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.

"Peter" wrote in
. au:


"Dale Parfitt" wrote in message
...

"Peter" wrote in message
...

"Owen Duffy" wrote in message
...
"Peter" wrote in
. au:

...
I must admit I had assumed that the 269 analyzer display the sign
of the reactance, I will have to reread the ad.

Ah, you were looking for honesty in advertising!

The online guff on the MFJ259B says:
"Read Complex Impedance as series resistance and reactance (R+jX)
or as magnitude (Z) and phase (degrees)."

The MFJ259B definitely does *not* show phase angle or reactance as
negative for cases where X is actually negative.

The same words appear in the MFJ269 online page, so it may also be
a misrepresentation.

I see in the MFJ269 manual, the same pretence over the sign of
phase and reactance. It contains the words "Besides Z, an angle
between zero and 90
degrees is shown. This angle represents the phase difference
between current and voltage at the terminals of the analyzer."

Of course, a phase angle between "zero and 90 degrees" does not
represent
"phase difference between current and voltage at the terminals of
the analyzer" in the case of a capacitive impedance.

Honesty in advertising... think again.

Owen

What was I thinking! I was impressed with what was being claimed.

I will continue with my product research and you can expect me to
float some other manufactures device on this group soon for
comments.

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
Thanks Dale

I have just had a look at the RigExpert site. Look impressive, but the
MFJ269 at about $400US was about my limit.
I think I will take a step back and conduct a more scientific review
of all of the antenna analyzers on offer, there for you should get
sick of my postings over the next couple of weeks/months.
I must say that the ability to save and analyze data on the lap top is
an appealing feature.

Peter,

It helps to identify what you really need from the instrument. The
difficulty in doing that is foreseeing where an unstructured learning
journey might take you.

You will tend to arrive a points where you want to measure something just
beyond your existing capability. If the quest is for pure learning, then
just concentrate on the things that are within scope, and enjoy the
learning.

I admit that it is a bit of an old world view of ham radio, that it is
quintessentially a technical learning activity... but call me a dinasour.

The resolution of sign with the '259B is not a show stopper, but it is a
convenience issue and in the hands of a person with inadequate knowledge,
it is potentially misleading.

TLLC (http://www.vk1od.net/calc/tl/tllc.php) can refer impedance made at
one point on a known transmission line (eg the tx end) to another point
(eg the load end). Of course, uncertainty of the TL parameters
contributes to measurement uncertainty. This technique is ok for one off
measurements, but would be very labour intensive for a sweep with
hundreds of observations.

The ability to calibrate the feedline 'fixture' as part of a VNA
measurement system provides the convenience of measurement referred to
your preferred reference plan. The AIM4170 is (as I understand it) half
of a VNA, but that should be enough to do the same thing.

So, for the advantages of the ham grade VNA over the MFJ259B, you pay
more money, get better measurement resolution (the AD converters have
better resolution than the MFJ259B), have capability for automation of
measurement referred to a convenient reference plane, but... you lose
portability... though there is no reason why a ham grade VNA with a basic
display system couldn't be portable.

Owen

The ability to calibrate the feedline 'fixture' as part of a VNA
measurement system provides the convenience of measurement referred to
your preferred reference plan. The AIM4170 is (as I understand it) half
of a VNA, but that should be enough to do the same thing.

So, for the advantages of the ham grade VNA over the MFJ259B, you pay
more money, get better measurement resolution (the AD converters have
better resolution than the MFJ259B), have capability for automation of
measurement referred to a convenient reference plane, but... you lose
portability... though there is no reason why a ham grade VNA with a basic
display system couldn't be portable.

Owen

The fixture cal is a pretty standard feature of all the ham VNAs (AIM
4170, TAPR VNA, N2PK) whether one or two port devices.

Making it portable is something I've been toying with.. The software is
not that complex (at least for the TAPR VNA), so running it on a PDA
velcroed to the top of the box isn't out of the question. One problem
is that the TAPR VNA is a USB slave, and most PDAs can't be a USB master.

Maybe a small touchscreen netbook? Granted, you're now talking $1000 for
the complete setup, but you'll have a real portable powerhouse, much
like the Anritsu SiteMaster at 1/10th the cost.


http://www.us.anritsu.com/products/S...QSidZ1016.aspx


I've also contemplated making something like a S-parameter test set for
the TAPR VNA (so you can do both directions) with a built in eCal.
Basically just high quality relays and terminations is what's needed.

Another useful add-on would be something that turns the VNA into a
spectrum analyzer (e.g. use the output as the LO to a mixer followed by
a BPF).. There's a lot of other problems with this, though.

On Sun, 16 Aug 2009 11:29:16 +0800, "Peter" wrote:

Hi all

I'm looking at purchasing an MFJ269 antenna analyser and keen to hear
experience of others in this group regarding this or similar analysers.
Appears to be ideal if it is as good as MFJ claim.

I can't provide any info on the MFJ269, but I wonder whether the
MFJ993B automatic antenna tuner might serve a similar purpose, with
two big advantages over the 269. One is that it relies on your
transmitter rather than on an internal RF source so it is less likely
to be overwhelmed by nearby broadcast transmitters; and the other is
that it is also a decent antenna tuner.

The 993B uses some of the same circuits found in the 259. Of course,
there are some things the 269 will do that the 993B won't help with.

73,

Chuck
NT3G

I have an earlier version, the MFJ249 and it works very well.

"Peter" wrote in message
. au...
Hi all

I'm looking at purchasing an MFJ269 antenna analyser and keen to hear
experience of others in this group regarding this or similar analysers.
Appears to be ideal if it is as good as MFJ claim.


