Yes, it is good to have it all figured out before you hit the keyboard. That is why I emphasize in all my videos to plan before you jump. Know what you are going to do before you try to do it. It saves us so much frustration and tons of time. 🙂

The SWR curve is actually pretty broad. So, it is not inconceivable to have different settings putting you somewhere within this relatively broad dip. Furthermore, there is the difference in accuracy between the antenna analyzer and the VNA. 🙂

@@eie_for_you Great Videos Thanks for taking the time to help new ies and old-timers alike! Not many of us left, no more in sight!

@@bigdaadio.K2WW True that! I'm no spring chicken myself. I just *have* to share what I know and what I am learning (or re-learning) while I still have a brain to do it. There *is* going to come a time when I cannot. You are very welcome. It is my pleasure! 🙂

Thank you and you are very welcome! 🙂

Thank you and you are very welcome! 🙂

You are welcome! Next up is the input impedance of an R.F. amplifier intended for use in a 50 Ohm environment. Yeah ... impedance transformation/matching. On my bucket list! 🙂

Thank you and you are very welcome! 🙂

You are very welcome! 🙂

Good question. I am going to give you a very full rounded answer that should help you do better all around. GMRS uses Frequency Modulation, which means that stuff that *normally* affects the amplitude of the signal (like static crashes from lightning) does not affect the audio. This is referred to as being "full quieting" = a good signal. HOWEVER, if your signal weak into the repeater, the normal background noise that exists in the R.F. world starts to affect the audio quality. Your signal becomes "noisy." You are no longer "full quieting." This can sometimes be "fixed" by just moving your antenna a little bit, maybe standing up if you were sitting down, taking a half-step to the right or left, standing on one foot with your radio in the air and your tongue hanging out (just jokes! LOL 😀). If you are using a handheld transceiver (AKA: an HT), the "rubber duck" antennas that often come with them are pretty pathetic, poorly matched for the frequency, and poor signal radiators (also known as "rubber resistors"). Getting a better quality antenna can help. Don't go cheap here. Cheap just gets you another rubber resistor. If you are using a base station (mobile radio with a stationary antenna), we also think antenna, but also think coax (very often overlooked). At GMRS frequencies RG58 has really high losses (12 dB loss/100 ft at 400 MHz). It is convenient, but by the time your 50 watt transmitter power gets to the other end of 100 feet of RG-58 only about 4 watts is actually delivered to your antenna!!! The other 46 watts is being dissipated in heat in the coax. Hope this helps! 🙂

@@eie_for_you Thank you sir! I have the infamous baofeng HT at the moment with the stock antenna. My new antenna from single stuff is on its way. I am trying to hit a repeater 8-9miles away with no elevation advantage 😬 I did get the response of being too noisy and I also think I heard Morse code? Fairly confident it was Morse code, sounded like the movies. In any case I’ll try again with the new antenna. Thanks again for the “Elmer” lesson. (Just read the history on Elmer 😆)

You are welcome! 🙂

You are welcome! 😁😁😁😁😁😁

Thanks, man! I had to think about this a little... yeah, negative feedback with a capacitor in parallel with it to limit high end ... that would certainly do it. I agree with you on the fixed high input Z first stage; put the volume control between the first stage and the next. That is how I did it in my mixer project (Design End-to-End series). He is the reason I am here, my friend. That is my wallpaper on my desktop. 🙂

@@eie_for_you I'm completely with you, my friend - in my 'retirement' I'm an adjunct college prof, teaching engineering technology. While I'm not allowed to openly discuss my faith, I subtly include Christian values in the lectures and talk about the importance of integrity in the industries where they will likely work. Young people need to hear this from an old guy like me, as the rest of what they are constantly bombarded with is just the opposite.

