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Old August 23rd 10, 07:15 PM posted to rec.radio.amateur.antenna
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Posts: 50
Default Antenna analyzers, opinions please...

Antenna Newsgroup Denizens:

Apart from the professional 'lab grade' (and undoubtedly very expensive)
devices made by the likes of Agilent, there are on the amateur market
several antenna analyzers that are more reasonably priced.

I'm currently considering the purchase of such a device, and so...

I'm interested in hearing opinions, pro-con arguments, and/or receiving
pointers to reviews of such devices.

All thoughts and comments will be appreciated, unbiased or not.

Thanks!

-- Pete k1po
-- Indialantic By-the-Sea, FL

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Old August 23rd 10, 08:07 PM posted to rec.radio.amateur.antenna
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Posts: 1,374
Default Antenna analyzers, opinions please...

I have only one comment which applies to most if not all of the amateur
level products, as well as a very high quality HP impedance meter I used
years ago.

I live about 15 miles from hilltops where the local AM, FM, and TV
broadcast towers are. The signals from those stations are strong enough
to overwhelm the broad bandwidth detection circuitry in the analyzers
(and HP vector impedance meter) I've used, resulting in meaningless
readings when connected to an antenna. I find that I grab my MFJ antenna
analyzer for a host of jobs like measuring a ferrite core impedance,
checking the length of a piece of coax, and so forth. But for me it's
just about useless for the job of analyzing actual antennas. When I need
to measure antenna impedance I dust off an old GR bridge and use a
portable receiver for the detector in order to reject the strong ambient
signals.

Of course this isn't a problem for everyone, but it sure is for me and I
don't think my situation is unusual for an urban environment. I've had
to put common mode chokes on my thermometer thermocouple wire, my light
meter connecting wire, scope leads, and even in audio circuitry to keep
the RF out. But even one strong local station might be enough to upset a
typical antenna analyzer.

Roy Lewallen, W7EL

On 8/23/2010 11:15 AM, Peter O. Brackett wrote:
Antenna Newsgroup Denizens:

Apart from the professional 'lab grade' (and undoubtedly very expensive)
devices made by the likes of Agilent, there are on the amateur market
several antenna analyzers that are more reasonably priced.

I'm currently considering the purchase of such a device, and so...

I'm interested in hearing opinions, pro-con arguments, and/or receiving
pointers to reviews of such devices.

All thoughts and comments will be appreciated, unbiased or not.

Thanks!

-- Pete k1po
-- Indialantic By-the-Sea, FL

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Old August 23rd 10, 09:46 PM posted to rec.radio.amateur.antenna
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First recorded activity by RadioBanter: May 2009
Posts: 21
Default Antenna analyzers, opinions please...

I've used Autek Research "RF" and "VHF" Analysts for some time and
they've served my purposes for antennas and testing.

Also Heathkit, Diamond (VHF-UHF) and Daiwa power output & SWR meters
in-line on coax.

Not so important if one uses a Tansmatch or tuner with them built-in.

W5MTV


On 8/23/2010 1:15 PM, Peter O. Brackett wrote:
Antenna Newsgroup Denizens:

Apart from the professional 'lab grade' (and undoubtedly very expensive)
devices made by the likes of Agilent, there are on the amateur market
several antenna analyzers that are more reasonably priced.

I'm currently considering the purchase of such a device, and so...

I'm interested in hearing opinions, pro-con arguments, and/or receiving
pointers to reviews of such devices.

All thoughts and comments will be appreciated, unbiased or not.

Thanks!

-- Pete k1po
-- Indialantic By-the-Sea, FL


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Old August 23rd 10, 10:53 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Aug 2006
Posts: 50
Default Antenna analyzers, opinions please...

Roy:

Thanks for your input on the effects of interference from other
transmitters, especially BC transmitters, point well taken.

I suppose one might add some kind of carefully designed passive filtering to
the devices to 'notch' out offending BC stations, etc...

But... that would be messy and complicated.

Using a bridge with a tuned detector seems a much better approach. I do
have an old MFJ Rx resistance bridge at hand, but I was looking for a little
bit better accuracy. I must check e-bay, etc... for prices for a used
bridge of the GR class you have.

My current problem could likly be solved by using one of my (so-called) VSWR
meters, but I felt I might like to get a little more metrological capability
for a few bucks.

I've never had a vertical antenna before and currently I'm laying out a
radial field under a new vertical antenna. I just wanted to know when to
stop laying down radials.

