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Using FT8 to demonstrate Antenna Orientations

Discussion in 'Amateur Radio News' started by KM9G, Oct 6, 2021.

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  1. N3RYB

    N3RYB Premium Subscriber QRZ Page

    Especially not that Yaesu FL-101 that can do FM on 10m. That said I understand how to operate my equipment within it's limits and an AL-800H yawns at that level of power...

    Now my used coax. Yes don't buy that. It's all melted.

    What you are missing is I'm trying to work paths that are not reliably open. That is marginal paths where most signals are not going to get through. I like working *dead* bands. That's where the fun is.

    Can you buy me more property so I can put up a proper antenna for 160m? In the mean time I've got my coax heating inverted L for down there. Let me also talk to you about how I pretty much fire into the western slope of Blue Ridge....
     
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  2. WA6VVC

    WA6VVC Ham Member QRZ Page

    I'am not sure I understand you statement that the two thoughts go together Chip.:) Maybe I am over thinking it... locking up on the words "cannot tell anything about the radiation".

    Antennas can be modeled and tested on a range, computer or in a chamber. Patterns plotted, performance recorded as to the antenna in a control environment. We all know this.
    Having the long term knowldge of the either as the layers changes with time, time of day, launch angle, radiation, frequency, etc. That study is sure going to be helpful too.

    Antenna is a known.... Till the radio gods get a hold of it. Switching antennas and "pinging" the various stations says something about both. The big variable is chasing the ionosphere.

    More fun...here's a antenna test platform down the street from me. Those are not model planes in the pictorial selections.

    https://www.edwards.af.mil/Units/772nd-Test-Squadron/

    CAM
     
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  3. K8XG

    K8XG XML Subscriber QRZ Page

    Play Nice !
    [​IMG]
     
    Last edited: Oct 9, 2021
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  4. K8XG

    K8XG XML Subscriber QRZ Page

    .
     
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  5. W1YW

    W1YW Ham Member QRZ Page

    Read CAREFULLY.

    Since there are TWO COMPONENTS to the propagation --hardware and ionosphere-- you cannot separate the effect of one from the other with this data alone. Thus you CANNOT tell anything about the radiation patterns from this data alone. You cannot tell , in any way, which antenna is 'better' from this data alone.

    The 'you' in the quoted post is KM9G in the context of the video so presented.

    Why is it that OTHERS understand that completely and you do not?

    Please: lecture me about antenna testing. Make it sound like I never have spent a minute doing so, when today ( a good example)I was on the range for 9 hours....and have 4 anechoic ranges at my disposal down the halls from my office. I see a sea of blue wedgies.

    Metrology spoken here. I am all ears.
     
    Last edited: Oct 9, 2021
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  6. 2E0TWD

    2E0TWD Platinum Subscriber Platinum Subscriber QRZ Page

    I see nothing here that has caused the outrageous response from Mr. Chip.
     
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  7. W1YW

    W1YW Ham Member QRZ Page

    Stop trolling. Part 97 applies to US amateurs.

    For us, our Part 97-defined mission to 'enhance the radio art' means we should pursue the multitudinous resources we have available to us --most are FREE!--to understand the basics of antennas and ionospheric effects--and then take it further. Indeed, many of these basics are part of the test question base we use in order to obtain our licenses. That body of resources makes us a 'pool of those skilled in the radio art'--when we take advantage of it. The scientific method is a basis by which one 'enhances the radio art' as an applied science.

    In this case we have an OBSERVATION which is confused with an EXPERIMENT--and a lack of sufficient basis to claim the outcome so posed.

    THAT is: 'what's the fuss?' That's why KO0U, for example post 22, made his comment.

    Look--if a US ham (for EXAMPLE) wants to stick a shopping cart in a tree and make it an antenna and then boast about how they used FT8 to 'talk' to Lower Slobovia, that's a personal anecdote of limited interest (yes someone did this 'cartenna' a decade ago) . But we never saw a video on a prominent link about it.

