Is This Counter malfunctioning?

More info from Jack:

Yesterday Jack rode on the suspicious 300 m cal course. Then he cycled to another 300 m cal course, then cycled to a nearby 1/2 mile cal course. He used a protege electronic counter, so his Jones Counter was not a factor.

He obtained three riding constants:

Suspicious cal course: 480.64 revs/km
Nearby 300 m cal course: 479.03 revs/km
1/2 mile EDM cal course: 478.89 revs/km

This tells me that the suspicious cal course deserves its name. It appears to be about 301.1 meters in length.

Jack is going to do some taping, and to try to figure out how the measurement could have got so awful.

I received a note from Jack this morning. Looks like the mystery is cleared up>

Pete (Jack's message follows):

Jill and I steel taped the "300m" this evening, starting from the western end of the course. This nail is at the edge of a driveway where a new house is going up (an older house was razed for this). It is the "adjusted" end of the course, as the other is even with a utility pole, and the original measurements were based off of that.

When we got to the eastern end, we discovered the course was 1.25m over 300. I couldn't believe I could make such a gross mistake in laying out a cal course - after all, my steel tape, nominally 50m, has only about 40cm of markings beyond the 50m point, so to measure an extra 1.25 I would have had to measure an additional 20cm each of the 6 tape lengths.

Then it occurred to me that maybe the nail at the western end wasn't mine, marking the end of the cal course, but another nail put in by some surveyors as part of the new construction. When we measured back to that end, we then measured back 1.25m, expecting to find my original nail. It should be noted the nail there was not a PK or MagNail - no machining on the head, but I attributed that to wear from the construction vehicles passing over it.

Anyway, we could not locate another nail in the appropriate spot, but then Jill noticed a divot, with a smaller gouge, in the asphalt right where the nail should have been. It looked exactly like someone had used a hammer or crowbar to dig under the head of my nail and pull it out (it's possible it was a snowlplow, but that seems unlikely, as it was less than a foot off the shoulder of the road).

I'll go back tomorrow and take some photos. And if the workers are at the house, ask them if anyone screwed around with nails.

At least one mystery is cleared up.

Best,

Jack

This incident makes a strong case for the use of paint as well as nails to mark points.

If the Protege had been used instead of the Jones in the first place, there would have been no need to consider the possiblity of a skipping counter. I know some measurers fret about the possiblity of electronic counters skipping impulses, but I have never seen this happen with the Protege nor have I been able to induce this.

Jack writes:

Attached are 2 photos from the cal course. The first one (green paint)
shows what I believe to be the hole where the original endpoint nail
was located. If you look to the right you can see the longer, shallower
gouge where it looks like some tool was used to get under the nailhead
to pull it out.



The other photo shows the nail that's there now, and which I assumed to
be the endpoint. As you can see there is no machining in the head, as
there is in a PK or MagNail. It looks like just a large 4 or 6d
construction spike. I may go out there with my own crowbar and pull it
out. After all, turnabout is fair play, right?



Pete’s note: The nail looks like a PK to me. It has a rounded edge and I see a dimple in the middle.

I guess we'll have to wait for the extraction to find out for sure.