I figure that I just need to measure the input impedance of the antenna Zin
at my frequencies of interest and record the (hopefully decreasing)
impedance values as I lay down more radials. My assumption is that Zin =
Zant + Rg. where Zant includes the reactance and radiation resistance of
the radiator element at my frequency of interest and Rg is the ground
resistance. Hopefully Rg should decrease as I add raials. I intend to quit
adding radials when the impedance decrease becomes 'negligible' ( In the
sense of received S units [smile]).

Thanks again!

-- Pete k1po
-- Indialantic By-the-Sea, FL


"Roy Lewallen" wrote in message
...
I have only one comment which applies to most if not all of the amateur
level products, as well as a very high quality HP impedance meter I used
years ago.

I live about 15 miles from hilltops where the local AM, FM, and TV
broadcast towers are. The signals from those stations are strong enough to
overwhelm the broad bandwidth detection circuitry in the analyzers (and HP
vector impedance meter) I've used, resulting in meaningless readings when
connected to an antenna. I find that I grab my MFJ antenna analyzer for a
host of jobs like measuring a ferrite core impedance, checking the length
of a piece of coax, and so forth. But for me it's just about useless for
the job of analyzing actual antennas. When I need to measure antenna
impedance I dust off an old GR bridge and use a portable receiver for the
detector in order to reject the strong ambient signals.

Of course this isn't a problem for everyone, but it sure is for me and I
don't think my situation is unusual for an urban environment. I've had to
put common mode chokes on my thermometer thermocouple wire, my light meter
connecting wire, scope leads, and even in audio circuitry to keep the RF
out. But even one strong local station might be enough to upset a typical
antenna analyzer.

Roy Lewallen, W7EL

On 8/23/2010 11:15 AM, Peter O. Brackett wrote:
Antenna Newsgroup Denizens:

Apart from the professional 'lab grade' (and undoubtedly very expensive)
devices made by the likes of Agilent, there are on the amateur market
several antenna analyzers that are more reasonably priced.

I'm currently considering the purchase of such a device, and so...

I'm interested in hearing opinions, pro-con arguments, and/or receiving
pointers to reviews of such devices.

All thoughts and comments will be appreciated, unbiased or not.

Thanks!

-- Pete k1po
-- Indialantic By-the-Sea, FL


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Old August 23rd 10, 11:04 PM posted to rec.radio.amateur.antenna
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First recorded activity by RadioBanter: Apr 2010
Posts: 484
Default Antenna analyzers, opinions please...

On Aug 23, 6:15*pm, "Peter O. Brackett"
wrote:
Antenna Newsgroup Denizens:

Apart from the professional 'lab grade' (and undoubtedly very expensive)
devices made by the likes of Agilent, there are on the amateur market
several antenna analyzers that are more reasonably priced.

I'm currently considering the purchase of such a device, and so...

I'm interested in hearing opinions, pro-con arguments, and/or receiving
pointers to reviews of such devices.

All thoughts and comments will be appreciated, unbiased or not.

Thanks!

-- Pete k1po
-- Indialantic By-the-Sea, FL


i presently have 3 analyzers... an mfj269 which i use for taking up
towers to check antennas when i have doubt about the coax or switch,
checking tuning real quick on anything, and doing simple cable loss
checks. then i have a minivna which i am still learning to use, but
which has proved very helpful in tuning stubs and checking filters.
it also does the tuning checks from the shack but requires a pc for
operation so wouldn't be very useful up a tower. my third one is a
home made tdr, just a decent scope and pulse generator set up to do
tdr on cables from the shack end. indispensable for finding damaged
cables, isolating bad connectors or relay boxes, etc. i wouldn't want
to be without any of them right now.


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Old August 23rd 10, 11:17 PM posted to rec.radio.amateur.antenna
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First recorded activity by RadioBanter: Jun 2006
Posts: 1,374
Default Antenna analyzers, opinions please...

On 8/23/2010 2:53 PM, Peter O. Brackett wrote:
Roy:

Thanks for your input on the effects of interference from other
transmitters, especially BC transmitters, point well taken.

I suppose one might add some kind of carefully designed passive
filtering to the devices to 'notch' out offending BC stations, etc...

But... that would be messy and complicated.
. . .


Yes, it is. I've done it, but a lot of care has to be taken that the
filter doesn't have a significant effect on the impedance being
measured. At best, it usually also restricts you to a relatively narrow
bandwidth. It might be adequate for your particular purpose, however.
But for the job you describe of evaluating a radial system, a simple
homebrew resistance bridge is perfectly adequate. _Solid State Design
for the Radio Amateur_ had some examples, and I assume its successor
_Experimental Methods in RF Design_ does also.

Roy Lewallen, W7EL
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Old August 24th 10, 01:38 AM posted to rec.radio.amateur.antenna
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First recorded activity by RadioBanter: Jun 2009
Posts: 26
Default Antenna analyzers, opinions please...

