Goal: $300, Received: $160.00 (53%) Contribute Now
Donate whatever you can or Join the 14,000 other NAWCC members for only $80 (plus $10 for hard copy publications). Check it out here.

Page 1 of 2 12 LastLast
Results 1 to 15 of 17
  1. #1
    Registered User Jim Haney's Avatar
    Join Date
    Sep 2002
    Location
    Decatur, TN.
    Posts
    4,943

    Default Hamilton 4992B used by the Naval Observatory

    Marvin Whitney built these from a Hamilton 4992 B Military watch to use as a measuring tool at the Naval Observatory.

    The Observatory was using this instrument to see what error was in the TIME signal between the Station in Beltsville, MD (Washington, D.C.) WWV, and the location it was received in, Colorado or anywhere else. The error would be caused by interference in Radio signals in the atmosphere.

    This was the time signal and it had to be correct without any error. They broadcast it in several Megacycles 2.5,5.0,10.0,15.0.

    Some info from Google,

    https://books.google.com/books?id=xA...%2C5.0&f=false

    I got this from a Commander Al Betters a friend of Whitney's and he gave me the letter than Marvin wrote to him presenting this as a gift to him. He supplied photos to Whitney to use in the book Marvin was writing at the time. "Military Timepieces, c 1992.
    Cmdr. Betters was a Navy "Frogman" and his pictures are on page 580.

    I have seen 2 others, one owned by Military parts guru, Larry Crutsinger, http://www.hamiltonparts.com/ & fellow collector Fred Hansen.



    Click image for larger version. 

Name:	DSCN3380.JPG 
Views:	63 
Size:	204.2 KB 
ID:	256771Click image for larger version. 

Name:	DSCN3378.JPG 
Views:	51 
Size:	194.6 KB 
ID:	256772Click image for larger version. 

Name:	DSCN3379.JPG 
Views:	46 
Size:	191.2 KB 
ID:	256773Click image for larger version. 

Name:	DSCN3381.JPG 
Views:	54 
Size:	199.9 KB 
ID:	256774Click image for larger version. 

Name:	DSCN3382.JPG 
Views:	50 
Size:	178.7 KB 
ID:	256775Click image for larger version. 

Name:	DSCN3377.JPG 
Views:	62 
Size:	185.5 KB 
ID:	256776Click image for larger version. 

Name:	DSCN3383.JPG 
Views:	58 
Size:	197.0 KB 
ID:	256777Click image for larger version. 

Name:	DSCN3384.JPG 
Views:	62 
Size:	201.1 KB 
ID:	256778Click image for larger version. 

Name:	DSCN3376.JPG 
Views:	47 
Size:	192.7 KB 
ID:	256779
    Jim Haney

  2. #2

    Default Re: Hamilton 4992B used by the Naval Observatory (By: Jim Haney)

    Jim very nice it,s a beauty.

  3. #3

    Default Re: Hamilton 4992B used by the Naval Observatory (By: s. smith)

    Fantastic watch Jim, with an equally amazing provenance!
    Paul

  4. #4
    Registered user.
    Join Date
    Jul 2010
    Location
    Panhandle of Texas
    Posts
    439

    Default Re: Hamilton 4992B used by the Naval Observatory (By: Jim Haney)

    That is amazing. Thanks for sharing!

  5. #5

    Default Re: Hamilton 4992B used by the Naval Observatory (By: Donovan Martin)

    Great item, and greater provenance... thanks for sharing...

    earlier this year 4c78535 was sold, no box or provenance though.

    Outer chapter 1/100 of a minute....

  6. #6

    Default Re: Hamilton 4992B used by the Naval Observatory (By: Jim Haney)

    Thanks for posting Jim. Great item with outstanding provenance. With 3 of these known now maybe another will surface in the future. Looking carefully at these, i believe the mvt.,special dial and hands were supplied to the N.O. for casing at the N.O. in the 4 piece case. Maybe Lucite rather than Plexiglass as it seems to have aged well. The protective box also appears to have been made at the N.O. by some of the construction details. Thanks again!

  7. #7

    Default Re: Hamilton 4992B used by the Naval Observatory (By: 179)

    The box and documentation that came with Jim's example certainly goes a long way in defining the story behind these devices.

    As an update, I can confirm the existance of 2 additional examples of these devices - bringing the total of known examples to 5.

    Rhett
    Member: NAWCC Chapter 58, 149
    Website: http://rrstd.com

  8. #8
    Technical Admin Tom McIntyre's Avatar
    Join Date
    Aug 2000
    Location
    Boston. MA USA
    Posts
    18,946
    Blog Entries
    10

    Default Re: Hamilton 4992B used by the Naval Observatory (By: rrstd)

    A really neat artifact. It is particularly special to have the documentation from the guy who made it.

    Do these precede or follow the "NATO" 3992B's with a similar dial design for decimal minutes?

    Click image for larger version. 

Name:	3992Bdial.jpg 
Views:	5 
Size:	264.9 KB 
ID:	258707
    Tom McIntyre Click me.
    If you don't learn to laugh at trouble,
    you won't have anything to laugh at when you're old.
    Will Rogers

  9. #9
    Registered User burt's Avatar
    Join Date
    Sep 2008
    Location
    McKees Rocks,Pa.
    Posts
    424

    Default Re: Hamilton 4992B used by the Naval Observatory (By: Jim Haney)

    Jim,

    I was very impressed with this piece, with its historical providence as well as its special purpose as a timing "check" instrument. Kudos to Hamilton also.

