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Old February 21st 04, 05:35 PM
Bob
 
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I have a Diamond X-6000A triband antenna, and its SWR curves are 'wavy'
on VHF and a little on UHF, not the smooth symmetrical log curve one
might expect. It's likely the interaction of the other band resonances,
but nothing to lead me to believe it's broken.

I like the suggestion about trying a good quality dummy load on it (or
perhaps another analyser on the same group of antennas) before you
condemn the thing as junk.

Good luck!

B


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Old February 24th 04, 05:32 AM
Pete KE9OA
 
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While it is possible that your analyzer isn't working, it is also possible
that you do have some wild variances in impedance with your current setup. I
took a look at the return loss of one of my antenna systems with a tracking
generator/spectrum analyzer combination, and did see some multiple resonance
nodes. This measurement was done, using a Narda directional coupler, which
is flat out to 12GHz, as measured on an HP 8753E Network Analyzer.
Some sort of transfer standard such as an accurate 50 Ohm load would verify
if your analyzer is bad.

Pete

"Bob" wrote in message
...
I have a Diamond X-6000A triband antenna, and its SWR curves are 'wavy'
on VHF and a little on UHF, not the smooth symmetrical log curve one
might expect. It's likely the interaction of the other band resonances,
but nothing to lead me to believe it's broken.

I like the suggestion about trying a good quality dummy load on it (or
perhaps another analyser on the same group of antennas) before you
condemn the thing as junk.

Good luck!

B




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Old February 24th 04, 02:29 PM
Andy Cogswell
 
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"Pete KE9OA" wrote in message
...
While it is possible that your analyzer isn't working, it is also possible
that you do have some wild variances in impedance with your current setup.

I
took a look at the return loss of one of my antenna systems with a

tracking
generator/spectrum analyzer combination, and did see some multiple

resonance
nodes. This measurement was done, using a Narda directional coupler, which
is flat out to 12GHz, as measured on an HP 8753E Network Analyzer.
Some sort of transfer standard such as an accurate 50 Ohm load would

verify
if your analyzer is bad.

Pete


Considering that all 3 antennas showed appropriate SWR readings on their
respective frequencies on my wattmeter with on-the-air tests, and the
analyzer showed wild SWR readings on the same frequencies, I'd say the
analyzer is at fault. Works perfectly at HF/VHF, so I basically have an
MFJ-259 in an MFJ-269 shell until they fix it.

UPS picked it up yesterday. Hopefully I will hear something within the next
2 weeks.


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Old February 24th 04, 03:18 PM
Pete KE9OA
 
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I am sure that it is quite possible that your unit has a problem, but still,
a directional wattmeter is not the absolute means of measurement accuracy.
When working in an RF lab, even the Bird 43 series elements need to be
calibrated against a power meter, such as an HP 437. I wouuld still try an
accurate 50 Ohm load for characterization.
Good luck.

Pete

"Andy Cogswell" SHORECOGS at COMCAST DOT NET wrote in message
news
"Pete KE9OA" wrote in message
...
While it is possible that your analyzer isn't working, it is also

possible
that you do have some wild variances in impedance with your current

setup.
I
took a look at the return loss of one of my antenna systems with a

tracking
generator/spectrum analyzer combination, and did see some multiple

resonance
nodes. This measurement was done, using a Narda directional coupler,

which
is flat out to 12GHz, as measured on an HP 8753E Network Analyzer.
Some sort of transfer standard such as an accurate 50 Ohm load would

verify
if your analyzer is bad.

Pete


Considering that all 3 antennas showed appropriate SWR readings on their
respective frequencies on my wattmeter with on-the-air tests, and the
analyzer showed wild SWR readings on the same frequencies, I'd say the
analyzer is at fault. Works perfectly at HF/VHF, so I basically have an
MFJ-259 in an MFJ-269 shell until they fix it.

UPS picked it up yesterday. Hopefully I will hear something within the

next
2 weeks.




  #5   Report Post  
Old February 24th 04, 03:18 PM
Pete KE9OA
 
Posts: n/a
Default

I am sure that it is quite possible that your unit has a problem, but still,
a directional wattmeter is not the absolute means of measurement accuracy.
When working in an RF lab, even the Bird 43 series elements need to be
calibrated against a power meter, such as an HP 437. I wouuld still try an
accurate 50 Ohm load for characterization.
Good luck.

Pete

"Andy Cogswell" SHORECOGS at COMCAST DOT NET wrote in message
news
"Pete KE9OA" wrote in message
...
While it is possible that your analyzer isn't working, it is also

possible
that you do have some wild variances in impedance with your current

setup.
I
took a look at the return loss of one of my antenna systems with a

tracking
generator/spectrum analyzer combination, and did see some multiple

resonance
nodes. This measurement was done, using a Narda directional coupler,

which
is flat out to 12GHz, as measured on an HP 8753E Network Analyzer.
Some sort of transfer standard such as an accurate 50 Ohm load would

verify
if your analyzer is bad.

