Loading ...
Sorry, an error occurred while loading the content.
 

Re: [wsjtgroup] JTMS vs FSK441

Expand Messages
  • Bill VanAlstyne W5WVO
    Hey Tip, Apparently you are feeling like I stepped on a lot of people s toes, and you re running around trying to make nice for everybody. I m sorry if I
    Message 1 of 12 , Jun 30, 2010
      Hey Tip,
       
      Apparently you are feeling like I stepped on a lot of people's toes, and you're running around trying to make nice for everybody. I'm sorry if I offended anyone; that certainly wasn't my intent. My apologies if anyone felt slighted.
       
      But we have a problem, folks. I'm seeing more and more people on WSJT m/s who just flat don't know what they're doing. I got on this mode only a few years ago (January 2008, to be exact), and it wasn't like that then. Something has changed, and I tend to look to the educational aspects of a problem like this, because I don't know any other way of addressing it.
       
      Again, sorry to have offended. I have slapped my wrist sharply, and will now crawl back into my hole and go to sleep. Sad smile emoticon  Tomorrow dawns a new and brighter day.
       
      Bill W5WVO
       

      Sent: Wednesday, June 30, 2010 7:46 PM
      Subject: Re: [wsjtgroup] JTMS vs FSK441

       

      Hey Bill, be careful what you volunteer for.
       
      Bill has written some very useful tutorial notes and that is the reason we have them on the wsjtgroup WebPages, with his permission of course. I believe the two links at the top of the PJ Central Page that Bill mentions "You must read this and Also This" could be changed in a positive way which provides even more useful information.  Maybe even a FAQ page would be useful with links to a "New Comprehensive Operating Manual".
       
      WSJT now has a condensed version of the SOP <F5> so the link <Also This> is really not needed in such great detail. Perhaps that SOP should be shortened with only the information needed for  using wsjt modes. I posted an Interpretation of the SOP several years ago at http://www.ykc. com/wa5ufh/ Misc/ShortSOP. htm trying to shorten and simply the original SOP.
       
      The other link that takes you to the Ping Jockey Etiquette was written by me and critiqued by WB5APD, N0UK, K1SIX and a few others. This information was really needed at the time as many stations were experimenting with WSJT and PJ was new.  I am sure some of this information is still useful but maybe combined with other useful information in another format would inspire newbie's to learn more.
       
      Chris, N0UK is a member of this group and I believe would be open to improvements. PJ has become a very useful tool for NA stations and Chris doesn't get near the credit he deserves for maintaining the PJ pages. 
       
      My opinion is better written and more up to date information is needed.  Maybe a Comprehensive Manual as you mentioned and the PJ links are really one project. Links from PJ to the manual ... One thing to keep in mind is the WSJT8 work and how it ties in with a new manual? I don't know about you but I hate re-work and reengineering.
       
      I just wanted to be the first to say I believe you are both qualified and able to do a good job at technical writing wsjt data. Where can I vote...
       
       
      tip
       
       
       

       
       
       
      ----- Original Message -----
      Sent: Wednesday, June 30, 2010 6:12 PM
      Subject: Re: [wsjtgroup] JTMS vs FSK441

      Guess it's time for me to chime in and comment on some of the comments here. Smile emoticon
       
      First, going in chronological order, I want to speak to the problem Tip mentioned of "newbies" (using the term very loosely, as Barry pointed out) gettng confused by false SH decodes.
       
      I agree with Barry here that this is an education problem -- and in some cases just an IQ problem, not to put too fine a point on it. Being a professional technical writer, I'm more painfully aware than anybody here that a lot of people decline to read technical manuals that contain (or should contain) information they absolutely need to understand. Sometimes it is because the technical manual is written in poorly constructed English; sometimes the manual doesn't actually contain all the relevant information it should; sometimes the manual is written in language or sentence structure that is too complex for the average user to understand. Sometimes it is a problem with users having learning disabilities like dyslexia, which make it impossible to extract usable understanding from written text. And sometimes the intrinsic nature of the material, no matter how well presented, is simply "over the head" of the person who is trying to understand it. Personally, I would have a comprehension problem with any advanced academic paper on particle physics. I'm simply not that smart or well enough educated in that area, and I wouldn't get all of it, or even much of it. I would have to admit that particle physics just "isn't for me," to use Barry's delightfully delicate phraseology -- that is, it's over my head.
       
