User Manual

SARK-110-ULM User’s Manual

Rev 1.0 June 22

Since the precise cable length is not normally known in advance, there is a procedure to get the

cable length as follows. As a precondition the cable must be unterminated at the far end. Select

Smith chart mode and set a wide sweep frequency range. The Smith Chart will show a spiral

from infinite impedance and going towards the center. When setting negative length values, this

spiral will be progressively unrolled and transposed to the infinite impedance point when the

exact length will be set. Then, if a load is connected at the cable far end, the presence of the

transmission line will be discounted.

The screenshots below show an example of this in operation. A line of 28.2m of RG-58C/U coax

cable is unterminated at the far end. The first screenshot shows the measurement without

applying the TL compensation and the last screenshot shows the measurement once the

subtract feature has been applied.

4.2 Circuit Models

The SARK-110-ULM provides advanced analysis features, including the automatic determination

of the circuit models of small loop antennas or coils, capacitors and quartz crystals. It is also

capable of automatically determining different parameters having to do with transmission lines.

It is essential that the analyzer is calibrated before each measurement for accurate results when

using these functions. The open, short and load calibration loads have to be connected to the