# Radiation Emissions from CRT type VDU's /PPI's



## oldman 80 (May 7, 2012)

Any of you guys aware if they were significant or not, say after thousands of hours exposure to them.


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## Hugh Wilson (Aug 18, 2005)

No more than watching your television at home.


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## oldman 80 (May 7, 2012)

Hugh Wilson said:


> No more than watching your television at home.


O.k. BUT

I watch my TV from maybe 10 to 15 feet distance.
PPI's on the other hand, from very close. 
Maybe even say 3 feet from the base ?


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## John Dryden (Sep 26, 2009)

Nurse he,s in in the sparkies cabin again!


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## Hugh Wilson (Aug 18, 2005)

Maybe looking to put in an 'Industrial Injuries' claim.


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## oldman 80 (May 7, 2012)

Hugh Wilson said:


> Maybe looking to put in an 'Industrial Injuries' claim.


I Don't know - I never thought about that.
Depends on the answers I suppose.


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## Satanic Mechanic (Feb 23, 2009)

Do you look like this? - if so you may have a case [=D]


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## Satanic Mechanic (Feb 23, 2009)

R651400 said:


> The eht in early ppi's similar to a TV set was not considered to be troublesome though others may have different ideas.
> Sun tans come from *infra-red waves* and more serious problems emit from radar magnetron microwaves as in the case of leaky mw ovens causing cataracts etc.


Ultra Violet surely


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## avide (Mar 1, 2013)

In some Russian sets HT voltage of 15kV for CRT tube was stabilised using a ultra high voltage triode GP-5 (ГП-5, 30kV max rated) connected in parallel to that CRT. This triode used to generate some light Roentgen radiation and sometimes was not shielded properly. It was used in Rubin 707 TV set and at least one radar display set. So something's up there. I don't know of any other set that stabilised HT this way.


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## trotterdotpom (Apr 29, 2005)

Yeah, but when did the Russkis ever worry about radiation? Imagine getting your balls fried while watching "The Tsar Has got His Hat On Street" - now that's a headache!

John T


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## Ron Stringer (Mar 15, 2005)

trotterdotpom said:


> Yeah, but when did the Russkis ever worry about radiation?


John,

You may be surprised to know that the "Safe distance" around the antennas of the early satcoms introduced on merchant ships (Marisat and INMARSAT-A terminals) was significantly lower under the requirements of the USSR than for ships of the USA, UK, FDR and other Western nations. It was only after protracted argument at IMO and INMARSAT that the USSR gave way and allowed the less demanding Western proposal for the international standard to be adopted.

Don't remember what 'deal' was done to persuade the USSR to drop their standards and accept the Western proposal.


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## trotterdotpom (Apr 29, 2005)

Yes I am surprised to hear that. Maybe they agreed to stop using uranium in their Chernobyl Class Satcom Domes. 

John T


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## avide (Mar 1, 2013)

You scored a point!
CRT tubes use lead glass to "consume" all x-rays created when electron beam hits the screen. So the only source could be rather HT tube set than a CRT tube itself. Did English and American radar display need more than 10-12kV of HT?

I've seen an CRT radar display with GP-5 triode unshielded (this valve is really bigger than typical octal mini). Maybe a part of its casing was removed. Diagram was the same as in tv set.
You couldn't miss GP-5, look.







Apply a 20 grand HT on anode and it will work like a charm. It wouldn't mind even 25kV either. But at 25kV it'll generate some X-rays of energy similar to these used in medicine diagnostics. 

Fortunately power rectifiers never worked at voltage higher than a few kV, so X-rays produced there were of low energy. So even at this thyratron (>2A, 6kV) nothing more than a thin steel shield was required:







I think that RF radiation from leaking waveguide or transmitter could give more problems than x-rays from display set.

Russians cared about security even to this point that they installed some gates with switches. I've seen it in their high power transmitter Vyaz-M2 (its final stage used two GU-5B valves in push-pull, that gave 5kW to antenna on CW and at least 3kW on AM).








Some service work with final stage of this transmitter - note that casing has been removed prior servicing and whole module slid out. There were "V" connectors similar to those in a 'span.

Sometimes switches were bypassed and other jackets taken away by servicemen because of easier repairing. Maybe that makes big difference.


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## sparks69 (Dec 18, 2005)

I think there was a much greater risk from blue asbestos in the "good old days"


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## ChasD (Mar 27, 2008)

Having recently had cataract surgery to both eyeballs, I have some practical experience, and, being from that generation who measured the magentron output by waving a hand over the open waveguide, I'd venture to suggest that eyeball problems probably had more to do with 25years of tropical sunlight than anything coming out of the radar. 
Not to mention having ears fried by induced voltage in the headphone band !
On the plus side, I - and colleagues I know - seem to have significantly better overall condition than shoresiders of a similar vintage - apart perhaps from glowing a gentle green in a darkened room ! But mebbe thats a sparky thing !(Bounce)


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## cajef (Feb 8, 2012)

After 30 years working for Decca about 75% of that time on installation and service of radars I am not aware of any of my previous colleagues having any sight problems, personally I may glow a bit in the dark and have other bits falling apart but touch wood my eyes are original and still fully functioning even though I have worn contact lenses for nearly fifty years.


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## David Paterson (Nov 1, 2008)

*Radiation from Radar sets in radio roomsI*

I read with special interest your comments on Radiation hazards in radio rooms,I was an R/O on trawlers which nearly all fitted with the Marconi Radiolocator 4 and 4A Radars as the main radar set and a Decca radar as the second set,They were usually positioned next to the operating desk as everything was shoehorned into a small radio room as it was on Tugs which I sailed on later. Both I and friend of mine suffered with prostate cancer I had the operation to have it removed but sadly my friend died as a result of his. I would be interested to know if any other R/O,s had got prostate cancer .??


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## BobClay (Dec 14, 2007)

I was at sea for 21 years, 16 of them as a sparks. A few years ago I had a malignant melanoma taken off my back but I'm sure this wasn't due to any form of radio equipment radiation, but good old bronzy rays from our nearby star, uncle Sol.
The closest I can get to blaming radar is working up on the scanner with only shorts on in tropical climes. I'd sue somebody about it, but haven't yet figured out who owns the Sun. ☺


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## trotterdotpom (Apr 29, 2005)

BobClay said:


> I was at sea for 21 years, 16 of them as a sparks. A few years ago I had a malignant melanoma taken off my back but I'm sure this wasn't due to any form of radio equipment radiation, but good old bronzy rays from our nearby star, uncle Sol.
> The closest I can get to blaming radar is working up on the scanner with only shorts on in tropical climes. I'd sue somebody about it, but haven't yet figured out who owns the Sun. ☺


Bob, I'm pretty sure it's Rupert Murdoch .... go gett'im tiger!

Glad to hear things have gone OK with your melanoma - I know a few where it didn't unfortunately.

JOhn t


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