    KM9G is going in the right direction to do a relevant antenna comparison. But this video, IMO didn't fly.

    Have a great day.

    73
    Chip W1YW
     
    Last edited: Oct 9, 2021
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  8. WA6VVC

    WA6VVC Ham Member QRZ Page

     
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  9. WA6VVC

    WA6VVC Ham Member QRZ Page

    WOW... Wasn't looking to push that that button. Just wanted to get a better understanding with my limited knowldge and felt I had a little handle on some of the antennas tested.
    Then share the a really BIG test chamber near by. Maybe I did read it right and somebody else missed my point. Have a hamming good day.

    CAM
     
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  10. W1YW

    W1YW Ham Member QRZ Page

    The best one can do at HF is have the three antennae separated by many wavelengths, on the same ground and topography, same coax length and do real-time switching : A/B, A/C comparisons (in this case) . That will tell you the best antenna AT A SPECIFIC ionospheric condition at a SPECIFIC time for a SPECIFIC path.

    In fact, to get precise gain differentials you need to set one antenna--the 'strongest'-- and then use a precision attenuator on RX to measure the differential for the others. This does not work with FT8, and likewise does not work with merely looking at an S meter, for example. Why? because the RSSI roundoffs leads to huge 1-2 dB+ measurement uncertainties, when the typical antenna gain differentials or only a few dB (if that)... Just think about the poor accuracy of the 'bars' on your phone as an extreme example.

    Never trust an RSSI measurement (if at all) without a differential and a precision attenuator in line. And never measure at different times (beyond real time switching).

    73
    Chip W1YW
     
    Last edited: Oct 9, 2021
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  11. KO4CES

    KO4CES Ham Member QRZ Page

    Interesting question, and without engaging in all the technical mumbo-jumbo, my 40 meter pattern appears as a teardrop, similar to what you show -- resulting in the same area of the United States.

    I'm in Daytona Beach, Florida, and my EFHW matchbox begins in the south (Miami) and points towards the north (New York). On average, I also have a few reports behind me, in South America, and a few to the right, in Europe; additionally to the left, in California and Washington.

    20 meter shape is a solid 180 degrees across the United States and into Europe -- similar to a Japanese fan. Occasionally, reports come from Hawaii and Australia.

    Antenna: Homebrew 40' 40/20 EFHW
    Comparison Antenna: Bushcomm SWE-100
    Radios: FT-991A at 10-25 watts; IC-705 at 5-10 watts
    ALC: Always below red
    FT8 Transmit Power Level: Varies between radios, -16dB to -20dB

    I hope the information helps you. Your videos are always appreciated.
     
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  12. DO1FER

    DO1FER Ham Member QRZ Page

     
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  13. W1YW

    W1YW Ham Member QRZ Page

    Cornelius--

    Please do not put YOUR comments inside MY quote.

    That is not what I said at all. You should not attribute your comments to me.

    Again, there is no value whatsoever in comparing the three antennas as KM9G asserts. I just went into detail why. I even told you (a way) how to do it (see post #55) properly (albeit with uncertainty in the data values).

    Measurements are not a basis for 'what I feel'.

    Spock - How Do You Feel? - YouTube

    There are not fifty different way to measure properly in this case. And we learn nothing by pretending a wrong way is 'ok' as an 'experiment'. If you want to use that as an incentive to learn way(s) to do it correctly, well, that's a very different story.

    That isn't how the video presented the objective. And THAT is 'what is the fuss'...

    Jeez, can we do something right on this thread:0)?
     
    Last edited: Oct 9, 2021
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  14. 2E0TWD

    2E0TWD Platinum Subscriber Platinum Subscriber QRZ Page

    My comment was regarding your “Trolling” of WA6VVC, you should apologise for your outright rude response. I have no interest in whether you liked the video or not. Apologise for your hateful rant.
     
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  15. W1YW

    W1YW Ham Member QRZ Page

    No apology needed. No trolling done.

    After he clarified his query I fully answered it accurately and cordially in post #55.

    Now stop trolling... please read before you lead.
     
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