CQ WW Contest Committee member CT1BOH has set-up a public.tableau account with the 7 million skimmer RBN spots during 2017 CQWW CW Contest.

Go to this link https://tinyurl.com/y8jhn27r

In the page you can compare Contest Calls in the different skimmers world wide. You can compare your signal against your competitors, check if claimed power makes sense, understand antenna performance, etc.

The graph plots for every band, and for every hour of the contest, the hourly median SNR signal of selected contest calls, for a selected skimmer.

I will give some examples:

The link opens with CR3OO versus CR3W on 40 meters, as heard by KM3T-2 Skimmer (a very active and reliable East Cost Skimmer).

Notice that CR3OO is constantly stronger than CR3OO during the two days of the contest, except the last 3 hours of the contest. Although CR3OO was just using an Inv. V the location is fantastic towards the USA, and much better than CR3W, but there was a minor storm and the dipole fall from the tree to the ground. So there was only the beam fixed to Europe. That explains why CR3OO signal dropped considerably during the last three hours.

Now select a European skimmer on the right of the screen. For example DL3KR a very active skimmer. You will notice that there is no big difference between signals of CR3OO and CR3W, except again at the end of the contest.

Was CR3W beam just to USA?

Another example:

Remove CR3OO and CR3W from Contest Call list (mouse over each call and click the X) and add K3LR and W3LPL, and select DL3KR skimmer

It is interesting to note that W3LPL is stronger at DL3KR skimmer during the night both days.

Both K3LR and W3LPL are big stations. Why is there such a difference?

Probably different take-off angles of antennas set-up?!

Also interesting that in first day, after 07Z K3LR becomes stronger. Is is because of different take-off angles due to after sunrise in Europe? Or is it because K3LR keeps the stack into Europe and W3LPL puts the stack into Asia?

Last example:

Can we use this tool to check if competitors are using adequate Power according to claimed category?

Lets select 40 meter for band, CR3OO, CR3W and CT9/OK6RA for contest calls and select DL3KR skimmer Both CR3OO and CR3W use 1.5K, but CT9/OK6RA is claiming low power 100W We look at the graph and everything makes sense. Good!

CT1BOH José Nunes