange frames). It must be asynchronous as > Packet, Pax or ARQ FAE, at least to be able to share the frequency > (collisions must be managed), > > * I don't think a powerful coding is really necessary. I think a ratio of > 1/2 (one information byte received for two bytes transmitted) is sufficient > (as in ARQ FAE or ALE DBM). Big block codings as in JT65 or Olivia with > ratio of 1/5 or less would be exagerated and will decrease drastically the > characters throughput. I don't think convolutional codings are conveneint > for ARQ modes as you must introduce a relatively big delay before deciding > what was the received characters. These codings are more convenient for > continuous modes (as in PSK63F), > > * an "ARQ memory" is absolutly necessary. You can forget coding but you > can't forget this tool. It is equivalent to a repetition coding and it > permits to reduce drastically the number of retries, > > * if you have an "ARQ memory" the minimum S/N is not given by the message > itself but by the possibility to detect the frame. If you detect the frame, > you will be sure to decode it (directly or through one or two retries). > This means that you could do a system very quick and also sensitive in the > same time (if you accept the number of necessary retries). Practically, the > minimum S/N will be determined by the speed of transmission of the frame > prefix (in ARQ FAE , for 50 bauds the minimum S/N is about -13 dB. This > means that for 500 bauds it would be -3 dB and for 5 bauds it would be -23 > dB). The speed prefix transmission must be independant from the message > speed transmission, > > * if I would want to do a very quick ARQ mode (but I'm on very slow modes at > the moment), I will prefer a THROBX modulation (a choice of 2 carriers over > n) than an OFDM, this because the maximum power transmitted is very low if > you want to keep linear (1/sqrt(n) if n is very big). > A configuration with a mean power/peak power below 1/3 is not a good > configuration. > I would switch from a non coded transmission (good conditions) to a coded > transmission (bad conditions) according to ionospheric conditions (as > determined on frames reception). A predetermined (i.e known) sequence as in > 110A to determine the channel transfert function would be perhaps > interesting. > > * I think MFSK modulations are better than PSK modulations. > > * Doing a very quick ARQ mode is not very "fun"... Doing a system able to > permit exchange between several Hams would be much more fun. > > 73 > Patrick > Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/sked Check our other Yahoo Groups http://groups.yahoo.com/group/dxlist/ http://groups.yahoo.com/group/contesting http://groups.yahoo.com/group/themixwgroup Yahoo! Groups Links
RE: [digitalradio] Re: Has anyone looked into FPGA-based digitalmodes?
LDPC is to old to be under patent protection. The doctoral thesis that defines it is from the 60s. The problem is they did not have the computing power to utilize LDPC. It was rediscovered in the 90s. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Jose A. Amador Sent: Monday, August 04, 2008 11:10 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Has anyone looked into FPGA-based digitalmodes? Block codes and interleaving are used by many professional protocols, like DRM, DVB-T, DVB-S, DMBT, and actually, not in vain. Enhanced ATSC uses two layers of Reed-Solomon coding, so, why leave those signs pass as unseen ? The best seem to be LDPC and turbo codes, but there might be some patent issues with them, of which I am not sure right now. 73, Jose, CO2JA
RE: [digitalradio] Re: Has anyone looked into FPGA-based digitalmodes?
AX25 is also an ARQ mode. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net <http://thehamnetwork.net/> -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Charles Brabham Sent: Monday, August 04, 2008 4:17 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Has anyone looked into FPGA-based digitalmodes? PACTOR, being an ARQ mode is incapable of sharing a frequency with more than one other station. That, along with the extreme bandwidth and lack of effective signal detection makes PACTOR unsuitable for digital HF networks on anything but a very limited scale. - A few afficianados can play around with it, but in that case as the network grows, more and more participants cop out and use the internet band-aid to cover up for the mode's basic lack of suitability for HF networking. Or they do like WinLink and run roughshod over their fellow hams, operating what amounts to a QRM mill that takes up more and more spectrum as the "network" grows. HF Packet, warts and all, is currently the only digital mode that a serious HF network can be built upon. The secret to this performance edge is AX25, which allows multiple stations to share a single frequency. The more reasonable bandwith there is also a positive factor that appeals to responsible amateurs who know how to play well with others. They call this "spectral efficiency" and if your mode of choice does not have it, best to keep it for keyboard use and leave the networking to the networkers. It is fashionable to diss Packet radio and AX25 - but none of the detractors have been able to demonstrate anything that does HF Packet's job any better... In fact, nobody has come up with anything yet that even works as well. Performance talks, and "fashionable PC attitudes" walk when actual networkers look at the available digital modes. That's the way it is... Maybe someday there will be an actual improvement over AX25 and Packet for HF networking. When this happens, I'll be one of the first to put the new system on the air and into actual use. BUT I have witnessed and been part of several efforts to improve upon AX25 and Packet over the last couple of decades, and what has been found in every case so far is that it is awfully easy to sit around and diss AX25 Packet for HF networking, but not so easy to come up with something that actually works as well, much less any better. If there was anything actually better out there, the HF digital network would already be using it and AX25 Packet would only be found on the VHF/UHF bands. But there isn't, so... 73 DE Charles Brabham, N5PVL [EMAIL PROTECTED] - Original Message - From: Jose A. Amador <mailto:[EMAIL PROTECTED]> To: digitalradio@yahoogroups.com Sent: Sunday, August 03, 2008 9:16 PM Subject: Re: [digitalradio] Re: Has anyone looked into FPGA-based digitalmodes? I believe that both the AX.25 and the BBS model are OK, but that the packet channel coding is a disaster in the sense that a single erroneous bit trashes a frame. That fires up the retries chain that are so detrimental to the link capacity, and may sever it as well. Pactor does a _LOT_ better, as it is able to use frames with errors that would be useless on packet using different FEC mechanisms. Source compression may help as well, as FBB and WL2K do. If the signalling speed can be made to match the channel and the protocol yield capabilities under a certain level of errors, a huge relative improvement can be achieved. That is the big adventage of WL2K, the use of Pactor II and its better channel coding. The rest is much alike the old BBS system, reworked. I believe that something that achieves similar results to those stated above will certainly be a step ahead. 73, Jose, CO2JA --- Bill McLaughlin wrote: > To echo what Rick stated, > > FAE400 is an extremely useful ARQ mode that has a lot of potential; > robust yet reasonably narrow. Works very well, just a shame so few use it. > > NBEMS is also a good ARQ suite, but a lot slower when using HF > friendly modes. No sure the lock-up time using MFSK16 has been > resolved but the new FLDIGI had the mode THOR, an incremental shift > keying mode similar to DominoEX. Not sure if that will be implemented > into NBEMS, although it certainly has that potential, especially as it > retains DominoEx's tolerance to frequency accuracy. > > The ax25 packet structure was fine; problem was/is that ax25 at 300 > Baud on HF, unless near MUF, is a less then optimum speed choice. It > actually works fairly well at 110 Baud but it is slow. > > I think there are many good protocols out there, but not many want to > experiment. > > 73, > > Bill N9DSJ
RE: [digitalradio] Digital Modes Overview Wiki Project ?
You can put it on my site, thehamnetwork.net, which is a wiki. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: Andrew O'Brien [mailto:[EMAIL PROTECTED] Sent: Thursday, June 12, 2008 5:22 AM To: DIGITALRADIO Subject: [digitalradio] Digital Modes Overview Wiki Project ? Since I received many comments about the "Digital Modes in 2008: An Overview" item i quickly composed a couple of weeks ago, I thought about improving the article and opening up the article for others to add to it. I also planned to perhaps add pictures of how each mode appears in a basic "waterfall". I though the best idea would be to add the item to Wikipedia and invite others to go there and improve on my draft. Alas, Wikipedia rejected my article because it was an "original" and an 'essay". Does anyone have any ideas on how the brief item below can be turned in to something acceptable by Wikipedia or any other project sharing WIki-type applications? Andy K3UK
RE: [digitalradio] AX25 Protocol group
More to the point it shouldn't be done. If such a large scale upgrade were to take place a modern robust protocol should be put into place. Something with good FEC, for one thing. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net <http://thehamnetwork.net/> -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Jeff Moore Sent: Monday, June 02, 2008 6:17 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] AX25 Protocol group Actually, I suspect that it will be nearly impossible to do. Given the number of systems that can't be upgraded without all new hardware (not everybody is going to go for that). Thx for the headsup on that! Jeff M -- KE7ACY - Original Message - From: Phillip <mailto:[EMAIL PROTECTED]> Hi Jeff, If the above is correct it will be one huge task.. 73 Phillip ZL2TZE . <http://geo.yahoo.com/serv?s=97359714/grpId=1871183/grpspId=1705063108/msgId =27647/stime=1212439658/nc1=528/nc2=5028926/nc3=5349275>
RE: [digitalradio] USB Sample Rate - Vista Help
I killed my one running copy of Vista so cannot help. The software _should_ be setting the rate it needs. If not, complain to the developer. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Tony Sent: Tuesday, May 27, 2008 7:14 PM To: digitalradio@yahoogroups.com Subject: [digitalradio] USB Sample Rate - Vista Help All, Does anyone know how to change the NATIVE sample rate for USB sound cards with Vista? Having distortion problems with a USB sound card while running digital voice. The Vista default is 44.1K and the software needs 48K to run. I'm told the normal way of changing sample rate will not work; the native setting is hidden somewhere in Vista. Any ideas? Anyone else running digital voice with Vista? Thanks, Tony -K2MO
RE: [digitalradio] Dayton FCC Forum
My interpretation is he was not stating an opinion on the topic, but just saying that an opinion would be needed to clarify such use. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Rick W. Sent: Sunday, May 25, 2008 4:15 PM To: digitalradio@yahoogroups.com Subject: [digitalradio] Dayton FCC Forum But was he really saying that getting weather maps and general e-mail use was included with buying and selling stocks and these uses are a prohibited communications? Or was he saying that the first two uses were OK and only the stock activity was not legal? 73, Rick, KV9U
RE: [digitalradio] Memristors : Electronics' 'missing link' found
I have been trying to understand this since I saw the news the other day. I wonder what impact such a device might have on RF or audio. For example, what is its reactance? Why is does it not appear at the macro level but has to be nano-technology? Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Andrew O'Brien Sent: Friday, May 02, 2008 3:52 AM To: DIGITALRADIO Subject: [digitalradio] Memristors : Electronics' 'missing link' found BBC News : Details of an entirely new kind of electronic device, which could make chips smaller and far more efficient, have been outlined by scientists. The new components, described by scientists at Hewlett-Packard, are known as "memristors".
