Thanks to all the respondents about the monoscope tubes.
We had some pretty smart predecessors.
Dave
On 2/14/2020 11:23 PM, Instrument Resources of America wrote:
The original monoscope tube dates back to the 1930's when RCA first
made its 1898 a 3" diameter electrostatic deflected tube, looking much
like any other 3" inch CRT. Except for the pin in the center of the
screen. It produced a video signal of a 'girls head' when its internal
target plate was scanned. Then came the 1899 a 5" diameter
magnetically deflected tube which produced the 'Indian head' test
pattern that many television stations would broadcast when they ceased
their regular programming for the day, usually around one, or two A.M.
I myself, as I'm sure there must be others here as well, are old
enough to remember seeing this Indian head test pattern being
broadcast late at night. Eventually the 1899 became customizable with
just about anything that a station would want, circles to be used for
linearity, height, and centering adjustments, wedges for resolution
and video bandwidth measurements, plus the stations call sign. The
1899 was replaced by the 2F21 about the mid 40's. These monoscope
tubes and their supporting vacuum tube electronics were called
monoscope cameras. Regular televisions cameras were not used for the
purpose of transmitting the test pattern for fear of burn in on the
expensive, image orthicon camera tubes, and unnecessary added hours of
wear and tear. RCA also made a 1698 2" diameter 'character generator'
monoscope, (similar to the Raytheon CK1414 being discussed here,)
primarily used by the U.S. army during the 1950's. For those of you
who are curious enough to see a good pic of the RCA TK-1A 'monoscope
camera', and it's 2F21 monoscope tube, plus some reading material, you
can go here, http://www.chalkhillcom.com/museum/RCA2.htm I have
these tubes as part of my tube collection, except for the 1899. Hope
that all enjoy the reading, Ira.
On 2/14/2020 3:54 PM, Mac Doktor wrote:
On Feb 14, 2020, at 2:11 PM, Toby Thain <[email protected]>
wrote:
Thanks very much for the suggestion! Even the glass etching ability
sounds quite useful for other purposes. (Tangent: I wonder if that
could
be used for edgelit projects...)
Also a very effective way to give an expensive brass model locomotive
enough "tooth" on the surface for the paint to stick permanently.
Pickling is always a fall-back.
By the way, what is a "Monoscope"? I've never heard the term before.
Here's the brochure:
http://www.frank.mif.pg.gda.pl/other/Raytheon/Raytheon_symbolray_an.pdf
And @TubeTimeUS got one working:
http://tubetime.us/index.php/2018/06/04/a-vacuum-tube-rom/
I have a couple of these. $15 apiece at a hamfest. I had no idea what
they were but they were too cool to pass up. It took me several
minutes to figure out what they were after I got home. I finally
looked in at just the right angle and as soon as I saw some letters
the lights came on.
I think both have leaked, unfortunately. Really did have me going for
about five minutes.
Terry Bowman, KA4HJH
"The Mac Doctor"
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