      I wrote a paper a while back on using SH messages in FSK441, and I covered false SH messages (and how to avoid being confused by them) in pretty close detail. Looking back at that paper recently, I saw I could have written an even more granular treatment of this subject and presented even more options, but that would only have made the matter just that much more complex. And how many people have actually read that paper anyway? How many of the people who tried to read it actually understood it? I have no idea, but I think I can safely say it isn't anywhere close to 100% in either case.
       
      So, what to do? Bottom line, I don't believe that the opportunity to mask false decodes is any part of a good set of reasons for changing the digital meteor scatter protocol. Let's first do a better job of trying to get the operators who use the existing protocol smart enough to use it. Failing that, maybe we concede defeat and go to a less cognitively intense protocol.
       
      It could start with replacing the "you must read this - and also this" links on the PJ page with material that is more accessible, more up-to-date, and better written. I'd be happy to provide such material, but the owner of the page (whom I've never even communicated with on any basis) would have to concur. Tip might have a much better connection there than I have. Second, the accessibility of the material that I (and others) have written for the WSJT group on Tip's website could be more accessible in terms of web page design. Due to the use of frames, it's impractical to put together a URL that would take an interested person directly to any one document. (Not impossible if you know how to do it -- but most people don't. And then once there, you are outside the context of the website's frame structure with nowhere to go.) In summary, any one of us should be able to point a newbie (or a not-so-newbie) to a specific article's URL and say "go here and read this."
       
      I'm also willing to take on the project of writing a comprehensive manual for WSJT meteor scatter operation using FSK441, something that to the best of my knowledge hasn't ever been done -- or if it has, it hasn't been done well enough to become ubiquitous and essential. It is badly needed.
       
      Since this post has already become so long, I'll address the other matters I wanted to comment on in a separate post on this thread.
       
      Bill W5WVO
       

      Sent: Wednesday, June 30, 2010 3:24 PM
      Subject: RE: [wsjtgroup] JTMS vs FSK441

       

      Hi again Randy.  Well, it looks like you did not fully understand what I was referring to.  I was not talking about the HSCW that we did for a few years - and which the Europeans practiced for many years prior to that, using speeded up and slowed down tape recorders.  I was talking about plain normal speed CW and SSB meteor scatter work.  But I cannot see any reason why the rules that were used then do not still apply.  Just because it is easier (than it used to be) to get full calls in a single ping does not mean that it is necessary.  However I don't think you disagree, I'm just saying...
       
      As for how the procedures were communicated, there were QST articles about the practice of meteor scatter, and sheets handed out at talks at hamfests, etc.  We got together on 75 meters to make skeds and discuss operating procedures, and we used the US mail to make skeds and etc.
       
      As for when we are ever going to work on 2 meters, I am afraid that is not very likely from my new home QTH.  I have a significant noise problem to my west and my antenna is now smaller and only at 25 feet.  However I am working on getting going again on EME, and hopefully when the moon is high the noise will not be a problem, so there is hope then.  Also I hope to make the EME station a portable (antennas on a trailer), so maybe if I find a quiet spot we can make it on MS some day too.  You never know!
       
      73, Russ K2TXB


      From: wsjtgroup@yahoogrou ps.com [mailto:wsjtgroup@ yahoogroups. com] On Behalf Of Randy Tipton
      Sent: Wednesday, June 30, 2010 3:33 PM
      To: Russ K2TXB; 'Bill VanAlstyne W5WVO'
      Cc: '[WSJTGROUP] '
      Subject: Re: [wsjtgroup] JTMS vs FSK441

       

      Snip: For meteor scatter work, piecing calls together is long standing tradition, dating back to long before any digital modes were even thought of, and even before personal computers existed.
       
       
       
      Russ my discussion is only HSMS related where I have some experience.