RE: [digitalradio] Re: Multiple Digital Modes: Time to get rid of most ?
The decoding delay is minimal and probably not even noticeable, even in chat mode. The delay in a chat is waiting for a buffer to fill so the FEC packet can be constructed. In non-FEC mode characters are sent as typed. So for a 20 character message it requires the time for 20 keystrokes, calculation of the FEC and then the transmission of the 20 characters plus FEC characters. It might be interesting to try the following: 1. Send a start of message character, 2. Send each character as it is typed, and buffer each character. 3. Calculate the FEC on the buffer and transmit the FEC characters. 4. Send an end of message character. 5. The receiver displays each character as received. 6. After the FEC is received and decoded the receiver displays any corrected characters in the appropriate place on the display. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Vojtech Bubnik Sent: Wednesday, April 23, 2008 8:21 PM To: digitalradio@yahoogroups.com Subject: [digitalradio] Re: Multiple Digital Modes: Time to get rid of most ? BTW, PSK63F has error correction, but I never heard it on air. FEC will always introduce decoding delay. 73, Vojtech OK1IAK
RE: [digitalradio] UI Design
One possibility is for modem developers to no provide a UI. Instead provide a HTTP or other network interface that can be accessed using web protocols. The UI is then developed by someone else and hosted in a web browser. Before I retired my work was with such a system used to monitor corporate server farms, i.e. 100 or more PC servers in racks. This management system used a web browser UI to allow access from any desktop. The system monitored a plethora of information, e.g. temperature, disk capacity and failure status. One caution about the UI article: There is a difference between a web site and an application interface. A web site needs to grab attention immediately others the user will try a different site. The user of an application will expend more effort toward understanding the application. The motivation is higher since a process of download, install, and setup already consumed effort by the user. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net <http://thehamnetwork.net/> -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Simon Brown Sent: Friday, February 01, 2008 3:35 AM To: Digitalradio@yahoogroups.com Subject: [digitalradio] UI Design UI Design is something I am not very good at but am very interested in. Here's an excellent article I came across this morning, well worth reading, it will take you just one minute. http://www.smashingmagazine.com/2008/01/31/10-principles-of-effective-web-de sign/ Simon Brown, HB9DRV
RE: [digitalradio] RFI source found - sort of
Your ultimate recourse is to the FCC if any RFI is being generated. They will send letters advising the party to fix the problem. If the party does not respond and does not fix the problem the FCC can get serious with enforcement actions. It can be a slow but steady process with the FCC. Before reaching that point you can contact local clubs for help, or turn to the ARRL. Clubs or the local ARRL section will have RFI experts who can asses the situation and bring "expert" opinion to bear on the offending party. A representative with credentials from a national organizations tends to focus an offenders attention. Documenting those steps makes it easier for the FCC to escalate the issue. You can use your body as an RF attenuator. Stand with your back to the possible source with the radio held close to your chest. Turn around and note the null in the signal to get a direction fix. Then try it 25-50 feet down the street. Good luck. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Tony Sent: Thursday, January 31, 2008 3:30 PM To: digitalradio@yahoogroups.com Subject: [digitalradio] RFI source found - sort of All, I was able to track down the general location of an RFI problem I've been hearing since December. It's in the vicinity of 3 new homes on a cul-de-sac not far from my QTH. I'm told the pulse noise sounds like the RFI from an invisible electric fence. At this point, it's hard to tell which home it's coming from with the HF mobile because the signal strength is overwhelming at the location. I'll have to get up close with a portable AM radio; I'll probably need some shielding around it. Wish I knew exactly what the noise was; I'd hate to 'accuse' a neighbor of causing RFI and have it turn out to be the power company. I have a recording if anyone is interested. The question is, what to do in the worse case scenerio if the home owner decides not to take action to remedy the problem? Anyone on the reflector been through this before? Apologies for the off-topic note Andy -Please reply direct... Tony -K2MO Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/sked DRCC contest info : http://www.obriensweb.com/drcc.htm Yahoo! Groups Links
[digitalradio] TV Whitespace Testing
The FCC is doing testing for the use of broadband wireless in the space between TV channels. See http://www.pcmag.com/article2/0,2704,2250638,00.asp. The challenge is kind of like BPL: preventing interference with any adjacent digital channels. From my reading, it looks like they are trying to sense when adjacent channels are in use and not use that space. This makes sense for a commercial product since it would be a challenge to get users to configure systems to avoid active channels. I wonder if we could get some channels made available for hams? Possible propose using specific whitespaces on a regional basis. The proposal would determine two open channels in an area and use the whitespace between them. For example, channels 18 and 19 here in Houston are not used so they would be an available whitespace. (I am not sure how the digital channel assignments change availability of whitespace.) Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net
RE: [digitalradio] Re: Emergency agencies/ ham equipment/ hams in emcomm
In Katrina and Rita shelters were opened where there were people in need. Whether supplies could readily reach them was a problem to be solved, not a requirement for shelter location. You are not understanding the widespread nature of these disasters. It was easier to solve the supply problem than the rescue problem. A supply truck or helicopter with supplies can make it in once a day. The multiple vehicles, trucks or helicopters, to evacuate people were not available. Your "hypothetical" versus others "real world" experience is misleading you. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net Your first paragraph indicates that the shelter was so remote and isolated that it required helicopter delivery of food and water. Yet you also indicate that you were in your truck which indicates you could drive to the shelter. Maybe you were driving a monster truck? Some of this appears to be an appeal to emotion. I HAVE been around long enough to know neither the ARC or SA would open a shelter in a location that was not reachable by regular supply vehicles nor that had SOME kind of communications. I am pretty sure that the government authorities would not authorize this either. To do otherwise is simply asking for the shelter staff to require 'rescuing' at some time in the future thereby adding to the problem. Consequently, when you say no communications, you are overstating the facts. Now maybe, a runner in a vehicle may the only means of communication, but never the less, it is communications. Jim WA0LYK
RE: [digitalradio] Emergency agencies/ ham equipment/ hams in emcomm
I fully concur with Rick's comments. I find Bonnie's responses very off-putting with respect to trying ALE. The same can be said for Winlink 2000 even though I run a Telpac node. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Rick Sent: Thursday, January 10, 2008 7:46 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Emergency agencies/ ham equipment/ hams in emcomm Alan, However, if you folks continue to attack your friends, you won't have many left! You can claim that only anti-digital hams are on QRZ, but more likely you will find that QRZ is the true democratic melting pot of contemporary viewpoints. You may not like what most hams are thinking but they reflect the overwhelming majority view. 73, Rick, KV9U
RE: [digitalradio] Re: Curmudgions and an idea for digital operation
Jim, That yourself, family and property are supposed to come first, even in ARES. It is common sense that a volunteer operator is not going to be focused on their activity if they are worrying about all the other issues. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of jgorman01 Sent: Thursday, January 10, 2008 3:32 PM To: digitalradio@yahoogroups.com Subject: [digitalradio] Re: Curmudgions and an idea for digital operation Rick, My family comes first, my property second, friends and neighbors third, and ham radio last. If I had a choice of going to my son's practice or a drill, my son would win out. Tough cookies if the emcomm folks don't like my attitude. Jim WA0LYK
RE: [digitalradio] Emergency agencies/ ham equipment/ hams in emcomm
I walked the piney woods and hills of East Texas in cold and rain looking for the astronauts and parts of the shuttle Columbia. Ham radio via repeaters was the only way to communicate on a wide scale in that area at that time. Yes, cell phones worked in some areas but would have been a PITA when you wanted a message to all the numerous groups deployed in the woods. The FBI manager directing the effort said, "If we wanted a message to go through, we gave it to the hams." Right now we are organizing for a communications disaster should a repeat of the Rita evacuation occur in the Houston area. Cell service gets wiped out when 1,000s of people are stuck bumper to bumper on the freeways. The NGOs like United Way and the Food Bank do not want to allocate their resources toward developing communications capabilities. They will provide stations. We provide the people. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net So I'll ask the folks on this list what have you contributed to amateur radio at all, much less public service? Besides help us understand every possible interpretations of various part 97? :-)
RE: [digitalradio] Re: Oregon Governor Allocates $250,000 for Digital Communications Network
How is the government going to get operators? Any full time staff will have a multitude of other duties to perform. As a taxpayer you should appreciate the government supporting volunteers and obtaining equipment that is less costly than the equivalent commercial gear. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of jgorman01 Sent: Wednesday, January 09, 2008 11:29 AM To: digitalradio@yahoogroups.com Subject: [digitalradio] Re: Oregon Governor Allocates $250,000 for Digital Communications Network Not knocking the volunteers for sure. I do have a question. How come the money wasn't invested in public safety equipment using public safety NTIA assigned frequencies to do the same thing? These don't require ham licenses to operate and could expand the resource pool of operators. As a taxpayer, I would want to know why my government has to rely on volunteers to provide public safety communications. I know the current administration and politicians probably have every intention of letting the equipment stay with ARES. But, as you know, things change, sometimes for the worse. This may not always be the case. And even if it happens in your area, it may not occur elsewhere. I'm just worried we are setting ourselves up to be "purchased" sometime in the future. Jim WA0LYK
RE: [digitalradio] Bozo Guide for SVN (subversion)
I have not seen a bozos guide but can assist you. Offline from the group might be better... I am using Goggle Code as the repository for "The Ham Network" since it uses SVN. Since I work with Windows I also have a utility called Tortoise SVN that integrates with Windows Explorer. Via right click I get a menu that lets me do day to day operations on my local and Google repository. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of cesco12342000 Sent: Saturday, January 05, 2008 7:02 AM To: digitalradio@yahoogroups.com Subject: [digitalradio] Bozo Guide for SVN (subversion) Hi, Is there a "bozo SVN guide" for windows? The task is not to retreive anything, but to put a project into sourceforge or similar. The project is about 50 VC++ files and some libs. Any instructions would be appreciated. 73, Cesco, HB9TLK
RE: [digitalradio] Re: HF BBS systems
