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foxtrot_xray

Interesting Find..

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So, while driving cross country, I loaded in a whole bunch of stations into my phone - mainly along my route - that, if I got the itch, I would stop and recover.

 

In Nevada, at a section where the old, original US50/Lincoln Highway (SR 722) joins the current alignment, I saw a cluster of three marks:

KQ0337 - M 46

KQ0480 - M 46

KQ0335 - M 46 RM 1

 

Notice the two 'M 46' stations. Looking at the first, you'll notice the first log, 1953 simply says "Pre-Earthquake Position". It then has a couple logs after it.

Whereas the second M 46 has other logs.

I found M 46. Which one did I find? Why have a second PID for the same station for a pre- and post-earthquake PID?

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I suspect that you found KQ0480. Check the stamping carefully to see if it matches

https://www.ngs.noaa.gov/cgi-bin/ds_mark.prl?PidBox=KQ0480

 

I'm puzzling over this mess, and the picture is still cloudy. Key to it all may be the latest NGS data sheets and comparing them to the ~2000 sheets captured at Geocaching, as some editing has been done to the entries before 2000 as well as adding newer recoveries. NGS even says that the trail isn't clear.

 

There was a 1934 series 46 as shown by nearby disks. Disk M 46 KQ0337 may be gone.

 

The recoveries at https://www.ngs.noaa.gov/cgi-bin/ds_mark.prl?PidBox=KQ0480

show somebody went out and measured this disk in 1954 by triangulation and leveling, as both horizontal and vertical are ADJUSTED. Perhaps they created confusion by re-using the designation in 1953 when they placed a new disk for this measurement?

 

They would have set RM 1 (KQ0335) and RM 2 (KQ0336) at that time 1953/4, as I've never seen a RM for an elevation-only mark. I'm guessing someone worked up ADJUSTED elevation data for RM 1 and RM 2 from the later leveling (see GC data sheets) but then decided it wasn't accurate enough in relation to M 46 (1954) because they were so close together the standard tolerance would be very hard to meet. On recognizing that, they were downgraded on the later data sheets.

 

Note that the GC log and photo for KQ0335 do NOT show the stamping RM1 which is called for, so it was probably KQ0480 they found.

 

I'm a bit puzzled where the HH1 coordinates on the RM's came from. The didn't come from a sportsman's HH2 GPS receiver and there is no recent recovery, nor any OPUS Shared Solution for them.

 

Hope that heads you in the right direction to figure the rest of it out. Argue with me if you don't like my reasoning.

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All,

 

There are Geocache Found Logs for

 

M 46 RM 1

 

0fc46b94-a75b-41b4-830d-9d136dc56022.jpg

 

and KQ0337 the 1934 M 46

 

0e85248c-d0fc-426f-b39e-4b3bb60c0e9d.jpg

 

I believe that the exact same disk is shown in both logs and it appears to me that the original 1934 has been slightly modified to 1954. My idea is that the post earthquake visit saw no reason to do a full reset, but just fine tuned the L/L and elevation.

 

I have recovered a couple where the entire concrete post setting was disturbed by highway widening and plunked back into a back-hoe dug hole. kayakbird

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I think Kayakbird has it:

"it appears to me that the original 1934 has been slightly modified to 1954. My idea is that the post earthquake visit saw no reason to do a full reset"

 

Compare the stamping of the 3 on N 46 KQ0340

 

The pictures have to be of the same disk. Someone didn't bother to figure out which mark they found when they went to log. Nobody has actually logged RM1 on geocaching.

 

5c312811-044d-4f5a-9282-d715b3ebd23f.jpg

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I recovered RM1 and RM2 of M 46.

I can't get pics off my phone until I get home from my trip (or, until I have some time where I'm alone and can sit down..) I don't even have enough time to finish my reply here, really. D'oh.

 

In either case, in finding this one mark it seemed to match the other marks in the line. (Again, once I have time, I'll upload pics..!)

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I'm a bit puzzled where the HH1 coordinates on the RM's came from. The didn't come from a sportsman's HH2 GPS receiver and there is no recent recovery, nor any OPUS Shared Solution for them.

 

 

The HH1 coordinates are calculated from the box score. I've run across this for many reference marks. I recall seeing a post from either Dave Doyle or Malcolm Archer-Shee indicating the calculated positions were added as HH1 coordinates.

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So I got pics uploaded. You can check them out for M46 and RM1 here -

 

RM1 - https://www.geocaching.com/mark/details.aspx?PID=KQ0335

M 46 - https://www.geocaching.com/mark/details.aspx?PID=KQ0480\

 

Thinking about it, I likely logged the wrong one, since the disk IS stamped 1934, and not 1954. However, it is very easy to tell in my pics that there IS NO OTHER MARK THERE.

 

Since the RN's and AZ are all stamped 1954, I have a feeling that this station in 1954, was re-leveled to and made a horizontal control station. Instead of updating the original datasheet (KQ0337), they created a new datasheet/pid (KQ0480).

 

I dunno tho - I can honestly say I haven't' seen anything like this before. :)

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foxtrot xray & all

 

I think that NGS is totally erroneous in keeping two Datasheets going for this single piece of brass with a 0.7 ft elevation difference!

 

KQ0337 HISTORY - 1953 MONUMENTED CGS

KQ0337* NAVD 88 - 1530.373 (meters) 5020.90 (feet) ADJUSTED

KQ0337* NAD 83(1986)- 39 17 56. (N) 117 55 07. (W) SCALED

KQ0337 DESIGNATION - M 46

 

KQ0480 HISTORY - 1954 MONUMENTED CGS

KQ0480* NAVD 88 - 1530.15 (+/-2cm) 5020.2 (feet) VERTCON

KQ0480* NAD 83(1994)- 39 17 55.97819(N) 117 55 07.77443(W) ADJUSTED

KQ0480 DESIGNATION - M 46

 

Maybe you could write a note on KQ0337. kayakbird

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