Using Antenna Analyzers (007b )
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- เผยแพร่เมื่อ 7 ก.ค. 2024
- This video not only goes through how to make certain measurements using an Antenna Analyzer, but I also help you understand a little about HOW the Antenna Analyzer does what it does.
I will demonstrate these measurements using an MFJ-259C Antenna Analyzer.
I discuss how to make the following measurements:
* SWR
* Impedance - Capacitance & Inductance
* Coax Loss
* Distance to Fault
* Velocity Factor
Here is the link to the Power Point Slides pdf:
drive.google.com/file/d/1fbsa...
This was great! Easily understood. I have an old 259 on its way back from repair at MFJ. This will get me going with it. Thank you! 73zzz
Thanks, man! I am glad it helps! Have fun discovering :-)
This is EXACTLY what I needed to see! I have a MFJ-269c and I'm glad I found this channel!
Thank you! I am very glad it helped.
Thanks! I’m still not an expert, but I learned a lot! You’re a good teacher. Kind regards, Darryl PH1DTE
You are very welcome and ... thanks! 🙂
Great video very very informative . You’re a good teacher. Only 329 tombs up is this means that ham radio operators don't want to learn.
Thank you so much for your encouragement! 🙂
Another great video Ralph. Well done !
Just what I was looking for on using my new to me MFJ 269c.
Glad it was a help to you! :-)
thank you for the video explanation which is quite clear about the use and calculation of this mfj analizer. May be useful. thx.
You are welcome!
Excellent! Thank you. I don't have an MFJ-259 yet, but it is on my list of equipment to obtain. I always wondered what the gate and mode buttons did. I suspected it had more functions than are normally shown in radio & antenna related videos.
I am so glad that this was helpful to you. There are several different Antenna Analyzer options out there to consider beyond the MFJ like Comet and Rig Expert. This would also include the nanoVNA and mini VNA tiny, both of which will do everything the MFJ analyzer will do and more; these require a bit more of a learning curve, though.
My adivise? Shop around. Think beyond your current applications to things you might want to do in the future and buy what fits present and future plans.
Thanks, saving to my antenna tuning bookmarks and subscribing.
I'm so glad that you found this video helpful! Thank you for the encouragement! 🙂
Thank you very much for the video Ralph ! I understood everything, but i don't know who is selling this instrument. I am older than you, and for years i was using tricks to make TX s or repair RX or make and tune antennas by using and theory. My 73 s from 5B4ER.
Thank you for the encouraging words! :-) The unit I was using there is an MFJ-259C; the current version is the MFJ-259D manufactured by MFJ. This is available through various vendors including Amazon.com. There are also other antenna analyzers out there manufactured by other companies. Two of the more common are the RigExpert (www.gigaparts.com/rigexpert-aa-230-zoom-antenna-analyzer-100khz-to-230mhz.html) and the Comet Antenna Analyzer (www.gigaparts.com/antenna-analyzer-1-8-500mhz.html). Hope this helps.
If we trust the analyzer, then the swr has changed and that is what the transmitter sees. also nice to use the match efficiency feature. R there stands for resistance not real. x shows resonance, Also think lower-longer for length changes.
Well, you are kinda right here. Impedance is made up of the real, or purely resistive, portion and the imaginary, or purely reactive portion. You are right that the X portion *can indicate* resonance, but only when it drops to zero; this is when the capacitive reactance equals the inductive reactance and they cancel each other out. It is, of itself, the reactive portion of the impedance.
The manual for the MFJ-259C (pg 5) states, "The lower line displays the Resistive (R) and Reactive (X) impedance components for the attached load."
Yes, the **impedance** that the transmitter sees is indeed the same as the **impedance** that the Antenna Analyzer reports. SWR is potentially another story.
No transmitter has a perfect 50 Ohm, non-reactive output impedance (not possible in the real world). The SWR that the transmitter sees depends on two things: [1] the source impedance (this is the transmitter's actual complex output impedance) and [2] the load impedance (this is what the transmitter sees at the end of the coax & what your antenna analyzer reports). If these are the same, then we have a nice SWR.
How far off from this perfect, non-reactive 50 Ohms is the output impedance of my transmitter and should I be concerned?