Part of the "need for speed" is technical innovation, part of the ARS. The current digital techniques do not come anywhere close to the Shannon-Hartley limit. There are those of us who are working on this. Attaining this goal would improve spectrum usage for all modes of operation on the bands. Part of the motivation is to replace the modems designed for commercial usage. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of jgorman01 Sent: Saturday, December 29, 2007 5:24 PM To: digitalradio@yahoogroups.com Subject: [digitalradio] Re: HF BBS systems It seems like the "need for speed" has become a goal unto itself with little advantage to the broad majority who have to live with the wide bandwidths that higher speeds require. I'm curious as to why the need for speed is driving some folks when it comes to amateur to amateur communication. Perhaps someone can explain it to me. It appears obvious from Rick's comment that a lot of amateur radio software developers seem to get more kicks out of working on lower speed, low snr protocols. I also keep seeing the "need for speed" touted as technical innovation when in reality it is using off the shelf commercially produced modems. Where's the innovation that a bandwidth limit is going to stop? Is it just that it will keep us from using faster commercially produced modems? Jim WA0LYK
RE: [digitalradio] Questions on digital opposition
If I need something to go from Houston to Austin I need to use HF NVIS. The higher bands are not usable. Although, having said that, I do believe the higher bands could be used for longer distance communications than is done presently. The requires getting towers, beams, and perhaps SSB in place. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of W2XJ Sent: Wednesday, December 26, 2007 3:15 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Questions on digital opposition I see the point about document transfer, but wouldn't higher speed modes at higher frequencies be more efficient? For situations where infrastructure is in place, wouldn't a well planned DSTAR network be much more efficient? 100 kbps from a portable radio located almost anywhere would seem to be a much more powerful tool than a painfully slow HF link. Rud Merriam wrote: > You are entitled to your opinion. However, I am interested in digital > communications including email over HF. As a license ham I will claim > my ability to work in that mode. > > As an AEC and active in emergency preparedness beyond ham radio I do > see a role for digital communications including email and other > document handling capabilities via ham radio. All modes have a role in > EmComm, or as in my preferred viewpoint, a communications disaster. > Such a disaster does not occur only when infrastructure is destroyed > but also when the infrastructure is overwhelmed. This can occur in > situations like the hurricane Rita evacuation in the Houston area. > There are also situations where transferring documents is more > accurate and more quickly done in modes other than voice or CW. > > > Rud Merriam K5RUD > ARES AEC Montgomery County, TX > http://TheHamNetwork.net > > > -Original Message- > From: digitalradio@yahoogroups.com > [mailto:[EMAIL PROTECTED] On Behalf Of W2XJ > Sent: Wednesday, December 26, 2007 12:53 PM > To: digitalradio@yahoogroups.com > Subject: Re: [digitalradio] Questions on digital opposition > > > I think the whole thing is pointless. Why to I want to try to send > email > via a slow speed serial stream when I have 100 meg Internet on the > computer next to the rig? I firmly believe that these systems are too > organized to be dependable in an emergency. That is when you loose a lot > of infrastructure. Simple systems, temporary installations all with some > form of emergency power is what is required in an emergency. Modes > should be those that can be supported station to station. Basically if > it is not part of the rig, it is too complicated for an emergency. Now > that CW is not an FCC requirement that is no reason to abandon it as a > primary emergency mode. It is still the mode that permits one to > accomplish the most with the least. > > > > Rud Merriam wrote: > >>This is meant as a couple of constructive, clarifying, questions for >>those who express strong displeasure with Pactor. >> >>Would you decrease your opposition if Pactor III did not expand its >>bandwidth? >> >>Could you accept wide band digital modes if they all operated in a >>fixed bandwidth, i.e. not expanding or contracting due to band >>conditions? Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/drsked/drsked.php View the DRCC numbers database at http://groups.yahoo.com/group/digitalradio/database Yahoo! Groups Links
RE: [digitalradio] Questions on digital opposition
You are entitled to your opinion. However, I am interested in digital communications including email over HF. As a license ham I will claim my ability to work in that mode. As an AEC and active in emergency preparedness beyond ham radio I do see a role for digital communications including email and other document handling capabilities via ham radio. All modes have a role in EmComm, or as in my preferred viewpoint, a communications disaster. Such a disaster does not occur only when infrastructure is destroyed but also when the infrastructure is overwhelmed. This can occur in situations like the hurricane Rita evacuation in the Houston area. There are also situations where transferring documents is more accurate and more quickly done in modes other than voice or CW. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of W2XJ Sent: Wednesday, December 26, 2007 12:53 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Questions on digital opposition I think the whole thing is pointless. Why to I want to try to send email via a slow speed serial stream when I have 100 meg Internet on the computer next to the rig? I firmly believe that these systems are too organized to be dependable in an emergency. That is when you loose a lot of infrastructure. Simple systems, temporary installations all with some form of emergency power is what is required in an emergency. Modes should be those that can be supported station to station. Basically if it is not part of the rig, it is too complicated for an emergency. Now that CW is not an FCC requirement that is no reason to abandon it as a primary emergency mode. It is still the mode that permits one to accomplish the most with the least. Rud Merriam wrote: > This is meant as a couple of constructive, clarifying, questions for > those who express strong displeasure with Pactor. > > Would you decrease your opposition if Pactor III did not expand its > bandwidth? > > Could you accept wide band digital modes if they all operated in a > fixed bandwidth, i.e. not expanding or contracting due to band > conditions? > > > Rud Merriam K5RUD > ARES AEC Montgomery County, TX > http://TheHamNetwork.net > > Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/drsked/drsked.php View the DRCC numbers database at http://groups.yahoo.com/group/digitalradio/database Yahoo! Groups Links
[digitalradio] Questions on digital opposition
This is meant as a couple of constructive, clarifying, questions for those who express strong displeasure with Pactor. Would you decrease your opposition if Pactor III did not expand its bandwidth? Could you accept wide band digital modes if they all operated in a fixed bandwidth, i.e. not expanding or contracting due to band conditions? Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net
RE: [digitalradio] Re: Winlink Can Be Reliable in Emergencies
A perspective I have mentioned before focuses on the situation when a "communications emergency" occurs. This is when normal means of communications are incapable of handling the traffic load. This perspective focuses not on whether infrastructure fails but whether it can sustain a load. There are situations where infrastructure is functional but overwhelmed, especially cell phones. The Rita evacuation in the Houston are wiped out cell phone service in the immediate vicinity of the evacuation routes. Many organizations were caught short when this happened. For example, United Way and the local Food Bank were scrambling for supplies but could not coordinate their efforts. They were short because many local supplies had gone to Louisiana for Katrina. I also think more use of VHF for covering NVIS distances is possible. A nearby digi can connect at times to a Winlink Telpac node in Austin. That is a distance of 130 or more miles. Since local use of NVIS would be to reach the state EOC in Austin it is a feasible route if dependable. This is using FM so SSB might work reliably. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Rick Sent: Wednesday, December 19, 2007 4:24 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Winlink Can Be Reliable in Emergencies Quite a few emergency planners are counting on the internet staying operational except in the immediate disaster area. As an example, our ARRL Section leader wants members to move all digital to Winlink 2000 and is focusing most resources to developing an interlinked repeater system for voice and digital although I have not heard how this is being done. They even have "nets" that work through Winlink 2000 since many ARES members are Technician class licensees and can not operate lower (NVIS) HF bands with voice or digital. While there are fewer and fewer chances of losing telecommunications infrastructure for very long, it does occur. At that point, many of these systems may not function since they are based upon many things continuing to work. Some of the more foresightful emergency planners (not necessarily ARES/RACES) in my area, realize that even repeaters are not a sure thing either and have actually done exercises over multi-county distances without them. Do you really see much of a use for CW, other than longer distance messaging, perhaps via NTS? Even that is rarely done from the little traffic that I tend to see coming out of disaster areas. There may or may not be a simultaneous communications emergency, so that changes the calculus too. Other than myself, I would be hard pressed to list any other hams in my county who have at least some CW skill and are involved with emergency communication. There are several things that I want to explore in the coming year: - whether or not the ARQ PSK modes will be competitive with ARQ ALE/FAE 400. Maybe both? Maybe the developers who will be coming up with a Windows version of flarq could consider other modulation waveforms? - how effective will 2 meter SSB work between mobiles and base stations using voice and digital modes compared to HF NVIS operation. Even with extremely difficult terrain such as we have in this area. 73, Rick, KV9U
RE: [digitalradio] Re: Technical Question: FDMDV / QPSK in PSK31
I think I am correct, and admittedly picky, to say that what is described is a form of source encoding with QPSK modulation. QPSK only applies to the modulation of two independent bit streams in a signal. A clear way of looking at this is that based on I/Q modulation the I carries one bit stream while the Q carries the other. The encoding below determine how the two bit streams are created. The URL did not work for me. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Andrew O'Brien Sent: Thursday, December 06, 2007 9:19 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Technical Question: FDMDV / QPSK in PSK31 On Dec 6, 2007 9:39 PM, Vojtech Bubnik <[EMAIL PROTECTED]> wrote: > > > It is QPSK, not BPSK. > > 73, Vojtech > > > And while on the subject of QPSK, here is an old article about PSK31 QPSK that I wrote around 2000 for the Logger32 help files, it includes quotes from Peter Martinez that he granted permission for me to use . Andy K3UK QPSK (Quaternary Phase Shift Keying) Operation Andrew J. O'Brien, KB2EOQ QPSK is referred to as an error-correcting PSK mode. Strictly speaking, it is not error-correcting in the traditional sense, but we'll leave that for another discussion. You will find it very useful in copying very weak signals. You will also discover that it is used less than BPSK. The usual convention among QPSK'ers is to use BPSK to establish a QSO and then switch to QPSK You will rarely find someone calling CQ in QPSK mode. Some radio amateurs will switch to QPSK if a BPSK QSO with weak signals is producing poor copy. PSK veterans will point out, however, that while QPSK outperforms BPSK when weak signals are the issue, QPSK will perform no better than BPSK if noise is the signal limiting condition. In the ancient, early days of PSK31, in the last century, QPSK was used as the mode of choice for some PSK nets, but that does appear to be the case in the 21st century. . Tuning a QPSK Signal snip QPSK can perform better than BPSK when band conditions are poor due to polar flutter. At such times you may be able to get copy from a QPSK signal even though the "cross" in the tuning window is poorly formed. Note: QPSK requires that BOTH stations in the QSO be using the same sideband! While this is not important for BPSK QSOs, it vital when using QPSK. QPSK-Reversed BPSK is demodulated the same way whether you are on upper or lower sideband. This is not true for QPSK, which operates like RTTY. You must shift the signal in