E-skip during the VHF test: How good was it?

[WOVERBECK at ccvax.fullerton.edu]

     Much has already been said about the day-long sporadic-E
opening that occurred Sunday during the 1996 June VHF contest.
As noted in my earlier posting here, John Desloge, N6MU, had
never heard six-meter E-skip before the contest.  But when it
was over, he had worked more than 180 grid squares as the main
operator in the N6MU+N6NB effort.  (I mainly watched and gave
advice as John operated a VHF contest seriously for the first
time).

     After it was over, John asked an excellent question:  
"Just how good a six-meter opening was this?  Is this typical 
of six meters, or was this really unusual?"

    In various parts of the country, there may be different 
answers to that question.  It prompted me to do a little 
research into past six-meter scores in the June VHF contest in
California.

     We operated at my cabin on a 7,000-foot mountain near
Tehachapi (about 40 miles east of Bakersfield in grid square
DM05, San Joaquin Valley section).  Looking east, the site
is about 5,000 feet above average terrain for 100 miles
across the Mojave Desert.  In that direction, it's almost
as good as Mt. Pinos (30 miles south of Bakersfield), which
is everyone's consensus #1 VHF contest site in California.  
How did our performance measure up against the best previous 
efforts on Mt. Pinos?

     Here are our 1996 six-meter totals:

1996	N6MU	537 QSOs	189 multipliers

     By far the highest VHF contest scores ever achieved on the
west coast were posted in 1987-1990 by the N6CA group.  These 
were massive efforts put on by a coalition of talented VHF-UHF
enthusiasts and seasoned HF contesters.  They operated on Mt.
Pinos.  Here are their six-meter scores, as reported in QST:

1990	N6CA	331 QSOs	>106*

1989	N6CA	296 QSOs	93 multipliers

1988	N6CA	446 QSOs	174 multipliers

1987	N6CA	730 QSOs	253 multipliers

* (The 1990 multiplier total was not in the top ten listed in 
QST; #10 was 106 multipliers)

     This makes it look as if the 1996 opening was one of the
best we've experienced in California.  But if we look further
back, there were some years when conditions may have been even
better than those in 1987, which was the best year of the
modern era.

     Scores in the modern era are not directly comparable to
those posted before 1985 (when the grid square multiplier
system was first used in the June contest).  Also, there is 
more VHF activity today than there was even 10 years ago, let
alone 20 years ago.

     In spite of that, we can get some idea of what band condi-
tions were like in earlier years by comparing states-worked 
totals on six meters.  As a single operator, I went to Mt. 
Pinos for many VHF contests during the 1970s.  Thanks to great
E-skip, I set new national scoring records in 1974, 1976 and 1977.
Here is a comparison of our score this year with my best scores
in the 1970s (on six meters only):

1996	N6MU	537 QSOs	34-36 states*

1977	N6NB	362 QSOs	46 states

1976	K6YNB	321 QSOs	38 states

1974	K6YNB	311 QSOs	40 states

*(Since grid squares cross state lines, it is not possible to
determine exactly how many states we worked in 1996, but 14
states are beyond the boundaries of any grid square that 
we worked).

     I was running almost the same equipment in the 1970s as
we used this year, including the same kilowatt amplifier (it has 
two 3-400Zs in grounded grid) and identical five-element Yagis.
What I remember best about the banner year of 1977 was that
six meters was open all afternoon and evening Saturday and
most of the day Sunday.  There was double-hop Es to everywhere.
In working 46 of the 48 contiguous states, I missed only
Rhode Island and (inexplicably) Indiana.  Conditions were
even better in 1974--but for a shorter period of time.  That
year I worked 40 states in about four hours of sheer VHF
madness.  Amazingly, those 40 states did not include four of
the easiest (usually):  I never worked Washington, Oregon, 
Idaho and Montana.  All four can be worked on routine meteor
scatter from Mt. Pinos just about any time.

     So how good were conditions during the 1996 June contest?
Out here they were very good--but not the best on record by 
any means.

     I have a question for the HF contesters who have read this
far.  Let's say that the best VHF E-skip in the last two decades
occurred in 1996, 1987, and 1974-77.  Is there any pattern
in this?  Were any other extremes in radio propagation in 
evidence in those years?

     (No one knows for sure what causes sporadic-E skip to
occur; that question has been hotly debated ever since the
discovery of this propagation mode during the 1930s).

					-Wayne Overbeck, N6NB