On Aug 23, 4:53*pm, "Peter O. Brackett"
wrote:
Roy:

Thanks for your *input on the effects of interference from other
transmitters, especially BC transmitters, point well taken.

I suppose one might add some kind of carefully designed passive filtering to
the devices to 'notch' out offending BC stations, etc...

But... that would be messy and complicated.

Using a bridge with a tuned detector seems a much better approach. *I do
have an old MFJ Rx resistance bridge at hand, but I was looking for a little
bit better accuracy. *I must check e-bay, etc... for prices for a used
bridge of the GR class you have.

My current problem could likly be solved by using one of my (so-called) VSWR
meters, but I felt I might like to get a little more metrological capability
for a few bucks.

I've never had a vertical antenna before and currently I'm laying out a
radial field under a new vertical antenna. *I just wanted to know when to
stop laying down radials.

I figure that I just need to measure the input impedance of the antenna Zin
at my frequencies of interest and record the (hopefully decreasing)
impedance values as I lay down more radials. * My assumption is that Zin =
Zant + Rg. *where Zant includes the reactance and radiation resistance of
the radiator element at my frequency of interest and Rg is the ground
resistance. *Hopefully Rg should decrease as I add raials. I intend to quit
adding radials when the impedance decrease becomes 'negligible' ( In the
sense of received S units [smile]).

Thanks again!

-- Pete k1po
-- Indialantic By-the-Sea, FL

"Roy Lewallen" wrote in message

...



I have only one comment which applies to most if not all of the amateur
level products, as well as a very high quality HP impedance meter I used
years ago.


I live about 15 miles from hilltops where the local AM, FM, and TV
broadcast towers are. The signals from those stations are strong enough to
overwhelm the broad bandwidth detection circuitry in the analyzers (and HP
vector impedance meter) I've used, resulting in meaningless readings when
connected to an antenna. I find that I grab my MFJ antenna analyzer for a
host of jobs like measuring a ferrite core impedance, checking the length
of a piece of coax, and so forth. But for me it's just about useless for
the job of analyzing actual antennas. When I need to measure antenna
impedance I dust off an old GR bridge and use a portable receiver for the
detector in order to reject the strong ambient signals.


Of course this isn't a problem for everyone, but it sure is for me and I
don't think my situation is unusual for an urban environment. I've had to
put common mode chokes on my thermometer thermocouple wire, my light meter
connecting wire, scope leads, and even in audio circuitry to keep the RF
out. But even one strong local station might be enough to upset a typical
antenna analyzer.


Roy Lewallen, W7EL


On 8/23/2010 11:15 AM, Peter O. Brackett wrote:
Antenna Newsgroup Denizens:


Apart from the professional 'lab grade' (and undoubtedly very expensive)
devices made by the likes of Agilent, there are on the amateur market
several antenna analyzers that are more reasonably priced.


I'm currently considering the purchase of such a device, and so...


I'm interested in hearing opinions, pro-con arguments, and/or receiving
pointers to reviews of such devices.


All thoughts and comments will be appreciated, unbiased or not.


Thanks!


-- Pete k1po
-- Indialantic By-the-Sea, FL- Hide quoted text -


- Show quoted text -


Hi Pete, If you are evaluating a radial field for a vertical, then
the value you should be shooting for is 30-35 ohms, with no
reactance. As you know this is 1/2 the impedance of a 1/2 wave
dipole-70 ohms in free space. I have never done this, but an
impedance below 40 ohms with little reactance should provide you with
an efficient vertical. Once you get around this value, I guess there
is nothing to be gained by adding more radials. What your analyzer
tells you, as others have mentioned, depends on the rf in the area.

Gary N4AST
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Old August 24th 10, 02:09 AM posted to rec.radio.amateur.antenna
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First recorded activity by RadioBanter: Jun 2006
Posts: 1,374
Default Antenna analyzers, opinions please...

On 8/23/2010 5:38 PM, Gary wrote:

Hi Pete, If you are evaluating a radial field for a vertical, then
the value you should be shooting for is 30-35 ohms, with no
reactance. As you know this is 1/2 the impedance of a 1/2 wave
dipole-70 ohms in free space. I have never done this, but an
impedance below 40 ohms with little reactance should provide you with
an efficient vertical. Once you get around this value, I guess there
is nothing to be gained by adding more radials. What your analyzer
tells you, as others have mentioned, depends on the rf in the area.

