Tektronix NetTek YBT250, Руководство пользователя

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Locating Interference
YBT250 Field Transmitter & Interference Tester User Manual
3- 65
NOTE
. To make accurate measurements of the forward link signals,
use a receive antenna with a frequency response and bandwidth that
is appropriate for the channel you are measuring. Use a high quality,
low-loss Band Pass Filter (BPF) to reject signals outside the signal
band. If you take measurements near a high-power transmitter, such
as commercial TV or radio, a BPF may be necessary for the scanner
to produce useable results.
To enter the attenuation values of the antenna, filter, and connecting
cable:
1. Tap the Edit button.
2. Tap the Input tab.
3. Enter the total cable, antenna, and/or BPF dB attenuation loss
value in the
Attenuator Loss field.
4. Tap the OK button.
EMF Cable/Antenna Factors
The YBT250 requires two system-dependent numeric factors to
make the correct EMF calculations; cable loss factors and antenna
factors. These factors are stored in separate ASCII files.
The antenna factor represents a conversion between the field strength
seen by the antenna and the power measured by the instrument, at
specific measurement frequencies. Without an antenna factor defined
at the measurement frequency, you can only measure power in dBm.
The cable loss is important for accurate measurements. Without
accounting for cable attenuation, you will still be able to measure
field strength, but the instrument warns you that the results would be
more accurate with a cable loss value defined at the measurement
frequency.
Of these two factors, the antenna factor table has more impact on
measurement accuracy than the cable loss factor table. If you can
only create one table, create the antenna factor table.