Archive for May, 2011

VHF Contesting School Articles — Save and Read as Time Permits

Tuesday, May 3rd, 2011

  I wrote these articles back in early 2010.   I hope they motivate many hams to enjoy a VHF contest.   These articles are not fast food.   Take your time reading and absorbing them.    Some will probably have honest differences with what I say and that’s fine.   I’ve never done a VHF contest from any place other than my EN63 QTH, so mine is a Midwestern perspective.   
   You are free to pass this info along to anyone who might be interested.   The busy summer contest season starts June 11-12 so right now is a good time to get educated.   (Here is a summer 2011 VHF/UHF contest calendar:  http://kc9bqa.com/?p=4624)
  These links are in order from a basic introduction, to antennas, to tips, rover operation, logging, scoring.   The whole 9 yards is in here.   
   http://kc9bqa.com/?p=1677   VHF Contesting School — Introduction.
   http://kc9bqa.com/?p=1689    Antennas – The Most Important Part of Your V/UHF Station.
  http://kc9bqa.com/?p=1700    What Bands and Frequencies to Use.
  http://kc9bqa.com/?p=1717     How to Log a V/UHF Contest.
  http://kc9bqa.com/?p=1727    Helpful Hints — Being a Smarter Operator.
  http://kc9bqa.com/?p=1737    Go Roving!   Put the Antennas and Rigs in the Mobile.
  http://kc9bqa.com/?p=1740    More Detailed Rover Info.
  http://kc9bqa.com/?p=1750    Rules and Scoring.    

  Enjoy!   Again, feel free to pass this on to anyone you can think of.   If you have questions or comments, email me or use the “comment” feature here on the website.

VHF Website to Visit — www.kcvhfgridbandits.com

Sunday, May 1st, 2011

    Long-time readers here have heard me talk up N0IRS’s website www.kcvhfgridbandits.com.   But we get new visitors all the time so enjoy the link.    Don’t let the reference to KC (Kansas City) fool you.   What’s on that website is prime material for attracting any ham, anywhere to the weak-signal side of VHF/UHF.  

    If I knew how to really “do” a website, it would probably look a lot like N0IRS’s.  For me, the part I like best about JD’s website is his huge collection of audio/video clips of actual on-air VHF/UHF activity.   Eskip openings, tropo openings, contest contacts, it’s all there.   Take some time at his website and enjoy all it has to offer.

Let’s Talk About “Tropo” on 144 MHz and Higher

Sunday, May 1st, 2011

    We talked about  6m and 2m sporadic E skip in the last post (http://kc9bqa.com/?p=4660)
    Here in the Midwest, it’s more common for a good band opening on 144 and higher to be the result of favorable weather patterns.   When I typed, “Tropospheric Ducting” into Google, many good links came back and I’ll refer you there for your own study.   I also know that many readers of this website may have their own ideas about tropo, or tutorials they have learned a lot from.   It’s all good.   Share a link here, if you care to.   Or send a comment.   Others will appreciate it.   
    When the VHF/UHF bands are enhanced with tropo, it’s usually because of a temperature inversion.  This is where warmer, drier air aloft is over cooler, more humid air near the earth’s surface.  This type of setup is common in coastal areas, (Gulf, Atlantic, Pacific and yes, Great Lakes, to a lesser extent)  and virtually non-existent west of the Rockies, from what I’ve been told.    
     Tropo occurs to varying degrees.    The best time of day to listen for it is around sunset, and overnight into about the middle of the next morning.    How do you know tropo is up a little?   Guys you usually hear about S1 or S2 at a few hundred miles are more like S5-S7.   That sort of enhancement is more common than most realize, but you pick up on it after you’ve spent time behind your rig.  
     A big tropo opening will have stations coming in from 400, 600, 800, maybe even 1200 miles away.   And unlike E skip, which can be in for just a few minutes, big tropo openings tend to last for hours, sometimes even a few days.  If the right weather pattern gets “stuck”, you’re in for a BIG TREAT.   What’s the right weather pattern?   Again, this is oversimplifying, but a big high pressure system either over you or just to your east is a great start.   Warm, humid weather that isn’t moving is something to look for.    A good tropo opening coincided with the July 2006 CQ WW VHF contest.   Also the Sept. 2009 ARRL VHF.  You tend to notice enhancements more in a contest because so many signals are on the air.   Outside of contests,  we’ve had strong tropo in mid-August of 2009 and 2010.   I know this because the openings coincided with our wedding anniversary getaways.    Read about those by searching the mid-August archives of kc9bqa.com for 2010 and 2009.  
     There was a great tropo opening in mid-January of 2010, a week before the Jan. ARRL VHF Sweepstakes.   All kinds of 500-1000 mile contacts were being made.   The weather setup was a foggy one.   We had the most beautiful ice fog clinging to trees in the morning, and that pattern stuck around for 2-3 days.   Too bad that Jan. 2010 tropo didn’t fall on the contest weekend!  
     Right here in the Great Lakes, many ops know about localized enhancements that we often get from about late July thru October.  Evenings, overnights and up to about 8-10am the next morning often have very strong signals near the Great Lakes.   Sometimes that tropo extends inland from the Great Lakes quite a ways.   If I could only be on 2m, 222, 432 and even higher bands like 900 and 1296 for 4 months of the year, it would be July thru October. 

