MFJ-269 Antenna Analyzer experience
Dale Parfitt wrote:
"Peter" wrote in message
Peter VK6YSF
Again- look at the RigExpert A-200A. Batteries seem to last forever, it's
USB upgradable and it DOES resolve the sign of R +/-JX.
Dale W4OP
Or, for a non-handheld device, the TenTec TAPR VNA (Vector Network
Analyzer) works quite well (albeit it, too, has a broadband detector).
I've used it with both the PC software and CocoaVNA on a Mac.
The N2PK VNA has a more narrow band detector, but isn't available as a
off-the-shelf box.
Kind of depends on what you want to do with it. I have a MFJ-269 (and a
259, as it happens), and it's a really handy tool when standing under
the antenna or doing "pruning" and those sorts of things, where you
basically are "spin the frequency knob and look for the dip". I don't
know that I'd use it as a precision measurement instrument to measure
inductors and capacitors. .. BTW, the whole "doesn't show the sign of X"
isn't a big deal in practice. A small bump of the frequency dial shows
that X is either getting bigger or smaller as frequency goes up or down.
If your impedance is varying so fast with frequency that you can't
figure it out, the MFJ isn't for you anyway, since it's a fairly
imprecise oscillator anyway. If you are looking to do precision
measurements of impedance at a bunch of points, as you write them down
or plot them, it's obvious, and, in any case, it's not a great tool for
that.
If you're looking to do something like adjust a phased array, you need
one of the network analyzers. It's a lot better than trying to use this
thing and opens/shorts, etc.
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