D-STAR illegal in France

Discussion in 'Amateur Radio News' started by G4TUT, Jun 29, 2010.

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  1. G4ILO

    G4ILO Ham Member QRZ Page

    Do you really think digital voice will bring immunity to interference? I don't. When I turn on the office computer my APRS station stops receiving packets. And that's only 300 baud data. You'll still need power to overcome the QRN, and a noisy FM signal may still be intelligible where a digital one won't.

    I also think you overestimate the ability of newly licensed, cash poor hams to adapt cheap old radios to work in the digital regime. The amount of technical knowledge required to obtain a ham radio license these days is negligible.
     
  2. SV9OFO

    SV9OFO Ham Member QRZ Page

    I really want to thank you for your participation and for making that point.

    Do you actually believe that we have reached a halt in communications progress? That there is nothing more to invent, nothing more to include and nothing more to do in order to reach a given goal, be it greater range or faster data or more robust transmission?

    If so, then you must know that your position is an insult:

    - to those that created turbo code and LDPC for retrieving data streams over some billions of miles away,having the first being used in the pioneer 10 & 11deep space probes

    - to the makers of that very AMBE or MELP, which are despite their proprietary frame and incompatibility with the ethics of the radio amateur community, a marvellous piece of work (MELP can do voice in 600BPS!),

    - to those at NASA that sent live motion picture from moon to earth utilizing special low-spectrum techniques and a really slow scan rate, to be upscaled to normal video rate in Perth, Australia, and be distributed all around the world.

    So-called "advanced technology" awaits patiently to be invented. It is out there, hidden into the math and physics of the universe.

    Right beneath the enormous rocks of ignorance, convenience and compromise, which each can be lifted only with the cranes of knowledge, imagination and inspiration respectively.

    Sometimes we throw more rocks to the pile and we call them "patents"...

    as for APRS, sorry m8 but APRS sits on the very limited, wideband and vulnerable to AM noise Frequency Modulation. It is totally normal for Packet radio to be sensitive to nearby interference due to the very natore of its modulation scheme.

    FM modulation intellegibility falls rapidly in the presence of strong AM interference due to the compromise of discrimination slope which always requires limiting and transformation of frequency shift to amplitude change.

    if SNR in FM audio falls below -db regarding limiter threshold,

    the best signal processor in the world (human brain) fails to reject the noise because high frequency content in the hiss is so much that stops the rapid changes of the envelope from being reproduced aurally. no non-random sound for the ear to capture, no info for the brain to decode. This (FM's limiter) is the source of the rapid audible QSB between 100% noise and audio when receiving a distant FM signal mobile (while in motion).

    Let alone the fact that receive bandwidth of the FM receiver on which you base your APRS operation is twice as wide as could have been needed. Set a path with very weak signals (with heavy BER) in normal packet radio. Then using the same rigs, try packet modulation using SSB RTTY or QPSK or GPSK 300 baud. Then, come back with results... I believe most of us await them with great interest.


    As for the ability, financial or other, of young hams, say no more to me. I built my first TX-RX set when I was 9 years old, and there was no internet at that time. Nowadays, kids play over PIC 's that control their entire room. And do it on the cost of parts only. Thanks to unlimited internet knowledge. Don't underestimat them. They are far better than you are afraid they are, better than I could ever hope. And I am truly glad about it.
     
  3. EI4GMB

    EI4GMB Ham Member QRZ Page

    Analogue V Digital

    Sorry for interjecting but I currently have digital TV and It suffers from picture break-up and loss of signal!!!My old analogue system did not suffer from this!!!Can we expect similar problems with digital voice???
    EI4GMB
     
    Last edited: Jul 7, 2010
  4. SV9OFO

    SV9OFO Ham Member QRZ Page

    Many users in swiched over regions suffer from similar problems.

    This is because the requirements on the receiving circuits have increased up to four times (the number of channels that fit on a single 8mhz channel - in analog would fit one, in digital would fit 4 or even more.) This does happen in a very broadband signal as in Freeview.
    Problems like this usually occur due to obsolete design of antenna boosters who can't manage an 8 mhz wide signal equally powered all over it's spectral width.

