FT8 (or other digimodes) on 2 meters?

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by KO4LZ, Jun 6, 2020.

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  1. K3RW

    K3RW Ham Member QRZ Page

    I used an IC-7100 on 2m FT8 while mobile, as a rover in the VHF contest this past weekend.

    My HO loop for 2m had not yet arrived for mobile ops, so I was stuck using it on a 2m 5/8s whip... vertically polarized and on a mag mount. The few times I could park I ran 2m SSB and FT8 on my Arrow antenna. But 80%+ were mobile on the whip.

    And yet it worked. And worked rather well. I was not only cross-polarized, running mobile, on a mag mount, and maybe 20w into a lousy match. The bands weren't crowded, but I worked several grids over... and given the geography here that is kind of amazing. Same was true on 2m. Then I tried it on 6m out of desparation (screwdriver tuner wasn't matching). Voila. Worked a lot of 6m FT8 on the same whip. And 6m FM. But SWR on 50.125 was sky high, so np luck there.

    432 here is usually much quieter. I worked several stations on FT8 though more on SSB. In previous contests before FT8 came around I usually worked JT9 to a couple of folks.

    I didn't try 222 FT8 but ran 223FM since more people had that. Next contest I intend to.

    I don't know of anyone within 150 miles active on 902, especially digital 900. 1296 I haven't heard about digital at all, most is FM and SSB. The local boards here had posts recommending FT4 instead of FT8 due to excessive drift in the IC-9700 during the longer transmit cycle.

    There are several meteorscatter folks in the region but mostly on 6m. So thats also a possibility for 2m on up, but there are fewer ops by far (here) compared to other modes.
     
  2. G8HGN

    G8HGN Ham Member QRZ Page

    In Europe FT8 is used extensively, and apart from FM, is the main mode for day to day QSOs.

    Since February 2018 I have had over 1500 contacts on 2M, with 60 of those over 1000km, split 50/50 tropo' & Es. My ODX is 2960km on sporadic E.

    It also work at 70cms, not so many contacts but 12 over 700km, ODX 1628km. All on tropo' of course.

    As Europe is fairly densely populated compared to some parts of the States, it may be more difficult for you to find partners. But it works FB, using modest power & antennas(50W & 11 ele 2M/50W 24 ele 70cms).

    73 Bob G8HGN
     
  3. KN4ZKT

    KN4ZKT Ham Member QRZ Page

    Paul,
    There is a lot of 2m weak signal activity in the southeast. To work any real DX you'll need a least a 9 element yagi and some height. Otherwise, you'll need to pray for some tropo ducting, then at that point almost any antenna works. I currently have a 9 element for 2m, and can work about 320 miles on SSB with 100 watts, and about 500 miles on FT8. Feel free to shoot me a email via QRZ if I can help get you connected to more folks. There is a massive VHF-chat group on Slack that is very handy for connecting with folks in your area.

    73s.
    -David
     
  4. KX4AZ

    KX4AZ Ham Member QRZ Page

    Now that I am an FT991A owner I am starting to think about running FT8 on 2m. But I also got to thinking about how, in theory, you could run the FT8 mode via FM...i.e. sending the raw audio tones via FM on both ends would work too, wouldn't it? That would open up the FT8 mode even to the humble Baofeng HTs, or am I missing a fundamental concept here?
     
  5. AA4PB

    AA4PB Ham Member QRZ Page

    You are missing the fundamental concept that when you transmit a single audio tone via SSB you output one single RF frequency. When you transmit that same single tone via FM you are shifting the RF frequency across the spectrum (set by the deviation) at the tone rate. While you CAN transmit an FT8 signal over FM, only one station can transmit at a time on the FM channel without causing QRM. You also loose the weak signal ability of FT8 because the FM carrier must be demodulated in order to recover the FT8 signal. Essentially you loose all the benefits of FT8 if you run it over FM. Packet radio or AFSK RTTY is much better suited for use over FM if you want to send digital data or use a keyboard.
     
  6. KX4AZ

    KX4AZ Ham Member QRZ Page

    You're right, I completely forgot about that aspect, so it would only be usable in a 1 to 1 communication mode on the same frequency, in which case the other digital modes would be more appropriate.
     

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