     The best way to discover tropo is to be near the rigs, and calling CQ.   Also, if you can, make plans to be a night owl more often in the summer.   I hope that KA0KYZ’s 144.230 net from EN33, near Rochester, MN, every Wednesday at 9pm central will spur more late-night activity.   Terry likes to be up until 10, 11, midnight and honestly, that’s when you will find the pleasant surprises us sleepyheads miss.    
    I’m very excited for the summer of 2011 because we now have KA1ZE’s 144.205 activity every morning @ 8am eastern/7am central, 7 days a week, from FN01xt.   Stan has a huge signal and many guys from multiple states are already on board, working each other and comparing daily propagation.   All are welcome and Stan already has his own mailing list, which he wants you to join.   See this post for full info  http://kc9bqa.com/?p=4582   Help spread that info everywhere.   This daily activity on 144.205 is going to catch a lot of band enhancements.   

     Here’s 2 websites to monitor for propagation enhancement.  
    1)  http://www.mountainlake.k12.mn.us/ham/aprs/path.cgi?map=na   This map plots 2m APRS reports from all across the USA.  When you start seeing yellow or orange shades, that means there’s probably band enhancement.   You will notice this most during the evenings, overnights and into the next morning, before the sun gets too high. 
    When you start seeing long red paths, hope that they are accurate.   I say “hope” because sometimes this map is fooled by bogus APRS spots.  But this resource is still very useful.   If you ever see a “starburst” pattern of reds, with multiple paths centering all on the same area, then it’s very likely that there’s a 2m E skip opening.  
2)  http://www.dxinfocentre.com/tropo.html  These maps are *forecasts*, not actual conditions.  So just like the weatherman, they are sometimes wrong.  When you start seeing greens and yellows being forecast for your area, there’s a chance you’ll make 2m contacts (or higher bands, too) well beyond your normal range.   And of course, be aware of that daily tendency for late evening, overnight into the next morning to be best. 
     Veterans will tell you to not rely on those maps too much and they’re right.  The best way to find out if a band is open is to have many hams on the bands, calling CQ.  If everyone did that, we’d find good conditions a lot more often.

Do 6m Sporadic E Skip Openings Predict 2m Openings?

Sunday, May 1st, 2011

    My short answer is no, not usually.   BUT… when 2m does open up with Sporadic E skip (Google it, and learn for yourself)  it’s far more rare than 6m, so you really want to be ready for it and take advantage.   This is timely info because this week, 6m started opening up.  In fact, the MUF (Maximum Usable Frequency) went as high as 108 MHz, which is pretty darn good for late April.   I know the MUF went that high because guys in NY, PA, CT, NJ and MA who DX the FM broadcast band were reporting Es up to the top of the dial.   
    Of course, for 2m to open up via sporadic Es, we need that MUF to get into the 144-148 MHz range.   It is extremely rare for the MUF to get up to the 220 MHz band, and to my knowledge, it has never happened on 70cm.

    I’d say E skip on 2 meters only happens about 4-10 times a year.  For instance, K7ULS in DN41, near Salt Lake City, UT was in (to my EN63 QTH) for about a half hour last June.    2 meter E skip tends to be short-lived and not as strong as the Es on 6m.   It tends to occur in the late morning until mid/late evening.   My guess is that less than 10% of 6m openings end up going as high as 2m.   I wish we had a network of at least 10-20 guys in every state that monitored (and called CQ!) consistently on 2m SSB, every day and evening.  If we had that, we’d find there’s a lot more Es than we realized.  We’d catch a lot more of the mini-openings that might only last for a few minutes.  

    Here’s a few ways to keep track of whether you might suddenly start making contacts beyond 500 miles on 2m.
    1)  Put the internet to work for you with this link:
http://www.vhfdx.info/spots/map.php?Lan=E&Frec=MUF&ML=M&Map=NA&DXC=N&HF=N&GL=N
When 6m is open, you will see little boxes on that map display frequencies in MHz like 51, 66, 75, etc.   You want those higher numbers to be *between* you and the area you’re working.  You use those “clouds” of higher MUF to bounce or skip your signals off of.  That whole website has a lot of useful features.  Click around and have fun learning about it.   There were several times last summer where that map showed MUF’s above 160 MHz.  Those times coincided with 2m sporadic E skip openings.   (Some guys also DX the NOAA weather radio stations at 162.4-162.55 MHz)
    2)  Another way to keep track of whether 2m might be opening up via sporadic Es is this:   If you notice that 6m E skip is getting very strong to stations only 400-500 miles away, that’s important.  Short skip on 6 means the MUF is climbing, and 2m may open up in the direction of the short skip on 6.   It’s then time to get on or near 144.200 and call CQ.  
    Short CQ’s are best on VHF.  Especially if you’re trying to work E skip, which can literally be in for only a minute or two.  Whenever I hear a guy start up with “CQ, CQ, CQ, CQ.   This is AB9XYZ, AB9XYZ, AB9XYZ.  CQ, CQ, CQ, CQ…”  I smile  because I know someone used to HF is now trying out VHF.  Use shorter CQ’s for VHF, especially if the band is open or busy.

