Re: 7904 excessive shadow/flare
Chuck Harris <cfharris@...>
I know that, but my 7904's beat my 7854 in the flare departmenttoggle quoted messageShow quoted text
by easily double. They also have much brighter maximum intensity
than does the 7854.
I haven't explored the differences, but the 7904's all have a worse
time than *any* other scope I have ever seen.
As to what it looks like, if you go to a slow sweep, something on
the order of 20ms/div, and allow a single bright spot to draw a
center-line trace, you will see several other spots moving both
faster, more diffuse, and towards the outer reaches of the CRT screen.
It is clear that they all are "tethered" at the center of the
It is the inevitable cost of having such a high anode voltage with
a mesh lens. The mesh lens is an imperfect lens. It produces a
repeating series of ghosts images that are at intervals from the
desired image. The intervals are related to the beam size, and the
mesh's pitch. I think they are like the wavelets you see when a
collimated light source is aimed through a narrow slit... which is
exactly how a mesh (window screen) lens works.