Cable loss

The setting of the CMU200:
1. Press “ RESET ” button to reset the machine.
2. Press “ Connect Control ” button, press the “AF/RF ” button and set as follows:
RF TX Output: Scroll to “ RF3 OUT ”
Ext. Att. Output: 0dBm
RF Input: Scroll to “ RF4 IN ”
Ext. Att. Output: 0dBm
Press “Connect Control ” button again to go back to the spectrum screen.
3. Activate the spectrum function of the CMU200: Press the “ Menu Select ” button, and press “ Basic
Function ” button Press” RF ” Press “ Spectrum. ”
4. Press “Menus ” button, and then press “ Spectrum.”
5. Press “Analyzer Level ” button and set the following value:
“ Reference level ” : 0 dBm
“ RF mode ” : Manual
“ RF attenuation ” : Normal
“ Trigger Source ” : Free Run
6. Press “ Analyzer Setting ” button and set the following value:
“ Center ”: 900/1800MHz, for a EGSM band measurement.
“ Span ”: 50 MHz
“ RBW ”: Auto
7. Press “ Generator ” button and set the following value:
“ RF Level [ON] ”: Press “ ON/OFF EXP/CMP ” button to make sure the signal is on, and set the power level as 0dBm.
“ Frequency ” : 900/1800MHz, for a EGSM band measurement.
“ Modulation ” : Off
8. Press “ Marker ” button and press “ Ref [R] [ON] ” button. Press “ ON/OFF EXP/CMP ” button to make sure the marker is on and then press 900/1800MHz to set the marker at the specified frequency.
To measure the cable losses, connect cables as follows at the RF3 & RF4 ports of the CMU200:
1. Connect two 10dB attenuators at the RF3 & RF4 respectively.
2. Connect two ends of one cable to RF3 & RF4, write down the loss as L1.
L1=0 – value read by the marker
3. Connect the cable that we want to measure cable loss together with the cable in the last step at RF3 &
RF4, write down the loss as L2.
L2=0 – value read by the marker
4. The measured cable loss would be L2-L1
Value read on CMU200
Freq(MHz) 900 1800
One RF cable -20 -20.4
Two RF cables -20.3 -20.8
Three RF cables -20.6 -21.2
Freq(MHz) 900 1800
Cable loss measure with a