a way that the decoder expects or it will not decode. In the case of QPSK, this leads to problems with standards, since the mode is so new. In actual practice, most hams appear to be operating BPSK using AFSK and upper sideband. This means that, when they switch QPSK (without reversing), they must be decoded by the other station using upper sideband and QPSK (without reversing). However, the standard of RTTY operation is lower sideband, and this means that most hams, operating as just mentioned, are operating QPSK-reverse, based on the RTTY standard. What this really means is that, when you and another station decide to switch to QPSK, if you do not know whether that station is using upper or lower sideband, there is a chance that you will not decode that station. If you click again on the mode pane, it will switch from QPSK to QPSK-reverse, and you should begin to copy. One trick is to set all three Rx windows on the signal to be copied, set one aux window at QPSK and the other at QPSK-reverse. When you see which Aux window starts to print readable copy, switch your main Rx window to that mode and you can then So What Is QPSK? How QPSK Got Its Name Peter, G3PLX, says in an article entitled "PSK-31, A new radio-teletype mode with a traditional philosophy," says that he called it "quadrature polarity reversal keying" (which of course would have come out as QPRK), but that everyone else calls it quaternary phase-shift keying (QPSK). It is an error-correcting mode that relies on four phase-shifts rather than two, to create the basic scheme. Peter Martinez' (G3PLX) Description of QPSK The QPSK mode used in PSK31 takes the binary data-stream, at the point where it would otherwise go direct to the BPSK modulator, and feeds that through a 5-bit shift-register. A logic operation then forms the parity function of the 1st, 2nd, and 5th stages, and another forms the parity function of the 1st, 3rd, and 5th, giving two bit-streams at the same 31.25 bps rate as the original data. These two bits form a binary number, the four values of which are mapped to the four possible phase-shifts in the QPSK modulation. Thus a single data-bit from the source results in a 5-bit-long predictable sequence of 90-degree and 180 phase-shifts, interlea
RE: [digitalradio] Re: Technical Question: FDMDV
Which still leaves me confused. Whether it is QPSK or BPSK it doesn't matter. That determines the bits per symbol (or baud). Bit rate has nothing to do with tone separation. A 50 baud signal should have either a 50 Hz or a 100 Hz separation by my understanding. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Vojtech Bubnik Sent: Thursday, December 06, 2007 8:39 PM To: digitalradio@yahoogroups.com Subject: [digitalradio] Re: Technical Question: FDMDV --- In digitalradio@yahoogroups.com, "Rud Merriam" <[EMAIL PROTECTED]> wrote: > > The statement about it being "50 baud, RRC filtered..." confuses me. > > My understanding of theory is that baud equals the spread between tones in > an OFDM or 2* baud in basic multi-tone signal. That does not fit with a 50 > baud and 75 Hz separation. > > What am I missing? It is QPSK, not BPSK. 73, Vojtech Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/drsked/drsked.php View the DRCC numbers database at http://groups.yahoo.com/group/digitalradio/database Yahoo! Groups Links
[digitalradio] Technical Question: FDMDV
The statement about it being "50 baud, RRC filtered..." confuses me. My understanding of theory is that baud equals the spread between tones in an OFDM or 2* baud in basic multi-tone signal. That does not fit with a 50 baud and 75 Hz separation. What am I missing? Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of cesco12342000 Sent: Thursday, December 06, 2007 4:19 AM To: digitalradio@yahoogroups.com Subject: [digitalradio] Re: New Digital Voice Mode FDMDV > Spectrum analyzer display showing the 1.143 kHz occupied bandwidth Should be 1125 hz. (75hz sapacing * 15) Each carrier is 50 baud, RRC filtered (0.5 rolloff) -> 75hz BW.
RE: [digitalradio] Re: The sorry state of VHF/UHF Packet
Rick, Having groups on RF becomes practical if the network is designed to handle the messaging. The design probably needs (1) higher speed "last mile" transfer (but the speed may not need to increase a lot), (2) group / bulleting messages streaming / broadcast with fills vs. point to point transfers, (3) intermediate distance VHF/UFH relays with high speed transfer, and (4) HF national / intercontinental transfer via streaming with fills. This will all need to be studied and designed, not just grown ad-hoc. Intermediate stages will need to use the Internet, and probably retain Internet usage as a backup / alternate path. RF would be used only for "real-time" messages; group archives available via Internet. Latency in a group is fairly big. Consider the time-shifting that occurs between Europe and the States. We still manage to have cogent discussions. --- If an agency is using email via Outlook and Exchange they are putting messages on a server to be picked up at the convenience of the IC. The Outpost software package for EmComm is sort of a server based system. It polls, retrieve, and posts from a distributed set of nodes. NNTP is built to do that and integrate all the message bases. There are scenarios where the group message approach makes sense. How about locating and communicating with people in shelters? Send all individual's messages using NNTP to all shelters. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Rick Sent: Friday, November 30, 2007 9:12 AM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: The sorry state of VHF/UHF Packet Rub, Although I agree it would be nice to run this group, and perhaps a few other ham discussions over some kind of RF network, how can this possibly be practical? It could take days to deliver such messages, assuming you had some kind of server system to coordinate it. It seems to me that the reason that we went to internet discussion groups, and that was long before these kinds of groups, such as with usenet and listservs, was because the ham based approach (even with wormholes/internet like wireline) could not begin to work well enough. Consider that some of those who rail against wireline discussions for ham radio, were the earliest adopters of using wireline for those very discussions! The one place that discussions could happen, in close to real time, would be more local and possibly regional ones with less latency, but you would often not have the critical mass of enough participants to make that as useful. For emergency use, almost all the communications is tactical and that means voice. There can be some cases where messaging would be helpful but I would mostly be using it for e-mail to reach out of an affected area to the internet, for timely delivery. You would need to be very careful that such messages were confirmed received if they were emergency/priority time value traffic. Do you know of emergency plans in place now that would actually recommend putting messages on a server to be picked up that the convenience of an IC? 73, Rick, KV9U Rud Merriam wrote: > Personally, I would like to do email over the radio to other hams. It > just appeals to me. > > I would also like to see the NNTP protocol used for newsgroups > implemented on radio. The DigitalRadio group should be handled on > radio. Newsgroups would be useful in a number of ways. They can handle > bulletins while setting them as a lower priority than mail and other > newsgroups. > > Emergency communications could be supported although some explanation > and training for end users might be needed. For example, instead of > emailing to an incident commander a message would be posted on an > incident management newsgroup. The incident commander could pick up > the message from any served location. Others could see the message and > respond also. > > Hams could be encouraged to use a system by bonus points for sending > contest and field day entries via the system. > > Rud Merriam K5RUD > ARES AEC Montgomery County, TX > http://TheHamNetwork.net > Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/drsked/drsked.php Yahoo! Groups Links
RE: [digitalradio] Re: The sorry state of VHF/UHF Packet
Which radio? ...and ampr.org is impossible to deal with. If IP addressing became useful going to an IPv6 subnet where every ham could have a 100 addresses would be a better approach. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Bill Vodall WA7NWP Sent: Thursday, November 29, 2007 12:57 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: The sorry state of VHF/UHF Packet > 9600 off the shelf We "may" finally have the first off the shelf 9600 baud data radio. It's been on the market for a couple months and still nobody has given it a good test. > ampr.org - 44 net. Stuck in the early 90's - see http://www.no-ip.com or http://en.wikipedia.org/wiki/Hamachi for modern replacements. > Time for the days 3rd cup of coffee eh? 73 Bill - WA7NWP
RE: [digitalradio] Re: The sorry state of VHF/UHF Packet
Personally, I would like to do email over the radio to other hams. It just appeals to me. I would also like to see the NNTP protocol used for newsgroups implemented on radio. The DigitalRadio group should be handled on radio. Newsgroups would be useful in a number of ways. They can handle bulletins while setting them as a lower priority than mail and other newsgroups. Emergency communications could be supported although some explanation and training for end users might be needed. For example, instead of emailing to an incident commander a message would be posted on an incident management newsgroup. The incident commander could pick up the message from any served location. Others could see the message and respond also. Hams could be encouraged to use a system by bonus points for sending contest and field day entries via the system. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Charles Brabham Sent: Wednesday, November 28, 2007 7:39 AM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: The sorry state of VHF/UHF Packet What was it that caused Packet networks in the United States to decline over the course of a decade that saw astounding growth and advancement of the Packet network in Europe? ( 19.2 access, 78.2 fulldup backbone )
RE: [digitalradio] The sorry state of VHF/UHF Packet
I work in C++ using MS Visual studio. My latest venture into Linux was targeted at getting KDE running. I openly solicit collaboration on protocols via my web site (see signature line). Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of keyesbob Sent: Tuesday, November 27, 2007 5:54 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] The sorry state of VHF/UHF Packet What language are you programming in? Do you use an IDE? If you use the autotools (automake, autoconf) for build configuration it might take a bit of getting used to if you're mainly a windows developer but once you use these, your code becomes very portable (you'll find that many things will build on BSD, Solaris, even MacOS X without any changes). But of course, lots of this depends on the devices your program utilizes.
RE: [digitalradio] Re: The sorry state of VHF/UHF Packet
Using Windows does not mean the application is closed source. There is a great deal of open source Windows software. You keep making so strange generalizations like "closed source" and "appliance operators". They hinder your getting your ideas across. I mention Winlink only to indicate that I do have packet experience. My ARES group uses packet for KB-KB communications. We are trying to get more operators using packet. But there is also D-STAR up and running... My first program was in Fortran IV in '68. I suspect I __have__ worked with more operating systems. AX.25 is a mixture of protocol levels. It was a not bad idea at the time. The use of modem chips was a bad choice for an RF environment. Again, not a bad idea at the time. To get a better idea of my thinking see my web site in my signature. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net
RE: RE: [digitalradio] The sorry state of VHF/UHF Packet
I have signed no NDAs for Windows development either professionally or personally. I keep trying Linux but every time I do I run into some hassle that is off-putting. After the holidays (and my wedding on the 29th ) I probably will get back to looking at Linux. The development I do for ham radio I want to be portable. I want to at least have code compile cleanly on Linux. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, November 27, 2007 2:55 PM To: digitalradio@yahoogroups.com Subject: Re: RE: [digitalradio] The sorry state of VHF/UHF Packet I have personally found that GNU/Linux is a wonderful development environment but that is just my opinion and I wouldn't choose to bash those using Windows even if I found all of the NDAs you are required to sign (for Win Dev) to be overly cumbersome.
