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Psk31 on FM. I know I know. A dead horse.

Discussion in 'Ham Radio Discussions' started by KF5UNI, Dec 4, 2015.

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  1. KF5UNI

    KF5UNI Ham Member QRZ Page

    I was downloading some ham radio apps onto my phone. I saw some PSK 31 apps and downloaded a couple if for no other reason , then because I just like the way the mode sounds.

    Being a Technician, and poor, my HF and SSB options are limited at the moment. So I began to wonder if anyone has used PSK31 in FM on 2M or 70cm and ran a quick Google search. From this search I gathered 2 things:

    1: A lot of people have had the same question I have.
    2: A lot of people are against the idea, and for some good reasons.

    BUT

    It seems to me there is a good reason for this mode over FM, and that reason: Acoustic Coupling. I can just hold my radio and my phone up against one another and it works great. No extra wires or TNC to fiddle with, no extra money to spend. I've tried this with Packet and it sucks. The data always comes in damaged even under full quieting.

    So my question: is there a FM data mode better suited to acoustic coupling. Maybe I'm missing something for someone in my situation but it also seems to me that this would appeal to younger hams as well. Idk what do you think about it?
     
    Last edited: Dec 4, 2015
  2. W5WN

    W5WN Platinum Subscriber Platinum Subscriber QRZ Page

    Back in the '60s there used to be some RTTY on 2 meter AM. That worked pretty well but I don't know whether anyone used acoustic coupling. Although, I do remember RTTY phone modems that were accoustically coupled and they worked well.

    If you want error free data transfer you should use another mode like packet.
     
  3. K0RGR

    K0RGR Premium Subscriber QRZ Page

    The one that we use is MT63/2KL. It is excellent for acoustic coupling, and fairly fast, though there are much faster modes available that are not as easily done acoustically. With MT63, I find just setting an HT next to a laptop works well enough.

    PSK31 works fine over FM, and properly done, can increase range over voice. We used to have a net that was centered in Peoria, IL, using PSK over SSB. I could check in from here in Minnesota each week - a distance of over 300 miles. But, like you, there were some who had nothing but FM, and I could work some of those at distances of over 100 miles. PSK is not the best choice for DX on two meters - it performs poorly when there is a lot of multipath distortion, which is very common on VHF/UHF. Modes like Olivia work much better for that, and you can work stations you can't hear with that mode.

    Find out if your local ARES group has a digital net on VHF. Odds are they will be using MT63, but may do faster modes, too. If not, consider starting one!
     
  4. VE3KUT

    VE3KUT Ham Member QRZ Page

    fldigi does digital over FM. Emcom uses it. Believe it's JT65 though.

    Edit: Lol, two posts simultaneously & RGR got it. MT63. I knew it was one of the letter-letter-number-number modes...<g>
     
  5. W7CJD

    W7CJD Ham Member QRZ Page

    Locally, over the border, there was mention of training for JT65 and fldigi on a repeater.

    I don't know how that worked out.
     
  6. VE4CY

    VE4CY XML Subscriber QRZ Page

    Why not get some friends to join in with you, find an unused simplex channel, and do it! Using a signal that's about 60 Hz wide in a 25 Khz channel is kind of a waste though. :)

    Actually, a lot of the 'sound card' modes can be acoustically coupled using mics and speakers. You could do other modes as well. You're not limited to PSK on 2M FM

    I have an iPad app that decodes SSTV using the iPad's microphone. I've decoded 20 meter SSTV in the car while I was driving. I leave my iPad on the floor near the speaker and tune my IC-7000 to 14.230 Mhz. As the tones come in, they print out on the iPad's screen. The only bad thing is that the images get a little noisy and broken up from the engine/wind/road/highway sounds.
     
  7. KC4YLV

    KC4YLV Ham Member QRZ Page

    Yep, got the app for my phone. I've got an Allstar node that will pull the latest weather map and send it via 70cm FM SSTV if you hit *71. Works surprisingly well with just the phone held next to an HT.
     
  8. KC1CHJ

    KC1CHJ Premium Subscriber QRZ Page

    Our ARES group has a net every week that is for testing/training on digital. We use a local repeater on 2 Meters. We use Fldigi and use PSK125RC4 as the protocol. Works great. Sometimes we also relay digital messages (we use Flmsg to create messages) on HF so that we know we can then support local (FM 2 Meter) and HF longer distance (for relays and contact to other ARES teams or the state EOC)

    Steve
    KC1CHJ
     

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