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[TowerTalk] MFJ-259B vs Vectronics 584B ?

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Subject: [TowerTalk] MFJ-259B vs Vectronics 584B ?
From: W8JI@contesting.com (Tom Rauch)
Date: Fri, 2 Feb 2001 22:40:43 -0500
I'm not sure what the Vectronics thing does, but I'm sure it is 
mostly a software change and manual. What was done is beyond 
me, but I'll try to find out.  
 
> It invites you to calculate by saying "the Magnitude of the impedance
> [Z) is the square root of the addition of square of the resistance (R)
> and the Reactance (X).  By considering the definition of Z and by
> adjusting the TUNE knob until the lowest SWR reading is obtained, it
> is possible to read the antenna's pure reactance."  So I guess

Hmmm. I don't know what someone was trying to say there.
 
> I understand the MFJ 259B will tell you the reactance (X) and the
> Phase (+j or -j).

You get the individual amounts, but it does not pretend to know! 

Most other analyzers that claim to give the sign of reactance. They 
mostly make a guess.

If you have a quarter, flip it and call heads inductive and tails 
capacitive. It will be as good as the displayed sign when you are on 
an antenna with most analyzers.
 
> Conclusion:  The $149 Vectronics model is not an MFJ 259B.  Sorry to
> break the bad news.  However, it looks like it would be a big help
> adjusting antenna length, tuning stubs, finding shorts and opens,
> measuring velocity factor and cable loss, testing baluns, measuring a
> capacitor or inductor, and using as a grid dip meter or  frequency
> counter.

Analyzers make poor grid dip meters. The rest they can do pretty 
well. Anything the 259B can do, you can do with a calculator and 
what this sounds like it tells you. The 259B just does all the fancy 
stuff in software.

I like the 259B, because I can barely add and subtract numbers 
more than ten without a calculator. And I know how to get the 
sign....I just add a T connector and through a cap or inductor 
across the open port to see if Z increases or decreases.


73, Tom W8JI
w8ji@contesting.com

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