RE: [digitalradio] The sorry state of VHF/UHF Packet
Bashing operators using Windows and the software for it are not going to gain you friends. With decades of software development experience I find Linux a PITA. My opinion and my results from working with it. You and everyone else are entitled to your opinion. I have developed on more operating systems than you have worked with, including development on embedded systems with no operating system. The issues with packet are (1) no FEC, (2) a terrible protocol to start with, and (3) no inexpensive higher speed data radios available COTS. Because of the above it is abysmally slow and frustrating to operate. I do have a packet station up for Winlink. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net
RE: [digitalradio] Re: PSK63 activity!
How much skill is needed to recognize the few symbols transferred during a contest exchange? Does that translate to general transfer of information? Contesters specialize and tune their equipment. Does that translate into the ability to quickly rig a dipole at an emergency center? The former EC for my county is a contester. He recognizes the difference in skills. I tried to communicate on HF with him a few weeks ago. I had just got my fence dipole antenna installed. He and I could not communicate. I was able to communicate with others in the county. His contesting setup just went right over my head since it was focused for DX. He probably would have done better with his backup antenna stapled to the rafters in his attic. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Rick Sent: Monday, November 19, 2007 1:07 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: PSK63 activity! Rud, I am surprised you would make such a statement since the skills of being able to hear properly and transfer that skill to correctly copy and record the messages is exactly the same skill needed as a contester. You must have a high level of accuracy in each activity to do well. Most contesters also tend to also be fairly conversant with the technical side of amateur radio, typically well above the average ham participating in emergency communications. They are much more knowledgeable about antennas, rigs, interconnections, efficiency, etc. Many (most?) of the operators involved in emergency communications tend to be newer Technician class licensees with very limited experience. In fact, this is so pronounced that leadership here in our Section tends to focus on technologies that dovetail with those kinds of limitations. 73, Rick, KV9U Rud Merriam wrote: > This is also rationalization. The ability to provide disaster > communications entails many skills. Good contesting is virtually > meaningless to that skill set. > > > Rud Merriam K5RUD > ARES AEC Montgomery County, TX > http://TheHamNetwork.net > Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/drsked/drsked.php Yahoo! Groups Links
RE: [digitalradio] Re: PSK63 activity!
This is also rationalization. The ability to provide disaster communications entails many skills. Good contesting is virtually meaningless to that skill set. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Monday, November 19, 2007 6:26 AM To: digitalradio@yahoogroups.com Subject: RE: [digitalradio] Re: PSK63 activity! However, if there is any practical reason for contesting other than vanity and ego, it would be learning to become better operators. In doing this, we make the best use of spectrum in preparation for serving others as a partial payment for the spectrum that was awarded to us for doing this public service when called upon to do so.
RE: [digitalradio] PSK63 activity!
More akin to an AM contest of the 60s including SSB to encourage it. RTTY is an older digital mode. It _should_ be replaced by the newer narrow band mode just as SSB replaced AM, and for the same reasons. Equivalent performance with improved RF usage, mainly bandwidth. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of "John Becker, WØJAB" Sent: Sunday, November 18, 2007 7:21 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] PSK63 activity! At 07:10 PM 11/18/2007, you wrote: >Yes, it is very gratifying to see it finally take off a little. Now, if >we >can only convince the RTTY contest sponsers to specifically include and >mention PSK63, Skip with all due respect. why ? It's not RTTY. Would this not be like adding CW to a side band contest? Or vice verse. John, W0JAB Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/drsked/drsked.php Yahoo! Groups Links
RE: [digitalradio] Testing Digital Codes at Bit Level
In addition, if you have a systematic code versus convolutional or trellis encoding is the bit flipping not applicable? One of my other research activities is on Low Density Parity Codes since they approach channel capacity better than other codes. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net <http://thehamnetwork.net/> -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of John B. Stephensen Sent: Tuesday, November 06, 2007 2:30 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Testing Digital Codes at Bit Level If you have an inner and outer code that would be the situation, but I'm not sure that flipping one bit would always be accurate. A Viterbi decoder might generate small bursts of errors. HDTV uses TCM with an outer Reed-Solomon code. Even though there are 12 interleaved convolutional encoders, they still use an RS code that is capable of correcting bursts of 8 errors. 73, John KD6OZH - Original Message ----- From: Rud Merriam <mailto:[EMAIL PROTECTED]> To: digitalradio@yahoogroups.com Sent: Tuesday, November 06, 2007 20:10 UTC Subject: RE: [digitalradio] Testing Digital Codes at Bit Level I understand about the use of soft decoders. If the protocol uses a soft decoder and another hard decoder the latter works at the bit level. A standard example is using Reed-Solomon for the hard decoder. Would the bit flipping be representative of the atmospheric effects for the outer hard decoder, e.g. RS decoder? Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwor <http://thehamnetwork.net/> k.net
RE: [digitalradio] Testing Digital Codes at Bit Level
I understand about the use of soft decoders. If the protocol uses a soft decoder and another hard decoder the latter works at the bit level. A standard example is using Reed-Solomon for the hard decoder. Would the bit flipping be representative of the atmospheric effects for the outer hard decoder, e.g. RS decoder? Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net <http://thehamnetwork.net/>
[digitalradio] Testing Digital Codes at Bit Level
I would like to test some digital codes at the bit level, rather than the audio level. Does anyone know of a program that will introduce noise by changing bits in a bit stream? Is anyone familiar with any published works on the web that discuss testing at this level? --- I have a feeling that the above questions are not going to be answered so lets try the roll my own approach for AWGN and Fading in the first attempt. Gaussian Noise: is it valid to generate a stream of noise bits where exceeding a threshold amplitude level injects an erroneous bit into the data stream? I am assuming that noise cannot remove a bit but is that a valid assumption? Fading: is it valid to simulate fading by removing some bits in the data stream? Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net
[digitalradio] Poisson, Shannon, and the Radio Amateur
This is an interesting paper (http://tinyurl.com/d5bdo) by John Costas from 1959. It elaborates the point I made earlier today that, counter intuitive as it seems, the better approach for communications in a non-channelized environment is broad bandwidth modes. In that mode of operation everyone uses the same bandwidth but appears as noise to one another. The paper goes into that in detail but is readable even to those who are not mathematicians. It also provides a good explanation of Shannon-Hartley. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net
RE: [digitalradio] Re: ALE400 - Narrow band ALE mode now available
Yes, the laws of physics do get in the way. They say that wider bandwidth is the technique to use. The trick in that situation is that the bandwidth is used by multiple users at the same time. Everyone is background noise to the other guy. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- It just seems to me that to replace existing technology, the newer stuff has to be able to do all the old technology could do and much more in the same or less bandwidth. I'm not seeing this in these digital modes. Yep, laws of physics do tend to get in the way. Those interested in what can be done if the bandwidth were available should read the proceedings of the AMSAT meeting held this month in Pittburgh. They are talking about a geosyncronous satellite with 6MHz of bandwidth available. Supposedly being able to be reached with 5 watts and a 60cm dish. They think this is the future of emergency communications. 73 de Brian/K3KO
RE: [digitalradio] Re: QEX Article on HF Digital Propagation
This is to address the question of why a mode can work at -10 dB when Shannon-Hartley indicates this is not possible for that mode. The calculations adjust the reported dB for a 3kHz signal to the show the dB for bandwidth of the mode. This is the dB applicable for Shannon-Hartley. I lacked the ambition this evening to calculate the Eb/N0 for the modes to see how they compared on that basis. I just tossed in the theoretical channel capacity to show the theoretical capacity. The results are also applicable to the threads on possible new modes of operation. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of "John Becker, WØJAB" Sent: Saturday, October 27, 2007 7:16 PM To: digitalradio@yahoogroups.com Subject: RE: [digitalradio] Re: QEX Article on HF Digital Propagation Sorry but I may have missed something. Your point is ? ? ?