@@carlosanvito May 21, 2011 was the beginning of judgement day on the world And it shall come to pass in that day, a great tumult from the Lord shall be among them; and they shall lay hold every one on the hand of his neighbor, and his hand shall rise up against the hand of his neighbor. Zechariah 14;13 "Tumult" = confusion & disbelief ...on purpose, by design for the punishment of mankind! Division is the result. Babylon is fallen(world systems). Division is worldwide in religions, politics, economics, news, industry, sciences, sports, medicine, entertainment, and even between the sexes. ...have you followed world events lately? The Lord is known by the judgement which he executeth, the wicked is snared in the work of his own hands. Higgaion. Selah. Psalm 9;16 Whoso keepeth the commandment shall feel no evil thing, and a wise man's heart discerneth both time and judgement. Ecclesiastes 8;5 And the seventh angel sounded; and there were great voices in heaven, saying, The kingdoms of this world are become the kingdoms of our Lord, and of his Christ; and he shall reign to ever and ever. And out of his mouth goeth a sharp sword, that with it he should smite the nations: and he shall rule them with a rod of iron: and he treadeth the winepress of the fierceness and wrath of Almighty God. Revelation 11;15 19;15 spoiler alert: The biblical calendar has been known, published(1974), and carefully studied for half a century now... There are forty+ time-paths from the bible pointing to 2033 as the last day. Go look up: Ebible2 timelines T - minus 9 years and counting... That is what young people need to know, Carlos FEED MY SHEEP

@@carlosanvito Because I have called, and ye refused; I have stretched out my hand, and no man regarded; But ye have set at nought all my counsel, and would none of my reproof: I also will laugh at your calamity, I will mock when your fear cometh. Proverbs 1; 24-26 GOD is our refuge and strength, a very present help in trouble He looketh on the earth, and it trembleth: He toucheth the hills, and they smoke. Psalm 103;32 Bow thy heavens, O lord, and come down: touch the mountains, and they shall smoke. Psalm 144;5 READ THE BOOK ! And an highway shall be there, and a way, and it shall be called the way of holiness; the unclean shall not pass over it; but is shall be for those, the wayfaring souls, though fools, shall not err therein. Isaiah 35;8

@@carlosanvito So very true! They've heard the message of "me first at all costs" ... "it is all about me and what I need" so much that selflessness is a rarity. 😞 Lying is OK if it is "for a good cause" (usually their own). Yes, integrity is so important. Keep up the good work! 🙂

LOL!🤣 TMB!! I gotta use this! Thanks! 🙂

Yes, you are right. This signal generator has a fixed 50 Ohm output impedance. However, there is a setting for the channel which we can set to the impedance that it will see on outs output which corrects the voltage as indicated on the display to accommodate the load impedance that actually exists on its output. It doesn't change the actual output voltage. It changes the voltage as *indicated* on the display. With that said, I DO personally own a signal generator whose output impedance is NOT 50 Ohms. While it is a good bet that most mainstream signal generators output impedance is 50 Ohms, it certainly in not a given. There is a whole class of them, for instance, which are 600 Ohms and 75 Ohms. So, let's be careful about our assumptions. 🙂

@@eie_for_you That's right, that's why I wrote “All signal generators I know”. But that wasn't right either, because I have an old Wien-Robinson oscillator that I hadn't thought of, whose output impedance I don't know. But I doubt that it has 50 ohms.

@@egonotto4172 True that! It is a good assumption, in general, that all signal generators of modern design will have an actual output impedance of 50 Ohms unless they have some specialized purpose. The cable TV industry is all about 75 Ohm as is the CCTV because 75 Ohm coax has less loss than their 50 Ohm counterpart. Parts of the audio industry was all about 600 Ohms; that is where the whole dBu steps in (1 mW into 600 Ohms is 0 dBu). 🙂

Thank you so much! ... and you are very welcome! 🙂

Thank you! Yeah, the higher frequency stuff is a LOT trickier! As an adjunct to this, there is my video on measuring non-50 Ohm stuff with a 50 Ohm VNA. 🙂 kzbin.info/www/bejne/mpinhGeon8dgfbc

I'm glad you liked the video! You made me think ... I thought for sure I said to turn on the little amplifier ... yup, at 10:29. 🙂

Check out this video: kzbin.info/www/bejne/mIHQpXyMotF9pc0 🙂

I'm glad you found it helpful ... and refreshing ;-)

Thank you! 🙂

Thank you very much for your service to your country! I was in the U.S. Air Force. Enjoy! 🙂

If you take in my video on measuring non-50 Ohm things using a 50 Ohm VNA (kzbin.info/www/bejne/mpinhGeon8dgfbc) you will see that I am in agreement. If we absolutely do not know what the input impedance is, where do we begin and how do we accommodate this? An initial measurement without impedance matching gives us a ballpark. From this ballpark, how precise do we need to be? Many times this ballpark is sufficient, but not always. Then we have to turn to impedance matching business. In my next video I do NOT do impedance matching because the amplifier I will be testing the input impedance of is SUPPOSED to be in a 50 Ohm system, though it turns out ... not so much. 🙂

If you look in the description, you will find a link to the "go along with the video" sheet that I provided which has the schematics and the formulas in it. 🙂

Honestly, I never paid much attention to the lines. I look at the numbers associated with the marker. If they fixed that, I haven't updated mine with the new firmware. 🙂

@@eie_for_you OK. For me the lines are the key, and the numbers are just detail. The lines tell me what structures I need to move a marker to the centre.

