Nixie anode types

[Mac Doktor]

I've noticed that Nixies have different kinds of anodes. Some have a fine, rectangular mesh, others a more coarse mesh, and some a honeycomb design. What's the reason? Performance vs. legibility?

Terry Bowman, KA4HJH
"The Mac Doctor"

https://www.astarcloseup.com/

“The book said something astonishing, a very big thought.
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The Sun was a star, but close up.”—Carl Sagan, Cosmos, 1980

[Robert G. Schaffrath]

Just theorizing but it would appear to be for legibility. The anode has to cover the the surface area of every digit for uniform lighting and firing current. At the same time, too much anode material blocks the light. Of the various tubes I have, Rodan GR-111Pa’s use a very fine spiral type wire. B7971’s use something akin to window screen. My Philips ZM-1022’s use a honeycomb type anode. IN-12’s use a square hole anode. Some small Burroughs Nixies I have use a microdot type screen. Really seems to be a trade off between surface coverage and legibility. 

[Paul Andrews]

I would say that the different anode styles are definitely an attempt to trade off effectiveness, visibility and ease of manufacture.

Some early nixies didn’t have an anode mesh. They just used the cage at the back. I guess this wasn’t too successful though given that all later nixies have the grid. Some (a lot of?) nixies have an additional anode, part way up the stack of digits, it is usually shaped like a 1. I have multiple types of top view nixie that have a rectangular anode grid that doesn’t cover the whole stack - these tend to be later versions of the same model, so it would seem that the design was continually being refined, which is not really surprising. Off the top of my head, the only one I can remember like this is the CD27. This tube also has the grid set two digits down in the stack. Finally, the planar ZM1350 uses a transparent coating of tin oxide as the anode grid. The technology evidenced in these tubes is quite advanced, but ultimately short lived.

My favorite anodes are the horizontal grids found in the ZM1177, ZM1175 etc., not to forget the unique grid of the ZM1212/ZM1210.

[Bill Notfaded]

Another neat one is the ultra fine mesh IN-8 nixies.  Harder to find but really look great!   http://www.swissnixie.com/tubes/IN8FINE/

Bill

[Bill Notfaded]

Speaking of anodes did you see these tubes?

Where are the anodes in these big Mama's?

Bill

[Dekatron42]

The anode is the rear large surrounding metal plate and possibly also two of the special electrodes that you can see in between the digits, they look sonething lik -|-|-|- if you look at the auction photos here, 2nd and 7th from top if I see correctly: https://www.ebay.com/itm/nixie-tube-PAIR-giant-round-long-life-NEON-READOUT-valve-BURROUGHS-1-8-inches-x2/254603559779?hash=item3b478e0363:g:fGkAAOSwZgBexnKE

/Martin

[Bill Notfaded]

I can see those now that I look between the digits!  Thanks Martin.  I don't like the fact that the seller says they are untested... seems pretty suspect.

Bill