Downloaded from https://www.everyspec.com MIL-STD-1311D METHOD 1216A BASE MATERIAL INSULATING QUALITY 1. Purpose. This test is conducted to classify the insulating quality of base material. 2. Apparatus. a. 100 MHz Q meter; Boonton 190A, or equivalent, with external coil. This coil shall be so constructed that with it and the empty adapter connected to the Q meter (see procedure) it will have a minimum Q of 250 at 100 MHz and the Q meter will have sufficient range to retune to 100 MHz with a base inserted into the adapter. b. Base adapter (figure 1216-1). c. Distilled water bath. d.
Eight pin octal bases molded from the base material being classified and with the pin and index guide dimensional limits of group 1 of EIA-209-A. e. Noninductive calibrating resistors; International Resistor Company Type F metallized high frequency resistors, or equivalent. 3. Procedure. a. Immerse the base in a 50 ° C minimum distilled water bath. b. After 48 hours immersion, remove base from bath and dry with a 2 to 5-minute air blast. c. Attach the base adapter to the C terminals of the Q meter by means of the terminals composed of the two parts No. 4 of figure 1216-1 and attach the external coil to the L terminals of the Q meter.
Odd numbered pins of base adapter shall be connected to one C terminal, even numbered pins connected to the other C terminal. d. Insert the base under test into the adapter and tune to 100 MHz noting the resulting meter reading. Next, remove the base from the adapter and insert several calibrating resistors into the fuse clips, one at a time, and note the meter reading for each when tuned to 100 MHz. From this series of readings, a curve of resistance versus Q is drawn from which the equivalent resistance of the base may be determined. 4. Resultant measurement. a. The following tabulation specifies appropriate zone number for various resistance ranges: Resistance range (ohms) Zone No.
0 to 5,500 ............................................. 1 Over 5,500 to 8,500 ............................................. 2 Over 8,500 to 10,000 ............................................. 3 Over 10,000 to 12,500 ............................................. 4 Over 12,500 to 15,000 ............................................. 5 Over 15,000 to 20,000 ............................................. 6 Over 20,000 to 25,000 ............................................. 7 Over 25,000 to 32,000 ............................................. 8 Over 32,000 to 40,000 ............................................. 9 Over 40,000 to 50,000 .............................................
10 Over 50,000 to 75,000 ............................................. 11 Over 75,000 to 100,000 ............................................. 12 Over 100,000 to 150,000 ............................................. 13 Over 150,000 to 250,000 ............................................. 14 Over 250,000 ............................................................... 15 METHOD 1216A 1216-1 25 March 1970