--
Peter VK6YSF

http://members.optushome.com.au/vk6ysf/vk6ysf/main.htm

From:
Date: Wed, 19 Aug 2009 Time: 15:45:00

Have a look at the AIM 4170 at http://www.arraysolutions.com/

I have that and a MFJ analyzer.

For a quick antenna adjustment, the MFJ is easier to use.

For in depth analysis, the AIM can't be beat.

If I had only one, I would prefer to have the AIM.


I'll second that. The AIM4170 *is* expensive, especially when you add on
15% UK sales tax (and it took me 18 months to take the plunge), but it
does so much more than the MFJ units.

Instant computer readout, in nice graphical form, of all the antenna
system parameters over any selected frequency range up to 170MHz. They
claim to have interference reduction capability to minimize the effects
of close AM MW signals, but I don't live close enough to an AM
transmitter to test this.

The other nice thing about the 4170 is the ability to control it
remotely. With the 4170 connected to the antenna system in the shack and
controlled by a local PC, it's then possible to remotely access the PC
from a cheapy notebook in the backyard. You can make antenna adjustments
out in the yard and see the effects of the changes immediately, without
having to repeatedly walk back indoors to look at the 4170 PC. This
feature alone has saved me a *lot* of time:

http://homepage.ntlworld.com/wadei/A...Control%20HOWT
O%20-%20090106.pdf

Well worth a look.

--
73
Ian, G3NRW

I have just had a look at the RigExpert site. Look impressive, but the
MFJ269 at about $400US was about my limit.
I think I will take a step back and conduct a more scientific review
of all of the antenna analyzers on offer, there for you should get
sick of my postings over the next couple of weeks/months.
I must say that the ability to save and analyze data on the lap top is
an appealing feature.

Peter,

It helps to identify what you really need from the instrument. The
difficulty in doing that is foreseeing where an unstructured learning
journey might take you.

You will tend to arrive a points where you want to measure something just
beyond your existing capability. If the quest is for pure learning, then
just concentrate on the things that are within scope, and enjoy the
learning.

I admit that it is a bit of an old world view of ham radio, that it is
quintessentially a technical learning activity... but call me a dinasour.

The resolution of sign with the '259B is not a show stopper, but it is a
convenience issue and in the hands of a person with inadequate knowledge,
it is potentially misleading.

TLLC (http://www.vk1od.net/calc/tl/tllc.php) can refer impedance made at
one point on a known transmission line (eg the tx end) to another point
(eg the load end). Of course, uncertainty of the TL parameters
contributes to measurement uncertainty. This technique is ok for one off
measurements, but would be very labour intensive for a sweep with
hundreds of observations.

The ability to calibrate the feedline 'fixture' as part of a VNA
measurement system provides the convenience of measurement referred to
your preferred reference plan. The AIM4170 is (as I understand it) half
of a VNA, but that should be enough to do the same thing.

So, for the advantages of the ham grade VNA over the MFJ259B, you pay
more money, get better measurement resolution (the AD converters have
better resolution than the MFJ259B), have capability for automation of
measurement referred to a convenient reference plane, but... you lose
portability... though there is no reason why a ham grade VNA with a basic
display system couldn't be portable.

Owen

Owen I would never call you a dinasour or should I say from one dinasour to
another! I agree with your sentiments entirely of ham radio being a
technical learning activity.

For me the outlay for any antenna analyzer is significant, but I'm prepared
to pay a bit for the instrument that covers foreseeable needs, but that will
be as you say will cater for measurements just beyond my current capability.

Let the evaluation continue.

Regards

Peter

Ian Wade G3NRW wrote:

The other nice thing about the 4170 is the ability to control it
remotely. With the 4170 connected to the antenna system in the shack and
controlled by a local PC, it's then possible to remotely access the PC
from a cheapy notebook in the backyard. You can make antenna adjustments
out in the yard and see the effects of the changes immediately, without
having to repeatedly walk back indoors to look at the 4170 PC. This
feature alone has saved me a *lot* of time:


I tend to make my SWR readings right at the antenna, whenever possible.
That length of coax to the xceiver will only make it look better in most
cases.

- 73 de Mike N3LI -

Michael Coslo wrote:
Ian Wade G3NRW wrote:

The other nice thing about the 4170 is the ability to control it
remotely. With the 4170 connected to the antenna system in the shack and
controlled by a local PC, it's then possible to remotely access the PC
from a cheapy notebook in the backyard. You can make antenna adjustments
out in the yard and see the effects of the changes immediately, without
having to repeatedly walk back indoors to look at the 4170 PC. This
feature alone has saved me a *lot* of time:


I tend to make my SWR readings right at the antenna, whenever possible.
That length of coax to the xceiver will only make it look better in most
cases.

- 73 de Mike N3LI -

One of the advantages of the 4170 is the ability to calibrate out the
effects of the feedline.


--
Jim Pennino

Remove .spam.sux to reply.

On Sun, 16 Aug 2009 11:29:16 +0800, "Peter" wrote:

Hi all

I'm looking at purchasing an MFJ269 antenna analyser and keen to hear
experience of others in this group regarding this or similar analysers.
Appears to be ideal if it is as good as MFJ claim.

My only complaint is the little switch on the face of the unit that is
depressed to enable measuring UHF SWR. It must be depressed ONLY if
the unit is already powered up. If it is depressed before you power
up, as I understand, some of the solid state parts may burn out when
you power up. The 259 model does not have this problem, as it only
measures up through the VHF range.

Operation is limited in the UHF range of about 415-470 MHz -- you can
only take SWR measurements.

Bob
k5qwg