[TowerTalk] MFJ-259B vs Vectronics 584B ? DE K0FF

[K0FF]

----- Original Message -----
From: <K4IA@aol.com>
>
> I got mine yesterday.  Comparing it to the MFJ catalog description, it
looks
> like the Vectronics model is an older and less sophisticated version of
the
> MFJ 259B.  > might be comparable to the original MFJ 259.

**Looks very similar to my MFJ 259. SWR and Resistance only. 1.8-170, can be
easily modified for BCB and lower. A very good all around general purpose
test unit.  'FF

>
> > I understand the MFJ 259B will tell you the reactance (X) and the Phase
(+j
> or -j).

**Neither the 259B or the 269 tell you the sign. They simply measure the
reactance, and calculate the other parameters (J, L, C) from that. THey
can't distinguish an inductor from a capacitor.
Even though they are still only 50 Ohm bridges, they will calculate SWR etc.
as if they were other values i.e. 75, 450 for dircet readout. Reportedly the
269 uses a higehr resolution A to D converter.
Only the Autek VA-1 will give the sign ( and the AEA I think), but
truthfully, in those instanecs where this information would be helpfull,
e.g. analyzing a tower or a long wire for use as a 160 antenna, all these
instruments are usless duee to BCB interference. Mixed results are reported
by those using the Analyzer Filter and other schemes to remove the BCB-I.
'FF
>
> 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.
>
** Concenses is that the dipper is usless, but otherwise, you can make a
myriad of mesurements with this type of simple unit, and interpolate other
parameters with a sharp pencil.

Truth be, if you want to accuratly measure return loss, use a return loss
bridge, If it's parralel reactance you need to know, break out an Rx meter.
A real grid dipper like the old Megacycle Meter is still to be bested. "Q"
can best be read on a "Q" meter, etc.

My r.f.  test bench is a conglomeration of inexpensive old tube type gear,
and a few modern units for portability.

Happy Homebrewing, Geo>KØFF
http://homepages.dstream.net/K0FF



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