[ARC5] Front panel widows

[Brian]

The original window material in the Command transmitters and BC-221 family 
was nitro-cellulose acetate - the basis for early cine film. The original 
solvent gradually evaporates, leading to physical distortion and coloration. 
You could smell the solvent in the early cinema projection rooms. The 
degradation is not reversible. The observation that a solution was to buy up 
old stock transmitters to scavenge their windows will not beat the natural 
chemical and physical degradation.

The better solutions emerging from this discussion are the use of Perspex, 
Lexan, other clear cyano-acrylates and polycarbonates, though even these 
will change shape over time. Plenty of this material is used for 'gels' over 
follow spots for stage shows - and so becomes a cheap source of our raw 
material. Think how sexy your transmitters would look with yellow, green, 
blue and red windows!

The scales and numbering on the Command transmitters varied between 
manufacturers and most definitely with operational frequency range; on the 
lower frequency models, the markings were closer spaced. So, the possibility 
of making 'one size fits all' is a forlorn hope.

My solution was to photocopy an engineering mm scale onto clear plastic and 
cut to fit. Cheap and cheerful. In the old days of Drawing and Design, 
scales with all sorts of spacings and numberings were available.

73 de Brian, VK2GCE.