Gary N4AST


The actual value you get when the radial system loss is minimal depends
on a number of factors, including the height and diameter of the
vertical. I've also seen convergence to other resistance values when the
ground was dry on the surface but apparently wet at some depth below. In
that case, radial current can be significant at quite a distance from
the antenna (as opposed to the exponential-looking decay you see in the
current on radials buried in moist ground), making the system act more
like a system of elevated radials. In those systems, radial length also
plays a role in determining the feedpoint resistance value.

The bottom line is that I don't trust a single value or its comparison
to 36 or 40 ohms as being a reliable indication of efficiency. You
either need to look for convergence of the feedpoint resistance as Peter
proposed, or even better yet, look for convergence of field strength
values at a fixed location as you increase the number of radials.

Roy Lewallen, W7EL
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Old August 24th 10, 02:24 AM posted to rec.radio.amateur.antenna
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First recorded activity by RadioBanter: Dec 2006
Posts: 102
Default Antenna analyzers, opinions please...

On Aug 23, 8:38*pm, Gary wrote:
On Aug 23, 4:53*pm, "Peter O. Brackett"
wrote:



Roy:


Thanks for your *input on the effects of interference from other
transmitters, especially BC transmitters, point well taken.


I suppose one might add some kind of carefully designed passive filtering to
the devices to 'notch' out offending BC stations, etc...


But... that would be messy and complicated.


Using a bridge with a tuned detector seems a much better approach. *I do
have an old MFJ Rx resistance bridge at hand, but I was looking for a little
bit better accuracy. *I must check e-bay, etc... for prices for a used
bridge of the GR class you have.


My current problem could likly be solved by using one of my (so-called) VSWR
meters, but I felt I might like to get a little more metrological capability
for a few bucks.


I've never had a vertical antenna before and currently I'm laying out a
radial field under a new vertical antenna. *I just wanted to know when to
stop laying down radials.


I figure that I just need to measure the input impedance of the antenna Zin
at my frequencies of interest and record the (hopefully decreasing)
impedance values as I lay down more radials. * My assumption is that Zin =
Zant + Rg. *where Zant includes the reactance and radiation resistance of
the radiator element at my frequency of interest and Rg is the ground
resistance. *Hopefully Rg should decrease as I add raials. I intend to quit
adding radials when the impedance decrease becomes 'negligible' ( In the
sense of received S units [smile]).


Thanks again!


-- Pete k1po
-- Indialantic By-the-Sea, FL


"Roy Lewallen" wrote in message


...


I have only one comment which applies to most if not all of the amateur
level products, as well as a very high quality HP impedance meter I used
years ago.


I live about 15 miles from hilltops where the local AM, FM, and TV
broadcast towers are. The signals from those stations are strong enough to
overwhelm the broad bandwidth detection circuitry in the analyzers (and HP
vector impedance meter) I've used, resulting in meaningless readings when
connected to an antenna. I find that I grab my MFJ antenna analyzer for a
host of jobs like measuring a ferrite core impedance, checking the length
of a piece of coax, and so forth. But for me it's just about useless for
the job of analyzing actual antennas. When I need to measure antenna
impedance I dust off an old GR bridge and use a portable receiver for the
detector in order to reject the strong ambient signals.


Of course this isn't a problem for everyone, but it sure is for me and I
don't think my situation is unusual for an urban environment. I've had to
put common mode chokes on my thermometer thermocouple wire, my light meter
connecting wire, scope leads, and even in audio circuitry to keep the RF
out. But even one strong local station might be enough to upset a typical
antenna analyzer.


Roy Lewallen, W7EL


On 8/23/2010 11:15 AM, Peter O. Brackett wrote:
Antenna Newsgroup Denizens:


Apart from the professional 'lab grade' (and undoubtedly very expensive)
devices made by the likes of Agilent, there are on the amateur market
several antenna analyzers that are more reasonably priced.


I'm currently considering the purchase of such a device, and so...


I'm interested in hearing opinions, pro-con arguments, and/or receiving
pointers to reviews of such devices.


All thoughts and comments will be appreciated, unbiased or not.


Thanks!


-- Pete k1po
-- Indialantic By-the-Sea, FL- Hide quoted text -


- Show quoted text -


Hi Pete, *If you are evaluating a radial field for a vertical, then
the value you should be shooting for is 30-35 ohms, with no
reactance. *As you know this is 1/2 the impedance of a 1/2 wave
dipole-70 ohms in free space. *I have never done this, but an
impedance below 40 ohms with little reactance should provide you with
an efficient vertical. *Once you get around this value, I guess there
is nothing to be gained by adding more radials. *What your analyzer
tells you, as others have mentioned, depends on the rf in the area.

Gary N4AST


Hi Pete, long time since I've seen a post from you on this NG!

