Measuring Inductors And Capacitors - AEA CIA-HF Operating Manual

4. Begin cutting inch-long pieces off of the unterminated end of the phasing line. The resonant
frequency of the SWR curve will increase as the line is shortened.
5. As the SWR dip descends lower in the plot, shorten the cuts to ¼ inch long. This allows you
to finely tune the line. In addition, use the WIDTHq key to increase the display resolution.
Use the F4 softkey to zoom in on the dip. Once the SWR reaches a minimum, your antenna
is tuned.
6. Repeat this process for the second phasing line. It is imperative that the bottoms of the two
SWR curves are aligned on the same frequency. If the bottom of one of the curves is at 0
over a narrow group of frequencies, average the two extreme frequencies where the SWR is
at a minimum.
¼ Wave Shorting Method
1. Enter 2 1 2 5 0 ENTER to set the center frequency to 21.250 MHz.
2. Use a very sharp ice pick to short through the coax cable.
3. Determine the position that produces the lowest SWR point at the center frequency. Cut the
cable at this point and install a coax connector. Your cable is now tuned.
4. Repeat this process for the second phasing line.
You can also use the ½ Wave Cutting or ¼ Wave Shorting methods described above to tune
phasing lines any number of degrees for a particular frequency. For example, if you want to cut a
transmission line for 21° at 3.795 kHz, simply use the following equation to determine the
frequency for 180°:
Since 21° at 3.795 kHz is equivalent to 180° at 32.529 MHz, simply use the ½ Wave Cutting
Method to tune the line for 32.529 MHz.

MEASURING INDUCTORS AND CAPACITORS

When measuring inductors and capacitors, it is highly recommended that you assemble an
accessory connector to maximize Analyzer accuracy. To do this, solder one end of a 50-ohm
resistor onto the center pin of a coax PL-259 connector. Then, splice an alligator test lead to the
resistor; solder a second test lead to the connector shell (Figure 3).
For best results, when determining the value of an inductor or capacitor, take measurements at
the frequency where the Reactance of the load is equal to the 50-ohm resistor in the accessory
connector.
180 x 3.795 = 32.529 MHz
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FIGURE 3. 50 OHM ACCESSORY CONNECTOR
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