Antenna Measurement Problem

[winglj]

Hi, everyone.

I am now doing some antenna measurement with HP 8510 network analyzer. I also connect the RF signal generator to a extender to do the anechonic chamber measurement.

Every thing is OK while doing bench test for S parameter, but for chamber measurement, the network analyzer always shows that the IF signal overload, even I try to reduce the signal generator output to its minimum (-20dBm).

By observing the receving signal, it seems at lower frequency which the receving signal over -10dBm (I am not sure, but the network analyzer shows channel 'a' is -10dB), the IF will overload.

My question is whether I need to add a 10dB attenuator to the extender to overcome this problem?

Thanks in advance.

 

[sergio mariotti]

I'm not sure... but i think that for antenna measurement, a special set of instruments are needed. I don't rem. the name but it's basically an 8510 but taylored for antenna measurement.

To answer more specifically to your question.... Have you applied the rough law " longer the cables, slower the measurement" ? This topic is well described on Agilent AN1291-1B. Without ad hoc delay lines (that are placed on the rear of the 8510 rack), you only perform very slow measurement ( i.e. 20 sec for 20 meter log cables)