Generally, it is pretty close and, no, you probably do not need to be concerned UNLESS you measure the SWR at the end of the coax with your antenna analyzer and then with the built in SWR meter in the radio and they are dramatically different. Then you need to check your analyzer with a known to be good 50 Ohm load (not a dummy load like for a transmitter because they, too, are far from a good standard load - try scanning one sometime to the extents of their advertised frequency limits with a VNA like I have!). If the antenna analyzer is good, then there could be something not so good in the transmitter.
Very informative.... Thank you so much... can you show how to use the meter to set an antenna tuner?
Good thought! I will add this to my list of videos to create. Fortunately, I have an old Drake antenna tuner I can use to demonstrate this.
In a nutshell ...
Connect the analyzer to the tuner *in place of* the transmitter, set the analyzer's frequency to the desired target frequency, tune the antenna tuner to minimize the indicated SWR on the analyzer. Done.
Please know that the output impedance of the transmitter might not be exactly the same as the analyzer, so you *may* have to do a little *minor* adjustment of the tuner once you reconnect the transmitter to get the optimum SWR. With that said, this should get you really really close.
Love it 😊😊😊
I'm so glad it was helpful! 🙂
I have a gap. I can''t get a good connection on it'I made the mistake of putting the antenna in the air before I put a coax end on the cable. first let me say I'm on the nervous sided. . I can't get a good end on the cable that is hanging down on the last pl 239 on it we burned the dye;electrode on the connector by getting it two hot by the solider iron.
I understand your pain in trying to put a PL-259 connector (AKA: Male UHF connector) on the end of a feedline! It is not the easiest connector to get on there and get it right. Your comment has spurred me on to create an unscheduled video to show how to do this effectively. In fact, that what I have been working on all afternoon. Keep a watch out for the new video "Terminating RG-8 coax with a Male UHF connector." My goal is to have it out today ... but, you know how goals can be!
ok which one do itrust the swr or the analyzer ???
sorry I haven’t replied sooner. I have been and still am very sick. which one to trust? There are so many variables. Application: how accurate do we need to be for our application? will it actually make a difference in the end use?
If yes, then there are good SWR meters with low self-SWR and then there are others. Some of the really old models were much better designed (e.g. Heathkit stuff).
Then we talk antenna analyzers. I was unpleasantly surprised to discover that there are manufacturers of such which provided no performance specifications for their analyzer of any kind. when I contacted them to get some, the equity went into a black hole. The device seems to do OK for measuring SWR, but, with the company unwilling to certify ANYTHING about their product in writing, I wouldn’t lean too heavily on its accuracy.
So there is the swirly, not so direct answer.
Don't leave me!
I'll be here as long as the Lord wants me to be. No worries.
I appreciate the time you spent making this video. Your information was good but there were times when the video was not showing what you were talking about and/or what you intended to show was not being shown. At other times the insert window blocked part of a necessary area so you couldn't see. Finally, the music was unnecessary and to me irritating. I'm sure you had to spend time putting the music into your video and this time could have been spent doing something more productive. I'm sure I will be torn up for making these comments but I think someone needs to tell you truthfully what they think about the video in its entirety. Again, thank you for sharing your knowledge with us who don't know as much as you.
I am glad that you found my video helpful and that it has useful information.
Regarding your concerns, this video was made very early on in my "career" as a TH-camr, videographer and post production editor. If you watch some of my more recent videos, I think you will discover a significant improvement as I have learned and stretched for improvement.
Esse mfj já era muito caro e agora tem os nanovna baratos e muito preciso nas medidas
"This mfj was already very expensive and now has the cheap nanovna and very accurate in the measurements"
Yes, you are right! For what you get, the MFJ unit IS very expensive. The nanoVNA is much more affordable and more accurate ... however, the MFJ doesn't require the whole "calibration" step ... it is more of a quick measurement, very ballpark sort of device. I wouldn't depend on it to measure impedance. BUT, the nanoVNA does really, really well. One note ... as I understand it, if you change the frequency extents (START, STOP), you lose you cal and have to do it again; this even if you are narrowing the SPAN. :-(