WOW Dave! An electrical engineering degree would have been handy to stay with you during your explanation. But, you give us non-technical folks something to reach for. I'm glad that you dumbed things down at your conclusion. That being said... We newish hams are so fortunate that you continue to lecture on KZread. You sir, are a treasure to ham radio!

@davecasler

3 жыл бұрын

Thank you!

To bring a musician’s understanding of resonance to the antenna system: BRILLIANT! Thanks, Dave.

I have an EE degree, I was very glad to hear Dave give the long answer to the question. 100% right as usual, but sometimes people don’t have the patience. To me, it was music. Excellent Dave

As a retired EE (microprocessor/computer world) and a new HAM, I thank you for an excellent and clear explanation. I appreciate the "long" answer.

"It is the job of the antenna to do the impedance matching between the 50 ohms of the transmitter and the 377 ohms of free space." It's sentences like this right here that is why I'm not only a subscriber but a patron. You don't just go in depth, you word things in such a way that every so often one sentence completely tears down a conceptual barrier that's been planted in my head for years. Bravo!

@joachimoberhammer3020

3 жыл бұрын

it's not correct. The tuner matches the transmitter to the resistive part (R) of the antenna, so it does an impedance transformation between the 50Ohm of your transmitter to the whatever impedance your antenna has, and it eliminates any reactive part (X). Whether the antenna itself is radiating well (i.e. matched) to the 377Ohm free space at your sending frequency is a different story. Thus, the tuner does NOT match the transmitter to the 377 Ohm of the free space, only to the resistive part of the antenna, which, for a well radiating antenna (at a specific frequency), is then hopefully also well radiating. If you have a poorly radiating antenna, the tuner will do it's nice job and get the VSWR down, but that does not mean that your power is radiated, might just be used up in the non-radiating resistive part of the antenna (or any other lossy elements in between). Even for a poor radiator the tuner is helping, as it will increase the power which you actually get out, i.e. it will increase the radiated power as compared to the non-tuned case. But the best solution is always to take care to have an efficient radiator (in which case you only need an impedance transformation and then not even a tuner, but the tuner can do its job here as well within its limits, it just narrows down the bandwidth since the tuner is resonant and an impedance transformer is not). I'm always surprised how much misunderstanding and misconception is in the HAM community about things which are the actual core of their business.

@w8natshenanigans705

3 жыл бұрын

In the meantime, I'm never surprised by how willing someone is to give a lecture about something that wasn't even mentioned, just to sound superior. It's nice that you know that 'the tuner does NOT match the transmitter to the 377 Ohm of the free space', but I didn't mention tuners once. Twice in your tome, you reaffirmed that it's the ANTENNA's job to match to the 377 Ohm of free space. This is the very concept I was commenting on.

@Jerrythenerdful

2 жыл бұрын

The statement of matching to free space is utter nonsense.

@DeShark88

Жыл бұрын

@@joachimoberhammer3020 You just didn't listen carefully enough. He's right (as are you). The job of the ANTENNA is to match the impedance between the 50 Ohms coming in and the 377 Ohms of free space. Note he didn't say the job of the TUNER. The job of the TUNER is to match the impedance of the transmitter with the impedance of the antenna. They are, as you say, two different things. But that's exactly David's point. As it turns out you're both in accord.

@subramanianr7206

Жыл бұрын

​@@Jerrythenerdful Yes, Dave is a big comedian and I like his jokes 😂 De VU2RZA

I'll have to watch this 49 more times i guess.

@qrptedmac

3 жыл бұрын

Lol. I thought I was the only one.

@robertlewis3336

3 жыл бұрын

Nope. I know even less now than before I watched.

@BusDriverRFI

3 жыл бұрын

Please don't. For your own sanity.

@davecasler

3 жыл бұрын

Oh go ahead and watch it 49 more times. I can always use the views!

You sir have forgotten more than I will ever know! Thank you for taking the time to make these videos.

I vaguely remember an old parable about blind men describing an elephant. That’s not what you get from Dave! You get everything explained.

