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How to read the W8S VOACAP Charts

Discussion in 'Amateur Radio News' started by KD5W, Sep 24, 2023.

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  1. KD5W

    KD5W XML Subscriber QRZ Page


    This video covers the basics on generating and reading the VOACAP charts provided on the W8S website. I briefly explain the REL, MUFday, and SDBW and show how to use them to help predict the best time to try a contact.

    Last edited: Sep 24, 2023
    KC5OMC, N7GPP, WA5TXY and 4 others like this.
  2. W1YW

    W1YW Ham Member QRZ Page

    Excellent tutorial!
    KD5W likes this.
  3. KD5W

    KD5W XML Subscriber QRZ Page

    Thank You!
    N3AZB likes this.
  4. KE8BHP

    KE8BHP Ham Member QRZ Page

    I just started using voacap, thanks for the explanation.
    KD5W likes this.
  5. AB4PP

    AB4PP XML Subscriber QRZ Page

    Very Informative. Thanks for the presentation. Looking forward to using it. // AB4PP
    KD5W likes this.
  6. NN2X

    NN2X XML Subscriber QRZ Page

    I like the below display the best from VOCAP (Wheel)

    Here I ask VOACAP to provide analysis from Morocco to Dallas, Texas, using 100 watts CW, and choosing 3 Element Yagi at 35 ft,

    This for me cuts to the chase

    DE NN2X


    Wheel Display.png
    N6SPP, N3AZB, KL7KN and 2 others like this.
  7. KA1BSZ

    KA1BSZ Ham Member QRZ Page

    wonder how this is compared to the ARRL propagation charts?
  8. VK4KX

    VK4KX Ham Member QRZ Page

    Great tutorial on how to use VOACAP, but nothing beats getting first hand experience for yourself.
    I like using VOACAP, and like most software programs they are not perfect as there have been occasions when it said I had no chance of a contact with a particular DX station but I made the contact anyway. So even if the software says no, give it a go, you may be pleasantly surprised. It is a useful tool and saves one from sitting at the radio for endless ours waiting to see if there is propagation I guess, just like the advent of DX Clusters and chat pages to tee up a QSO.
    N7GPP, KN4ULD, KF5RHI and 2 others like this.
  9. WA1GXC

    WA1GXC Ham Member QRZ Page


    The Providence Journal Sunday edition predicts bluefish and tautog will be biting off Point Judith at 5:45AM next Monday.

    Be aware that VOACAP, the Space-Weather data block and prognostications appearing on the homepage, etc. are statistical
    probabilities based upon observed smoothed correlations.

    Statistics are about groupings of events or groups of individuals, not about any one unique event. As noted above, many times the
    predictions are just plain wrong. Our predictive models presume we understand exactly what is going on up there, 200 miles or more above
    our heads. We flatter ourselves. The processes are inscrutable. The Universe is not amused nor guided by our arrogance.

    Be your own educator, researcher, observer. After a time, you may advance your listening skills and even be able to discern possibilities
    of uncommon but useful good propagation paths by the timbre or subtle characteristics of the signals you're hearing.

    Several weeks ago, there was a 45-minute opening to South Asia on 15m, late afternoon local time--in the midst of what appeared to
    be absolutely awful overall HF conditions. Worked 3 Indian (VU2) and Vietnam (3W) stations during the best path opening to that area I've heard in 5
    decades as a radio operator. 140w CW, wire antennas.

    Many decades ago heard a 75w E.R.P. marine coast station in northern Scotland banging-in
    for about 5 minutes on frequency 500kHz--600meters. 2100 Eastern Standard Time.

    Conventional wisdom is conventional. Be your own scientist.

    Last edited: Sep 27, 2023
    KA2FIR and W7CJD like this.
  10. W7CJD

    W7CJD Ham Member QRZ Page

    My longtime favorite is G4ILO VOAProp

    I haven't used it since my Windows 7 tablet had an attempted hack and Microsoft locked me out.

    I still have XP Pro on a SSD I could use in my AOpen DE7000

    Last time I tried it I think an update line of code was needed to connect to VOACAP. I will check back to see if it will run.

    It looks at propagation the way I see it on the map.

    I would like to have it on a small Windows 7 tablet again.
  11. W1YW

    W1YW Ham Member QRZ Page


    Let's dig out the Old Farmer's Almanac! :)
    WA1GXC likes this.
  12. WA1GXC

    WA1GXC Ham Member QRZ Page



  13. KL7KN

    KL7KN Ham Member QRZ Page

    Thanks to your concise summary, I clicked on your link. The video is well done and the information valuable to a/any new user of the product.

    Thanks for taking the time to make the video and posting it here on the Zed.
    Also, thanks for avoiding the 'Talking Head' format seen all too often here.
  14. W1YW

    W1YW Ham Member QRZ Page

    Harry , WA1GXC , points out that VOACAP is only as good as its assumptions. We all need to take that statement seriously: probabilistic forecasts are GUIDES not futures.


    IF you want to look at the forecasts as being 'NOISE' DOMINATED, the 'smoothed' predictions are helpful but not locked in stone.

    Nonetheless, KD5W did a great tuorial on how to use VOACAP.

    Getting on the air and 'trying out' prop is still the best way to see what's cookin' and what works, at a given time.

    Chip W1YW
  15. NI9Y

    NI9Y XML Subscriber QRZ Page

    Thanks for a super presentation.

    ....I've been using VOCAP for many years with super results. The charts are self-explanatory for the most part.
    The other applications in the VOCAP folder are also very intersting and useful for predicting propagation. I use the charts just or fun while listening to the bands to check out the accuracy which is usually very accurate. There are many variables you can enter for just about any antenna configuration.
    DX-View also is very useful to see the various SNR and times. Comparing the DX-Cluster signals to your location and Reverse=Beacon really gives you an excellent view of propagation values.

    Dan, Ni9Y


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