15 years of E-Skip analysis: 2005-2019

This article was originally published in the September 2019 WTFDA VUD

The 2019 season marked the 15th consecutive year I’ve been actively paying attention to E-Skip propagation from Southern New Jersey. With this inglorious milestone comes a fairly large amount of data and observations. Always wanting to go back through the seasons and assess if my perceptions of the good ones vs. the bad were on the mark and inspired by what seemed like a lacking 2019 Es campaign, I decided to go through an exercise and tally up results from the last 15 E-Skip seasons into different categories. The research is initially based off of my logging and observations (2005-2014 from Florence, NJ and 2014-present from Tabernacle, NJ), but not completely. Particularly in early seasons, not paying attention as closely and before the advent of SDRs and when round-the-clock audio recording through software was not as common, there are gaps in my observations. So, I relied on the logs of several different active DXers and WTFDA members, within reasonable proximity to me and who often recorded similar activity amongst the more common Es clouds. Those are Russ Edmunds (PA), Dan Oetting (MD), Rick Shaftan (NJ), Michael Temme-Soifer (NJ), and Steve Walko (PA).

I included E-Skip openings between April and August. The high MUF opening of Labor Day weekend 2011 just missed the cut, as do any winter openings.

Sporadic-E is unpredictable, obviously, and every season we encounter openings where someone 40 or 50 miles away might have top-of-the-dial conditions and ourselves less fortunate. That said, I generally was able to amass data that was representative of the northern Mid-Atlantic region (roughly encompassing NJ, DE, Eastern PA, Eastern MD, and Southeastern NY). Move beyond 200 miles in any direction and this data probably changes rather significantly. It’s doubtful 15 years is enough to draw any large conclusions (unlike Pat WA5IYX’s tireless efforts of observation), but this still may be of some interest.

Number of E-Skip openings with MUF into FM of 30 minutes or greater
The first tally I made was the number of observed E-Skip openings with a MUF of 88 MHz. for at least 30 continuous minutes. One calendar date could have multiple such openings, provided the MUF dropped below 88 MHz. for at least 30 minutes. A year-by-year graph of the results is below:

Many of us in the PA/NJ region felt 2018 was the most active E-Skip season we’ve personally witnessed, and the data backs that claim as it leads the way with 36 E-Skip openings with a 30-minute FM MUF, six more than the two-way tie for second place (2008, 2011). The awesomeness of the 2018 season stands in contrast to the results of the other recent Es seasons. Anecdotally, I’ve always felt the E-Skip seasons between 2006-2011 were better than what we’ve had lately, and indeed, while each of the seasons between 2006-2011 had 25 or more E-Skip openings with a 30-minute FM MUF, only one such season since 2011 has had 25 or more such openings (the aforementioned 2018).

This past season (2019) had 18 openings with a 30-minute FM MUF, tied for fourth-fewest. 2012 was the lousiest season by this metric (just 14 such openings), and by memory that definitely checks out (yet, the July 24, 2012 marathon opening helped salvage the season).

Number of “strong” openings (E-Skip opening with MUF of at least 102 for 2 hours or greater)
It was difficult to come up with a way to quantify how to categorize a “strong” opening. Particularly now aided with SDRs, a 15-minute burst can easily be more productive versus a 2.5-hour opening that seems to be stuck with the same target area (here’s looking at you, South Florida). Any other metric that did not include duration, however, seemed too subjective (i.e. number of RDS hits? Number of locals overtaken?). Using new logs or total number of logs as a barometer was also not a consideration. Thus, I settled on using an E-Skip opening that had an observed MUF of 102 MHz. or greater for at least 2 hours. A year-by-year graph of the results is below:

The 2010 E-Skip season was famous for disappearing shortly after the July 4th holiday, but June 2010 alone had 5 “strong” openings, including a multi-hour opening on the 18th that produced reports of E-Skip up to TV 13 in the Midwest. This past season had the second-lowest high MUF opening total (only the July 20 event). Of the years in this report, my confidence is lowest in 2005, with myself very much being in the “newbie” category that year, but I could find no evidence of a “strong” opening that season in the Mid-Atlantic based on the reports I combed through.

This metric is not perfect. Perhaps the duration should be shorter. 2018 would rank higher if this was shortened to 90-minutes (intense openings on June 15, 2018 and June 25, 2018 would have made the cut). I am open to feedback.

Number of openings with at least one “unique” log (station received 1450 mi. or greater OR 550 mi. or less)

The “unique” log category I expected to be strongly skewed toward recent years with the proliferation of the SDR. Being able to record the whole band for hours at a time certainly increases the probability of receiving a unique E-Skip log. Interestingly, it comes at a time where it’s harder than ever in almost all areas to find open channels, so I still wanted to plot the results and see what the data looked like.

2015 was the year I began using an SDR full-time, and it definitely associates with an uptick in longer (or, more so in my experience, shorter) than normal E-Skip logs. Yet, 2008’s total of 8 holds its own (I would have loved to have used an SDR that season!), and I was surprised to see 2011 lead the way with 11 such logs. 2011 featured multiple openings to Puerto Rico and two instances of Mexico (5/31, 7/12).

The most active E-Skip months

It should come with little surprise that June ranks as the most active E-Skip month in terms of 30-minute FM MUF openings (42.8% of openings occurred in June). July is just behind with 36.8%, while May ranks a distant third with 13.2%. August is fourth at 6.6%, however, since 2015, there does seem to have been a shift of sort. Each of the last five Mays has featured just one E-Skip opening with a 30-minute MUF, while the month of August has had ten such openings in that same timeframe. The only openings in this research noted in April were April 27, 2011 (a long-duration high MUF event) and April 28, 2016 (a rare strong opening to the Austin, TX area here in NJ).

Conclusions
The 15-year average amount of 30-minute MUF into FM openings per season is 23.2, while the average “strong” opening total per season is 3.8. Overall, this was an enjoyable exercise and I would love to dive deeper to look at favorable dates and regions received via Es.