I watched this video and the local University sent me a BS in Electronics Engineering. Wow, Dave, I learned more about feed line and antenna theory in that one video than in all the rest of my HAM studies combined. 7-3 KD2SML

You make complicated things a bit less complicated 🤓🤏👍 Thnx Dave

Thanks Dave for taking the time and creating this awesome video. I could watch another 2 hours so don’t worry about the length of the video.

W0W! Thanks Dave for answering my question, I've been having a round or two moving snow off our roof up here...one of those years. Spring is coming fast and now I can spend more time getting my shack set up. Sooo appreciated your valued if not overwhelming answers, I will need time to fully digest it all. The "No" rather answered the Q, but the remaining lecture drove it home. Reminds of my USN ET school of many many years ago. Regards, Dave (also)

Excellent explanation of a very complex subject!! I love the introduction of music to explain resonance!

This is a terrific video, Dave. It has filled in several gaps for me as a medium-new ham. Thank you!

Thanks, David - great information here!

David, you're the best! Thanks for efforts!!!

Best description of tuning I have heard - great job 👏 thank you

Probably one of your best! Thanks!

Thanks for the explanation, Dave. Antenna tuners are necessary evils in MW and HF radio. I've always thought of an antenna tuner as a device that "fakes" the transmitter into thinking it's feeding a resonant 50 ohm load. Without exception, AM broadcast stations have an "ATU shack" at the base of their tower(s) to fake the transmitter into a 50 ohm load when the tower is anything BUT 50 ohms. I try to put up antennas that are resonant for the bands I use. It is always painstaking and trial and error - usually hard to keep them that way.

@timothystockman7533

Жыл бұрын

The broadcast transmitter actually sees a 50+j0 load; there is no faking. When possible, broadcast towers are of the proper height to be close to natural resonance, and the ATU is mostly used to match the ~24 ohm radiation resistance of the tower to the 50 ohm coax. But they are also used to trim out minor reactance to make the tower electrically resonant at the assigned frequency if the tower is not exactly the right height. Environmental factors can also change the base impedance and may need to be trimmed out. Of course, if the tower is far from the correct height, as in the old days when stations went to 640 and 1240 for Conelrad, the ATU has to null out some major reactance to get the tower to resonate. Typically a station would have had a second ATU for Conelrad with big contactors to make the switch. When the tower is part of a directional array, the base impedance is determined by the array parameters. A few arrays have bizarre things like negative towers (towers with a negative base impedance which actually absorb power). Stations which run different patterns at different times usually have a separate ATU at each tower for each pattern with RF contactors to make sure the coax always operates at 50+j0. Towers which are not used for particular patterns are switched to detuning networks which make the towers electrically invisible. There is nothing inherently evil about an ATU. Broadcast stations typically use large air-core inductors made from tubing and vacuum capacitors for best stability and low loss. A properly designed and built ATU is a thing of beauty. Broadcast stations may use a device called an Operating Impedance Bridge in-line to measure impedance during normal operation to see if it has drifted too far, but when the antenna system is built from high quality, stable components, I found the OIB mostly unnecessary.

You are a genius, Dave. Thanks for simplifying things.

Thanks for the excellent video Dave. It's good to know the theory behind my antenna tuner.

Overly lengthy yes. But in covering everything and not subtracting from the topic I took away 2 invaluable nuggets of information this time Dave Thankyou.

I got much more out of this video than what was advertised. Thanks Dave.

Thank Dave for this in depth explanation 👍🏻

Thanks for the explanation. Finally discovered your channel and I hope you are still actively broadcasting. By the way, noticed your Air Pilot in the background. Yeah, I too love lanterns only I absolutely can't stand the smell of kerosene. Another thing I love is my balanced fed, all band, tuned doublet antenna.

Great explanation Dave. Thanks

Excellent explanation. I just subscribed after listening to this video.

Excellent video! Thanks!

Pretty sure I need to watch this one more time, with no distractions.

Well Dave, at 32 minutes in, you gave me the answer. I struggled to follow the first half hour. You did prove, beyond a reasonable doubt, that my degree is not in EE. Michael Edmonds is right. You're a great asset!