RE: [digitalradio] Re: QEX Article on HF Digital Propagation
I took the dB results from the authors web page and calculated the bandwidth adjusted dB and the Shannon-Hartley channel capacity: Report SNRBWBW Adj Adjusted Capacity Mode (dB) (Hz) 10log(3k/b) SNR (dB) (bps) SSB 9 3000 0.009.00 9482 CW -155017.782.78 77 PSK31 -1131.25 19.828.82 97 PSKFEC -1231.25 19.827.82 88 RTTY -5 21511.456.45524 MFSK16 -13 316 9.77 -3.23177 MFSK8 -14 316 9.77 -4.23146 FeldHell-11 450 8.24 -2.76276 FMHell (105)-105517.377.37148 Olivia32/1000 -12 1000 4.77 -7.23250 Olivia8/500 -9 500 7.78 -1.22406 Olivia16/500-12 500 7.78 -4.22232 DominoEX11 -11 26210.59 -0.41245 DominoEX11FEC -13 26210.59 -2.41171 DominoEX8 -12 346 9.38 -2.62218 I took BW numbers from various web sites so if anyone disputes the values used feel free to tell me so. I can recalculate the values. I suspect that the BW used is sufficient to give a better feel for understanding the performance. In another message I see Rick wondering about the BW for PSK-31. I saw some other values reported but did not pursue that question and went with the conventional usage. For CW I just used a number for reasonable character speed. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Rud Merriam Sent: Saturday, October 27, 2007 1:47 AM To: digitalradio@yahoogroups.com Subject: RE: [digitalradio] Re: QEX Article on HF Digital Propagation Jose, Just as you were posting this message I was stumbling on a web site that agreed with your comment. With further searching I think I have the relationship. The QEX article has the statement that to go from the 3kHz bandwidth used you "subtract 34 dB and add 10 log of the desired bandwidth in Hz". But I think he has it wrong. My search found that you adjust by taking 10log(BWoriginal/BWdesired) and adding it to the given figure. I think the author neglected to consider that the power of the signal is unchanged during the calculation. The result is you need to add 19.82 dB to the reported values to obtain the SNR for a 31.25 Hz signal. As proof (I hope ): Signal: 3000 Noise (3kHz): 3000 SNR(dB): 0 Signal: 3000 Noise (31.25Hz): 31.25 SNR(dB): 19.82 Where the noise is 1 Watt-s per Hz. The article reports that PSK-31 work down to -12 dB in AWGN this actually means it work to 7.82 dB. The channel capacity for that SNR per Shannon-Hartley is 88 bps. PSK-31 attains less that half the channel capacity. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Jose A. Amador Sent: Friday, October 26, 2007 2:26 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: QEX Article on HF Digital Propagation Yes, a 3 kHz voice channel...not the inmediate environment of the digital signal, but much, much farther away. And as noise floor is related to bandwidth... Your mileage may vary... 73, Jose, CO2JA Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/drsked/drsked.php Yahoo! Groups Links
RE: [digitalradio] Sub Channel DQPSK
Thanks, John. I was thinking of posting a message directed at California operators to see what their experience was going over the pole to Europe. Your VE-land experience provides the same information. It is interesting sorting out the anecdotal reports, including yours, the theory / studies, and the realities. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net <http://thehamnetwork.net/> -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of John Bradley Sent: Saturday, October 27, 2007 8:45 AM To: digitalradio@yahoogroups.com Subject: RE: [digitalradio] Sub Channel DQPSK For what it's worth Rud, PSK31 appears much more susceptible to phase distortion that wider modes such as MFSK and OLIVIA. Here, we are just over 50 degrees north latitude and have many more occasions to experience the Northern "flutter" from the aurora. This phase distortion knocks out PSK31 pretty fast. Also makes SSB ops Sound like Donald Duck There are times when this will show up on relatively short hops (less than 500km) on 80 and 40 M John VE5MU Would the phase distortion that can corrupt a PSK signal occur the same on a M-PSK signal? If the phase distortion affects all the sub channels then doing differential PSK among the sub channels would work where symbol to symbol DxPSK would not work. Rud Merriam K5RUD ARES AEC Montgomery County, TX <http://TheHamNetwork.net> http://TheHamNetwork.net
RE: [digitalradio] Re: QEX Article on HF Digital Propagation
Jose, Just as you were posting this message I was stumbling on a web site that agreed with your comment. With further searching I think I have the relationship. The QEX article has the statement that to go from the 3kHz bandwidth used you "subtract 34 dB and add 10 log of the desired bandwidth in Hz". But I think he has it wrong. My search found that you adjust by taking 10log(BWoriginal/BWdesired) and adding it to the given figure. I think the author neglected to consider that the power of the signal is unchanged during the calculation. The result is you need to add 19.82 dB to the reported values to obtain the SNR for a 31.25 Hz signal. As proof (I hope ): Signal: 3000 Noise (3kHz): 3000 SNR(dB): 0 Signal: 3000 Noise (31.25Hz): 31.25 SNR(dB): 19.82 Where the noise is 1 Watt-s per Hz. The article reports that PSK-31 work down to -12 dB in AWGN this actually means it work to 7.82 dB. The channel capacity for that SNR per Shannon-Hartley is 88 bps. PSK-31 attains less that half the channel capacity. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Jose A. Amador Sent: Friday, October 26, 2007 2:26 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: QEX Article on HF Digital Propagation Yes, a 3 kHz voice channel...not the inmediate environment of the digital signal, but much, much farther away. And as noise floor is related to bandwidth... Your mileage may vary... 73, Jose, CO2JA
RE: [digitalradio] Re: QEX Article on HF Digital Propagation
Rick, Good questions. My only response right now is "I dunno". Back to the books. The QEX article based its results on a rate of 2% character error rate. PSK-31 with AWGN needed -11 dB. Crunching the numbers that at -10 dB you need a bandwidth of 227 Hz for 31.25 bps. At -11 dB would need somewhat more. Pushed to give some kind of answer I wonder if (1) since our received bandwidth is much wider than 31.25 Hz perhaps the sidebands are helping the situation and (2) is the reported SNR accurate? Additionally, for the latter is the SNR for just the 31.25 Hz bandwidth or for the entire received bandwidth? Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Rick Sent: Friday, October 26, 2007 7:53 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: QEX Article on HF Digital Propagation My understanding is that the Eb/No is more of what you would find at the antenna terminals, without the bandwidth of the receiver? Using your data on your web site, how does this relate to say, PSK31 modulation? Would the SNR also be at zero with the 31 bps baud rate with the B/C (Bandwidth in Hz divided by the Channel capacity in bps) at ~ 1.? Then how do you get the much lower SNR ascribed to a mode such as PSK31? ( ~ 10dB or so?) According to your chart it would need about 7 times the B/C ratio? I had thought the ratio would be somewhat fixed at about 63 Hz BW to 31 bps or around ~ 2.. What am I missing? The BW is actually much wider than the number we usually use for PSK31 to get the much lower SNR? How do you make a wider bandwidth for a given mode? Isn't the bandwidth based on the baud rate to begin with? 73, Rick, KV9U
[digitalradio] Sub Channel DQPSK
Would the phase distortion that can corrupt a PSK signal occur the same on a M-PSK signal? If the phase distortion affects all the sub channels then doing differential PSK among the sub channels would work where symbol to symbol DxPSK would not work. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net
RE: [digitalradio] PSK under ionospheric flutter, was: QEX Article on HF Digital Propagation
Vojtech, Good points. After some further reflection on the article I am not sure many conclusions can be made from the material beyond its specific results about the modes covered. The various modes are to dissimilar in all aspects to draw any conclusions on whether PSK is better than MFSK, for instance. There must be a study somewhere, probably sponsored by the government or military, that does a direct comparison. The book on digital communications I am using, Sklar, does have charts for AWGN comparisons. Those only go so far in predicting real-world capabilities with fading, multi-path, and Doppler. Ah, more digging into the internet... Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net
[digitalradio] Pactor OFDM??
I just read the Pactor 3 specification. I am not sure that it is OFDM. It is multi-tone but the spacing of the tones seems wider than OFDM requires. But I may be missing something in the technical definition OFDM of that differentiates it from MT. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net Pactor has proven the worth (necessity?) of using full time FEC and a moderate baud rate OFDM signal using PSK. Otherwise, you wouldn't you need some kind of training pulse sequence as used on the 8PSK MIL-STD/FED-STD/STANAG modems? 73, Rick, KV9U
RE: [digitalradio] Re: QEX Article on HF Digital Propagation
Rick, The measurement of SNR and Eb/No are two different measurements. The confusion comes because they are both cited in dB. It took me quite a lot of rereading material to clearly understand them. I dumped my understanding of it onto my web site at http://thehamnetwork.net/wiki/#Shannon-Hartley%20%5B%5BShannon%20Limit%5D%5D . To see the math and graphs clearly you need to have some support software installed. See http://thehamnetwork.net/wiki/#Graphics%20%5B%5BMath%20Expressions%5D%5D for details. The actual Shannon Limit is -1.6 dB for Eb/No. The limit for SNR is not expressible, that I have seen, as a single number. Instead it is determined by the power, noise, and bandwidth. More simply, by the SNR and bandwidth. One of the datum I found interesting is that below 0 dB SNR the channel capacity drops precipitously. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Rick Sent: Friday, October 26, 2007 1:39 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: QEX Article on HF Digital Propagation Something that has long been unclear to me is how can we have all these modes that work far below zero db S/N and yet the Eb/No (energy per bit relative to noise) can theoretically not go much lower than between 1 and 2 dB below zero dB according to the Shannon Limit? Then you need to take the value of the baud rate and bandwidth of the signal into consideration and that ratio is multiplied against the Eb/No. Wouldn't that further raise the required S/N ratio? We often see measurements of modes that work -5, -10, even -15 dB S/N? What are they measuring if not something related to the Eb/No? Pactor has proven the worth (necessity?) of using full time FEC and a moderate baud rate OFDM signal using PSK. Otherwise, you wouldn't you need some kind of training pulse sequence as used on the 8PSK MIL-STD/FED-STD/STANAG modems? 73, Rick, KV9U
RE: [digitalradio] RE: QEX Article on HF Digital Propagation
Any chance of you locating that study information? I would like to use every technique possible to maximize the data in a 500 Hz signal. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Walt DuBose Sent: Thursday, October 25, 2007 9:51 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] RE: QEX Article on HF Digital Propagation One other comment. I have said before on this list that I have seen and used to have data produced by SouthWest Research Institute here in San Antonio that shows the maximim probable data capability of a single PSK signal. This study was done for the U.S. Government in research to find the best robust, medium throughput mode for a nation command alert system os some sort. I suspect it had something to do with always being able to keep the President informed under the most trying conditions with some sort of broadcast system. The upshot of all this as a limited discussion of a number of hams that were at the reporting session that the current MIL-STD modems could be improved on but that to obtain the desired throughput you would need more than the bandwidth associated with normal SSB transmitters. While amateur radio main not want a 4 or 5 KHz signal and the throughput that the government wanted, I think that a compromise bandwidth, something between that of PSK31 and perhaps 1 KHz with OFDM signal might be adequate for hams use on HF. As many have said before...if you REALLY want/need 100 error free copy, you are going to need an ARQ function and FEC. The "trick" is finding just how much of you signal you are going to give to FEC vs user data and how hard do you want to enforce ARQ. 73, Walt/K5YFW Walt DuBose wrote: > Rud Merriam wrote: > >>After a comment off list from Demeter I checked the Pactor >>specifications. It uses DBPSK or DQPSK. >> >>Why do the reports about Pactor indicate it is more robust than the >>QEX article would indicate? >> >> >>Rud Merriam K5RUD >>ARES AEC Montgomery County, TX >>http://TheHamNetwork.net >> > > Rud, > > If you go back to the DCC presentation of KN6KB of a few years back on > his new > software modem...he measured the robustness of Pactor, MT63 and several other > modes and Pactor wasn't that much more robust than MT63 at a -5 dB SNR. > > If I invested a $K Buck or so in Pactor III and WinLink, I'd claim it > was the > best thing since sliced bread...woudln't you? > > 73, > > Wa;t/K5YFW > > Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/drsked/drsked.php Yahoo! Groups Links