  10. #10

    Default Re: Hamilton 4992B used by the Naval Observatory (By: burt)

    The two examples below, show some of the variation from piece to piece. As can be seen, the lucite cases are slightly different in size as well as construction details.


    Click image for larger version. 

Name:	NO4992B_1.jpg 
Views:	22 
Size:	122.8 KB 
ID:	271057Click image for larger version. 

Name:	NO4992B_2.jpg 
Views:	26 
Size:	154.6 KB 
ID:	271058Click image for larger version. 

Name:	NO4992B_3.jpg 
Views:	29 
Size:	150.1 KB 
ID:	271059
    Member: NAWCC Chapter 58, 149
    Website: http://rrstd.com

  11. #11

    Default Re: Hamilton 4992B used by the Naval Observatory (By: rrstd)

    Tom

    The decimal watch dial you show was fairly common. I believe these watches all started life as standard Zenith or Hamilton comparing watches and had new dials put on some time after WWII. The ones I have seen were converted in England. They were used for ease of calculation. In fact so many Zeniths seem to have been converted that the conventionally dialled watch seems to be rarer than the converted version. The original dial is of much higher quality.

    RMW

  12. #12

    Default Re: Hamilton 4992B used by the Naval Observatory (By: rrstd)

    Rhett, is 4C20179 in a lucite case like the one on the right in post #10 already in your list of 5?
    Member Chapter 149

  13. #13
    Registered User Clint Geller's Avatar
    Join Date
    Jul 2002
    Location
    Pittsburgh, PA
    Posts
    852

    Default Re: Hamilton 4992B used by the Naval Observatory (By: Dave Chaplain)

    I am puzzled by the opening post in this thread. The speed of radio waves in air is about the same as it is in vacuum, which is 300 million meters per second, or about 186,000 miles per second. So that means that a radio wave emitted from the ground and reflected from the ionosphere will be received at a point about half way around the Earth in about a tenth of a second. Changes in the time of travel of an electromagnetic wave between any two points on the Earth's surface will result from variations in the height of the ionosphere above the ground - not from radio wave interference (Maxwell's Equations are linear!), nor from Doppler shifting (relativistic Doppler shifts only affect the frequency of an electromagnetic wave, not its speed). Presumably, these variations about the mean value are a couple of orders of magnitude or so smaller than the mean value itself. So that means that the variations one is attempting to measure are on the order of a few milliseconds, or less. So how can one expect to measure variations so small accurately with a timekeeper whose escapement beats only once every 200 milliseconds? The dial of the timepiece is completely incapable of registering time intervals that small. So it seems like the tool is hopelessly mismatched for the intended purpose.
    Clint Geller, FNAWCC, # 84,947

  14. #14
    Registered User grtnev's Avatar
    Join Date
    Jan 2009
    Location
    Minden, Nevada
    Posts
    368

    Default Re: Hamilton 4992B used by the Naval Observatory

    Jim,

    Very, very interesting. Thanks for sharing.

    I did note that the position of the regulator is essentially all the way toward S - which is interesting.

    Richard
    Last edited by grtnev; 04-20-2017 at 04:52 PM.

  15. #15
    Registered User Jim Haney's Avatar
    Join Date
    Sep 2002
    Location
    Decatur, TN.
    Posts
    4,943

    Default Re: Hamilton 4992B used by the Naval Observatory (By: Clint Geller)

    Quote Originally Posted by Clint Geller View Post
    I am puzzled by the opening post in this thread. The speed of radio waves in air is about the same as it is in vacuum, which is 300 million meters per second, or about 186,000 miles per second. So that means that a radio wave emitted from the ground and reflected from the ionosphere will be received at a point about half way around the Earth in about a tenth of a second. Changes in the time of travel of an electromagnetic wave between any two points on the Earth's surface will result from variations in the height of the ionosphere above the ground - not from radio wave interference (Maxwell's Equations are linear!), nor from Doppler shifting (relativistic Doppler shifts only affect the frequency of an electromagnetic wave, not its speed). Presumably, these variations about the mean value are a couple of orders of magnitude or so smaller than the mean value itself. So that means that the variations one is attempting to measure are on the order of a few milliseconds, or less. So how can one expect to measure variations so small accurately with a timekeeper whose escapement beats only once every 200 milliseconds? The dial of the timepiece is completely incapable of registering time intervals that small. So it seems like the tool is hopelessly mismatched for the intended purpose.




    Clint,
    You would have to start with the box which states the WWV or microwave signals and come up with your own theory based on your doctorate degree.
    Jim Haney

Similar Threads

  1. Use of "Special" by the Illinois Watch Co.
    By Dan Alexander in forum American Pocket Watches
    Replies: 17
    Last Post: 05-08-2016, 11:53 AM
  2. Hamilton 4992B 22 Jewels E. H. Eldridge on the Dial
    By Eugene Romanenko in forum American Pocket Watches
    Replies: 9
    Last Post: 08-20-2014, 11:26 PM
  3. American Pocket Watch Hamilton 4992B ...here is one for the record books-!
    By technitype in forum Watch Repair
    Replies: 10
    Last Post: 08-19-2013, 11:59 AM
  4. You Tube Video: How A Watch Works by the Hamilton Co.
    By grtnev in forum American Pocket Watches
    Replies: 1
    Last Post: 09-09-2010, 09:04 PM
  5. Replies: 1
    Last Post: 06-12-2005, 11:38 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •