Antenna Tuners

[The DB]

Coax 1 is an output for the MFJ-949E, there is also a coax 2 output. On the coax 1 output there is a feed line that is run to said dual band antenna.


The DB

[KOA4705]

Coax 1 is an output for the MFJ-949E, there is also a coax 2 output. On the coax 1 output there is a feed line that is run to said dual band antenna.


The DB

Coax 1 output is matched at 27.2 Mhz as shown in your video, S11/vswr. Coax 1 what type and length did you used? Did you measure the vswr, return loss or impedance of coax 1 output when the MFJ-949E was in bypass?
Joe

[The DB]

Coax 1 output is matched at 27.2 Mhz as shown in your video, S11/vswr. Coax 1 what type and length did you used? Did you measure the vswr, return loss or impedance of coax 1 output when the MFJ-949E was in bypass?
Joe

Its about 20 feet of rg-58 that is permanently attached to the magnet mount antenna.

If you look at the earlier part of the video before I switched the antenna tuner from the bypass to the tuned side, the un-tuned VSWR of the un0tuned antenna is shown on the top chart.


The DB

[KOA4705]

Coax 1 output is matched at 27.2 Mhz as shown in your video, S11/vswr. Coax 1 what type and length did you used? Did you measure the vswr, return loss or impedance of coax 1 output when the MFJ-949E was in bypass?
Joe

Its about 20 feet of rg-58 that is permanently attached to the magnet mount antenna.

If you look at the earlier part of the video before I switched the antenna tuner from the bypass to the tuned side, the un-tuned VSWR of the un0tuned antenna is shown on the top chart.


The DB

What is puzzling me is the low vswr when the antenna tuner is in bypass. 4.2:1 @ 26.86 Mhz,
5.64: 1 @ 27.52Mhz. A 2 Meter 1/4 wave vertical antenna is .0457 wave lengths @ 27.2 Mhz. The antenna feed point impedance would be capacitive with very low resistivity. In the order of 1-j1.3k ohms. Even with a 20 foot length of RG-58, at the transmitter end that would equate to a 17:1 vswr. Could you run a R,X impedance plot in bypass mode and post it to make sense of this. Something about antenna being dual band?

[The DB]

I was surprised at that at first as well. As I said I am using a round pizza sheet for a ground plane, which I am sure is a bit to small to be optimal. That being said, I am not seeing any evidence of CMC's as simply changing how the coax is layed out, as well as touching it in various places during various scans doesn't seem to change anything when it comes to SWR or gain.

I thought I mentioned somewhere that the antenna was in a house, but cannot find it now. It was in the first take that I stuttered to much for my liking so I redid the video, along with the fact that I need to redo this test outside where there are less obstacles when the weather around here improves. This is an oversight on my part and was meant to be in the final release of the video. I will leave this in the description of the video as it was meant to be in the video in the first place.

Moving the antenna around inside the house is enough to change the antenna's SWR, and how the antenna tuner needs to be adjusted to tune said antenna. Just moving an antenna around on a vehicle also has this type of effect, although to a smaller degree. On most vehicles there aren't things around the antenna itself like in a house affecting it, especially the antenna's tip, which is the most sensitive part of the antenna to foreign objects being near it.

It doesn't matter where I move the antenna in the area that I can move said antenna, when I adjust the tuner for it I get a better received gain on port S21 than when the tuner is in bypass.

That being said.

I don't see going outside making that much of a difference to the two questions I asked in the video, remember those?

Paraphrased, the first question that was asked is... Does using an antenna tuner change the output of an antenna? As the measurements of the second antenna attached to port S21 show, this is absolutely the case, and so far has been the case with every antenna I have yet measured.

The second question was... If there is a change in RF output, is that change for the better? This has also happened for every antenna I have, as of yet measured, key words here being "as of yet".

With my understanding of how antennas work, I don't see moving these antennas outside to a more open range changing this outcome. Now that I have the means of easily running such a test, I plan to do this test multiple times in the future on many different CB and Ham antennas and installations (some ham antennas of which are specifically intended to be run this way), so we will see.


The DB

[KOA4705]

I was surprised at that at first as well. As I said I am using a round pizza sheet for a ground plane, which I am sure is a bit to small to be optimal. That being said, I am not seeing any evidence of CMC's as simply changing how the coax is layed out, as well as touching it in various places during various scans doesn't seem to change anything when it comes to SWR or gain.

I thought I mentioned somewhere that the antenna was in a house, but cannot find it now. It was in the first take that I stuttered to much for my liking so I redid the video, along with the fact that I need to redo this test outside where there are less obstacles when the weather around here improves. This is an oversight on my part and was meant to be in the final release of the video. I will leave this in the description of the video as it was meant to be in the video in the first place.

Moving the antenna around inside the house is enough to change the antenna's SWR, and how the antenna tuner needs to be adjusted to tune said antenna. Just moving an antenna around on a vehicle also has this type of effect, although to a smaller degree. On most vehicles there aren't things around the antenna itself like in a house affecting it, especially the antenna's tip, which is the most sensitive part of the antenna to foreign objects being near it.

It doesn't matter where I move the antenna in the area that I can move said antenna, when I adjust the tuner for it I get a better received gain on port S21 than when the tuner is in bypass.

That being said.

I don't see going outside making that much of a difference to the two questions I asked in the video, remember those?

Paraphrased, the first question that was asked is... Does using an antenna tuner change the output of an antenna? As the measurements of the second antenna attached to port S21 show, this is absolutely the case, and so far has been the case with every antenna I have yet measured.

The second question was... If there is a change in RF output, is that change for the better? This has also happened for every antenna I have, as of yet measured, key words here being "as of yet".

With my understanding of how antennas work, I don't see moving these antennas outside to a more open range changing this outcome. Now that I have the means of easily running such a test, I plan to do this test multiple times in the future on many different CB and Ham antennas and installations (some ham antennas of which are specifically intended to be run this way), so we will see.


The DB

Steve like you I have a passion to understand how this stuff
works. When using a matching network (tuner) at the shack end of
the transmission line. The transmission line end impedance is
transformed to 50 ohms. Transmitter's source impedance is 50
ohms. Maximum power from the transmitter will be delivered to the
transmission line. Increasing the power to the antenna.The
transmitter Power delivered to the antenna is the transmitter
output power minus the transmission line losses. Also there are
losses in the tuner. The vswr on the transmission line is solely
determined by the antenna feed point impedance.Tuner will have no
effect on line vswr.The losses on the transmission line are
directly proportional to vswr.
Joe

[The DB]

Steve like you I have a passion to understand how this stuff works.

I do have a passion for antennas and how they work, to the point that I have supplemented my extensive experience with quite a bit of research.

When using a matching network (tuner) at the shack end of the transmission line. The transmission line end impedance is transformed to 50 ohms.

No argument here.

Transmitter's source impedance is 50 ohms. Maximum power from the transmitter will be delivered to the transmission line. Increasing the power to the antenna.

With modern radios that have high SWR protection, yes this is true. That being said, the NanoVNA I used to get the results I that I got does not have this feature. Being a stand alone device that is battery powered, it doesn't send a large amount of power to the antenna under test to begin with. This lack of changing the output power is actually required for this device which directly measures return loss, as well as gain from a second antenna, so for the test above this point is irrelevant.

The transmitter Power delivered to the antenna is the transmitter output power minus the transmission line losses.

Yes, all antenna systems are like this. Further these losses are predictible.

Also there are losses in the tuner.

Of course.

The vswr on the transmission line is solely determined by the antenna feed point impedance.Tuner will have no
effect on line vswr.The losses on the transmission line are directly proportional to vswr.
Joe

Yes. This is also true.

However... Nothing of what you said here disagrees with the results I posted in that video.

Seriously though, its like you are treating me like a a newbie or something. Let me assure you, I am not.

A little background. While I use a VNA, when it comes to tuning an antenna I am not interested in superfluous things like VSWR and reactance. Yes I check them to make sure they are acceptable, but they are secondary to me. I prefer measuring field strength, and have used various devices over the years to do so, from field strength meters to a spectrum analyzer to now a receiving antenna attached to the second port of a two port VNA. Its because of this that I asked the question of weather an antenna tuner affects the output of the antenna, something that almost no one has bothered to actually test, even though the equipment needed to run such a test is widely available and has been for decades. I'm not interested in what my, your, or anyone's knowledge says should happen, I am interested in actual measured results. If said results disagree with what I think should happen I have found my next area of study.

If you want to have a discussion related to my video, or the topic of this thread I am happy to have such a discussion, but please don't assume that just because I disagree with you about something that I am a newbie that needs to be taught the basics of how an antenna system (with or without a tuner) works. You have not pointed out anything in your last post that I didn't already know, and I have discussed at least as much on this and other forums in the past.


The DB

[KOA4705]

Steve like you I have a passion to understand how this stuff works.

I do have a passion for antennas and how they work, to the point that I have supplemented my extensive experience with quite a bit of research.

When using a matching network (tuner) at the shack end of the transmission line. The transmission line end impedance is transformed to 50 ohms.

No argument here.

Transmitter's source impedance is 50 ohms. Maximum power from the transmitter will be delivered to the transmission line. Increasing the power to the antenna.

With modern radios that have high SWR protection, yes this is true. That being said, the NanoVNA I used to get the results I that I got does not have this feature. Being a stand alone device that is battery powered, it doesn't send a large amount of power to the antenna under test to begin with. This lack of changing the output power is actually required for this device which directly measures return loss, as well as gain from a second antenna, so for the test above this point is irrelevant.

The transmitter Power delivered to the antenna is the transmitter output power minus the transmission line losses.

Yes, all antenna systems are like this. Further these losses are predictible.

Also there are losses in the tuner.

Of course.

The vswr on the transmission line is solely determined by the antenna feed point impedance.Tuner will have no
effect on line vswr.The losses on the transmission line are directly proportional to vswr.
Joe

Yes. This is also true.

However... Nothing of what you said here disagrees with the results I posted in that video.

Seriously though, its like you are treating me like a a newbie or something. Let me assure you, I am not.

A little background. While I use a VNA, when it comes to tuning an antenna I am not interested in superfluous things like VSWR and reactance. Yes I check them to make sure they are acceptable, but they are secondary to me. I prefer measuring field strength, and have used various devices over the years to do so, from field strength meters to a spectrum analyzer to now a receiving antenna attached to the second port of a two port VNA. Its because of this that I asked the question of weather an antenna tuner affects the output of the antenna, something that almost no one has bothered to actually test, even though the equipment needed to run such a test is widely available and has been for decades. I'm not interested in what my, your, or anyone's knowledge says should happen, I am interested in actual measured results. If said results disagree with what I think should happen I have found my next area of study.

If you want to have a discussion related to my video, or the topic of this thread I am happy to have such a discussion, but please don't assume that just because I disagree with you about something that I am a newbie that needs to be taught the basics of how an antenna system (with or without a tuner) works. You have not pointed out anything in your last post that I didn't already know, and I have discussed at least as much on this and other forums in the past.


The DB

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Post Merge Complete

Added 1 day 22 hours 46 minutes 10 seconds after previous.

Steve like you I have a passion to understand how this stuff works.

I do have a passion for antennas and how they work, to the point that I have supplemented my extensive experience with quite a bit of research.

When using a matching network (tuner) at the shack end of the transmission line. The transmission line end impedance is transformed to 50 ohms.

No argument here.

Transmitter's source impedance is 50 ohms. Maximum power from the transmitter will be delivered to the transmission line. Increasing the power to the antenna.

With modern radios that have high SWR protection, yes this is true. That being said, the NanoVNA I used to get the results I that I got does not have this feature. Being a stand alone device that is battery powered, it doesn't send a large amount of power to the antenna under test to begin with. This lack of changing the output power is actually required for this device which directly measures return loss, as well as gain from a second antenna, so for the test above this point is irrelevant.

The transmitter Power delivered to the antenna is the transmitter output power minus the transmission line losses.

Yes, all antenna systems are like this. Further these losses are predictible.

Also there are losses in the tuner.

Of course.

The vswr on the transmission line is solely determined by the antenna feed point impedance.Tuner will have no
effect on line vswr.The losses on the transmission line are directly proportional to vswr.
Joe

Yes. This is also true.

However... Nothing of what you said here disagrees with the results I posted in that video.

Seriously though, its like you are treating me like a a newbie or something. Let me assure you, I am not.

A little background. While I use a VNA, when it comes to tuning an antenna I am not interested in superfluous things like VSWR and reactance. Yes I check them to make sure they are acceptable, but they are secondary to me. I prefer measuring field strength, and have used various devices over the years to do so, from field strength meters to a spectrum analyzer to now a receiving antenna attached to the second port of a two port VNA. Its because of this that I asked the question of weather an antenna tuner affects the output of the antenna, something that almost no one has bothered to actually test, even though the equipment needed to run such a test is widely available and has been for decades. I'm not interested in what my, your, or anyone's knowledge says should happen, I am interested in actual measured results. If said results disagree with what I think should happen I have found my next area of study.

If you want to have a discussion related to my video, or the topic of this thread I am happy to have such a discussion, but please don't assume that just because I disagree with you about something that I am a newbie that needs to be taught the basics of how an antenna system (with or without a tuner) works. You have not pointed out anything in your last post that I didn't already know, and I have discussed at least as much on this and other forums in the past.


The DB

What were the original two questions that started this discussion LOL Something like would the power delivered to the antenna increase. Would it be for any good. By no means do I think your a newbie. I really enjoy these discussions with you. Like you I have a nanovna and a lab of RF test equipment. I remember back in the day making impedance measurements. Using a Genrad RF bridge, a generator as a signal source and a receiver as the detector. One data point at a time it was tedious and time consuming. Technology has come a long way.
Joe

[MDYoungblood]

I lost what the original question was too. I watched a video on a guy wanting you to buy a 1K dollar antenna analyzer over those less than 100 dollar NanoVNA's. My knowledge on the subject would let me use the cheaper tool.
As for the antenna tuner question itself, the tuner has it's place but there is nothing in comparison to a well tuned antenna.

JMO

3's

Greg

[The DB]

Actually, going back to the wording of the op in the title and first post in this thread, I am actually wondering if by "Antenna Tuners" he was actually referring to "Antenna Analyzers"? Depending on his knowledge level, which I don't know, it would be an easy mistake to make. I mean, we do use antenna analyzers to tune antennas do we not?

What were the original two questions that started this discussion LOL Something like would the power delivered to the antenna increase. Would it be for any good.

The questions I asked in my video? Does an antenna change the output signal strength of an antenna? And if so will it be for the better?

By no means do I think your a newbie. I really enjoy these discussions with you. Like you I have a nanovna and a lab of RF test equipment. I remember back in the day making impedance measurements. Using a Genrad RF bridge, a generator as a signal source and a receiver as the detector. One data point at a time it was tedious and time consuming. Technology has come a long way.

My apologies, I misunderstood your intent.

I also own several pieces of old equipment. I have an old noise bridge, as well as two grid dip meters from back in the day. They are in working order, and I have brought them out at occasional ham radio club meetings and field days to show how they work, and even compare them directly to much more modern equipment. I think for me, this equipment is part of the history of how we got to where we are today.

I lost what the original question was too. I watched a video on a guy wanting you to buy a 1K dollar antenna analyzer over those less than 100 dollar NanoVNA's. My knowledge on the subject would let me use the cheaper tool.

If its someone who has not used any form of antenna analyzer before, I would suggest a RigExpert, mostly because they are more user friendly. That being said, you would have to pay something like $1600 to get one that covers the frequency range of the NanoVNA, although most people don't need that kind of frequency coverage.

Most people could get away with an AA-35 zoom, their cheapest model, especially those who specifically operate on the CB band, although it is still five times the price. There are also tons of youtube videos showing how to use a NanoVNA for various things, including antenna tuning, so I may have to reconsider this.

In any case, making the jump from an SWR meter to any form of antenna analyzer (even the simpler ones like the old MFJ's) is a rather big jump. If all you see on an antenna analyzer is X = 0 and R = 50 its really nothing more than a fancy SWR meter to you. And the newer ones are far more capable than the old standby MFJ's that are out there, and can even do things like calibrate out the effects of feed lines so you can see what is happening at the antenna itself... It really is a different world than even a decade ago.

For me, the NanoVNA is actually my second VNA, I also own an old (I can't believe I would call it that at this point) Aim4170c.

As for the antenna tuner question itself, the tuner has it's place but there is nothing in comparison to a well tuned antenna.

When talking about single band antennas, especially antennas that cover the very narrow frequency range of the CB band, I agree with you, there is no good reason to use an antenna tuner for such a situation. That being said, mostly outside of the CB band, there exists a need for a hobbyist to be able to access multiple bands across 30+ MHz of spectrum with one or two antennas. While not the only way to achieve such a feat, in this environment an antenna tuner really can shine when used right. I've even seen such antennas outperform things like fan dipoles, which is another way of achieving essentially the same goal.


The DB

[KOA4705]

I lost what the original question was too. I watched a video on a guy wanting you to buy a 1K dollar antenna analyzer over those less than 100 dollar NanoVNA's. My knowledge on the subject would let me use the cheaper tool.
As for the antenna tuner question itself, the tuner has it's place but there is nothing in comparison to a well tuned antenna.

JMO

3's

Greg

The Nanovna has certainly put the fly in the ointment for the
lower priced handheld VNA market. As far as resolution, 100 points
is OK. I just cal only in the frequency band of interest and I
pay attention to the span. Some of the second party software is
now up to 400 points. Agree about antenna tuners and antenna feed
need to present a low vswr to the transmission line /coax.

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Post Merge Complete

Added 30 minutes 51 seconds after previous.

Actually, going back to the wording of the op in the title and first post in this thread, I am actually wondering if by "Antenna Tuners" he was actually referring to "Antenna Analyzers"? Depending on his knowledge level, which I don't know, it would be an easy mistake to make. I mean, we do use antenna analyzers to tune antennas do we not?

What were the original two questions that started this discussion LOL Something like would the power delivered to the antenna increase. Would it be for any good.

The questions I asked in my video? Does an antenna change the output signal strength of an antenna? And if so will it be for the better?

By no means do I think your a newbie. I really enjoy these discussions with you. Like you I have a nanovna and a lab of RF test equipment. I remember back in the day making impedance measurements. Using a Genrad RF bridge, a generator as a signal source and a receiver as the detector. One data point at a time it was tedious and time consuming. Technology has come a long way.

My apologies, I misunderstood your intent.

I also own several pieces of old equipment. I have an old noise bridge, as well as two grid dip meters from back in the day. They are in working order, and I have brought them out at occasional ham radio club meetings and field days to show how they work, and even compare them directly to much more modern equipment. I think for me, this equipment is part of the history of how we got to where we are today.

I lost what the original question was too. I watched a video on a guy wanting you to buy a 1K dollar antenna analyzer over those less than 100 dollar NanoVNA's. My knowledge on the subject would let me use the cheaper tool.

If its someone who has not used any form of antenna analyzer before, I would suggest a RigExpert, mostly because they are more user friendly. That being said, you would have to pay something like $1600 to get one that covers the frequency range of the NanoVNA, although most people don't need that kind of frequency coverage.

Most people could get away with an AA-35 zoom, their cheapest model, especially those who specifically operate on the CB band, although it is still five times the price. There are also tons of youtube videos showing how to use a NanoVNA for various things, including antenna tuning, so I may have to reconsider this.

In any case, making the jump from an SWR meter to any form of antenna analyzer (even the simpler ones like the old MFJ's) is a rather big jump. If all you see on an antenna analyzer is X = 0 and R = 50 its really nothing more than a fancy SWR meter to you. And the newer ones are far more capable than the old standby MFJ's that are out there, and can even do things like calibrate out the effects of feed lines so you can see what is happening at the antenna itself... It really is a different world than even a decade ago.

For me, the NanoVNA is actually my second VNA, I also own an old (I can't believe I would call it that at this point) Aim4170c.

As for the antenna tuner question itself, the tuner has it's place but there is nothing in comparison to a well tuned antenna.

When talking about single band antennas, especially antennas that cover the very narrow frequency range of the CB band, I agree with you, there is no good reason to use an antenna tuner for such a situation. That being said, mostly outside of the CB band, there exists a need for a hobbyist to be able to access multiple bands across 30+ MHz of spectrum with one or two antennas. While not the only way to achieve such a feat, in this environment an antenna tuner really can shine when used right. I've even seen such antennas outperform things like fan dipoles, which is another way of achieving essentially the same goal.


The DB

The questions you asked in your video? Does an antenna change the output signal strength of an antenna? Yes And if so will it be for the better? Yes
Never had a Grid dip meter but built a noise bridge. But
there's a story....This happened in the early 90s. The noise
bridge accuracy degraded with frequency. Worked fine up to the 40
meter band. It used a conventional transformer wound on a small
ferrite core. Noise source on the primary. Secondary winding was center tapped which made
up the bridge circuit. What I found was the the voltage across
secondary windings would became unbalanced as frequency increased.
Anyway I was pulling out my hair trying to come up with a
solution. At the time I lived in New England. So luck would have
it while tuning around the bands 75 or 40 meters band I heard
somebody in QSO discussing transmission line transformers. It was
(W2FMI)Jerry Sevick located in New Jersey. What are the odds of this!
Now thinking about it I was looking at a gift horse in the mouth, remember not
much of a internet back then. Jerry worked for Bell Labs, transmission line transformer
Guru etc. So I broke into the QSO and asked him If he could give me some advice
about a transformer issue. So I explained the circuit and issue. His response was "is
the transformer your using a conventional or transmission line
transformer". I told him conventional, his next response was "I
can't help you" That was it! I was shocked, at least he could of recommended a
transmission line transformer or something. All I could think was
he was hounded by people when he got on the air or maybe annoyed
by me breaking into his QSO? For the first affordable VNA I first
started looking at the DG8SAQ SDR kits. It had to be use with a PC.
Then the Aim4170 but they stop production and were not available.
Then for around the same price range I found a HP8753A
(as is) so took a crazy chance. When I got it realized I had to
buy the S parameter test set to make it usable and a cal kit LOL.
HP8753 is not portable it weights 45 LBS. When the Nanovna became
available I bought one. The only antenna I use with a matching
network is a 80 meter doublet 80M-10M. Feeding it with 75 feet of
600 ohm ladder line and a short section of 450 ohm line to get it
the shack.
Joe

[The DB]

Home made is always a plus, but to many don't bother with that anymore, even when it comes to antennas. Its sad but I guess its the way the world is headed. I give props to anyone who attempts a home made item, no matter what it is, even if they fail at it. Its a big part of what used to make this hobby so great.

Jerry Sevick? I have a few of his books.

I know Ward Silver, N0AX, he lives in the next county over from me and shows up to a lot of meetings for the local clubs (at least pre-covid). Hes much the same way, if its to difficult a question he doesn't like to get into it to much. Aside from that he is a great guy. At said meetings he does have some great talks about various aspects of radio. I have several of his books as well, although if you own very many recent ARRL books its hard not any books that he was involved in...

I also noticed that W5BIG stopped making the AIMxxxx and VNAxxxx equipment. The AIM4170 was a good product for its day, but I guess with the newer VNA's that came out they found it hard to compete. I honestly bought the NanoVNA just to see how good a $50 VNA actually was, and was very surprised. It has far more capability than a vast majority of hobbyists will ever need...


The DB