RE: [digitalradio] RE: QEX Article on HF Digital Propagation
I should have been more clear in my comment. The QEX article shows that PSK31 is terrible under conditions that induce phase changes. The MFSK16 and Olivia did much better. Even RTTY worked well under those conditions. PSK31 failed, bad copy even under good SNR, with 3 ms multipath and 10 Hz Doppler. It did not do well with 2 ms multipath and 1 Hz Doppler. Since Pactor uses PSK I wondered if it would similarly fail as shown by the PSK31 results. I suspect that it handles Doppler better through frequency tracking algorithms. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Walt DuBose Sent: Thursday, October 25, 2007 9:38 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] RE: QEX Article on HF Digital Propagation Rud Merriam wrote: > After a comment off list from Demeter I checked the Pactor > specifications. It uses DBPSK or DQPSK. > > Why do the reports about Pactor indicate it is more robust than the > QEX article would indicate? > > > Rud Merriam K5RUD > ARES AEC Montgomery County, TX > http://TheHamNetwork.net > Rud, If you go back to the DCC presentation of KN6KB of a few years back on his new software modem...he measured the robustness of Pactor, MT63 and several other modes and Pactor wasn't that much more robust than MT63 at a -5 dB SNR. If I invested a $K Buck or so in Pactor III and WinLink, I'd claim it was the best thing since sliced bread...woudln't you? 73, Wa;t/K5YFW Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/drsked/drsked.php Yahoo! Groups Links
[digitalradio] RE: QEX Article on HF Digital Propagation
After a comment off list from Demeter I checked the Pactor specifications. It uses DBPSK or DQPSK. Why do the reports about Pactor indicate it is more robust than the QEX article would indicate? Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net > -Original Message- > From: Rud Merriam [mailto:[EMAIL PROTECTED] > Sent: Thursday, October 25, 2007 1:10 PM > To: 'digitalradio@yahoogroups.com' > Subject: QEX Article on HF Digital Propagation > > There is a great article in the QEX I just received (Nov/Dec 2007). The > author is Daniel Crausaz HB9TPL in Switzerland. He reports on modeling and > testing PSK, RTTY, Olivia, MFSK, DominoEx and Feld-Hell under various > propagation conditions. I need to digest his work with respect to the OFDM > proposal since the results indicate PSK may not be an optimal choice. > > Olivia works better under all the conditions tested. MFSK seems to be > second. At first glance I would say this is because the transmission rate > is so slow for Olivia at 2.5 character per second. I would find that > painfully slow for even a chat mode. > > Interestingly, RTTY performs about the same under all the conditions > tested. > > PSK either works well or just fails. It has problems in flutter conditions > which seem to me be the conditions prevalent a lot of the time. > > > Rud Merriam K5RUD > ARES AEC Montgomery County, TX > http://TheHamNetwork.net >
RE: [digitalradio] QEX Article on HF Digital Propagation
You might try emailing the author for a copy. I checked the QEX web page because they always feature an article. Unfortunately it was another article for this issue. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Peter G. Viscarola Sent: Thursday, October 25, 2007 4:06 PM To: digitalradio@yahoogroups.com Subject: RE: [digitalradio] QEX Article on HF Digital Propagation > There is a great article in the QEX I just received (Nov/Dec 2007). Darn! I KNEW that as soon as I didn't renew my subscription, they'd publish an article that I'd want to read. I don't s'pose somebody wants to violate the copyright by scanning the article in and post it somewhere, huh?? Oh, never mind... forget that I asked that. de Peter K1PGV Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/drsked/drsked.php Yahoo! Groups Links
[digitalradio] QEX Article on HF Digital Propagation
There is a great article in the QEX I just received (Nov/Dec 2007). The author is Daniel Crausaz HB9TPL in Switzerland. He reports on modeling and testing PSK, RTTY, Olivia, MFSK, DominoEx and Feld-Hell under various propagation conditions. I need to digest his work with respect to the OFDM proposal since the results indicate PSK may not be an optimal choice. Olivia works better under all the conditions tested. MFSK seems to be second. At first glance I would say this is because the transmission rate is so slow for Olivia at 2.5 character per second. I would find that painfully slow for even a chat mode. Interestingly, RTTY performs about the same under all the conditions tested. PSK either works well or just fails. It has problems in flutter conditions which seem to me be the conditions prevalent a lot of the time. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net
RE: [digitalradio] OFDM Proposal: Details
John, I work in C++. I would like to see your code since I can read Pascal. Having the executables would be good since could test a port in C++ against the original code. I am aware of your work and publication of it in QEX. Totally off topic but technically interesting, did you (and everyone else here) know that Pascal was developed by writing the language in itself? The creator, Wirth, wrote the Pascal compiler in Pascal. Then he used Fortran, I believe, to do a quick and dirty port of the Pascal code into Fortran. He compiled the Fortran version. Using that executable he compiled the original Pascal. From then on he could compile Pascal using itself. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net <http://thehamnetwork.net/> -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of John B. Stephensen Sent: Wednesday, October 24, 2007 10:53 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] OFDM Proposal: Details Rud: What language are you developing in? I have some software that generates and receives OFDM with 8PSK subcarriers using .wav files containing I and Q samples. The source code is about 1500 lines of Delphi (Pascal). It's fairly slow as it uses a DFT and IDFT and floating point arithmentic, but that won't matter as much for 500 Hz wide signals as it did for 1.5 MHz wide signals. It uses BICM-8 which is a variation of Ungerboek's TCM that is supposed to work better on fading channels and includes a Viterbi decoder. There is no frequency correction mechanism as one program was used to generate files for an arbitary waveform generator. The other was to test the file generated by the first program. The software and a signal generator were used to generate a signal on 6 meters and 70 cm for testing an FPGA-based decoder. 73, John KD6OZH - Original Message ----- From: Rud Merriam <mailto:[EMAIL PROTECTED]> To: digitalradio@yahoogroups.com Sent: Wednesday, October 24, 2007 10:03 UTC Subject: [digitalradio] OFDM Proposal: Details For your amusement and consternation here are my latest thoughts on doing an OFDM protocol. Symbol rate: 62.5 Hz(128 samples @ 8000 Hz) Guard interval: 2, 4, 8 ms adaptive to conditions Subchannels: 8 (62.5 125 187.5 250 312.5 375 437.5 500) Bandwidth: 437.5 Hz Raw BPS: 1778, 1600, 1333 adaptive (guard band change) Base frequency: undetermined MODULATION (somewhat firm) Waveform: DQPSK with constellation at 45, 135, 225, 315 degrees Generation: 8 separate generators providing continuous waves through the guard bands Phase change: start of symbol period Shaping: post generation raised cosine over symbol and guard period DEMODULATION (somewhat speculative) FT: 128 bin every 32 samples for locating subchannels Synchronization: square of subchannels identified by FT to locate bottom subchannel by 125 Hz signal Frequency drift: subchannel selection based on output of synchronization Phase detection: phase averaged over symbol period, differential with last symbol A main goal is to keep the bandwidth within 500 Hz. The symbol rate is as suggested by John KD6OZH. First testing will probably be with his 8 ms guard band but I would like to make it adaptive to short that period if multipath conditions allow. DQPSK to get more throughput and because getting the absolute phase is a challenge. Any suggestion to use absolute phase would be appreciated since that gains a couple dB. The Fourier transform is mainly to identify the potential subchannel locations to allow adjusting for frequency drift. Once high energy bins are determined the signal is filtered at various of those frequencies and the square used to detect the doubled lowest frequency (125 Hz). That also locates the symbol period for synchronization. Actually, the possible frequency includes the guard band so it may be one of three values. By determining that value the guard band period is also determined and the actual guard band removed. Rud Merriam K5RUD ARES AEC Montgomery County, TX <http://TheHamNetwork.net> http://TheHamNetwork.net
[digitalradio] Comments on Communicational and Technology from CA
http://www.networkworld.com/community/node/20911 Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net
RE: [digitalradio] OFDM Proposal: Details
John, One more time, thanks. A lot to mull over in your message. I am working from Lyons for DSP and Sklar for the digital communications. Plus whatever I can scare up on the web. Any other suggestions for reference materials? Two big gaps are going from the DSP in Lyons to practical implementation and between the DSP and digital. Lyons does not really talk about communications and Sklar does not go into the DSP enough for me. Sklar also seems to be a little behind the curve on DSP and recent developments. Sklar does cover the Ungerboek material so I will review it again. I don't follow the "one bit with QPSK and 2 using 8PSK" since QPSK will carry 2 bits and 8PSK 4 bits. I was also reviewing some other material. From it I was considering using 1/4 Pi DQPSK to avoid crossing through the origin during phase changes. There would be room for a 9th sub carrier and still fit in 500 Hz. Why wouldn't sub carriers above and below the data sub carriers not count for the bandwidth used? More than 9 sub carriers exceeds 500 Hz. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net <http://thehamnetwork.net/> -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of John B. Stephensen Sent: Wednesday, October 24, 2007 8:37 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] OFDM Proposal: Details Differential PSK should be more reliable in the presence of frequency drift and Doppler spread. There are two ways to do this: 1) compare the phase with the previous phase of the same subcarrier or 2) compare the phase with the phase of the next higher or lower subcarrier. In the first case, the first symbol transmitted is always all zeroes. In the second case, there would have to be at least one pilot subcarrier that is unmodulated. If you want pilot subcarriers, it should be possible to put them 62.5 Hz above and below the outermost data subcarriers as they take no extra space if they are not modulated. A good way to do FEC is to use trellis-coded modulation (TCM). One bit is added to the data stream for each subcarrier. This, 1 data bit is sent using QPSK and 2 data bits are sent using 8PSK. The advantage of sending the data and ECC bits on one subcarrier is that the error-correcting code can be designed so that no extra bandwith is needed and that the addition of the extra bit actually decreases the required SNR rather than increasing it as you would first expect by increasing the number of points in the constellation. Ungerboek came up with a set of codes that can decrease the required SNR by 3-6 dB (with no fading) when going from QPSK with no ECC to 8PSK with ECC. The improvement is larger when fading occurs. The amount of improvement provided by TCM depends on the complexity of the state machine used to generate the ECC bit. However, a simple algorithm with 4 states provides a 3 dB improvement. A Viterbi decoder is used to calculate the most probable set of state transitions that the incoming signal has taken from symbol to symbol and then backtracks to determine the most likely combination over an entire data frame. It can also make decisions based on the actual value of the incoming signal rather than on 3 already decoded buts. This adds another 2 dB of improvement. Its probably useful to place the audio subcarrier frequencies in the 500-1000 Hz range or higher so that harmonics of low frequency subcarriers don't interfere with higher-frequency subcarriers. 