    Check your signal and quality bars. If signal is high (above 50%) but quality jumps around all the time between 20% - 60% your booster could have problems managing the new type of signal. If you stay in a lot and many users fed by that booster have the very same problem you may want to talk to the building's manager and get to change the booster. If you are the single user of the antenna - booster combination, try bypassing the booster and check the results. If signal bar falls by 20% and quality stays still above 50%, you have found the source of problems.
    _____________________

    In narrow digital modes we do have that sudden loss, but in an A/B comparison of those two systems one finds out that if analog gives noisy audio, digital stays clear. It would take a total fade to noise for the FM analog signal to have the digital start losing sync and start gapping due to greater robustness of the digital. Of course the rule of transceiver performance applies to digital as with any other mode.

    As with the above example, same answer comes with digital. Some screwdriver lovers could have pushed their tranceivers out of linearity, and then come complaining that digital does not work. As with any piece of art, from cooking to IC design, and from painting to music composing, too much of something and too little of something else can destroy the effort.

    once upon a time we as hams discovered that *reducing* power when operating PSK31 actually increased our range! That was because our signal was cleaner and carried no intermodulation products. Same applies to all digital modes when they are not carried by FM but by devoted modulation schemes. We could have to reconsider some operating practices, like keeping out that huge 3CX1500A legal limit class C amplifier for FM work on 2m, because it would just give you an undecodable signal. Strong (signal strenght high, up to 90%) but with low quality (0%).

    having to check two bars instead of one is actually no different than our 5-9 report; signal quality and signal strenght instead of intelligibility and signal strenght. The fun part is that those are the exact analog to digital counterparts. We hams already use quality instead of intellegibility as report for a mode - that mode is FSTV (fast scan TV).
     
    Last edited: Jul 7, 2010
  5. G4ILO

    G4ILO Ham Member QRZ Page

    SV9OFO: No I certainly don't believe, and never intended to suggest, that there is nothing more to invent. But I don't see why ham radio has to slavishly follow path of innovation, especially if it creates obstacles to what many people come into the hobby for which is to communicate, by adding to the number of mutually exclusive choices.

    The hobby is called amateur radio, one of the meanings of which is that it is a hobby in which people like me, with no training or professional knowledge of radio, can use and if we wish experiment with radio. One of my concerns about pursuing technologies like this is that they make it increasingly difficult for ordinary amateurs such as myself to build, or even understand it. I can build a simple CW transceiver and understand it. I can build an FM transceiver and understand it. But a digital D-Star transceiver with so many "black boxes" in it is beyond my ability to build, and probably to understand.

    Is the hobby destined to become the experimental playground of the few people able to undcerstand this sophisticated stuff, while reducing the rest of us to the status of mere users? The more using my ham radio feels like using a mobile phone or the internet, the more I feel I may as well use my mobile phone or the internet and not ham radio.

    I think new technology is fine, if it gives ordinary hams something that a) they want and b) they couldn't get using the old technology. Then, I think most people would think the change was worth it. But I don't see any merit in trying to get people to adopt a new system just because it is new or different. If the old technology gets the job done to most people's satisfaction then I think we should stick with it.

    By the way I was actually referring to APRS on HF (300 baud packet) when I mentioned problems with interference.
     
  6. SV9OFO

    SV9OFO Ham Member QRZ Page

    For start, I will remind you that my position is that if D-star has to remain the way it is forever, ie never be free, I would love to see it belly up even more than you do.

    As in school, there are classes, there are levels to accomplish as with every game. If you have built a fm transmitter a zillion times, then one day you would want to move forward.

    I can't believe by any means that one should start experiencing with soldering irons over an SMD kit - but how about a colpitts oscillator? or a crystal three-stage CW transmitter? Of course it is level one and two in hobby. Some other hobbies start from making a human like figure with toothsticks to end up creating the Eiffel's tower in 1/120 scale in total detail out of toothpicks. Same scaling here.

    building something is far better than buying it when hobbying.
    I haven't said to anyone "grab a soldering station, some CPU and flash, a TI chip and a RAMDAC and build a d-star radio!". What I said was "grab a soldering iron and build an interface, or even buy one, and get using your SSB transceiver, a taste of digital just for the fun of it!

    And if someone could implement all D-star data system into some PC software we would all be happy!


    No, but it certainly has to fit you and me and every other involved, be it QRP CW operation on 40 using homebrew or some sparkling new model of transceiver or an autotuned antenna made by weird conductive polymers that expands or shrinks to resonance(!!!!) or anything.

