TB 9-6625-1932-24
NOTE
Perform steps listed below for all TIs which marginally pass (1)
through (11) above.
Perform (12) through (25) below for coaxial TIs with frequency
range between 10 MHz and 18 GHz.
Perform (26) through (35) below for waveguide TIs with
frequency range up to 18 GHz
Perform (36) through (46) below for waveguide TIs with
frequency range between 18 and 26.5 GHz.
Perform (47) through (58) below for waveguide TIs with
frequency range between 26.5 and 40 GHz.
(12) Connect equipment as shown in figure 3.
(13) Adjust programmable sweep generator CW-F1 frequency controls to first
cardinal test point frequency determined in 7 c above.
(14) Adjust programmable sweep generator LEVEL output controls to +3 dBm.
(15) Allow equipment to warm-up for 1 hour before proceeding to (16) below.
NOTE
Do not perform (15) above when repeating procedure for
remaining cardinal test point frequencies.
(16) Establish a 0.00 dB reference on receiver system at cardinal test point frequency.
NOTE
Ensure receiver system is in measurement mode.
(17) Disconnect fixed short from equipment setup (fig. 3). Record receiver system
readout indication (to include the + or - sign).
(18) Zero power meter No. 1 and connect TI to VSWR bridge No. 1 (No. 2). Record
receiver system indication.
(19) Perform (20) below if value recorded in (17) above is - (negative), or (21) below if
value recorded in (17) above is + (positive).
(20) Divide value recorded in (17) above by 2. Invert sign and add to value recorded
in (18) above. Record sum as return loss.
EXAMPLE A: If value of (17) above is -1.425.
(a) Divide -1.425 by 2 = -0.712.
(b) Invert sign of -0.712 = +0.712.
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