The Geiger tubes on these things are 65 years past their expiration dates.
If they can't reproduce the behavior on a modern meter then it's bogus.
Quoting: Anonymous Coward 80833944 The CVD-715 use a Ionization Chamber, not Geiger tubes, as detecting element. AFAIK, these can't expire.
Plenty of other parts in there to go bad after 65 years.
Ionization chambers go bad after about 10 years. They actually get more sensitive with age, which is why old smoke detectors go off all the time.
Do you have any source to back up your disparaging statements? Or you are just making up numbers to discourage discussion of the topic because you dislike it?
Because I have got a real interest in the subject and I have found documentation for all the models of Geiger Meters that appear in these videos, which by the way are still very popular and have plenty of people still using and trading them, without a single mention of parts going bad due to time. I also got the manuals for these instruments and again, no mention about time constraints.
And please, to all who insist in calling these equipment “Geiger counters”, the apparatuses in the videos I have shared are not Geiger counters, these are Geiger METERS, specifically designed to detect Gamma radiation, while Geiger counters are for small / trace radiation sources, their entire measurement range would be the first line of the scale of a Geiger Meter. The CDV-715 was intended for radiological survey in a NUCLEAR WAR AFTERMATH, these are no ordinary Equipment.
Source: Every smoke detector company on the face of the earth and everyone who has owned an old smoke detector.
Seriously, you expect any critical thinker to accept the results of a 65 year old uncalibrated piece of garbage by some clickbaiter on YouTube?
If this equipment was any good, why did the government get rid of it?
Geiger counter... Geiger meter ... Six in one, half dozen in the other. Both basically the same mechanism with different display outputs.
The results these people are getting on the videos should already tell you they're wrong. 1.5+R/hr and anyone holding the meter would be dead in no time.
Besides the fact that Geiger tubes and ionization chambers have a limited lifespan, capacitors inside the units are likely bad, and other parts like wound resistors could be bad, unsealed ceramic capacitors can go bad if exposed to moisture, etc.
Every electronic device has a rating called an MTBF or Mean Time Between Failure. HHS, DHS, CBP, DOT consider radiation detectors EOL at 8 to 10 years. I poked around and found some Chinese Ionization Chamber type radiation detectors with ratings as low as 20,000 hrs MTBF which is approx 2.25 years.
What is the rating on this old civil defense gear? Don't know, don't care, but the fact that you admit to possessing 4 of them that don't work at all and another 4 that don't read the same or won't zero ought to tell you something.
At a minimum they all need to be calibrated although I suspect they all need quite a lot more work than that. I'm usually not one to advocate wholesale replacement of caps but on high precision equipment like this it's absolutely critical that all internal parts are in spec.