    If someone, including me or you, readers of this thread, feels like a black box operator, ask yourself a question - would you engage into a QSO and provide an honest report (like 4-2-8) to an operator that claims that is using his homebrew QRP, even if their signal comes from your neighborhood? I bet you would. Just for the magic. Even if you have that country - grid square ten times confirmed. Well, since you already feel you want more than just connecting a key or a mic and an antenna to a black box, why not try a little bit to compete with those engineers that built that black box, by building a transparent one? Who would stop you but yourself? If you lack knowledge, knowledge is everywhere. If you lack time, then do something smaller but still rewarding. If you lack appetite, well, I want to do some digital just because I am fed up with analog building KW level professional amplifiers. Search elsewhere - we have got slots in spectrum starting from near DC to daylight, and not all that slots are covered by black boxes. There is only one rig that can do 4m, as bought from the store, afaik. There is only one manufacturer that does 3cm transverters. Some DC to daylight rigs have horrible performance in receive compared to some homebrew transverters. Build if you like, only you can stop you. Circuits, schematics and circuit descriptions are nearly everywhere.
    I would start then by ensuring that PC chassis has adequate grounding that follows the single grounding point rule, that the PC chassis is of a very high quality and conforms to standards (some "home cinema" grade chassis are more confining regarding emissions of interference), use ferrite rings on all I/O cables of the PC. Disconnecting all peripherals including monitor to find out if it is a peripheral that causes the problem, is a way to start.

    Some LCD monitors have nothing but a plastic cover and some 0,5mm foil to enclose the inverter board inside the aparratus. Could be causing the trouble.

    I had problems in both the SZ9ERK club station computer and my own shack. It took some time for me to spot them, my shack had a need for a new quieter monitor, SZ9ERK's computer is in the process of rebuild having better RFI characteristics as a whole due to the nature of its operation (digital modes).

    Try finding "spread spectrum" into your computer's BIOS CPU settings tab (given that you feel comfortable with it), enable (or disable if enabled) it and compare.

    73!

    ah. Regarding D-star, I have done some artwork (like your avatar) myself.

    [​IMG]

    [​IMG]

    My friend Julian, I am no advocate of D-star by any means. I try to understand current situation and I am trying to find the best way to go. If d-star was created only to disappoint amateurs into hating all DV modes, then D-star has to either open up or die overnight. Preferably right now. w. a shot in the head.
    I strive to support those that create options. I like options. Options that are based to ham spirit, that is.
    I like to be able to select what to play with next. I don't like any mode than you do, being forced to follow a stream that could lead to a waterfall.
     
    Last edited: Jul 8, 2010
  7. SV9OFO

    SV9OFO Ham Member QRZ Page

    And of course there could be people that would like us to throw away our FM rigs and repace them with d-star.

    So that they can "opt us out" of their system and get rid of us once and for all.

    I am terribly sorry to dissapoint them, but as you said, for as long an old rig works, it will be in service. This is ham radio, and there can be no "Planned obsolescence" for any type of equipment, as there hasn't been any since the era of spark.
     
  8. EI4GMB

    EI4GMB Ham Member QRZ Page

    Thanks for sharing

     
    Last edited: Jul 8, 2010
  9. SV9OFO

    SV9OFO Ham Member QRZ Page

    My pleasure, Fred. Thank you for your kind words. I am always doing my best on helping people, as all users of this forum do.
     
  10. G4ILO

    G4ILO Ham Member QRZ Page

    Thank you for your replies. I see that, although we may have different concerns, we are both speaking from the same side of the fence. I like your version of the D-$tar logo by the way. :)

    I hope you are right that there can be no planned obsolescence. The difference between FM, D-$tar and other modes is that they need fixed frequency allocations, and repeater licenses require official approval, so they must compete with each other to a certain extent. Besides that Icom can use incentives to persuade repeater groups to put up D-$tar repeaters instead of analog repeaters. So there are pressures to move to D-Star that are difficult for ordinary hams to do anything about.

    One gets the feeling that the RSGB and the ARRL decided that D-Star (specifically) was the way forward instead of considering that it would be wiser to wait and see if better, more open alternatives could be developed. Amateurs in France are fortunate that their authorities do not allow D-Star. The French have a bit of a history of developing their own versions of things instead of accepting something made somewhere else. Perhaps they will take an active role in developing a new digital alternative?
     
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