According to my DuMont handbook of CRTs, a yellow filter can be
used with a P7 phosphor CRT to allow viewing of the long decay
part without being "blinded" by the bright blue trace. I've searched
Ebay, Sphere Research and other sites looking for these.

Anyone have one good for a 3" round CRT or know of a good substitute
material (perhaps from a hobby store)?

TIA,

Steve.
--
Steven D. Swift, , http://www.novatech-instr.com
NOVATECH INSTRUMENTS, INC. P.O. Box 55997
206.301.8986, fax 206.363.4367 Seattle, Washington 98155 USA

On 24-Dec-2005, (Steven Swift) wrote:

Anyone have one good for a 3" round CRT or know of a good substitute
material (perhaps from a hobby store)?

Look up your local theatrical supply house in the phone book. See if they
are a Rosco dealer.
http://www.rosco.com/us/retail/index.asp

Rosco makes sheets of gels in many different colors. There must be one close
enough for what you want to do. Plus, they are very robust in that they have
to stand up to extreme heat.

I used that on my old Tek scope. It works great. Poor man's storage scope.

73, Colin K7FM

Steven Swift wrote:
According to my DuMont handbook of CRTs, a yellow filter can be
used with a P7 phosphor CRT to allow viewing of the long decay
part without being "blinded" by the bright blue trace. I've searched
Ebay, Sphere Research and other sites looking for these.

Anyone have one good for a 3" round CRT or know of a good substitute
material (perhaps from a hobby store)?

Theatrical lighting gels should work fine. Try a theatre supply store.
Ask for a "******* amber" gell, or a "#13 straw." Gels usually come in
both wide rolls and small squares that should be fine for a small CRT.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 24-Dec-2005, (Scott Dorsey) wrote:

"C'est un Nagra. C'est suisse, et tres, tres precis."

So how is the 650HR repair coming along Scott?

"COLIN LAMB" writes:

I used that on my old Tek scope. It works great. Poor man's storage scope.

73, Colin K7FM

I use P7 to get a quick at peak-peak noise. The decay time is just about right.

I got an email pointer to Edmund Opitical (use to be Edmund Scientific). They
also have filters.

Thanks,

Steve.
--
Steven D. Swift, , http://www.novatech-instr.com
NOVATECH INSTRUMENTS, INC. P.O. Box 55997
206.301.8986, fax 206.363.4367 Seattle, Washington 98155 USA

Jerry McCarty wrote:

On 24-Dec-2005, (Scott Dorsey) wrote:

"C'est un Nagra. C'est suisse, et tres, tres precis."

So how is the 650HR repair coming along Scott?

Slowly. The problem is that video is going into a proprietary chip
on the aperture board, and not coming out. I put the thing on the
shelf for a while; I should really try touching up all the solder
joints.

It does seem to be that stage rather than any of the RLC filter stages.

I _do_ have an "official spares kit" for the 650... but the aperture
chip is specific to the 650HR.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

"Steven Swift" wrote in message
...
According to my DuMont handbook of CRTs, a yellow filter can be
used with a P7 phosphor CRT to allow viewing of the long decay
part without being "blinded" by the bright blue trace.

The really (really) old marine radars had such a filter, the RCA, some
of the Decca, and similar post WWII radars are mostly in the junk pile by
now, but any old-time marine radar repair shop will probably have old
displays that seem a shame to junk. I suspect some of those places might pay
you to haul off the entire display (including the filters). Seems like the
filter for that phosphor had almost an orange cast to it, no?

Old Chief Lynn

Hi,

I don't know of a source for you, but I wanted to mention
that Heath used exactly that system (P7 phospher CRT with yellow filter)
in the SB-620 "ham-scan" spectrum analyzer (3RP7 CRT).
The earlier HO-13 ham-scan used a 3RP1, but also used a yellow filter.

73,
Ed Knobloch

Steven Swift wrote:
According to my DuMont handbook of CRTs, a yellow filter can be
used with a P7 phosphor CRT to allow viewing of the long decay
part without being "blinded" by the bright blue trace. I've searched
Ebay, Sphere Research and other sites looking for these.

All the equipment I've ever acquired with a P-7 CRT in it has employed
a orange optical filter, sometimes solid tinted plexyglass, sometimes a
cinemoid gell. This includes a number of really old marine radar sets
and some vintage hospital diagnostic displays including the exact same
heart monitor that can be seen on the movie "The Right Stuff" while the
would be astronauts are being run through the meat grinder at the
testing clinic.

As an interesting aside, I also had the exact same motorized
positioning chair that appeared in that movie too! Part of my chair, a
heavy gearbox motor and speed controller board ended up as the motion
engine driving the RA tracking (azimuth) feed car on the famous Big Ear
radio telescope of John Kraus at OSU in the 1990's when I was working
with that SETI project.