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New to Digital Modes and have a few questions.

Discussion in 'Working Different Modes' started by KD8HJR, Sep 12, 2011.

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  1. KD8HJR

    KD8HJR Ham Member QRZ Page

    I've recently posted two threads about indoor antennas with great success, and a lot of the replies mentioned digital modes for "less than perfect" antenna conditions. I've been trying to do research online about how to get started with Digital but without really knowing what to search for I obviously cannot find much...

    Looking through the online catalog at universal-radio.com, I found some boxes called TNC's that I think is where I need to start, but at $150 and up for one of these, I am just about WAY over budget! I planned on getting a radio on the air for three hundred less than I've already spent! (I should've known better than to think I could set a spending limit on such a hobby!)

    I'll tell you what I have to work with and maybe you can come up with a "pocket friendly" solution for me..

    Kenwood TS-940s
    MFJ-949E tuner
    Dell Inspiron N5030 laptop w/Win7 64bit (only USB ports)
    Home-brew 20 meter dipole strung around inside walls of 10 x 10 bedroom of 2nd story apartment.

    I have an Acer Desktop running Windows XP and Ubuntu 10.04, 2GB RAM, 500GB Hard Drive (if that makes any difference) if I ever get around to replacing the power supply.. Both computers have factory sound cards.

    Please keep in mind, the only way I can get a taste for this is if it is CHEAP... I can pinch out another $100 towards this and not a penny more (not that I want to limit myself, but because I have to..)
     
  2. W0BTU

    W0BTU Subscriber QRZ Page

    You can get on the HF digital modes (like PSK31) very inexpensively.

    If you can solder, you can often get on PSK31 for FREE.

    Check out http://www.w0btu.com/digital_modes.html. Then Google digipan and fldigi.

    Many people use the RigBlaster (good) or SignalLink (better). I have no experience with either. I made my own very simple interface out of junk parts.
     
  3. KD8HJR

    KD8HJR Ham Member QRZ Page

    Ok so in actuality, the TNC is nothing but a "connector" to tie the rig and computer together? The software on the computer is what actually runs the whole operation? So why not just use your computer's speaker output/microphone input rather than use a TNC at all? Wouldn't that connect rather easily using a 8 pin microphone connector for my Kenwood and connecting the audio "pin" to the speaker out on the computer and the headphone jack on the rig to the microphone in on the computer using some spare insulated wire? I have to be missing something...
    What, in fact, does the TNC do?
     
  4. W0BTU

    W0BTU Subscriber QRZ Page

    I don't know why anyone would want to spend money on a TNC, when you can download a free program and connect a few wires* between your computer and transceiver to accomplish the same thing.

    TNCs (Terminal Node Controllers) were popular back in the days when computers were much slower than they are now. Today, we have PCs fast enough to do everything the TNC can do right inside our PCs, using free software like fldigi, Digipan, and HRD.

    *Sometimes "a few wires" doesn't cut it. I (and others) have sometimes gotten by with that. With my present installation, I had to use an old modem transformer to eliminate a ground loop.
     
  5. KD8HJR

    KD8HJR Ham Member QRZ Page

    I did download Ham Radio Deluxe and played around with it a bit. It's a bit confusing to say the least but I did see some aspects of it that was interesting. It immediately wanted me to connect my rig and the TS-940s is on the list, so now I'm wondering how I could connect the rig to make the software even more useful. I didn't realize my rig was CAT enabled... I don't remember anything about that in the owner's manual, yet the software acts like it has the capability to run at least some portion of the radio. This all seems a bit overwhelming, especially since I had planned on using sideband only and now it feels like I'm getting in pretty deep with trying to connect the rig to a computer haha It definitely has my attention, I just have a feeling that I should've bought a new radio to fully enjoy all of this. (Didn't like the thought of menus however. I had a Yaesu VX6r with menus that kept me nose deep in the owner's manual, I didn't care for it)

    So about this ground loop... How will I know if I have one and how bad is it? I think if I am going to try digital, I will start with some simple wiring to get a feel for it, but I don't want to "smoke" anything... I just hate to spend more money on this TNC thing and end up not liking digital at all.
     
  6. W0BTU

    W0BTU Subscriber QRZ Page

    Try Fldigi first. http://www.w1hkj.com/Fldigi.html Much less overwhelming. :)

    I think Digipan is even simpler, but I haven't used it in years.

    I saw a blue vertical band every 60 Hz, and that was a dead giveaway that I had a ground loop.
     
  7. N7SMI

    N7SMI XML Subscriber QRZ Page

    A cable from the radio to the computer works fine for receiving. Where the TNC becomes very useful is in getting clean audio from the computer to the radio, and especially in keying the radio appropriately to transmit that audio. I have the Signalink USB and it works splendidly with my Icom. I had it installed and was making QSOs in 10 minutes - just plug in a USB cable to your computer, change some audio settings, and plug another cable from the Signalink into the mic or auxiliary input of the radio.

    The audio setup on most radio is separate from the CAT rig control (used to change frequency, settings, etc.). It will usually require a separate serial or USB to serial cable.
     
  8. W0BTU

    W0BTU Subscriber QRZ Page

    Yes. I would just try that. That will let you listen.

    (That's where I had my ground loop, BTW.)

    I never heard anyone say anything bad about a Signalink. Maybe it's easier to do that with one, but if you're careful with the audio level adjustments it's not needed just to get your feet wet on PSK31. There are many people on PSK31 with no TNC or external sound card.

    You don't even need a PTT line. 99% of the schematics you see on the web say you do, but you do not. VOX works just fine to key the rig.
     
  9. KD8HJR

    KD8HJR Ham Member QRZ Page

    Great information! I will make up a wire and listen for awhile.

    I appreciate it!
     
  10. ND6M

    ND6M Ham Member QRZ Page

    couple of comments.
    a TNC (Terminal Node Controller) is really just an external Modem. the installed computer soundcard will perform the same function, or you can use an external soundcard for most (all?) digital programs.

    a in-expensive sound card interface will work just fine, I use a (BUXCOM) RASCAL with the correct Din plug on my 940s and it is plug and play.

    on the 940, use the REAR Din jacks, that way the RX sound levels will be PRESET (just like the fone patch usage).

    the REAL reason for an interface is so the comp and the rig do not "see" each other due to the OPTO-ISOLATER in the interface
     
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