Calculating op-time is tricky. How do you define it? The time needed for making contacts were the sharpest definition. But it doesn´t count the time you spend in front of the radio calling fruitlessly CQ or tuning the band without working a new one. So most would agree that op-time is the time spent in front of the radio during a contest. But - how should the software know from the log when and how long you were operating your rig? 15 minutes without a qso in the log can mean that your 5 W to a wormwarming lowwire didn´t attract the attention of any station despite all your frantic efforts. 15 minutes without a qso could also mean that you spend some time on the tower enjoying the sight of the landscape (alternatively of a wet coax) or you spent some time in the living room to hug your XYL for letting you operate the next day, too ;-)

Calculating on-time needs a definition which time-span without qso in the log is off-time. That opens the field for debates. After publishing the op-times the opinions reached from "I didn´t expect a contester to have more than a few 10-minute-periods without qso" to "It´s not rare for a qrp-station to make only one contact per hour".

Here are the different calculated op-times based on five different off-time-definitions: longer than 10, 15, 20, 25 and 30 minutes without a QSO.

From 4215 computable WWDX-logs in all categories the following average operation time per station result:
>10 minutes as offtime: 12,8 hours
>15 minutes as offtime: 14,3 hours
>20 minutes as offtime: 15,3 hours
>25 minutes as offtime: 15,9 hours
>30 minutes as offtime: 16,4 hours

Setting the 20-minutes-result as 100 percent we have this deviations when using the same log and different off-time-definitions:
10min-rule    -15,8 percent
15min-rule   - 6,0 percent
20min-rule   ± 0
25min-rule   + 4,2 percent
30min-rule   +7,5 percent

But these differences are an average over a big number of logs and vary very widely from log to log. One station had an op-time of 17:26 hours with the 10-minutes-definition and 17:41 with every other deefinition. The other extreme was a small log resulting in 36 minutes op-time with the 10-minutes-definition and 3:44 hours with the 30-minutes-definition.

I don´t know about the definitions in the various logging-programs. Reading reports I assume that i.e. Wintest may have 10 minutes or even shorter like also the fine SH5-tool. Other loggers are said to use 30 minutes. In my opinion (not to be shared!) 15 or 20 minutes seem to be realistic times to describe most operating patterns in "contesting mode" other than "DXer´s mode" which means more time for trying to crack a pile-up. I don´t think that regular intervals of 20-30 minutes or even more without a qso occur even with qrp in "contesting mode" (perhaps during a VHF-/UHF-nightshift but not in WWDX).

From all SOAB-operators I took those ten each in SSB and CW nearest to the average SOAB-op-time in this contest. From those logs I extracted the individual operation intervals marking every quarter of an hour with at least one qso. The coloured stripes show the intervals, the grey lines are the periods between sunset and sunrise at the QTH of the station (click to enlarge).

They operated from 4 up to 21 intervals. The average operation interval lasted a bit less than 1,5 hours. They made 233 to 1111 QSOs (average 454) with a rate between 18 to 77 QSO per hour, averaging 35 per hour.

With e-mails I asked the 20 hams for potential comments about their operation pattern and received the following replies:

G4: As a SOAB with very limited antennas, I find contesting quite challenging since I am invariably chasing contacts rather than CQing. This makes for hard work in a very limited timeframe. Condx do not necessarily bother me although openings to Africa and Asia make it much more interesting.  I believe that a 12 hour/part time category for SOAB would be worthwhile since many of us SOABs know that we have absolutely no chance against the big guns but in a 12 hour/part-time category might actually improve our positioning.
Also, I tend to take part in most of the big contests such as CQWW, IARU, IOTA etc and will continue to do so simply because it is fun and I enjoy it. I do however, have a life outside of ham radio.

W2: In my case, most of the time I allocate to these contests is not the maximum I can do, usually due to either having other commitments ( & XYL) or the fact that I don't really try to win. I just like to play as long as I am able to stay awake. There are some contests where I do a much harder effort such as CQWW CW operating from a multi-multi. There are other contests where I am out to win like ARRL Sweepstakes CW LP.

9A: Before 2-3 years I work cqww tests to win some awards. And I have 4-5 awards for #1 in Croatia. Now I work this big contests only to pick up some interesting stations which I dont have in log before, or to run pile-up during opening to NA, JA, VK. Just for fun. And between two working weeks I need to sleep. So I work only by day and Saturday evening. How long depends on openings. I dont need more then 24 hours. When I work 36 hours, I´m sleepy on Monday during job :-)

UA4: My time for the competition is determined by my free time at home. I don´t operate for an award or trophy, so more for personal enjoyment.

UA9: I don´t try to reach a top-position but to work new or rare countries - especially on 80 and 160m. I operate mostly S&P and call only stations I´m interested in. But I´m active during day and night. 

Who are the WWDX endurance champions? Here we go with the average op-time in countries with at least 25 SOAB (click to enlarge):

Ok, don´t take it too serious. Big countries with a lot of individual participants may have a lower average due to statistics - but at least some food for thought and a smile.

Stay tuned - more to follow.