I see the variable inductor and variable capacitor in the MFJ-986. It makes perfect sense how it can make the whole transmission circuit resonant and balanced.

hi Dave. great video! On these days I replace my EFLW antenna with a Doublet with balanced feeder line .... now I easily operate 80..20m just use a MFJ qrp tuner .... Just a proof of concept of you video 73 paolo

Excellent explanation! Thanks. 73

Fantastic explanation. Thanks !!! As a beginner ham I need to understand what is really happening in those RF circuits. Long time electronics design engineer, but never did RF. Basic rules of PCB design were most of the time sufficient like gnd plane, C-decouple, some filtering of I/O. But radio is a different animal all together 🙂 And you have mentioned the great Nikola Tesla. One of the people who truly understood the working principles of the nature all together. Being my fellow countryman make it even more special 🙂 Understand first build later, as he was saying... Anyway all the bast to you Dave and 73!

Wow, best explanation ever!

Very informative for a total newbie, easy to follow and great presentation, my knowledge has increased 10 fold. I'm a bit unclear about 'j' But Hey, I'm a newbie :-) Please keep these videos coming! Happy New Year, 73's Richard.

Love it Dave!! Love ya man!! W5OAG

Superb! Thank you!

Howdy. I totally enjoyed Your assertiveness. For what it's worth, I am with You. What You say, I think, backs me up when I argue that a tuner + transmission line + non-resonant antenna + environment will radiate almost as much as a perfect resonant antenna. I recognize that the standing wave current nodes in the line will cause ohmic losses. Also, I recognize that the radiation pattern may anything but a clean doughnut. The pattern may have lobes sprouting at any direction. I have had discussions when it is argued that the tuner does not change the physical properties of the antenna. Yes. The implication being that the reflected power is all burnt up in the tuner and the transmission line. Regards.

Hey Dave, thankyou Sir, unfortunately this level is a bit above My station at this moment in time!, however, just listening to Your voice was making Me feel drowsy, I've loved it, I'm sure something may well have sunk into My pickle jar of a brain somewhere!, Greetings from England btw👍

love you dave.

Bravo Sir! Instruction AND drama... "Are you ready for this?.... Are you READY for this?" Loved it! 73 Chris M6VCJ

Your video is didactic and motivational. Congratulations

I am SO deficient in general "Antenna Theory" it's sad. I just don't get the "Magic" that make antenna's work. You have helped in such way that, I kind of, maybe, that I sort of, could possibly, maybe, understand this all one day...

Thx . Really interesting!

Thank you, thank you, thank you! I am a need to understand what is actually happening kind of guy, and you explained what is really suppose to be happening when a tuner is used. I have about a 1,000 feet of hardline coax (new end pieces) picked up around my neighborhood when our 3 cable companies rebuilt and repaired their build after Michael's 165MPH winds came through. My old FT101 serial number 458 (fresh from Japan) would have tuned to a 75 ohm feedline no issue but not so with the newer rigs. I have an still in the box new 7300 so if or not the tuner will mate with 75 ohm is unknown. I did aquire a few 75 to 50 transformers to also try. Anyway, the until now MYSTERY of tuning my meagure mind has been pondering all these 50 years has been revealed, even if a multiple of viewing this episode is still needed!!! Again THANK YOU !!!

@davecasler

3 жыл бұрын

The 7300 will tune 12.5 ohms to about 150 ohms resistive (3:1 SWR). For anything more complicated, you'll need an external tuner.

@americaswayout4489

3 жыл бұрын

@@davecasler I have several external tuners but would prefer just the internal or the internal along with a device seldom mentioned these days, it is made by MFJ and called a tuner extender. Just adjust it to the most noise on your receiver and retry the internal tuner and generally it will then tune, if not repeat the process with the next setting either side of the most noise. Thanks Dave, really appreciate yoir work.

haha, Dang Mr.Casler, it's not too long, I'm hopping for a part two, how to measure all these new words. How do I know I need a balun unun, what the heck is reactance....Thank you so much for this lesson. I've been searching for this kind of info for awhile. K8CDM, Dave

An antenna coupler tunes out the complex portion of the feedline/antenna in order to present the transmitter with a real 50 ohm impedance, it does this by selecting the capacitor and inductor values necessary to subtract the complex reactances out leaving only the real component.

Dave I love your channel, As to your comment about tuning forks, you can still get them from any reputable musical instrument store or science supply store.

Hi, Dave. I play frailing and melodic claw-hammer Appalachian banjo and have several tuning forks and they're still available quite commonly at music stores that sell acoustic instruments. Also, just for the fun of it I checked on Amazon just this moment and found dozens and dozens of different types of tuning forks for music as well as for other uses. Don't know why you'd think they're not available anymore lol.

👍👍📻⚡️🎤🎧😀👍👍 Thanks Dave! So much info!

Hi, Dave. I've learned a lot from your videos and articles in QST. My question concerns the usefulness of a certain type of HF antenna and tuner combination for Field Day use. I've set up an EMCOMM communications trailer and am currently running a 600 Ohm ladder line fed, inverted V doublet, 80-10 meters, fed from a manual tuner into a 4:1 current balun. It's a great antenna for EMCOMM because of its efficiency and the fact that I'm parked on only one or two HF frequencies. For Field Day I tend to "hunt and pounce" across a wide range of HF frequencies. I probably wouldn't be too popular during Field Day if I was constantly tuning up with the manual tuner every time I changed frequencies, so I'm wondering how well an external automatic tuner might work with this antenna set-up. I like the doublet HF antenna design because I can work all 80-10 meter HF bands with one antenna. I'm just wondering how well it might be suited for use as a Field Day antenna. 73 and thank you. K7SFA

Tricky concepts for newbies and veterans alike, you did a pretty good job. A smith chart might make the concepts you are trying to convey a bit more clear, but like I said you did awesome.

@davecasler

3 жыл бұрын

Indeed a Smith Chart would help. Sadly, they confuse the daylights out of me. I never encountered them in my schooling, and they're pretty rare in ham radio.

@mrkattm

3 жыл бұрын

​@@davecasler I also did not encounter Smith Charts in my undergrad EE course work, they really are not necessary with today's tools, however, they are a fantastic visualization tool when teaching this type of material to newbies (and veterans). I would recommend a RF design book titled, "RF Circuit Design 2nd Edition by Christopher Bowick" it is one of the best books on RF design for the non engineer that I have come across and I think that I have them all :o) There is also a youtube channel named "w2aew" where the host Allen has 4 or 5 excellent videos on smith charts. With these two sources you won't be an expert but you will be well on your way to being one. Again thanks for what you do and keep up the excellent work.

@mrkattm

3 жыл бұрын

​@@davecasler I also did not encounter Smith Charts in my undergrad EE course work, they really are not necessary with today's tools, however, they are a fantastic visualization tool when teaching this type of material to newbies (and veterans). I would recommend a RF design book titled, "RF Circuit Design 2nd Edition by Christopher Bowick" it is one of the best books on RF design for the non engineer that I have come across and I think that I have them all :o) There is also a youtube channel named "w2aew" where the host Allen has 4 or 5 excellent videos on smith charts. With these two sources you won't be an expert but you will be well on your way to being one. Again thanks for what you do and keep up the excellent work.

There is at least one video of Julius Sumner Miller on KZread explaining resonance that are really good!

Ohm-my God! I need a few engineering classes.

Excellent explanation! Thank you very much for this video. 73 DL2SST

Hey Dave, thanks for all your great videos. I have to say that I am not a fan of using antenna tuners other than to take out the last little bit of mismatch. As it is better to have an antenna that is as close to resonance as possible. Otherwise, all the tuner is doing is to hide the problems of a non-resonant/lossy and therefore an inefficient antenna. All that is being done is to make a bad antenna a nice dummy load to present to the transmitter :) I was kinda hoping that you may have commented on that aspect. Regards, Dave, VK2TDN

Great video Dave. You mentioned it very briefly in the video, but I was wondering what causes all the noise when a tuner is tuning? I tuned up a random wire antenna today and my tuner clicked and clacked like crazy. Are the variable capacitors and coils that loud when they are adjusted or is something else going on? Personally, I attributed it to tiny people pushing around switches like crazy... but I'm 98% certain there aren't actually tiny people pushing things around in there.

@neoeinstein

2 жыл бұрын

What you’re hearing during this process are a whole bunch of tiny electromagnetic relays that switch on or off the flow of electricity into the various capacitors and inductors that make up the tuning circuitry. Relays actually involve shoving or pulling a little contact back and forth to either engage or disengage a circuit. That’s the clicking that you’re hearing.

thanks for the information on how auto tuners work. I have auto mfj on my 590

Good day; May I ask for the advice? I have a VHS radio on the boat, there is 50 Ohm output for the antenna . It works within the range 156 MHz - 162,05 MHz, with broadcasting power 1W or 25W.. Unfortunately the antenna on the top of the mast is connected with the 75 Ohm coaxial cable. There is need to replace it with 50 Ohm cable. I have two questions: 1, whether working on this unmatched cable can destroy the radio? 2. Is it possible to use any balun or other way to achieve matchig, down without laying down the mast? I shall be grateful for the help. Mark

Cool. Now I know what the mystery box of wizardry is thinking :)

Unless tuning at the feedpoint i will stick with a manual tuner. The reason for this is that sometimes the Q on the tuning is very fine and with a manual tuner you can hunt out that very specific zone of capacitance and inductance to better receive weak stations. Now ask yourself just how many combinations of inductance and capacitance is available with an automatic atu? For sure most automatic ATU's cover most of the HF bands but when you need that more tricky tune to be so finely adjusted so as to bring in that weak station there is no guarantee that the automatic ATU can get as close as you can with a dial, it will get close but no guarantee it's exactly where you want it to be. If you have tuned in weak stations on various antenna designs with a manual tuner you will know what i am talking about and if you know a bit about electronics and capacitors in parallel and series you will know that you can arrive at many combinations but you can't cover all of the gaps everywhere without a variable capacitor or two and ideally a variable inductor.

Swoosh.. that went over my head 😀

Thank you for the theory and answer to the guys question. You have also helped me understand more about the theory used in the question pools for advancement as I want to know what the answers are about...not to just memorize the answers to past the test! 73 N6ZKI

REQUEST -- Dave: Can you provide a new episode explaining the "workings" of an automatic antenna tuner? I would like to have its "theory" explained as to how all the coils, relays, and so forth, work together for finding the best resonance tuning. Thank you.

Square waves are equivalent to a sine wave at the same (fundamental) frequency added to an infinite series of odd-multiple sine-wave harmonics at decreasing amplitudes.

@davecasler

3 жыл бұрын

Yes. Don't forget that the phases have to be right too.

@MarkRose1337

3 жыл бұрын

James, I never thought of it that way. Neat.

Great video as usual! I’ll say that orchestras are moving slowly to 442. In Europe they have been there a while, and some major orchestras in the US are moving, but slow. 432 and lower tunings are still used by period ensembles, like Baroque and earlier. Yes, you can still buy tuning forks. Still used by some timpanists, after hitting the fork you can hold it against your head, near the temple and it’s amplified in your head and you can flick the timpani head using other hand and re tune heads in the middle of a passage. 73 de KJ4KPW

@davecasler

3 жыл бұрын

Another factor is that people are taller (and wider) than they were 200 years ago, and so our poor taller sopranos have a harder time hitting 440, let alone 442. It does seem to be a bit of a bone of contention amongst the cognoscenti (of which I do not claim to be a part). Most people have absolutely no clue what any of this means! Our church organ and my own personal organ can be tuned up and down, mostly to match any instruments it may be accompanying.

@timothystockman7533

2 жыл бұрын

I call this "pitch wars". At some times, there seems to be a competition between orchestras to see who can tune to a higher pitch. No longer do they tune to 440, but 442, 445, or in extreme cases, even higher, in an attempt to make their music sound more exciting. Back in the day radio did a similar thing by running their turntables faster than 45 RPM. Not only would they have extra seconds for more commercials, but their slower competitor sounded like they were dragging; their music sounded tired and lifeless.

@nickwright7944

2 жыл бұрын

@@timothystockman7533 fascinating 👌

I have an Yaesu FT-991A. Dave, in your honest opinion, should I use an antenna tuner? I was considering a MFJ-929, as that's the most I can afford. Thanks and Best Regards. 73

Thanks!

@davecasler

4 күн бұрын

Thank you for your financial support of this channel! It is greatly appreciated! 73, Dave, KE0OG.

so again Dave you have me thinking. is this sorta like a pure sine wave and then you have a modified sign wave in inverters. is this sorta the same on the radios?

I've got one. I live in an apartment. Can I use (no other option) the electrical ground for ground? If they did it right, isn't it the same?

back in the day. I know you lived threw it. I puchased a army big stick for ten. used it on eleven and ten. that was the days when ten and eleven was in full swing.

You mentioned tuning forks. I just watched one of your videos on J poles. Is there a commonality between the two? From what I know of both (not much) I see a lot of commonality.

I will go there tomorrow

A tuner tunes it's output to the conjugate of the impedance of the load on the output of the tuner. This implies that the tuner tunes the load by cancelling any reactance in the load.

Dave there is a lot of talk about the radiating power lost when using a tuner, have you ever used a wattmeter at the transmitter and another at the antenna to see the actual wattages? And compare that to a 50 ohm antenna and the same 50 ohm feed line.

so the five 90 would not have the problem that you talked about on early ken woods?

Nikola Tesla's colorado springs antenna was 30" turned wood sphere covered with tin. Polished to a mirror finish. Covered in schalack. Finally, covered in black rubber paint. For the longest time I couldn't figure out why the medal needed to be polished to a mirror finish and then completely covered with rubber paint.

Hi Dave, Respectfully, the antenna tuner and an antenna do not match the impedance of free space. There are two (or more) correct ways to look at a tuner, depending on if you want to look at it with wave theory or just as a matching system, but the ultimate result to users is the tuner corrects the antenna system impedance at the insertion point and brings the entire system into "resonance". We also have to be careful with reflected power and standing waves. The impedance mismatch between a load (like an antenna in this video) simply sets up a standing wave. The standing wave STANDS with the result voltage and current distributed along the conductors in a transmission line vary. That voltage and current change is what causes increased (or decreased) transmission line loss. Reflected power does not keep bouncing back and forth until it is dissipated. Reflected power does not make it back to the PA where it dissipates as heat. This is easily demonstrated with a few simple experiments. None of the common antenna tuners we use, or that are inside radios, are symmetrical in SWR performance. They generally don't do well at all with 3:1 mismatches that are lower impedances and capacitive, but they can actually work better and more efficiently into high impedance loads. Typical tuners often exceed ratings in the high impedance direction. We need to be very careful specifying some exact matching range based only on an SWR range a manufacturer used. It might be best to avoid certain details rather than say something misleading. Sometimes it is better to just answer a question as simply as possible and not start adding things that wind up being incorrect or misleading.

👍👍👍👍 very nice Video 👍👍👍👍

I have a butter nut laying in my hall. the misses is about to kill me because it is there, but I guess you have to tune each one of the forty 75 any thing between ten and eighty. the one I have has nine bands on it I guess, but each one has to be tuned. the reason it is still laying there, because of where I came from. if you tinned the antenna on the ground and the erected it the swr would be different one the ground as to being erected. so my worry is going to be like in the old days of the eleven meter band. different on the ground as to when you put it up. My question is if ground mounted a few feet of the ground will the matching still be good we just tuned it to one. point five or below. .

I think there's more to say that's typically not said: could you talk about the effect of a capacitor or an inductor in changing the relationship between the current and voltage, and how that relates to resonance?

The so called antenna tuners within radios or close to radios are not literally antenna tuners, but they are matching networks. In the usual case of a badly adapted antenna with a non-50-Ohm impedance the matching network has to maximize the power transference from radio to the antenna at the used frequency, which then falls into the category of conjugate matching, where the impedance of the antenna is "mirrored" in such a way that the impedance is the same, but the reactance is negative. According to the following paper from 1965 "K. Kurokawa, “Power waves and the scattering matrix,” IEEE Trans. Microwave Theory Tech., 13, #2, pp. 194-202, April 1965." the power wave reflection is reduced to 0 in case of conjugate matching, but that does not mean that all the power is transferred, and it also does not mean that the travelling voltage wave reflection wave is 0 too, because the reflection coefficients for power and travelling waves are calculated differently. Nevertheless, in that conjugate matching case the incident and reflected travelling voltage waves are reflected between the antenna and the matching network, and that is the reason why they do not get to the radio, and their energy gets dissipated mostly in the transmission line and the matching network, i.e. although power transference is maximized the remaining reduced reflected power is lost. More details on matching networks can be found in chapter 13 of the "Electromagnetic Waves and Antennas" book from Sophocles J. Orfanidis that is freely available online. There are losses in conjugate matching, and therefore we should strive to reduce the losses by adapting the antenna side with impedance transformers or similar things getting closer to the reflectionless matching case or use antennas that have hopefully out-of-the-box 50 Ohm impedance. Thanks and 73 from Tihomir CA3TSK

so that is why inverters with square waver power inverter need to be pure sign wave to work good on sensitive radio equipment ?

this has me thinking and that means trouble.. so where should the tuner be? before the amp or behind the amp. I''m thinking about all this. it is all mind boling?

@patrickbuick5459

Жыл бұрын

Since now the matching of importance is between the amplifier and transmission system, after the amp.

IS THIS THE SAME WAY WITH CONVERTER ? i WOULD LOVE TO HAVE A PURE SINE WAVE INVERTER

BTW Dave, you can get a tuning fork at a medical supply company. They are cheap if you want a 128,512 or 1024

In my excitement and trying to make sure I wrote what I wanted to express, and my memory I frequently forget to add my call sign. But not this time. 73 de AG7MW

Dave you keep me thinking. about radios and there trans mission phases tube veresers transistors.

Tuning antenna tuner that tunes the antenna. :D

@davecasler

3 жыл бұрын

An antenna tuner does not tune an antenna. It doesn't change anything about the antenna or for that matter the feedline. But it does make the combination of the feedline, the antenna, and to some degree the environment behave nicely for the radio's final amp.

My Head hurt, thanks.

E. H. Armstrong. Edwin Howard Armstrong. Enjoyed the Video. Thanks & 73 de N8YB

Great show. Thanks for the math. KD9HWH.

I would like to understand the differences between L-Network, PI-Network, and T-Network tuners. I once heard a vendor suggest an L-Network-based tuner has less circulating current than the other types suggesting more power is delivered to the feedline/antenna system?

@davecasler

3 жыл бұрын

Sounds like marketing hype. An L-network takes fewer expensive reactive parts, but you need to be able to switch the L in the other direction if called for.

Doesn't the function of impedance matching not come into play, vs 'tuning'?

3:30 Yes Bridges, They should not be at 2 Cycles per second, or 1 is dangerous too, amazing how people walking in time can bring down a Bridge

What is tuning? It is adjusting the resonant frequency. An antenna's resonant frequency may be adjusted by changing its length ala Stepir or it may be adjusted electrically by loading inductance or capacitance. An antenna tuner loads the antenna with inductance or capacitance to adjust its resonant frequency.

@timothystockman7533

2 жыл бұрын

@Tom Smith Antennas do not possess some special form of resonance which only responds to changes in length. They work just like any resonant circuit. If you add inductance or capacitance, which a tuner can do, it will shift the resonant frequency, just as it would if you added to a tank circuit. This misunderstanding is why I advocate for a question on the FCC exam which would help prospective hams to learn the correct concept of antenna resonance. I think some of the confusion comes from the fact that an antenna tuner serves a dual purpose: tuning (changing resonance by adding inductance or capacitance) and/or matching (transforming impedance). Some grab onto the matching function and forget about the tuning function. --de N3TS

@timothystockman7533

2 жыл бұрын

@Tom Smith I said nothing about bandwidth.

what's with the electric typewriter back there? Haven't seen that in 30.

Are you aware of anyone doing and posting results of a test where they measured parameters like X,R,Z, and theta at the shack and antenna ends plus field strength before and after tuning with the tuner at the shack, then at the antenna? Is it even possible? If possible, what equipment would be required? I truly want to put my mind at rest regarding all of this and there is nothing like empirical evidence to do so lol. Thanks.

I'm listing to you in one ear. I got part of it . square wave is something that is in cheap inverters and pure sign wave is what you need to run your sensitive radios and tv's that picture looks like a m f j manual tuner that I have. I have auto tuners on my radios. I know that I'm not talking about. what you are talking about but on antenna's if you have a die pole and it is not an inverted v what one that is stretched out straight. I live on the side of a hill and I stretch out my antennas. so I would like to know the difference