Pete, I'd take Roy's route and use a GR impedance bridge. I've used
the GR-1606A and the 1606B for the last 50 years. If you're not
familiar with it it's been the standard impedance-measuring device for
AM BC antennas for more than 50 years. It's accuracy cannot be beaten.
These bridges were expensive when new, but they are available rather
inexpensively now, and are stable as a rock. And as Roy said, they use
either a millivolt meter or a tunable receiver as the detector. Using
the receiver, interfering signals picked up with the antenna being
measured are eliminated, thus not degrading the accuracy of the
impedance measurement.

The GR-1606A measures from below 500 kHz up to 60 MHz. The GR-1602
measures well into the VHF range. If you should try one I know you'll
like it.

Walt, W2DU

PS--If you'd like to see the results of measuring W2DU's antenna
impedances, I refer you to Reflections, Chapter 15, Tables 15-4, 15-5,
and Fig 15-1, which is a graph of the data in the Tables. If you don't
have a copy of Reflections you can see this data on my web page at
www.w2du.com. Just select 'Read Chapters from Reflections 2'.
  #10   Report Post  
Old August 24th 10, 03:26 AM posted to rec.radio.amateur.antenna
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First recorded activity by RadioBanter: Aug 2010
Posts: 1
Default Antenna analyzers, opinions please...

I've been pretty satisfied with the AIM 4170. Check this out.

http://arraysolutions.com/images/Tun...m_Vertical.pdf

73,
Danny, K6MHE

On Mon, 23 Aug 2010 17:53:33 -0400, Peter O. Brackett wrote:

Roy:

Thanks for your input on the effects of interference from other
transmitters, especially BC transmitters, point well taken.

I suppose one might add some kind of carefully designed passive
filtering to the devices to 'notch' out offending BC stations, etc...

But... that would be messy and complicated.

Using a bridge with a tuned detector seems a much better approach. I do
have an old MFJ Rx resistance bridge at hand, but I was looking for a
little bit better accuracy. I must check e-bay, etc... for prices for a
used bridge of the GR class you have.

My current problem could likly be solved by using one of my (so-called)
VSWR meters, but I felt I might like to get a little more metrological
capability for a few bucks.

I've never had a vertical antenna before and currently I'm laying out a
radial field under a new vertical antenna. I just wanted to know when
to stop laying down radials.

I figure that I just need to measure the input impedance of the antenna
Zin at my frequencies of interest and record the (hopefully decreasing)
impedance values as I lay down more radials. My assumption is that Zin
= Zant + Rg. where Zant includes the reactance and radiation resistance
of the radiator element at my frequency of interest and Rg is the ground
resistance. Hopefully Rg should decrease as I add raials. I intend to
quit adding radials when the impedance decrease becomes 'negligible' (
In the sense of received S units [smile]).

Thanks again!

-- Pete k1po
-- Indialantic By-the-Sea, FL


"Roy Lewallen" wrote in message
...
I have only one comment which applies to most if not all of the amateur
level products, as well as a very high quality HP impedance meter I used
years ago.

I live about 15 miles from hilltops where the local AM, FM, and TV
broadcast towers are. The signals from those stations are strong enough
to overwhelm the broad bandwidth detection circuitry in the analyzers
(and HP vector impedance meter) I've used, resulting in meaningless
readings when connected to an antenna. I find that I grab my MFJ
antenna analyzer for a host of jobs like measuring a ferrite core
impedance, checking the length of a piece of coax, and so forth. But
for me it's just about useless for the job of analyzing actual
antennas. When I need to measure antenna impedance I dust off an old GR
bridge and use a portable receiver for the detector in order to reject
the strong ambient signals.

Of course this isn't a problem for everyone, but it sure is for me and
I don't think my situation is unusual for an urban environment. I've
had to put common mode chokes on my thermometer thermocouple wire, my
light meter connecting wire, scope leads, and even in audio circuitry
to keep the RF out. But even one strong local station might be enough
to upset a typical antenna analyzer.

Roy Lewallen, W7EL

On 8/23/2010 11:15 AM, Peter O. Brackett wrote:
Antenna Newsgroup Denizens:

Apart from the professional 'lab grade' (and undoubtedly very
expensive) devices made by the likes of Agilent, there are on the
amateur market several antenna analyzers that are more reasonably
priced.

I'm currently considering the purchase of such a device, and so...

I'm interested in hearing opinions, pro-con arguments, and/or
receiving pointers to reviews of such devices.

All thoughts and comments will be appreciated, unbiased or not.

Thanks!

-- Pete k1po
-- Indialantic By-the-Sea, FL


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