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FT8 Power, how much ????

Discussion in 'Working Different Modes' started by K4EM, Nov 12, 2017.

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  1. VK1AZ

    VK1AZ XML Subscriber QRZ Page

    I unintentionally did this to a gentleman last night on 20M at around 300M/500km distance from me, didn't hear what the actual S reading was but the sig report in wsjt was +18 which would have been wiping out his receive on the waterfall..... I was at the time running likely 50W .... yep more than the 5-25W people speak of but not that high and was working into JA at the time..... he actually messaged me via JTAlert to say I was a massive signal.
    You know what I did..... I apologised and actually dropped down to 40M for a time.
    As the evening progresses and the path opens into Europe from AU I find that 80 or 90W is actually need to complete the path at -12 to -20.

    What's interesting is watching hamspots and seeing good signal into the USA when running but I've only had one respond to CQ

    The waterfall is in my opinion addictive and takes some skill to get the QSO when conditions drop off, though when the conditions are up it's fish in a pond territory :)

    73 Phil
     
  2. K6BRN

    K6BRN XML Subscriber QRZ Page

    Hi Phil:

    I've had similar things happen, and so have a number of friends. Comparing notes, some of us have started calling this type of event "spotlight propagation" - i.e. 1-way propagation where we are received in a relatively small, well defined geographic area as if right next door even though we are hundreds or thousands of miles away. Propagation in the reverse direction is pretty normal. Earlier this year, the California to mid-Ohio path was showing this phenomena a lot. But not anymore. Not sure why.

    73 DE Brian - K6BRN
     
  3. VK1AZ

    VK1AZ XML Subscriber QRZ Page

    Hi Brian,

    Spotlight propagation :) i like it. Where I am in a couple hours i'll have stations in the 1000-2000km range booming in at +20/30 on SSB.
    JA on 20 seems to have just opened for FT8 here but still erratic.

    i've been spotted in the following US states right now
    HI, FL, SC, UT, VA at around -13/14 :)
    with 80W

    73 Phil
     
  4. W4NNF

    W4NNF XML Subscriber QRZ Page

    I've seen a lot more of this sort of behavior over the last month or so. Part of it is probably that the FT8 segments are just so darned crowded at times that tempers get frayed. Some of it is also probably due to new people who don't know much about the mode, and just ASSUME it always gets through. Or, like the goober who called you down on 40, just lids. Never been a shortage of them. ;)
     
  5. N2SUB

    N2SUB XML Subscriber QRZ Page

    Consider some excerpts from the WSJT manual:

    • "On the HF bands, world-wide QSOs are possible using power levels of a few watts (or even milliwatts) and compromise antennas."
    • "Consider reducing power if your QSO partner reports your signal above -5 dB in one of the WSJT-X slow modes. These are supposed to be weak signal modes!"
    • "Remember that in many circumstances JT4, JT9, JT65, and WSPR do not require high power. Under most HF propagation conditions, QRP is the norm." (manual written before FT8)

    There's no question the 'creators' intended it to be a weak signal mode. Weak signal normally means low power, and that was the whole idea...weak signals on a narrow bandwidth. Your signal is occupying very little bandwidth, which is why signal reports are [supposed to be] negative numbers. Running 500w on such a narrow sliver of bandwidth will interfere with adjacent weak signals. It's asinine to say weak signal is for 'receive only', because if everyone believed that there would be no weak signals to receive.

    Part 97 : Sec. 97.313 Transmitter power standards
    (a) An amateur station must use the minimum transmitter power necessary to carry out the desired communications.


    Since we all agree that FT8 is a weak signal mode, and in fact use WSJT to decode it (the WS stands for Weak Signal), and it takes very little power to make an FT8 contact (according to the 'creators'), we should not be using high power. I was on last night and the signals were extremely strong and extremely wide, and my 50w had trouble being heard. I threw the switch and went to bed. FT8 has turned into a pissing contest of 'my signal is bigger than you signal'., and one station running QRO can ruin it for everyone else. I'm really disappointed that it's come to this. I used to enjoy FT8 and JT65. You used to be able to actually have a QSO without another station stepping on you, or without having to work split. I guess those days are gone. Until the day when everyone blows their finals by operating QRO at such a high duty cycle.
     
    ND6M likes this.
  6. G0JUR

    G0JUR Ham Member QRZ Page

    couple of stations on 17m this afternoon really pushing the envelope, multiple decodes at the same time seperated by 100hz 200hz 300 hz both above and below there main signal. Tried everything I could to reduce the signals but as they were about -10db here I dont think it was receiver overload.

    still was entertaining to see the same callsign scroll up the screen from top to bottom 7 decodes in all on same tx period :confused:
     
  7. N2SUB

    N2SUB XML Subscriber QRZ Page

    I turned on 40m and my waterfall was a solid wall of red. It was hard to distinguish individual signals. :)
     
  8. VA3VF

    VA3VF Ham Member QRZ Page

    The problem is not high power per se. I'm all for low power, but as long as the signal is clean, higher power, up to the legal maximum, is fine, if that's what it takes to complete the QSO.

    Would I use 1KW to QSO N2SUB? No! Nothing against you, trust me, but it's because it would be overkill for a regular QSO. This lack of understanding is also what drives unnecessary split operations in FT8.

    Lastly, a lot of the problems these days are due to over population of the FT8 segments at certain times of the day, and propagation. I'm not discounting bad operating practices either.
     
    Last edited: Dec 6, 2017
  9. N2SUB

    N2SUB XML Subscriber QRZ Page

    Agreed. I think that is the main problem. It is like feedback in a sound system.

    Station 1 and Station 2 are at the same space on the waterfall but cannot hear each other. They are both operating low power.
    Station 1 turns up the power because nobody is answering his CQ.
    Station 2 is also calling CQ, but now he hears Station 1 calling CQ right on top of him.
    Station 2 turns his power up to let Station 1 know who's boss.
    Station 1 subsequently turns up his power, because he now sees Station 2 and wants to let him know that the frequency is in use.

    Etc, etc, etc. Hence, a pissing contest ensues to the detriment of everyone else. They can run 500w and say "I didn't want to use high power but he made me do it", or even better, "You MUST use QRO or nobody will hear you on FT8". Simply pull up PSKREPORTER, and look at your footprint. There's a pretty good chance it's the same at 50 watts as it is at 500 watts'.
     
    ND6M likes this.
  10. VA3VF

    VA3VF Ham Member QRZ Page

    Precisely. Never mind your CQs are not being answered. You may have worked everybody that's on the air at that particular time, or you are not 'needed' enough. If you are being reported, it proves you are getting out, and where propagation is favoring. Try different times of the day, or different bands.
     

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