      I started with HSCW and a few weeks latter WSJT was introduced. I only made a few contacts with hscw.  I did not know that was the earlier practice piecing letters copied. I don't remember seeing any procedures for assembling calls from individual letters or missing letters in the SOP's, how was this communicated as best practices etc? (Just curious as I have always been interested in the "early days of meteor scatter".)  I certainly am not questioning nor have the right to question anybody who did that prior to WSJT and I recognize it was part of the process. But now it is not necessary. Full calls are decoded in text in fact it is so good that if someone enters a call wrong, I see stations saying on PJ "Check My Call".  "YOU ENTERED MYCALL WRONG"
       
      I often times during contacts accepted receiving both calls correctly from two different pings but not three or more. I suppose one could do that but with FSK441 and JT6M it has not been  necessary. I have now 3,561 meteor scatter contacts using wsjt modes and I have not had to piece calls together. Even weak e's using JT6M provide correct decoded calls with no need to piece together.
       
      Thus the necessity of piecing calls together is not something I find necessary to do or practical with the wsjt modes.  I don't know what others do but for me, both calls mean "both calls" decoded during a single ping or two pings using today software and pc. 
       
      Often time with two meters I find myself waiting for a single call to move forward in the contact. That is why I generally remove the last %R in Tx2 so stations have a better chance of decoding both calls with my Tx2 message. The double 2626 I suppose lets someone listening know who is transmitting.
       
      So I suppose the answer to your question is I believe because it is possible to copy complete calls with the latest and greatest software and piecing of calls is unnecessary why not let the decoder do the assembling of the messages. Most HSMS contacts take less than 20 minutes using this method. It is not my call to say what "Both Calls" means and if piecing of letters over time is acceptable .... but I know when I decode and read in print K2TXB it is you. I ignore the garbage letters and character and wait for the next ping if I receive WSTXB. Most of the time it is just a few minutes away.
       
      For me the most important information off a poorly decode ping is the df and sound. Yes I can tell if a station is 600 Hz low or High by the ears. But like Russ, the hearing is going fast.
       
      By the way, if I remember right wasn't the line speed with hscw much faster than FSK441? If so seems like there should have been more information per ping.
       
      Russ, when are we ever going to work on two meters?
       
      my two cents...
      tip
       
       
       
       

       
      ----- Original Message -----
      Sent: Wednesday, June 30, 2010 1:00 PM
      Subject: RE: [wsjtgroup] JTMS vs FSK441

      Hi Randy and all.  I have to take exception to one thing that I think you are saying.  Correct me if I am wrong, but it sounds like you don't think a contact is valid unless you have received the complete call at one time, as opposed to piecing the calls together from partial decodes.
       
      If the latter is what you mean then I have to disagree.  For meteor scatter work, piecing calls together is long standing tradition, dating back to long before any digital modes were even thought of, and even before personal computers existed.  On those days of making skeds on 75 meters during the showers, and use of SSB or CW only, there was a common practice to keep a sheet of what was received on each of the 15 second sequences.  Each time a letter or letters were received or understood, it was written into the appropriate time slot.  Many of us would underline each piece that was new.  When all the underlined parts added up to complete calls, we would then start sending "S2", and "RS2" and finally "RRR".  (or "Roger S2", and "Roger Roger Roger", on SSB.  Often we would send a copy of this sheet along with the QSL card to show how well the signals were received.  This scheme was well known, common, and accepted by all concerned - at the time.
       
      I still do it with digital work, or for EME, and I am certain that all my contacts are completely valid.
       
      73, Russ K2TXB


      From: wsjtgroup@yahoogrou ps.com [mailto:wsjtgroup@ yahoogroups. com] On Behalf Of Randy Tipton
      Sent: Wednesday, June 30, 2010 12:38 PM
      To: Bill VanAlstyne W5WVO
      Cc: [WSJTGROUP]
      Subject: Re: [wsjtgroup] JTMS vs FSK441

       

      I fully understand Bill's explanation even thou I am not in complete agreement. I generally think of meteor scatter as not being a weak signal mode. True enough there are weak pings but as Bill explains if one is patient a better ping almost always follows. But I suppose the philosophy of "why waste a weak ping" is valid provided one does not progress the contact with partial calls. I remember doing this once when learning and moved to Tx2 with less than both calls and got burned when the next ping I received was a single tone message. oups
       
      The issue I have of "all or nothing" is those weak pings do not provide the operator with a DF.  The partial decoded weaker pings from FSK441 seemed to almost always provide a good df indication where the user could adjust his RIT,reduce the tol and be better prepared for the next received ping. Hearing pings in JTMS with no decode bugged me however it did not prevent a contact from being made.
       
