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Old August 19th 09, 01:33 PM posted to rec.radio.amateur.antenna
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Default MFJ-269 Antenna Analyzer experience


"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.

Regards

Peter VK6YSF

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



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Old August 19th 09, 04:45 PM posted to rec.radio.amateur.antenna
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Default MFJ-269 Antenna Analyzer experience

Peter wrote:

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.

Regards

Peter VK6YSF

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


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.


--
Jim Pennino

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Old August 20th 09, 04:09 PM posted to rec.radio.amateur.antenna
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Default MFJ-269 Antenna Analyzer experience

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
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Old August 21st 09, 02:51 PM posted to rec.radio.amateur.antenna
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Default MFJ-269 Antenna Analyzer experience

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 -
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Old August 21st 09, 04:30 PM posted to rec.radio.amateur.antenna
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Default MFJ-269 Antenna Analyzer experience

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

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Old August 21st 09, 07:27 PM posted to rec.radio.amateur.antenna
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Default MFJ-269 Antenna Analyzer experience

From: Michael Coslo
Date: Fri, 21 Aug 2009 Time: 09:51:05

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 -


Mike,

With the 4170 I can calibrate the instrument to compensate for the
feeder impedance. After calibration, the indicated impedance at the TX
end of the feeder is actually the antenna feedpoint impedance. This
makes life a *lot* easier.

--
73
Ian, G3NRW
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Old August 21st 09, 08:05 PM posted to rec.radio.amateur.antenna
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Default MFJ-269 Antenna Analyzer experience

Ian Wade G3NRW wrote:
From: Michael Coslo
Date: Fri, 21 Aug 2009 Time: 09:51:05

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 -


Mike,

With the 4170 I can calibrate the instrument to compensate for the
feeder impedance. After calibration, the indicated impedance at the TX
end of the feeder is actually the antenna feedpoint impedance. This
makes life a *lot* easier.


Oaky, well good enough. My vertical uses a stub on the feedline, so I
have to be out there anyhow.with a connector in the line. Seems like 6
of one, half dozen of the other situation.

- 73 De Mike N3LI -
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Old August 22nd 09, 06:58 AM posted to rec.radio.amateur.antenna
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Default MFJ-269 Antenna Analyzer experience

From: Michael Coslo
Date: Fri, 21 Aug 2009 Time: 15:05:13


Oaky, well good enough. My vertical uses a stub on the feedline, so I
have to be out there anyhow.with a connector in the line. Seems like 6
of one, half dozen of the other situation.

- 73 De Mike N3LI -


Agreed. But I guess your antenna feedpoint is more-or-less at ground
level. That's a little different from peering through binoculars at an
MFJ suspended at the feedpoint 50ft above ground .... grin

--
73
Ian, G3NRW
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Old August 21st 09, 11:44 PM posted to rec.radio.amateur.antenna
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Default MFJ-269 Antenna Analyzer experience

Ian Wade G3NRW wrote:

Mike,

With the 4170 I can calibrate the instrument to compensate for the
feeder impedance. After calibration, the indicated impedance at the TX
end of the feeder is actually the antenna feedpoint impedance. This
makes life a *lot* easier.


Easy, yes. But If you're not careful, this can be a great example of
garbage in, garbage out.

I frequently calculate out the feedline transformation when making
antenna measurements. But it's essential that you realize a small error
in estimating the feedline loss(*) or length can sometimes result in a
very large error in calculated impedance. This is particularly true if
there's a large impedance mismatch between the line and antenna.
Transmission line impedance, which can vary a lot from the specified
nominal value (I've seen +/-20% with coax, more with ladder line), also
has an effect on the result. So whenever I need accurate results or
whenever the line Z0 is quite different from the antenna impedance, I
start by carefully measuring the properties of the actual transmission
line I'll be using.

If you're not convinced, spend a few minutes playing with something like
N6BV's TLW calculator that comes with the ARRL Antenna Book.

(*) Some simplified techniques ignore transmission line loss altogether.
This can lead to very inaccurate results in some situations. And loss is
often quite different than the specified value, so it really has to be
measured if it makes a significant difference.

Roy Lewallen, W7EL


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Old August 22nd 09, 12:00 AM posted to rec.radio.amateur.antenna
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Default MFJ-269 Antenna Analyzer experience

Roy Lewallen wrote:
Ian Wade G3NRW wrote:

Mike,

With the 4170 I can calibrate the instrument to compensate for the
feeder impedance. After calibration, the indicated impedance at the TX
end of the feeder is actually the antenna feedpoint impedance. This
makes life a *lot* easier.


Easy, yes. But If you're not careful, this can be a great example of
garbage in, garbage out.

I frequently calculate out the feedline transformation when making
antenna measurements. But it's essential that you realize a small error
in estimating the feedline loss(*) or length can sometimes result in a
very large error in calculated impedance. This is particularly true if
there's a large impedance mismatch between the line and antenna.
Transmission line impedance, which can vary a lot from the specified
nominal value (I've seen +/-20% with coax, more with ladder line), also
has an effect on the result. So whenever I need accurate results or
whenever the line Z0 is quite different from the antenna impedance, I
start by carefully measuring the properties of the actual transmission
line I'll be using.

If you're not convinced, spend a few minutes playing with something like
N6BV's TLW calculator that comes with the ARRL Antenna Book.

(*) Some simplified techniques ignore transmission line loss altogether.
This can lead to very inaccurate results in some situations. And loss is
often quite different than the specified value, so it really has to be
measured if it makes a significant difference.

Roy Lewallen, W7EL


The 4170 makes this a lot easier as you can measure the feedline actual
parameters as well as calibrate out their effects.


--
Jim Pennino

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