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USING YOUR ANTENNA ANALYZER
Many have purchased an antenna analyzer. Some expensive, some real expensive. How can you use your device to better know what your
antenna is doing?
Your antenna system is not only the antenna. The electrical measurements include the feedline and grounding. A change in length
in feedline will change the measurements of the antenna. A change in grounding will do likewise. Therefore, how can you determine
what the measurements are of the antenna from the radio end of the feedline using your analyzer?
The readings of Impedance(Z), Resistance(R) and Reactance(X) will NOT be a direct reading of the antenna at the radio end of the
coax.
Of course, the most technical way to measure is with a Smith Chart. This chart is not hard to use, but it is inconvenient. Can you use
the readings on your analyzer to come close? Of course.
SIMPLIFIED MEASUREMENT
1. Measure the SWR with the analyzer at the radio end of the coax.
2. Scan frequency up or down to find the lowest SWR reading.
3. You have two values from this. This being your resonant point, you may have to adjust the antenna impedance because it did not go
to 1:1.
4. One value is to multiply the SWR value times 50.
5. The second value is to divide the SWR into 50.
6. For example, a 2:1 SWR minimum could be 100 ohms at the antenna or 25 ohms.
7. Now you can make the Resistance change (X=0) on the antenna. Now you have limited your guessing to two choices.
*AEA ANALYZER
(VIA ANALYZER)
This could apply to other analyzers also.
1. Set F5 to S. This is SWR.
2. Set F3 to SWR: RL:. Not necessary for other analyzers.
3. Scan the area of the band you are looking for and locate minimum SWR.
4. Set the F3 to "Normalized". Not available on some analyzers.
5. Use the Freq. to move up or down in frequency to locate the minimum "j".
6. On other analyzers this is the "X" or reactance value.
7. j0 means zero reactance or "X".
8. It may not show up on the frequency you found the lowest SWR.
9. On the AEA analyzer, it may not go completely to j0.
10.With the AEA analyzer, multiply the Z value times 50.
11. On other analyzers, use the Resistance (R) scale and read it direct. It will be close to the Radiation resistance of the antenna
with all you have connected.
This will let you understand your analyzer without running out to the antenna. However, it does not promote good exercise.
73,
Ralph WD0EJA
10-18