      I think that until the final optimization work is complete... maybe it can be made to force a manual decode via a mouse click for those shorter pings. I don't know if the partial calls and garbage from 40 - 60 ms blips adds much value except for the df. I suppose if one already has both calls and received only 2626 that is significant. (I have had this happen before)
       
      I don't know how many newbie's I have seen totally confused by the false decodes of short hand messages. I believe a "all or nothing" decode is a worth while quest. This morning I listened to KE7NR for about 15 minutes calling CQ using JTMS. I had 4 - 5 pings each seq and pages of nothing but perfect print. ie no garbage 
       
      I do not regard FSK441 as a "Flaky" mode but do acknowledge that reducing the garbage letters and characters decoded adds value provided it does not adversely effect qso completions.
       
      Bill thanks for your note, I saw Bill's comment on the PJ and asked him for an explanation.
       
      I remember the FSK441 A,B,C modes... Most agreed that FSK441A was better and the B & C were dropped. Thanks to Joe for continually looking for ways to improve our ability to communicate weak signal or whatever.
       
      my thoughts
       
      tip
      wa5ufh
       
      ----- Original Message -----
      Sent: Wednesday, June 30, 2010 10:15 AM
      Subject: [wsjtgroup] JTMS vs FSK441

      I commented earlier this morning on PJ that I didn't think JTMS was an acceptable replacement for FSK441 on meteor scatter. I want to explain my reasons for making that observation.
       
      Joe already covered a few of the drawbacks, including some objections from across The Pond to the minor change in messaging protocol. Personally, I couldn't care less about that, and I think Joe's explanation of why no one else should either covered all the bases.
       
      My problem with JTMS stems from its use of forward error correction (FEC), which essentially makes decoding meteor-scatter pings quite a bit more demanding of signal quality, strength, and duration. It has the effect (probably unintended) of making meteor scatter less of a weak-signal mode. In reducing or eliminating the typical FSK441 "garbage," it also eliminates, in many cases, the ability to tease partial decodes out of low-quality pings. This effect might be perfectly acceptable to many m/s operators, but I am basically a DXer at heart when it comes to meteor scatter. The contacts I really enjoy are the ones where I have to do a lot of manual fine-tuning of the FSK441 decoder in order to work that new edge-of-ms-range grid square.
       
      Meteor scatter is a weird mode in that the signal is often distorted in unpredictable ways by a given meteor trail's peculiar composition and geometry. While it is oftentimes true that simply waiting long enough will eventually produce a higher-quality ping that JTMS will decode cleanly, I would rather do as much as I possibly can with the weak, distorted pings that I get, put the Q in the log, and move on to the next opportunity. I suppose you could call it a contester's or DXer's mentality. Smile emoticon
       
      Some might say that this can lead to "stretching" the credibility of what is received and decoded -- but it is no different than what is done every day on CW and SSB. Unless you depend exclusively on a computer-driven decode engine that completely eliminates human wetware from the operation, there is always going to be some measure of human judgment and integrity involved. I maintain that FSK441 is no more "flaky" or "suspicious" in this regard than SSB/CW, and in most cases is less so, even without niceties like FEC. I don't buy that argument.
       
      So while appreciating immensely the terrific work Joe has been putting in experimenting with new digital mode ideas, I'll be perfectly happy to continue muddling along with FSK441 when it comes to m/s.
       
      ISCAT, on the other hand, holds some real potential, if the decoder speed can be made practical (i.e., without requiring that the user has a Cray III). I'm actually really excited about this one, and hope it can be evolved to the point where it's a day-to-day workhorse mode for weak-signal ionoscatter/ Es/F2 work.
       
      Bill W5WVO
      DM65qh
      New Mexico
       
       

    • Jim kennedy
      Hi Folks, I think that Bill is on target in his observations. We do have problems with stations not following the prescribed protocol as outlined on the WSJT
      Message 2 of 12 , Jul 1, 2010
      Your message has been successfully submitted and would be delivered to recipients shortly.