COKEVA 11940C, Operation Note

Page: 13 / 19

Cokeva 11940C Operation Note
8
Instrument Critical Specifications Recommended Model
Spectrum Analyzer Frequency Range: 30 MHz – 1 GHz
HP 8567A (10 kHz – 1.5 GHz)
HP 8568B (100 Hz – 1.5 GHz)
HP 8566B (100 Hz – 22 GHz)
Tracking Generator Frequency Range: 30 MHz – 1 GHz
HP 8444A, Option 059 (100 MHz – 1.5 GHz)
For use with HP 8567A or HP 8568B
Signal Generator Frequency Range: 30 MHz – 1 GHz HP 8656B (0.1 – 990 MHz)
Preamplifier*
Frequency Range: 30 MHz – 1 GHz
RF Gain: 20 dB
HP 8447D (100 kHz – 1.3 GHz)
(Gain >26 dB)
* HP 85685A RF Preselector may be substituted if a spectrum analyzer listed above is used.
Table 3. Recommended Test Setup Equipment
3 ‐ 17. Measurement Techniques
3 ‐ 18. The probe is designed to be held very close to potential radiating points. The plane of the probe tip loops must
be perpendicular to the radiating magnetic field as illustrated in Figure 2. For example, if the seam of an enclosure is
being tested for EMl, hold the probe as illustrated in Figure 7. When measuring the radiation from a coaxial cable,
position the probe tip as shown in Figure 8. The side of the probe with the calibration label should be facing away
from the cable being measured.
3 ‐ 19. The probe may be used as a source in susceptibility testing as described in Section 3 ‐ 11 and Paragraph 3 ‐ 16. In
this application, hold the probe within 1 cm of the electronic circuit component being tested.
4 ‐ 1. OPERATION VERIFICATION
4 ‐ 2. Operation Verification for the Cokeva 11940C consists of the Return Loss Measurement Test included in this
section. Actual antenna factor verification requires a calibrated broadband magnetic field. A return loss measurement
provides a reliable alternate method of determining the probe's electrical integrity. The test is performed over a
frequency range where the VSWR is approximately 1.25:1 for a properly operating probe.
Electrical damage is indicated by any large decrease in return loss (increase in VSWR) as specified in the test.
4 ‐ 3. Probes that fail this test, although damaged, may still detect electromagnetic radiation. In this case, the
antenna factors listed on the unit are no longer valid and the circuitry no longer rejects electric field coupling.
Recalibration of the probe's antenna factors is not possible.