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Thread: Analyzing Analyzers (#447)

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    Analyzing Analyzers (#447)


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    Turboomni (06-05-2021)

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    As the owner of several antenna analyzers and VNAs, and someone who has used other devices that I don't own as well, my opinion differs.

    Like David I started with the MFJ-259B. As far as this antenna analyzer goes, its ok I guess, but I wouldn't go back to it if I had prety much any other option at my disposal. I have learned by discussions and research over the decades now since getting this device that shortcuts were made. If you want an SWR meter, and several otehr functions of the device, sure its easy to use, but if you want accurate X and R readings you either need to measure directly from the feed point of the antenna (not always possible) or you need an electrical half wavelength of coax. These half wavelenghts of coax are also very narrow banded, to the point that if you have a half wavelength coax tuned to the center of the CB band that channels 1 and 40 won't really be accurate as shown on the device. That being said, I still have the device in my basement, just sitting there so I haven't sold it or thrown it away...

    The Rigexpert line is great for those wanting a simple to use measuring device. Unlike the MFJ listed above, with this antenna analyzer you can calibrate out the coax, which allows you to use it with any feed line length and still get true measurements of the antenna. The way Dave talked about one aspect of this analyzer, he made it sound like you can't use it outside of the ham bands. This is not true, you can set it to cover any frequency range you want within the specific devices limits. This costs the same or a little less than the MFJ-259's today, and is far more powerful and IMHO easier to use.

    I can't speak to the other antenna analyzer Dave has as I don't own one and have never used one.

    When it comes to the NanoVNA that Dave touched on, this is my go to device. It is both the cheapest and by far the most powerful device on this list, and short of broadcast engineer equipment that goes for thousands of dollars (even when used) is the most powerful option available that I am aware of. I only use the menu system on the device to calibrate out the coax, aside from that I tend to use the nanovna-saver software, which is easy to use, and increases the capabilities of the device further. Using a computer with a VNA for me is no problem as my older AIM4170c VNA only worked with a computer, so I am used to it. If you don't want to use a computer with the device, they do make a version of the NanoVNA with a bigger screen.

    I should also point out that Dave is not accurate when it comes to setting the NanoVNA to measure SWR on the device itself. It isn't that difficult, and once set, short of a firmware update the setting doesn't change, so once it is set its done. The screen on the device can show up to four types of measurements of your choice, so get it set up how you like and leave it alone.

    Long story short, imho from actually using these devices as well as others, if you want easier to use get the RigExpert that covers the frequencies that you need to cover. If you want capability or a price that doesn't break the bank, go NanoVNA.


    The DB

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    Very nice reporting on these instriments.

    Regarding the nanoVNA

    My son has one of those and any time he changes bands he runs this little calibration procedure where he puts adapters on it and runs the calibration. It has always seemed to give reasonable results.

    That said, when you say "calibrate out the coax".....
    Whenever you "calibrate the VNA" are you putting those adapters on the END of the coax so that the COAX ITSELF is included in the calibration?

    Something about that sounds reasonable......even if it is tough when you are shooting an antenna on a 40 ft pole!!!!

    I just thought I would ask for comment on that.

    Thanks,
    Bob

    Quote Originally Posted by The DB View Post
    As the owner of several antenna analyzers and VNAs, and someone who has used other devices that I don't own as well, my opinion differs.

    Like David I started with the MFJ-259B. As far as this antenna analyzer goes, its ok I guess, but I wouldn't go back to it if I had prety much any other option at my disposal. I have learned by discussions and research over the decades now since getting this device that shortcuts were made. If you want an SWR meter, and several otehr functions of the device, sure its easy to use, but if you want accurate X and R readings you either need to measure directly from the feed point of the antenna (not always possible) or you need an electrical half wavelength of coax. These half wavelenghts of coax are also very narrow banded, to the point that if you have a half wavelength coax tuned to the center of the CB band that channels 1 and 40 won't really be accurate as shown on the device. That being said, I still have the device in my basement, just sitting there so I haven't sold it or thrown it away...

    The Rigexpert line is great for those wanting a simple to use measuring device. Unlike the MFJ listed above, with this antenna analyzer you can calibrate out the coax, which allows you to use it with any feed line length and still get true measurements of the antenna. The way Dave talked about one aspect of this analyzer, he made it sound like you can't use it outside of the ham bands. This is not true, you can set it to cover any frequency range you want within the specific devices limits. This costs the same or a little less than the MFJ-259's today, and is far more powerful and IMHO easier to use.

    I can't speak to the other antenna analyzer Dave has as I don't own one and have never used one.

    When it comes to the NanoVNA that Dave touched on, this is my go to device. It is both the cheapest and by far the most powerful device on this list, and short of broadcast engineer equipment that goes for thousands of dollars (even when used) is the most powerful option available that I am aware of. I only use the menu system on the device to calibrate out the coax, aside from that I tend to use the nanovna-saver software, which is easy to use, and increases the capabilities of the device further. Using a computer with a VNA for me is no problem as my older AIM4170c VNA only worked with a computer, so I am used to it. If you don't want to use a computer with the device, they do make a version of the NanoVNA with a bigger screen.

    I should also point out that Dave is not accurate when it comes to setting the NanoVNA to measure SWR on the device itself. It isn't that difficult, and once set, short of a firmware update the setting doesn't change, so once it is set its done. The screen on the device can show up to four types of measurements of your choice, so get it set up how you like and leave it alone.

    Long story short, imho from actually using these devices as well as others, if you want easier to use get the RigExpert that covers the frequencies that you need to cover. If you want capability or a price that doesn't break the bank, go NanoVNA.


    The DB

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    Quote Originally Posted by Bobcat View Post
    Very nice reporting on these instriments.

    Regarding the nanoVNA

    My son has one of those and any time he changes bands he runs this little calibration procedure where he puts adapters on it and runs the calibration. It has always seemed to give reasonable results.

    That said, when you say "calibrate out the coax".....
    Whenever you "calibrate the VNA" are you putting those adapters on the END of the coax so that the COAX ITSELF is included in the calibration?

    Something about that sounds reasonable......even if it is tough when you are shooting an antenna on a 40 ft pole!!!!

    I just thought I would ask for comment on that.

    Thanks,
    Bob
    Yes, calibrating out the coax is referring to including the coax in the calibration so you see what is happening at the antenna's feed point. I like to do this before the coax was run, but it isn't always possible. That being said, if you already have the hassle of people climbing to the antenna's feed point to tune it, it isn't really that difficult. At worse I use some GMRS radios to tell them when to attach each load to the feed line and when to attach the feed line to the antenna.


    The DB

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    That makes good sense! Thank you for the quick reply!

    Bob

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