[ARDF] Mt. Airy 2m ARDF comments

[Dale Hunt WB6BYU]

Matthew Robbins wrote:
> 
....
> As I was setting a few score-O points I put out late on Saturday, I
> realized the creek separating MO5 from the rest of the course was
> mapped in such a way that it was almost impossible to look at the map
> and find a suitable crossing point.  Furthermore, the straightline
> route to 5 not only crossed that creek, but also went straight up a
> 40-foot high earthbank that was clearly impassable (once you got
> there, not from looking at the map: vertical at the
> top, even overhung), and mapped not as an earthbank, but as
> closely-space contours.  


   Keep that in mind if you ever set a course for the Czechs.
   (At least, if it is mapped properly.)  Teach them to assume
   they can run in a straight line between controls!  (Actually
   there are some strong recommendations about not putting
   any dangerous terrain or impassable streams in the straightline
   route - I think the Czechs added them on purpose.)


 
> 2 was a little harder, I figured, because the map doesn't show any
> contours on the other side of Colerain Avenue, so you can't eyeball
> the contours for possible reflection paths.  I placed it at the
> intersection of the streams, where I figured it would be easier once
> you got to one of the roads above the streams, since this might be a
> control a beginner might decide to try after getting 3 and 1.


    You didn't see the Powell Butte 80m course in 1999:  if we
    had done it on 2m, most of the transmitters would only have
    been audible at the start due to reflections from other
    hills off the map.  As it was, I had to climb up to the
    first transmitter to be able to talk to Joe on an HT to
    walk him through reprogramming one of the controllers
    down on the back side of the hill.


...
> My real regret was the placement of the flags.  I've been on a crusade
> to keep the flags out of low visibility fight...
...So my idea is to hang the flag in the clear so anyone
> close will find it and clear the area.  (Oct 2004 addendum: The Worlds
> had control locations you could see from way off...


    Generally, something like 5 to 10m visibility is 
    recommended.  The ones in Brno were visible for too
    far:  up to 100m (from a road) for one I was at
    the first day.  (Though not from all directions,
    and it was through a Beech forest so you could only
    see it through certain paths through the trees.

    If they are too hard to see, everyone bunches up
    looking for it.  If it is too easy then sheer
    speed becomes more important than DF skill.

    They also should be placed so that competitors punching
    it don't make it more obvious to others.  For example,
    a clearing in waist-high brush wouldn't be a good choice
    if the flag were hidden but people standing there were
    obvious from a distance.


    By the way, the equipment in Brno virtually required that
    the flag be between two tree trunks, making it hard
    to see from certain directions.  The 2m transmitter
    antenna hung from one tree and the datalink antenna
    from the other.  Given the length of the cables
    available and the required 2m maximum spacing between
    flag and TX antenna, it required two trees not more
    than about 10' apart, with the flag between them.
    So this meant that the flag was NOT easily visible
    from two directions.  (Which is probably what happened
    to the competitor who ran past in full view about
    10m away from us: because of one hanging branch
    the flag wasn't fully visible until he was abreast
    of it, and he didn't look that direction.  Surprised
    he didn't notice the TX operator laying there in 
    full view, either.  Oh, well, he did finally come
    back and find it 10 minutes later.  Though I must
    admit to having missed one by no more than 3m in
    Hungary!)

    MORAL:  always look around you when you get close!!

    And, because this was in a managed forest (regularly
    thinned), there weren't many small branches left on
    the trees below 10m high or so!  On the second day
    the only support available for the 2m antenna was
    a precarious branch.  If someone had caught the coax
    and snapped it off, we would have been in trouble
    because there wasn't another one available.

    MORAL:  make sure your antenna mounts are solid!
    (We probably could have hung the antenna BETWEEN
    two trunks instead of from a single branch.


    Also, I did some statistics on how many competitors
    arrived in each minute of the cycle.  Just 20% found
    it while it was transmitting!  The most popular time
    was in the second minute after it turned off, with
    about 30%.  The least popular time was the minute
    before it came on, with only 10%.  It would be
    interesting to compare these percentages with those
    of other transmitters.

        - Dale WB6BYU
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