@@donepearce Aaaaah! I see. 🙂

Thanks, man! 🙂

In the simplest cases, yes. I have also seen nearby (downstream or upstream) resonant circuits or circuitry "pull" the bandwidth edge of a resonant circuit so this didn't apply. 🙂

Yeah ... it is a bit of a mind bender! 🙂

Good question ... The thru connector only affects the thru calibration. I know this is obvious, but I just wanted to be sure we are on the same page. If this were a lab quality calibration set, then the thru connector's characteristics are taken into consideration when the calibration is performed. This is done through extra parameters that we enter for this and all of the standards used. When we calibrate without these extra parameters, the VNA assumes ideal standards. Among other things, it means that the thru standard is assumed to have 0 loss and a perfect 50 Ohm, non-reactive impedance. With that said, if we use good quality through connectors, the effects on the thru calibration is actually pretty minimal, especially when we realize the type of stuff we are doing and the quality of the actual standards we are using. Very, very few people are willing to pay $1000++ for a set of laboratory quality standards for a nanoVNA. So, the MUCH shorter answer is, "Yes it does have an effect, but, all things considered, it is a very minor effect IF we are using a good quality "thru standard." Hope this helps. 🙂

Thank you! I'm glad that you found this helpful! 🙂

Thanks! 🙂

LOL! I was one of those slide rule guys many moons ago! 😀

Unfortunately, not everyone remembers what they learned to get their license. And ... not everyone who watches these videos are hams. 🙂

First, the trap is tuned for the 14 MHz band so as to "hide" the extra wire required for 40 m while on 20 m. There is the forever debate where you want the trap tuned by a lot of people; each of these have their "good reasons" for tuning it there. My personal preference is near the top of the frequencies I want for the 20 m band. Why? Again, my reasoning ... It hides the extra wire best where I need it hidden the most. Then, as I move away from the resonant frequency of the trap, it becomes less effective in hiding that extra wire. Thus, as I move away from the higher end of the band, the antenna will "look" somewhat longer, widening the good SWR on the 20 m band. The trap Q will not affect the tuning on 40m because it becomes "invisible" to it. We are far away from the resonant frequency of the trap. Be sure to take in the video on how to create your own capacitors for the trap: kzbin.info/www/bejne/jHqwmZmObtaol8U I hope this helps! 🙂

Yes, I know this and I acknowledge this at the beginning as I tell folks that there are two camps. Then, I give the hetrodyne concept a much more complete treatment starting at 7:38. I start with the purely analog versions, show how the digital versions work in this camp and then talk about the hybrid versions (like the RF Explorer) which uses a hetrodyne front end and an FFT back end. This presentation is based on the Rhode&Schwartz book "Fundamentals of Spectrum Analyzers." 🙂

Well ... actually, this is simply the trigonometric multiplication of the two signals as defined. The output of the Fourier is in the form f(x) (frequency domain) and this is in the form A(t) (amplitude at any time, t, a time domain representation). We could apply the Fourier analysis to it to yield the frequency components from this time domain function, but with the frequency components so obviously represented in the time domain function, to do so might be a fun thing to do, but not very productive. 🙂

The nanoVNA is a measurement device. It will not do the calculations for you. 🙂

Yes, actually! A company I worked for bought a 1,000 ft roll of multiconductor, twisted pair, custom cable that I had to test for impedance. The TDR method is the method that I used to do that.🙂

@@eie_for_you fantastic! Thank you! Looks like I've got some homework to do then 🤣

@@mjunek It's fun to discover stuff. When you see it working, it is very satisfying! 🙂

I'll point you to this video which will explain the answer to this question much better than I can easily do in a reply to your comment: kzbin.info/www/bejne/amm1f6Frqb2qaMk 🙂

Thanks! 🙂

😞 Sorry to hear that this is giving you such difficulties. Suffice it to say ... if everything is perfect, there is just the two sideband pips. If something is not perfect ( in other words, not perfectly linear), then there will be more sideband pips. Being that we live in a world with imperfect everything, we have to live with at least some extraneous sideband pips. 🙂