Pete


Considering that all 3 antennas showed appropriate SWR readings on their
respective frequencies on my wattmeter with on-the-air tests, and the
analyzer showed wild SWR readings on the same frequencies, I'd say the
analyzer is at fault. Works perfectly at HF/VHF, so I basically have an
MFJ-259 in an MFJ-269 shell until they fix it.

UPS picked it up yesterday. Hopefully I will hear something within the

next
2 weeks.






  #6   Report Post  
Old February 24th 04, 03:14 PM
Pete KE9OA
 
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I must have been asleep when I made this post....................It was an
8717 or 8718............the 8753 only goes out to 3GHz!

Pete

"Pete KE9OA" wrote in message
...
While it is possible that your analyzer isn't working, it is also possible
that you do have some wild variances in impedance with your current setup.

I
took a look at the return loss of one of my antenna systems with a

tracking
generator/spectrum analyzer combination, and did see some multiple

resonance
nodes. This measurement was done, using a Narda directional coupler, which
is flat out to 12GHz, as measured on an HP 8753E Network Analyzer.
Some sort of transfer standard such as an accurate 50 Ohm load would

verify
if your analyzer is bad.

Pete

"Bob" wrote in message
...
I have a Diamond X-6000A triband antenna, and its SWR curves are 'wavy'
on VHF and a little on UHF, not the smooth symmetrical log curve one
might expect. It's likely the interaction of the other band resonances,
but nothing to lead me to believe it's broken.

I like the suggestion about trying a good quality dummy load on it (or
perhaps another analyser on the same group of antennas) before you
condemn the thing as junk.

Good luck!

B






  #7   Report Post  
Old February 24th 04, 02:29 PM
Andy Cogswell
 
Posts: n/a
Default

"Pete KE9OA" wrote in message
...
While it is possible that your analyzer isn't working, it is also possible
that you do have some wild variances in impedance with your current setup.

I
took a look at the return loss of one of my antenna systems with a

tracking
generator/spectrum analyzer combination, and did see some multiple

resonance
nodes. This measurement was done, using a Narda directional coupler, which
is flat out to 12GHz, as measured on an HP 8753E Network Analyzer.
Some sort of transfer standard such as an accurate 50 Ohm load would

verify
if your analyzer is bad.

Pete


Considering that all 3 antennas showed appropriate SWR readings on their
respective frequencies on my wattmeter with on-the-air tests, and the
analyzer showed wild SWR readings on the same frequencies, I'd say the
analyzer is at fault. Works perfectly at HF/VHF, so I basically have an
MFJ-259 in an MFJ-269 shell until they fix it.

UPS picked it up yesterday. Hopefully I will hear something within the next
2 weeks.


  #8   Report Post  
Old February 24th 04, 03:14 PM
Pete KE9OA
 
Posts: n/a
Default

I must have been asleep when I made this post....................It was an
8717 or 8718............the 8753 only goes out to 3GHz!

Pete

"Pete KE9OA" wrote in message
...
While it is possible that your analyzer isn't working, it is also possible
that you do have some wild variances in impedance with your current setup.

I
took a look at the return loss of one of my antenna systems with a

tracking
generator/spectrum analyzer combination, and did see some multiple

resonance
nodes. This measurement was done, using a Narda directional coupler, which
is flat out to 12GHz, as measured on an HP 8753E Network Analyzer.
Some sort of transfer standard such as an accurate 50 Ohm load would

verify
if your analyzer is bad.

Pete

"Bob" wrote in message
...
I have a Diamond X-6000A triband antenna, and its SWR curves are 'wavy'
on VHF and a little on UHF, not the smooth symmetrical log curve one
might expect. It's likely the interaction of the other band resonances,
but nothing to lead me to believe it's broken.

I like the suggestion about trying a good quality dummy load on it (or
perhaps another analyser on the same group of antennas) before you
condemn the thing as junk.

Good luck!

B






  #9   Report Post  
Old February 24th 04, 05:32 AM
Pete KE9OA
 
Posts: n/a
Default

While it is possible that your analyzer isn't working, it is also possible
that you do have some wild variances in impedance with your current setup. I
took a look at the return loss of one of my antenna systems with a tracking
generator/spectrum analyzer combination, and did see some multiple resonance
nodes. This measurement was done, using a Narda directional coupler, which
is flat out to 12GHz, as measured on an HP 8753E Network Analyzer.
Some sort of transfer standard such as an accurate 50 Ohm load would verify
if your analyzer is bad.

Pete

"Bob" wrote in message
...
I have a Diamond X-6000A triband antenna, and its SWR curves are 'wavy'
on VHF and a little on UHF, not the smooth symmetrical log curve one
might expect. It's likely the interaction of the other band resonances,
but nothing to lead me to believe it's broken.

I like the suggestion about trying a good quality dummy load on it (or
perhaps another analyser on the same group of antennas) before you
condemn the thing as junk.

Good luck!

B




  #10   Report Post  
Old February 21st 04, 02:01 AM
Andy Cogswell
 
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Default


"Dave Edwards" wrote in message
...
Another MFJ victim....live and learn!


First MFJ product I've had problems with. I've owned a lot of products and
their analyzers are usually very good. I owned an MFJ-259 before this, but
wanted UHF capabilities, so I bought the 269.




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