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Discussion in 'CB Antennas' started by ctvanover, Oct 18, 2011.
MFJ Enterprises Inc.
Hey ctvanover, if you put your 259b in the feed line at the same exact point as your inline meter, how does the SWR compare on the two meters?
Make sure you check at the same frequency, use the same power, and that the jumper used with the inline meter is as short as possible, or if possible add the jumper length to the feed line using a barrel connector...when checking with the analyzer.
Don't think the 259B or any other analyzer can crank out more than a few milliwatts. I agree with checking at the same frequency and with the same arrangement of feedline.
That instruction manual is a necessity, and so is reading and understanding it! The root of the whole thing is understanding that impedance (Z) is a combination of both resistance(R) and reactance (X), or, Z = R + X. An SWR meter only reads 'Z', it can't tell you anything about 'R' or 'X', just the combination of those two things. The 'catch' to that is that there's an infinite number of 'R's and 'X's that can in combination can equal any particular SWR reading. The higher that 'X' is, the worse the antenna will behave because reactance 'X' doesn't contribute to radiating anything. It's what causes power to be reflected. Another 'catch' is that a typical antenna will almost never have an input resistance 'R' that will be the 50 ohms that's normally desired. It may be 'close', which will certainly work, but don't expect it to be 50 ohms exactly. (One reason why an SWR of 1.5:1 is considered acceptable!)
The biggest problem with all this is that the importance of SWR has been blown way out of reason. It is NOT the 'end all' of tuning antennas. It's only a very inexact indication of things.