Using The External Bridge - Deepace KC901V Manual

Firstly, test the cable's length with the steps shown in sections 4.3. If cable's ve-
locity coefficient is already known, electric length can also be known by calculating
cable's mechanical length. But it will be less accurate than actually measuring it.
When cable is connected to an antenna which cannot be disconnected easily,
user can follow section 4.3 to test the electric length. But we should choose those
frequency band whose phase variation tendency is steady and the phase-frequency
characteristic curve should be rather straight. In this way, usually the tested electric
length will extend to antenna's feed point. It will be more effective than adjusting the
antenna. If it's able to do the calibration on the end of the feeder, user still can use
such method to maintain the phase plane extended to feed point.
Press FUNC to enter system setting interface. There is an item "Cable data". En-
ter the testing result above into "Cable Length".
"Cable attenuation" means antenna's single attenuation in "Cable frequency".
The best way to measure cable attenuation is using S11. But since we are in an envi-
ronment which we cannot perform the calibration on the other side, usually it's not
able to do S11 measurement. In this time, we need to enter the data which is pro-
vided by the cable's factory. Of course we can also use S11 to measure it in far-end
open circuit. If there is fluctuating in the curve, take wave crest which is near the fi-
nal-expected frequency band and with less attenuation. Pay attention that the read-
ing number should be divided by 2. When the attenuation is unsure, set it as 0.
Once "Cable data" is set, instrument will try to cancel the cable influence with it.
After the measurement is done, reset the parameters in time to prevent mistakes in
future use.
Cable parameter is also effective in S21 measurement.

3.7 Using the external bridge

Press SHIFT + 7 button in FUNC menu, set the "bridge" option to "EXT". Connect
the External Bridge's INPUT to KC901V's Port 2 (at the left), connect the bridge's Re-
flection to Port 1 (at the right). Before measurement must use "User Calibration" to
calibrate. Connect an attenuator if necessary.
Use a high performance bridge can improve accuracy.
3.8 Necessary Preparation
3.8.1 Check battery status before taking the instrument out in the field. Let the
instrument run and observe the reading of voltage meter. If it's over 8.0V, it means
that there is at least half of battery capacity left. In order to avoid that the battery
gone flat by forgetting to turn off the instrument, setting it automatically turn off is
suggested. If user needs it to be operating in the field for a long time, take the power
charger with it. If it's impossible to charge the instrument outside, user can prepare
an external battery pack.
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