Hi, Today I want to tell you a little bit about an iconic soviet Geiger counter which is probably most famous for being used during the Chernobyl accident clean-up, the DP-5V.
It is primarily made out of a very strong, military-grade, green plastic. Some people love the colour while others hate it. I personally am somewhere in between.
The unit measures 19x17x8cm (with caring case) and weighs around 3kg. The cable connecting the Geiger counter with the probe is fixed and measures around 115cm which allows for moving the probe comfortable.
Unlike its older brothers, DP-5A and DP-5B, this Geiger counter doesn’t require the user to set the correct voltage manually before use. This means it is simpler and quicker to operate.
To power on the unit we simply need to turn the selector switch that is located on the right-hand side. Just like in polish DP-66M, the first position means the unit is turned off, the second is a battery test, the third is 200 R/h scale (bottom scale), the fourth is the upper scale in mR/h x1000, the fifth is the upper scale in mR/h x100 and so on until the eighth position which is x0.1.
The rotary switch is very hard to move which prevents the user from accidentally switching to a different scale. This being said, in my opinion, it is way too hard to move and I feel that I could break it just by switching from one scale to another. I much more prefer the selector switch on my Ludlum.
The scale on this unit, as well as the area around the selector switch, is covered in luminance paint (it is not radioactive like in DP-63-A). Unfortunately, since these units are pretty old, the glow does not last for very long. There are also two small light bulbs that can light up the display if we would be taking measurements in a dark environment. Turning the light on is done simply by flipping the switch on the left side of the unit.
Since this is a military Geiger counter, it is waterproof, however, I would still suggest you keep it away from a wet environment because the seals are old and can leak water inside!
Calibration can be done very easily by adjusting potentiometers after opening the unit.
One very annoying thing about this meter is the fact that it runs on obsolete soviet batteries. Luckily, it is fairly easy to make adapters for AA batteries using cardboard and some aluminium foil or to bend the contacts. The unit runs on 2 batteries while the third one is used to power on the light bulbs.
Another negative thing about this meter is its very small display which measures only 5x3cm compared to DP-66M’s 7.5x4cm or to Ludlum’s 6×3.8cm. The display on DP-5V also seems to be placed pretty deeply which makes the viewing angle much more narrow.
There is a headphone out but it uses a weird, obsolete connector which means that you can only connect the original headset to it. Sadly, mine did not come with the headset so I decided to make my own speaker using 2x screws, a buzzer with a generator and Polymorph plastic.
On the bright side, the needle moves smoothly and doesn’t jump around like in Universal Radiation Meter Model 1700.
The DP-5V has two Geiger Muller tubes, an STS-5 for the lower range and a SI3bg for higher. The beta window has an area of around 3cm^2 which allows more particles to hit the tube making the unit more sensitive.
Originally, these units came with B-8 Strontium 90 check source, however, mine had its removed.
Wrapping things up, this unit is a solid Geiger counter and is a great choice if you are just starting out or you are looking for something with more Cold War vibe.