Yesterday, I mentioned that it had been a six sigma day here, a statistics geek way of saying nowhere near
the normal. In fact, it was a once in a year event that brought several once in a lifetime events with it. Allow me to backup and explain.
From time to time, I've written on ham radio contests, and using a major contest for your entertainment and training. An easy example is an article in my
Ham Radio Series; #22. I believe learning is better if you get some fun out of it. What is there you could possibly learn? How about training your ears to dig out a station you need to communicate with while lots of interference is going on. It's getting out of your comfort zone, which we all know is necessary.
While I think the biggest contest activity of the year, the American Radio Relay League Field Day, is the weekend after next (June 25 and 26) this weekend was the one that I've been the most active in for about a decade, their VHF/UHF contest. While I could make contacts on three bands until I replaced my old antenna last January, this weekend I was limited to the six meter band. The old antenna worked fairly well on the two meter band (it was designed for and sold as a six meter antenna) and was at least as good as a wet noodle on 432 MHz. Correction: as good as a good wet noodle. I have worked people within about 30 miles on 432 MHz on that antenna.
Six meters is interesting because it gets some amount of all of the propagation modes that show up on other bands. In times of good solar activity, it can get F and F2 layer propagation. At other times, it can get sporadic E. While not terribly common, tropospheric ducting is possible on 6m, which is more common at higher frequencies, even microwaves. Bouncing signals off meteor trails is a common mode, auroras can affect it and so on. I've probably written most about Sporadic E propagation but the truth is it can be very difficult to know exactly how a signal gets from point A to point B. There are combination modes, where there can be an F layer hop that instead of returning to the ground gets reflected back up by the E layer. E layer ducting is also possible. Multiple hops reflected from the E layer back down to the ground then back up the E layer happen.
It's a simple fact of life that even with more data and more computing power than ever before, propagation is extremely complex, and attempts at propagation forecasts have a lot in common with weather forecasts; in particular, the experts are wrong quite often. Consider Sporadic E (usually written Es), and we're certainly in peak season now. An interesting site I've recently learned about is the Es Probability Index, EPI, by G3YLA in the UK. I just screen captured this map for 0000 (midnight) Universal Time Today. The color contours show the probability, with hotter colors, going through reds to whites, being the highest EPI values. At the bottom left is a slider than allows you to move the predicted time backwards and forwards 12 hours.
Those white rimmed silver areas are virtually assured of densities high enough for Es. Even this level of calculation has uncertainties, but at the most fundamental level, this is fluid dynamics and that means nonlinear partial differential equations - chaotic systems. What that means is that from moment to moment areas of higher or lower density can happen, where they're "not supposed to be" like waves in the ocean. The only way to really know what's happening is what I call BIC time, for Butt In Chair.
In my opening, I said this weekend "...brought several once in a lifetime events with it." The biggest one, the one that actually shocked me, was that while I know other guys in my area have contacted Japan on 6m, and I've fairly often seen reports of contacts with Japan (usually the US end was northwest of me) I've never heard Japan. On Saturday night, for the first time in my life, I heard a guy in Japan, JH4UYB, calling CQ ("calling anyone for a contact"). And he answered me after my first call. Here's a screen capture of what could be a valid contact with Japan (meticulously edited to remove my Personally Identifying Information).
There's a problem related to the nuances of the contest exchange. The required exchange is just our locations (given as four character grid square names), but he sent me a standard non-contest reply; the -17 (the red row is his reply) was my signal to noise ratio (SNR) at his station. I tried for four minutes to get him to respond one more time but since he started out with a -22 dB SNR, went down to -23 and was never heard again, a momentarily dense cloud in the ionosphere might have thinned back out. (The lowest SNR you'll see in this software is -24 dB). Technically, as a contest contact, I got his grid square when he called CQ, and he got mine when I first called him (yellow bars on the right panel), so it actually is a valid contest contact. It's possible he may have received my reply, "R EL98" and sent a reply that went below the noise floor the computer can't copy, but I can't know that without asking him.
The other once in a lifetime events are more mundane. I've got confirmed contact with all of the lower 48 states, and use my time to collect grid squares. Ordinarily, it just gives me BIC time to stay and try to hear Alaska and Hawaii. I got around 25 new grid squares, and made duplicate contacts with another bunch that I have record of having contacted but not confirmed. Saturday's propagation was otherwise not very remarkable. I have holes in the map I keep of grids I've worked through parts of Georgia, North Florida, N and S Carolina and other places that are too close, so that 6m generally skips over the area. I filled in some of those Saturday afternoon.
Sunday morning, on the other hand, was very unusual. It surprised me by being open to California in the morning. I've worked California and especially southern Cal several times, but always in the evenings. I think it was even late evening here, but certainly more like 9PM than 9AM like Sunday. I worked a few guys in the southern half of Cali, and a couple of new grids out west but all paths were close to straight west. The farthest north I worked was into the grid square just north of San Fransicko Bay. Yesterday in the early evening (here) the openings shifted into the NW. I worked Vancouver, BC, a few grid squares right around Seattle, then Portland area, up into Calgary around Banff Park, and that general area. Those paths shut down before 8, maybe 9PM.
The big name contests are generally two day affairs, starting at 0000 UTC Saturday (so Friday evening on the eastern time zone) and ending 2359 on Sunday night (Sunday evening here). This contest starts at 1800 UTC (2PM) on Saturday and ends at 0300 UTC Monday, or 11PM Sunday night. I wasn't in the chair the entire time, but I did spend most of the available time in it.