    Another piece of advice — yes, the call frequency is 144.200.  Yes, you should swing your beams around and call CQ anytime you’re near the rig.   Don’t fall into the trap of “just listening”.   If 20 guys listen and nobody calls CQ, what happens then?… (nothing)
    BUT… keep your QSO’s on 144.200 short.  If you want to have a ragchew, QSY up/down 10, 15, 20, whatever.  Main thing is to not tie up the call freq. for long, especially when the band might be open or busy.   I will say that in rural, isolated areas with few 2m SSB ops, there’s some merit to keeping .200 more busy.  Provided you take frequent breaks to invite others to join in or to let them use .200 to make their own calls for DX.  
    If you monitor 2m long enough with decent antennas, you will have special days where contacts are being made well beyond the usual 100-300 mile range.  On those days, you will understand why it’s important to not all clump together on 144.200. 
    New ops, especially those who are used to channelized repeater operating need to use their VFO’s and spread out from 144.200 when it’s busy.   Say you do catch a big E skip opening on 2.   Would you rather have 10 stations all fighting it out on 144.200, or would you rather hear clearer signals scattered from 144.170-144.230?    Let’s put it another way.   If you went to a grocery store and saw 10 people with full carts standing in one line, wouldn’t you slide over to the checkout gal who has nobody in line?  

     So far all I’ve been discussing is Sporadic E skip propagation.   It’s common on 6m in the summer, and not at all common on 2m.   How 2m and higher bands open up is usually via tropospheric ducting.   Or just good old, “tropo”.   This post is long enough, so I’m going to hold off on the tropo post for now.   I’ll also admit that I’m looking for someone to steer me to their favorite explanations of tropo.   I can give the basics, but I know I’ve read better articles than I could ever write.   If anyone has links to good tropo articles, steer me toward them.    

6m Openings — Learn about Sporadic E Skip, Antenna Options and Being a Smarter Operator.

Sunday, May 1st, 2011

    I saw my first widespread emails alerting me to 6m and FM broadcast band (88-108MHz) openings this week.  Tis the Season!    
    6m opens up from about May thru August.   It’s most widespread and predictable during June and July.  There is a secondary peak in Dec.-Jan, and honestly, 6 can open up at any time of the year.  But easily 70-80% of the fireworks is during the summer.  The propagation mode responsible for most of the openings is Sporadic E skip.   Google that term and you’ll learn far more than I can say here.   A typical 1-hop distance on 6m via Es is about 600-1200 miles.  There can be more than 1 hop, too.    I’m going to try to keep this short, and just hit the highlights.   If you become addicted to 6m, you can learn far more.   
   A reason even casual VHF’ers love 6m is that often times, you can work a lot of the DX with modest antennas, not very high up.   In fact,  sporadic Es can favor *lower* antennas, due to the high angle of the incoming signal.   A good station on 6m often has several antenna options.   A gain yagi higher up is good for working stations out to 200-300 miles via brute force, anytime, just like we strive to do on 2m, or 222 or 432 MHz.   A low yagi will often outperform the higher yagi during E skip openings, sometimes by a wide margin.  How low?  20-30′ will do.  You can also put a horizontal loop (or stack 2 for an extra 3db gain) to have the option of an omni pattern.    Some fellows swear by using a vertical, saying the polarity of a signal via E skip gets all scrambled up anyway.  Most 6m ops I know prefer horizontal, and that’s the way I roll, but hey —  try different antennas and learn for yourself.  
    To be perfectly honest, I have worked guys using loaded rain gutters, lawn chair squalos, G5RV’s and HF beams that were able to load up.   Heck, I once stumbled into a fellow who was mobile in western Nebraska.   He had 25w into a 1/4 wave mag mount, and he was at least S3-S5 for a half hour.   6m is called the Magic Band for a variety of reasons.    I have had times where the band opened up for just a minute.   I’ll hear guys with different accents ragchewing and before they even unkey the mic, they’re gone.   6 is a ball.   🙂   The more time you put into it, the more you will get out of it.  
    Because it gets very busy at times, it’s a good idea to know what you’re doing.   6 has always had a reputation for being a gentlemanly band, with good manners and intelligent ops.   Go here http://www.smirk.org/opaids.html and take some time to learn what’s up.   I can tell you one way to not aggravate anyone.   Leave the DX window of 50.100-125 alone, unless you’re hearing a) the Caribbean b) Alaska or Hawaii or c) the World.   DX on 6m is not US/US contacts, nor US/VE.    Now, there will be times (contests and especially Field Day) where you’ll hear domestic QSO’s in the DX window.   It’s an innocent mistake, 90% of the time.   Often times, a short, courteous explanation about the DX window is useful.   It helps the op making the mistake, and it probably educates many others who are listening along.