73, John KD6OZH - Original Message - From: Rud Merriam <mailto:[EMAIL PROTECTED]> To: digitalradio@yahoogroups.com Sent: Wednesday, October 24, 2007 10:03 UTC Subject: [digitalradio] OFDM Proposal: Details For your amusement and consternation here are my latest thoughts on doing an OFDM protocol. Symbol rate: 62.5 Hz(128 samples @ 8000 Hz) Guard interval: 2, 4, 8 ms adaptive to conditions Subchannels: 8 (62.5 125 187.5 250 312.5 375 437.5 500) Bandwidth: 437.5 Hz Raw BPS: 1778, 1600, 1333 adaptive (guard band change) Base frequency: undetermined MODULATION (somewhat firm) Waveform: DQPSK with constellation at 45, 135, 225, 315 degrees Generation: 8 separate generators providing continuous waves through the guard bands Phase change: start of symbol period Shaping: post generation raised cosine over symbol and guard period DEMODULATION (somewhat speculative) FT: 128 bin every 32 samples for locating subchannels Synchronization: square of subchannels identified by FT to locate bottom subchannel by 125 Hz signal Frequency drift: subchannel selection based on output of synchronization Phase detection: phase averaged over symbol period, differential with last symbol A main goal is to keep the bandwidth within 500 Hz. The symbol rate is as suggested by John KD6OZH. First testing will probably be with his 8 ms guard band but I would like to mak
[digitalradio] OFDM Proposal: Details
For your amusement and consternation here are my latest thoughts on doing an OFDM protocol. Symbol rate: 62.5 Hz(128 samples @ 8000 Hz) Guard interval: 2, 4, 8 ms adaptive to conditions Subchannels: 8 (62.5 125 187.5 250 312.5 375 437.5 500) Bandwidth: 437.5 Hz Raw BPS: 1778, 1600, 1333 adaptive (guard band change) Base frequency: undetermined MODULATION (somewhat firm) Waveform: DQPSK with constellation at 45, 135, 225, 315 degrees Generation: 8 separate generators providing continuous waves through the guard bands Phase change: start of symbol period Shaping: post generation raised cosine over symbol and guard period DEMODULATION (somewhat speculative) FT: 128 bin every 32 samples for locating subchannels Synchronization: square of subchannels identified by FT to locate bottom subchannel by 125 Hz signal Frequency drift: subchannel selection based on output of synchronization Phase detection: phase averaged over symbol period, differential with last symbol A main goal is to keep the bandwidth within 500 Hz. The symbol rate is as suggested by John KD6OZH. First testing will probably be with his 8 ms guard band but I would like to make it adaptive to short that period if multipath conditions allow. DQPSK to get more throughput and because getting the absolute phase is a challenge. Any suggestion to use absolute phase would be appreciated since that gains a couple dB. The Fourier transform is mainly to identify the potential subchannel locations to allow adjusting for frequency drift. Once high energy bins are determined the signal is filtered at various of those frequencies and the square used to detect the doubled lowest frequency (125 Hz). That also locates the symbol period for synchronization. Actually, the possible frequency includes the guard band so it may be one of three values. By determining that value the guard band period is also determined and the actual guard band removed. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net
RE: [digitalradio] Re: OFDM Proposal
Thanks, John, for this reference and the other responses. I do keep an eye on Phil's work and comments. Time for a direct question: How do you modulate an OFDM sub channel using an IFFT? Or is that not the way to do it in practice? I have experimented with Excel. Looking at the FFT of a cosine wave I get a nice solid single frequency bin. Doing a modulation of it with a phase change in the middle I get a number of bins which looks impractical to implement. A value in a single bin then running an IFFT generates a nice cosine. I can kind of make a PSK modulate signal by copying 3 values from the FFT experiment above but other attempts generate a mess. Again, that does not seem like a feasible approach. Musing about it while going to sleep I got thinking about another approach based on the observation that the sign of a value in the complex number controls the phase of the start of the curve. The process is: Generate a "symbol" If a phase change is needed change the sign in the bin Generate the next "symbol" The trick is that the "symbols" are offset by 1/2 the timing period, i.e. the start of the 2nd symbol is actually the midpoint of the 2nd symbol. This works because in OFDM the symbol period contains complete cycles of the waves. Possibly using the IFFT for an HF OFDM signal is inefficient, especially when working with a 500 Hz bandwidth signal. The 62.5 baud suggestion you made only using 9 tones so generating them directly would not be a CPU intensive process, especially using table lookups. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net <http://thehamnetwork.net/> -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of John B. Stephensen Sent: Monday, October 22, 2007 7:40 AM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: OFDM Proposal Look at KA9Q's web site, especially http://www.ka9q.net/code/fec/, for FEC software. 73, John KD6OZH
RE: [digitalradio] Re: OFDM Proposal
Ed, I am looking into the possibilities of OFDM. Right now I am stumbling over how to modulate the sub channels using the IFFT. Actually, I think it is done by putting equal values in the real and imaginary parts of a bin and then doing the IFFT but need to try it out. I am a big proponent of FEC feeling it is woefully underused in ham digital modes. If you ain't FEC'n; you ain't tryin'. More pragmatically if you don't need FEC then you are using more bandwidth or power than necessary. One form of FEC I am curious about is putting FEC on each symbol. It has been an awfully long time that I looked at the error correcting codes (ECC) that are used in computer memory so I do not recall the details. A little research should remedy that memory failure. But putting 2 bit detection with 1 bit correction on a byte wide symbol might be worth the effort. In other words, stand by while I play with this. I will keep the group updated either by direct results or questions. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Ed Hekman Sent: Sunday, October 21, 2007 11:55 PM To: digitalradio@yahoogroups.com Subject: [digitalradio] Re: OFDM Proposal Rud, I would really enjoy hearing some discussion on the use of OFDM on HF. I work on an OFDM project and have an understanding of how it works although I am not a system designer. I have also tried OFDM with HamPal (digital SSTV) and WinDRM (digital voice) and it seems to me that it offers a lot of potential for improving performance with HF multipath fading. To stimulate some discussion I would like to ask some questions for the experts in the field.
RE: [digitalradio] Vista Digital System Navigation for Hardware Setting and Info
As a software developer I push into nooks and crannies of an operating system. Microsoft tightened access to some of those places making it more difficult for me. Sometimes I am challenged to even find where to change the settings. I certainly do not mean to say Vista is bad. Right now I have something strange going on with the microphone input on my laptop. Sometimes the digital software accesses the microphone fine. Other times it does not. I have not pursued it in depth but I cannot get MultiPSK to access that input at all. DM780 connects to the input properly about 80% of the time. When it does not work I have to go through 3 dialogs to "reactivate" the input. There is probably some way to go there directly but I have not determined how. Probably even a setting that would eliminate the need entirely. Then again, it may be that the laptop itself is doing something flakey and it has nothing to do with Vista. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Rick Sent: Saturday, October 20, 2007 4:02 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Vista Digital System Navigation for Hardware Setting and Info I am a bit surprised at the comments about Vista vs. XP. 73, Rick, KV9U
RE: [digitalradio] Vista Digital System Navigation for Hardware Setting and Info
Bill, Thanks for that information. I am floundering a bit with Vista on my laptop so any help is beneficial. As a developer I usually can twist my head around the other developers way of thinking - eventually. I will admit that Linux and Vista are challenging me in this regard. I hate to think I may be turning into a certified old fart. I would clarify that the main issues in my message were about a live distro of Linux with ham software. I have since received an email direct from the authors with some guidance. It may be a couple days before I can try that software again. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net <http://thehamnetwork.net/> -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of WD8ARZ Comcast Sent: Saturday, October 20, 2007 9:34 AM To: digitalradio@yahoogroups.com Subject: [digitalradio] Vista Digital System Navigation for Hardware Setting and Info Navigating can be such a pain when going from xp to vista. Both worlds have there plus and minus properties and I am not advocating or bashing either. Just happen to use em and other operating systems, and I am glad to share that experience.
RE: [digitalradio] NBEMS HF testing frequency suggestion
I just burned the CD. I will setup the laptop and rig to try on these frequencies and nearby. Probably operational in 20-30 minutes. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Andrew O'Brien Sent: Thursday, October 18, 2007 8:35 PM To: DIGITALRADIO Subject: [digitalradio] NBEMS HF testing frequency suggestion Aside from 6M and 2M , where I had good results with NBEMS, I am anxious to try it on HF. I will assume that the low bands will make fast PSK too difficult but PSK125 and 63 with ARQ is worth testing on HF. NBEMS has a nice bacon feature , and a beacon feature too. I would like to suggest a 20M and 40M testing frequency for this weekend, I will suggest 14073 (dial frequency) and/or 7073 . Please QRL first, and move up or down a tad if the frequency is busy.I will be on tonight and tomorrow night with my beacon (when at the keyboard). -- Andy K3UK www.obriensweb.com (QSL via N2RJ) Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/drsked/drsked.php Yahoo! Groups Links
RE: [digitalradio] Re: Need to Expand the HF Auto Band Segments
I do not do boats much, but prefer not to listen to them, so prefer sailing. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Roger J. Buffington Sent: Thursday, October 18, 2007 10:53 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Need to Expand the HF Auto Band Segments Rud Merriam wrote: > > Roger, > > As a ham I am interested in using email via my radio. Part of it is > technical challenge of working on a system to do this. Part of it is > to explore the digital technologies. > > Much of my interest is aside from disaster communications, but there > is that, also. > > My license allows me to do this and I intend to do so within the > regulations. > > There is one ham's reasons for pursuing my part of this hobby. > > Rud Merriam K5RUD ARES AEC Montgomery County, TX > http://TheHamNetwork.net <http://TheHamNetwork.net> Works for me, friend. A little experimenting is a good thing. I like messing with radios and messing with boats, and messing around with radios on boats. I'll do my thing and you do yours. And I'll bet that you listen before you transmit, too, which the regulations require of us both. de Roger W6VZV Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/drsked/drsked.php Yahoo! Groups Links
