It’s That Time of the Year — Tropo Band Openings. Here’s Two Links that can Help.

   8am Tuesday

   This will be the first of two posts.  I learned last night that I’m calling the 144.240 net Wed. night, so I want to make an announcement about that shortly.

   Here are two links a lot of VHF’ers keep an eye on:
  1)  http://aprs.mountainlake.k12.mn.us/  Shows real-time band conditions on 2m, based on reports from APRS signals.  This morning, that map has a nice red area of good band enhancement from western WI southwest into NE/IA/KS/MO.  There’s also another area in the central Gulf Coast, but this is primarily a Midwest/Great Lakes blog. 
   Experienced VHF’ers will debate the usefulness of the APRS map.  It does sometimes show false openings, based on factors I don’t fully understand (hint, hint, this would be an excellent place for someone more technical than I to submit a “comment” explaining those factors).  The APRS/mountainlake map also should *NOT* be used to tell you whether it’s worth getting on the air or not.  I see all kinds of nights where the map looks very dead, yet 2m SSB contacts are being made out to 200, 300, 400 miles.  
   But this is a useful tool, and it’s a good idea to study it at various times of the day, and during different weather patterns.  You learn things over time that way.  For complete beginners, there is often better propagation in the early to mid-morning, and again, toward sunset and into the overnight hours.  This subtle rise in propagation is most often noted on bands like 144, 222, 432 MHz and higher.  It is most likely to happen during periods of warm, humid, stagnant weather.  But it’s not limited to that.  There was a great weekend-long opening back in January of either 2010 or 2011.  Of course, it happened the weekend *before* the ARRL Jan VHF.  
   Don’t confuse tropo openings with sporadic E skip on 6m (50 MHz).  The mechanism that opens up 6 meters most often is sporadic E-skip, which has to do with the ionosphere and not weather conditions closer to the earth’s surface.  It’s a pleasant coincidence that sporadic Es is most common in May, June and July, and that tropo openings on the higher bands (tropo can also improve 6m conditions sometimes, too) tend to occur in the warmer months. 
  
   2)  http://www.dxinfocentre.com/tropo.html  Attempts to forecast band conditions up to 6 days in the future.  Some will also debate the usefulness of these forecasts.  Hang around hams long enough (or any kind of enthusiasts, whether its sports, politics, etc) and you will find just about everything gets debated.  
   I have been a lifelong weather geek so anyone who tries to forecast V/UHF band conditions much like a weather forecast is going to catch my eye.  The Hepburn forecast tropo maps have been around a long time. 
   What I will say is that if you notice a green, yellow or greater openings is consistently forecast for more than just a day or two in a row, it becomes more likely that it will actually happen.  I also have noticed that no major, widespread, long-lived tropo opening (where you can work 400, 600, sometimes 1000 miles on 144, 222, 432 MHz and higher bands, sometimes for hours or a few days on end) happens without being forecast ahead of time by these maps. 
    What we don’t want VHF’ers to do is this:  Take a quick look at the Hepburn map, see black everywhere and say, “Well that’s it, no point in getting on the air and calling CQ.”  Because there are plenty of times where the bands are at least normal, or slightly enhanced, and the Hepburn maps miss it. 
   
    Save these links to your radio favorites.

   If you know of other links, please share them using the “comment” feature at the bottom of every post.

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