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APRS

Discussion in 'Working Different Modes' started by KE5KTU, Sep 6, 2010.

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  1. KE5KTU

    KE5KTU Ham Member QRZ Page

    I am new to APRS, and have done some research. It seems the bulk of the research is centered around the developer of APRS and UIview 32(which I have yet to get to work). The question that I have is that if I try to send someone in the APRS net work a message, as long as I am in range of an I gate and they are in range of an I gate will the message get there ? For instance if I am in Mississippi and a friend is in New York, can I send him a message on the APRS network. Also, I see where someone can send me an email using the APRS network via a computer and the internet, what I have not been able to find out is can I send someone an Email via the RF side of APRS ?
    I am looking for answers or a really good place to research APRS that is easy to understand and does not focus on the position reporting side of APRS.
    Thanks, jake
     
  2. G4ILO

    G4ILO Ham Member QRZ Page

    I wrote an article about APRS on my web page recently. It's really more of an overview for those who don't know what APRS is than a primer for those wanting to get started though. I think the best place to start is probably aprs.net, but I expect you have already found that.

    One of the problems with ham radio pages on the net is that a lot of old information never gets updated. A lot of pages talk about UIView but its author died in 2004 and did not leave the source code so it can never be updated and APRS like most other things has evolved. So I would recommend that you look at APRSISCE which you will find in a Yahoo group of that name, which is the current actively being developed APRS client for Windows (and Windows Mobile smartphones.) If you're interested in Linux then look at Xastir which is also actively developed.

    "If I try to send someone in the APRS net work a message, as long as I am in range of an I gate and they are in range of an I gate will the message get there?" In my experience, more often than not, no, unfortunately. The reason appears to be that to avoid flooding already crowded channels most gateways do not gate anything from the internet to RF. But it can be done. My own gateway is set up to do that and I have received messages while out on the hills with my VX-8GR.

    "Can I send someone an Email via the RF side of APRS?" Yes you can, exactly the same way as you can do it from an APRS client on a computer, by sending a message to EMAIL or EMAIL-2 with the address at the start of the message. Unfortunately the length of an APRS message is only about 64 characters so what you can send is a bit restricted. And there is no way for them to reply to the email and you receive it as an APRS message (or almost no way, investigate OpenAPRS for more information.)
     
  3. K0RGR

    K0RGR XML Subscriber QRZ Page

    Give it a try - it usually works for me.

    When travelling I-80 recently, my brothers in California and Colorado were able to track me via APRS and send us APRS messages most of the way. They were using the aprs.fi website to track me, and http://www.findu.com/cgi-bin/entermsg.cgi? to send the messages.
     
  4. VA3CQC

    VA3CQC Ham Member QRZ Page

    I believe if someone is monitoring the APRS-IS, then they'll receive your message as soon as it hits an IGATE, but like others have said it is unlikely it will be sent out over RF.

    I'm not very interested in the vehicle-tracking aspect of APRS (I don't want people to know when & where I'm speeding, that's lame come on! lol besides my phone and GPS already do this just not live over RF) but I'm fascinated by the peer-to-peer-like message routing, the WIDE algorithms and such. I've just got a VHF packet station set up with a TNC and it actually transmits legible packets (YESSSS!!!!) but it is not running APRS since my PC died and I can't find any decent mac software (it's taking forever to figure out Xastir). So it's coming along, hopefully I'll be sending some messages soon!
     
  5. G4ILO

    G4ILO Ham Member QRZ Page

    I'm not a Mac user so I could be talking nonsense but I think I read recently that there is something called Crossover that lets you run Windows programs on a Mac without having a copy of Windows. If so then you would probably be able to run APRSISCE/32, which is a lot easier to get going than Xastir.
     
  6. VA3CQC

    VA3CQC Ham Member QRZ Page

    Unfortunately, I happen to be a dying breed: a REAL Mac user, with PPC under the hood! No windows apps for me! I used to have a decent PC till it died on me, good thing my 5-year old G5 still rocks.
     
  7. KA9MOT

    KA9MOT Ham Member QRZ Page

    aprs.org

    There is absolutely nothing wrong with UI-View. One of the developers did die, but the other is alive and well. Updates have been slow in coming but it works very well on all of the Windows Versions. There is also a Yahoo group that can answer all of your questions.

    Ui-View is probably the most commonly used APRS software out there.

    I tried APRSISCE but found it very difficult. I believe UI-View is easier and better.

    I routinely send messages to KC0TPI-14 as he travels about the country delivering steel. Most messages get through, even when he is in NE and MT.

    I'm still trying to get Xastir to work for me.......
     
  8. KE5KTU

    KE5KTU Ham Member QRZ Page

    Thanks for all the information. I knew I would have a huge learning curve when I signed up for APRS. For some reason every time I have tried to use a program it has not worked for me. I got DIGIpan going and that has been it. I think I may need to get the netbook and what ever else I need and go to someone's house and let them show me what I am doing wrong !
    I have been trying to send messages out over the APRS network on the RF side, and I think tonight I will try to send myself an email and see how that works.
    Jake
     
  9. KA7O

    KA7O Ham Member QRZ Page

    Roughly, APRS messaging works like this (I'm simplifying this some):

    Station A sends a message to Station B - who is outside of A's RF range.

    A's message "finds" it's way to an I-gate (the whole WIDEn-n generic aliases deal). That I-gate passes the message to the APRS-IS. All other I-gates receive that message on their Internet side - however, only an I-gate that has heard B on it's RF side will "gate" that message out to RF. The assumption is, if an I-gate has NOT heard B on it's RF side in the last 30 (?) minutes, B is not within that I-gate's RF range and ignores the message.

    Now, when B receives that message, B is supposed to send an 'ACK' back to A so A knows the message 'got through'. "Path" is reversed. ACK finds it's way to the APRS-IS and is gated back to RF by "the" I-gate that has heard A on it's RF side.

    So - if you're trying to send a message to someone outside your RF range and they've not been heard by an I-gate in the last 30(?) minutes - that message isn't gated back out to RF and eventually times out as un-deliverable.
     
  10. G4ILO

    G4ILO Ham Member QRZ Page

    From WA8LMF (whose site has a lot of useful info for anyone wanting to get going on APRS): Roger Barker (G4IDE), the author of UI-View, died in late 2004. At his request, the source code for the program was destroyed, making impossible changes or updates to the final release (Ver. 2.03) of the program. The main UIview program, as distributed, is now an "orphan" frozen in time as of 14 March 2004, with an increasing number of defaults and settings becoming outdated. Fortunately, many of these can be changed after the initial install.

    Bob Bruninga has frequently written about the shortcomings of UI-View. Not with an intent to be derogatory, as he regarded G4IDE as a good friend who was working to resolve these shortcomings at the time of his death, but unfortunately the decision to destroy the source code made continuing with this task impossible. Therefore I feel that it is better to use and help encourage the development of the software that is actively being developed than to use abandonware that - according to Bob - is responsible for some of the problems in busy networks.
     
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