CD V-715 and CD V-717 Survey Meters

The CD V-715 Survey Meter

Family of CD V-715s

The CD V-715 was the most widely produced of all the Civil Defense radiation instruments with a total of 567,457 instruments produced. As far as I know Lionel, Victoreen and Landers Frary & Clark were the only manufacturers of the CD V-715. Here are 5 examples of CD V-715s. From left to right at bottom of photo, Lionel Model 1, Lionel Model 1A,Landers Frary and Clark Model 1A. The top row in the photo, Victoreen CD V-715 Model 1A and Victoreen Model 1B. Yeah, I know, they all look exactly the same.

The CD V-715 and CD V-717 are very high-range gamma radiation detecting instruments. THESE ARE NOT GEIGER COUNTERS!
To see the detecting range difference between the CD V-715 and the CD V-700 click here

The CD V-715 is a high range gamma survey meter for general postattack operational use. The ranges of this instrument are 0-0.5, 0-5, 0-50 and 0-500 roentgens/hour.

When properly calibrated, the response of this instrument is within the range of plus or minus 20 percent of the true gamma radiation dose from a Cobalt 60 or Cesium 137 radioactive source.

This instrument was designed for use by radiological monitors for the major part of their operation in the period following an attack. The instrument is primarily for surface monitoring survey but it can serve as supplemental equipment for aerial measurements. (continued below following photo)

Inside The CD V-715

Pictured above are a Landers Frary & Clark Model 1A and Victoreen Model 1B. The CD V-715 consists of a ion chamber detecting element, power supply, electronic circuitry to amplify the minute current from the detector, and a indicating meter. The detecting element of the the CD V-715 is an ionization chamber. (Click Photo To See Larger)

The CD V-710 medium range 0-50 r/hr gamma survey meter, which is similar to the CD V-715 except for it's range, and the CD V-720 high range beta-gamma survey meter have been replaced by the CD V-715. The CD V-710 will be phased out and replaced with the CD V-715 as states develop their own maintenance and calibration programs."
(From Radiological Defense Planning & Operations Guide SM-11.23.2 Revised March 1967 )

CD V-717 Survey Meter

CD V-717

The CD V-717 was designed for use in fallout monitoring stations. The CD V-717 has the exact same operating characteristics as the CD V-715 but with an added feature. The CD V-717 has a removable bottom with a 25 foot extension cable. The detector element (ion-chamber) is mounted inside the removable bottom. This allows for the placement of the detector element outside of the shelter area while the metering section of the metering unit would remain inside of the shelter area connected to the detector with the 25 foot cable. The CD V-717 originally had to be specially requested in addition to the other instruments (CD V-700, CD V-715 etc) for issue to use in fallout monitoring stations. The yellow bag is to protect the case bottom from the weather when it is placed outside the shelter area. Victoreen was the only manufacturer of the CD V-717.

CD V-717 open showing detector

Here is the CD V-717 opened up. The case bottom with the ionization chamber detector element can be seen at the left in the picture. Cable reel is at the center bottom with the cables ends hooked up. The case top with metering circuitry at the right of the picture. The CD V-717 operates on a single D-cell battery.

CD V-717 Description From the Radiological Defense Planning And Operations Guide Revised March 1967

CD V-717, remote sensor survey meter, is essentially and CD V-715 gamma survey meter with a removable detector unit for making remote measurements to distances of 25 feet. The ranges of this instrument is 0-0.5, 0-5, 0-50 and 0-500 r/hr. When properly calibrated, the response is within the range of plus or minus 20 percent of the true gamma dose rate from cobalt 60 or cesium 137 when the cable is connected for remote sensor use. The instrument response is within plus or minus 5 percent of the meter indication when the cable is not in the circuit. This instrument is for use by radiological monitors in monitoring stations during the early period following a nuclear attack. The instrument was designed to decrease the radiation exposure to the monitor by enabling to obtain outside dose rate readings while utilizing the protection of some portion of the structure.
(A webmaster comment: It's interesting to note the difference in the tolerance of plus or minus 20 percent with the cable in the circuit and plus or minus 5 percent without the cable out of the circuit.)

Ruggedized Meter
The metal-cased meter unit seen in these CD V-717 photos was the more durable ruggedized meter and can easily be indentified by the larger black frame around the face of the meter. I have a couple of CD V-715s with these metal-cased meters in them. I have seen comments on-line over the years that these meters being more durable were also to reduce EMP (Electromagnetic Pulse) effects on the internal electronics of the instrument. I haven't found any information about the metal-cased meter's effect on EMP in any of the FEMA/Civil Defense documents that I have. The FEMA CPG 4-1 Volume 3 states that "The CD V-717-1 uses a ruggedized metal-cased meter to meet the instrument requirements for water-tightness, shock, and vibration resistance." The parts substitution chapter in FEMA CPG 4-1, Volume 10 states that "The metal cased meter used on the CD V-717 model 1 may be used to replace any CD V-715 or CD V-720 meter where a more durable meter is desired." This reads to me like the CD V-717 was the only instrument originally equipped with the metal cased ruggedized meter. No mention of EMP though.