You are partially correct regarding the use of the cable making the needle movement slow but it is not due to it not being calibrated but just it being much slower at registering the dose. According to the manual it can take up to 2min for the 0.1x setting to register an accurate measurement, think it was 40sec for the x1 and a few seconds for x10 and x100.

@Weaponsandstuff93

3 жыл бұрын

Ah that makes sense thank you, I need to watch your video on it, didn't actually read all the manual as most of it is just the 715 manual. Weirdly the Soviet DP-3B with a similar length cable has no time issues what so ever regarding giving instant readings.

The CDV-717 manual states "The time to obtain a satisfactory dose rate indication is considerably increased when using th cable with the remote detector. Allow at least 4 minutes for the meter to reach a steady value when using x0.1 range, 50 seconds when on x1 range, and 9 seconds on the other two ranges" Hope this helps.

@Weaponsandstuff93

3 жыл бұрын

Cheers I was told this by someone else just now lol, I'll mostly use this with the ion chamber attached anyway. I wonder why this is fairly slow with the cable in use where as for example the Soviet DP-3B is pretty much instantaneous, might just be because the 3B runs at 26 volts...

@maxjohnson8582

3 жыл бұрын

Its because of the ion cahmbers ridiculously low opertaing current of around 6 micro amperes. The ion chamber runs at 50v and 6 micro amps (0.3 watts)

@Weaponsandstuff93

3 жыл бұрын

Very interesting, thanks for that.

Hmm... Wasn't expecting the cdv 717 to do that... In theory, the cdv 715 said it w as 500+ roentgen. As you said it was a calibration error. Hopefully the seller didn't say it was calibrated!

@Weaponsandstuff93

3 жыл бұрын

Nah it was the 720 that said 500R, the 720 has a beta plate on the bottom, which was too expensive to mass produce so the 715 and 717 did away with that. However it means the 720 can pick up SR90 etc when the 715 can't etc. And no lol I've never seen anyone claim an old device like this to still be calibrated, I'm amazed how well they still work seeing as they were made about 60 years ago.

@jlp1528

3 жыл бұрын

@@Weaponsandstuff93 some of the CDV-700 units are calibrated, though usually not recently. Of course, those are Geiger counters, which are much easier to calibrate than ionization chamber units.

@Weaponsandstuff93

3 жыл бұрын

Yeah there are those cool 700s with the new tubes that make them x10 the original ranges, so a lot more practical.

@jlp1528

3 жыл бұрын

@@Weaponsandstuff93 I have one of these, but they are normally pricey! $80, $100+ last I checked. I was lucky to score mine for $60. A very practical modification indeed.

Nice

@Weaponsandstuff93

3 жыл бұрын

Thanks for watching.

isnt the error threshold on the 715 and likely the 717 20% plus or minus actual reading? id have to dig out my box of cdv manuals, lol

I know you put some desiccant in but I wonder if over the years damp can get inside the reel of cable. I think damp is a real enemy for the ion chamber meters.

@Weaponsandstuff93

3 жыл бұрын

Yes moisture totally messes up the readings on ionisation chambers

Where did you get the X-ray device? And where can I get one? Lol

@Weaponsandstuff93

3 жыл бұрын

Ali express, look up "Dental x ray cameras"

I have a cdv 717 about 2 months ago I sent it to Ludlum Measurements to be profetionly calibrated but the meter max out on X0.1 and X1 and on the X10 it is saying that that it is 35 R/hr none of my other meters agree with it. I heard that some of the displays in the 717 can be faulty this mite be the case with my meter, his is seems to have the same problem.

@Weaponsandstuff93

3 жыл бұрын

Only thing I can say is as a few other people have told me, if it's being used on the lead it's much slower to adjust the reading correctly, fine for fallout outside a shelter, not fine for x-ray readings etc. So I'd only really trust the reading when the ionisation chamber is directly connected. Personally if you can get a British MD3 meter I find they are a bit like the CDV-720 but a lot more reliable (Due to being a 1980s retrofit as opposed to a 1960 meter)

@burkevelanovich6358

3 жыл бұрын

These reading are my meter taking back round

I bought a fp 203 filter and i sprayed deodorant and it stoped the smell but i have a question is it 100%safe cause i really would like to use it more but i am a bit anxious

@Weaponsandstuff93

3 жыл бұрын

Yes it's totally safe

@olisiekanski6142

3 жыл бұрын

Thanks for the answer and cool video you made

For a brief moment it was 3.6 Roentgen... Not great not terrible ;)

@chunguslover

3 жыл бұрын

You didn't see graphite BECAUSE ITS NOT THERE

@Weaponsandstuff93

3 жыл бұрын

Just for a moment

@jlp1528

3 жыл бұрын

@@chunguslover Some of the graphite from the first nuclear reactor - Chicago Pile 1 (CP-1) - was cut, engraved, and molded into acrylic blocks for display, which were given to various individuals involved with the project. Sadly, I'm not only fairly sure Chernobyl graphite is too hot for such things, but also that getting my hands on either would be darn near impossible anyway.

@chunguslover

3 жыл бұрын

​@@jlp1528 Interesting, I think you can actually buy CP-1 graphite samples online

@Weaponsandstuff93

3 жыл бұрын

I've seen RBMK (unused) blocks for sale but they're like £3000 so very overpriced, but a cool coffee table I guess. Best thing I have is a Trinitite sample from the Trinity test site.