Key Observations for dating early tubes

Dating early tubes requires detailed collection of evidence. Much of what I would like to know about tubes was not even well known to everyone working at the factories. The process to manufacture tubes was constantly and rapidly evolving.

Using techniques from studying 16th century genealogy, experience with complex logic problems, and professional approaches to documenting multi-dimensional matrices; I will reference many pieces of evidence to accurately date tubes.

The following represents my observations on the evolution of early RCA tubes:

Date:Fact:Source / Notes:
11-Nov-1918WWI ends, and with it the wartime patent infringement waiver.Well known; Wikipedia
20-Nov-1919American Marconi disolved. RCA formed
Dec-1919GE begins converting it's NELA park Cuyahoga Lamp factory for it's Research & Engineering plant. First experimental tubes made'Cuyahoga' Research opens
Dec-1919GE begins converting it's NELA park Euclid Glass works factory for it's Cleveland plant'Cleveland' plant opens
Dec-1919Moorhead Labs' Marconi license revolked
Jul-1920General Electric / AT&T cross license
Oct-1920GE production begins @ NELA Park, Cleveland plant, where Phosphorous getter compounds were usedDeduced; Cleveland was the first plant, and production had to start 2-3 mos ahead of product release.
Nov-1920GE moves from Shaw to rolled brass-sheet tube bases.
With H.Shaw President of A-P Radio Labs by Nov-1921 he likely cut off GE from buying his tube bases.
1-Dec-1920RCA releases: uv-200, uv-201
Mar-1921RCA releases uv-202 5w transmitter tube

Note this picture of three early uv-202s...without enlarging the picture, I can tell you the middle one was made in the Cleveland plant, can you?

Cleveland was using phosphorous to deal with vacuum issues. It's stem is marked 'H-12', the others unmarked.

Which plant didnt need a getter because it could achieve a high vacuum?

Harrison hadnt opened yet.
WLCo. did not make large envelope tubes, and these have no WLCo engravings.

Note the 'small patented' text on both the middle and left tube base. 

No getter (clear), early small text base...I can conclude that Cuyahoga's developmental factory the tube on the left.

More in a later article.
May-1921RCA signs agreement with Westinghouse Lamp Co. to supplement GE tube production demandsto do: trace Westinghouse PA factories
1-Sep-1921RCA introduces new 'Red' box designs
Dec-1921Westinghouse joins the RCA consortium
Jan-1922Westinghouse produces 4v 201 tube not accepted by RCA as equivalent. These tubes are mysteriously based using 'Shaw' bases, with faint marks from the Moorhead Marconi / Deforest production.

Future article: "Did WLCo. make tubes in San Francisco?" 
Tyne: Estimated 3200 made; Author: the first 'batch' delivered by WLCo would have been ony one months production.Orders for WD-11, WR-21, WB-800 tubes would have taken priority for sets being sold. I think less were made, perhaps 2000.
Jan-1922GE converts a second Tungsten Lamp plant with NELA Mfg Edison Lamp Works, Harrison, NJ
'Harrison' plant opens
aft Jan-1922GE Clevelend begins using a light phosphorous getter with it's uv-200, producing the coveted 'pink' detector tubes. These are all marked "H-14" on the stem press.Deduced: Since pink BBTT tubes exist, and Tyne suggests Harrison used only Mg getters, it seems pink detectors were made in the Cleveland factory
Feb-1922Westinghouse retools to use S-14 globe envelopes
inferred after RCA rejects tubular 201s
Westinghouse uses a new, distinct getter mix for its 1st 'correct' uv-201 tubes, resulting in 'amber' tubes.

These vary from 1/3 to 2/3 coverage of the envelope top. Produced for no more than 6 months. (each factory produced perhaps 5k tubes/day. WLCo was the only RCA factory making WD-11 tubes. If WD-11s were 80% of production: [5000*.2=1000/day] * 6mos = approx 180,000 amber WLCo tubes made
Production estimate source: author. All examples seen have the marks "A-5" on the stem. Beneath is the mark "y" or "x", perhaps meant to indicate experimentation
Apr-1922GE's Harrison plant ships it's first tubes, using exclusively Magnesium/Aluminum getter mixes for 201s. (later this would become known as Harrison #1 when a second Harisson plant was opened in around 1932.)Tyne; 'Saga of the Vacuum Tube'; Dowd 'Code Marks'
Apr-1922Ohio Box Company printing marks indicate 'Green Box' cartons are in use, with '422' & '622' date codes seenAuthor
Radio Corporation changes from the (RC) logo to the new (RCA) logo
Sep-1922Westinghouse retools to use S-14 globe envelopes
Oct-1922Westinghouse Lamp Co. joins GE in making tubes.
Oct-1922RCA releases uv-201-ATyne; 'Saga of the Vacuum Tube'; presumably. The factory cutovers to use thoriated tungsten were likely not that intrusive to plant operations, and happened in a matter of weeks
Dec-1922RCA releases uv-199
Jun-1923'with the new filament, and large plate...the UV-200-A disappoints, still drawing one amp'First reference to large plate change in media
Jul-1923the change to the 'Large Smooth Plate' design occured before the retool for tipless envelopes, and was reviewed as the "UV-200-A" in July 1923

1-Sep-1923Lamp manufacturers introduce the 'tipless' light bulb, which quickly led to tipless tubes
29-Sep-1923RCA announces it's sold 3.6m tubes (incl. all types)
Jan-1924Westinghouse Lamp Co. switches to a Magnesium/Aluminum getter compound
15-Aug-1924The 'tipless' radio tube is announced & released. Westinghouse was late to make the switch, perhaps handling all production while NELA was retooling.Note: 'Pink UV-200 H-14' tubes exist, wheras UV-201 do not. Both tipped and untipped 'Pink' detectors exist, pinpointing this phenomenon. My above hypothesis extends to include these tubes as phosphorous getter poisoning rather than intentional. Perhaps 'scrubbing' down for a switch to magnesium actually spead phosphates throughout the factory? It seems unlikely that they would be experimenting with phosphorous getters *only* in detector tubes at the same time phosphorous had been declared obsolete by GE.
15-Aug-1924GE's Cleveland plant continues producing it's 'pink detector' tubes, now tipless. Examples continue to use "H-14" stem press markingsDeduced from examples in author's collection of nearly a dozen pink detectors, combined with evidence related to production variations in getter use.
Nov-1924All NELA plants switch to Magnesium/Aluminum getters as standard for amplifier tubes. uv-200 phosphorous use, perhaps limited to Cleveland, continued for another year.Key date. Did Tyne, by stating 'all NELA plants', intend to exclude or include the PA WLCo. plant? He was imprecise in this statement, and should have constrained the assertion to amplifier tubes only.
Nov-1924Tools, machines, and/or ovens were Phosphorous contaminated, and when Magnesium was added, 'Rainbow' tubes were accidentally createdNote: this is the Author's Theory, based on extensive research. It explains the variation found, with some tubes showing less rainbow than others. I suspect there was no more than two months where Rainbow tubes were created, as this was perceived as 'burned out' by worried customers.Since many are 'Cunningham' branded, and Cunningham hand picked his tubes, he must have liked them and had them sell well
2-Dec-1924The box for the uv-199 was changed to be taller, and all boxes dropped references to 'made by GE' or 'made by WLCo.'I suspect a lot of specialized parts/order had to be managed to keep box sizes that were not standard. Cut those costs!
1-Feb-1925Last datasheet/revision of the UX-201-A, updated with a tall base, and brass pins.RCA datasheets
1-Feb-1925First bakelite bases used, introducing the engraved 'arched' Radiotron logo. Brother Dowd points us to factory codes being in use "by at least 1924" {Patrick Dowd-1978}. The devious factory warranty markings used make for a third dimension to variant collecting late BBNT and BKNT tubes made on into the 30's.
1-Feb-1925GE's Cleveland plant continues briefly to produce 'pink detector' tubes, now with bakelite bases and tipless. This accounts for three pink uv-200 variants.My guess is that the last pink variant was produced from 1-Feb-25 until the 15-Aug-25 switch to UX bases. Perhaps as late as May-26 when the 200-A released.
1-May-1926RCA replaces the UX-200 with the UX-200-ARCA datasheet and release press
1-May-1926abt May 1926, RCA changed from the 'Arched' to 'Horizontal' base engraving style, introducing a new set of factory codes in the engraving sets.
1-Jun-1930RCA switches engraving designs from Horizontal to the 'Staircase' design. The UX-200/201a was never produced with this change. Likely the market was declining and inventory was high. The 200/201 had quetly died.RCA datasheets released for UX-245