In this video I explain What SWR means and how it works. Of course my hose and rope demo are similar to what you would see in a 5th grade science experiment, but it really shows how it works quite well and you can try this at home.
THIS is a great example of what RU-vid instructional videos should be. Smart guy, no hoopla, to the point, great explanation that resonates (pun intended) with all audiences. I’m new to ham; this totally cleared up SWR for me. Thank you!!
Good stuff Alex. Part of the problem when we go out and do the "right thing" and get a FCC license, is that we are usually only memorizing test questions. I found myself wanting to understand WHY this or that answer was correct. These kinds of tutorials are great.
it has been years since I was a field tech. While I didn't work in these wireless realms of rf, much of what I did is lateral to your specialty. I miss the work. I loved being in the field, and I loved to geek out on this stuff. I would bore the hell out of everybody around me and I never understood why everyone would roll their eyes.
Both matter always. It doesn't matter the direction of the power transfer (into or out of the antenna), both the center and ground play the same role in the antenna radiation plot.
Consider it as a reference voltage. Electricity cannot flow unless there is a different voltage path for it to flow. Without the ground, there is no reference voltage (zero volts) to which the electricity can flow.
Thanks for this tutorial, I am an airline pilot and ham radio operator mostly CW, I learned in both scenarios that at least for HF antennas one should always look for a 1.0 in one of the many available meters for those frequencies. I understand the radiation pattern and particular needs are also clue factors, however I must say that regardless of those two factors a low SWR is always desired, not only to obtain the best possible signal but also to prect your equipment unless you are using an antenna tunner that tricks the transceiver?
svsoftair - In most cases and SWR of 2.5 is acceptable for most situations unless you are running up against the limit of your transmitter. Of course tuning devices are excellent for multi-band antennas and always a good idea. Ideally you have the radiation pattern you want and good SWR for a good system.
So I understand what poor SWR does on the transmit side but what is its effect on the receive side? Does it just receive less of the signals power thus needing a more sensitive recover?
Wyll Surf Air Good question. It is the same thing, but in the opposite direction. In the case of a receiver, it receives a signal from the antenna. Thus you have the exact same system, but the exciter is the antenna instead of the antenna being the load. Basically it is me swinging the rope from the end attached to my deck. it makes no difference.
HI Alex, eating up all your info like free hotcakes... can I make a small suggestion though? you seem to use the word 'system' to describe a wide plethora of things... It could be just me..
Does anyone know how the Taranis works out SWR? It feels like the number is displays are worked out differently. For example I have an antenna with an SWR reading of 17 and one with a reading of 32. Presumably the lower reading is better but how do those figures compare to what we normally see?
put a dummyload resistor( i assume its 50 ohm )across the antenna terminals and look at the measurement. That should be the 1:1 value anything higher would an unknown fraction worse but all relative to that.
This explanation is flawed people, but you'll lap up and praise anything on RU-vid. Stop trying to take short cuts, read a text book and learn the right way, that is if you can read.
So what have you produced? Nothing? Oh my what a surprise! An internet troll criticizing a patented inventor. Do the World a favor and go play in traffic.
@@CAGreve1231 I'm not trolling at all, you are spreading misinformation and everyone is praising you for it. It takes for someone like me to keep this type of thing in check, I take my radio very seriously, and I worry about the future of it with so many like you on YT. As far as my own production, I am not interested in doing that, and nor should I have to, it is irrelevant. You need a lesson in manners, and if you were a real man, you'd own up to your mistakes and take it on board so things can progress without polluting people's minds with false theory. You could even thank me. But no, you go for the old troll routine and question what I have done in relation to radio. Mate, I've done a lot, including this.
@@CAGreve1231 and what's a patented inventor got to do with it? I don't know what you've invented, and now frankly, I don't care. I hope it's not radio related. I know of a very popular antenna manufacturer with a prevalent yt channel, and he doesn't know about CMC, and he confused antenna resonance with SWR in his videos. Remarkable.
@@CAGreve1231 that's a very poor attitude you have. Haha, and how many patents are out there? How many being used, sold, achieved? Now tell me what Voltage Standing Wave Ratio really is without googling it. Tell me what we're really measuring here and why. First of all, what are standing waves.? I tried to point you in the right direction. I'm not a ham by the way, CBer here.
You barely explained why a low SWR may be desired, too busy tying a rope to your, um, deck. And you said something about hitting resonance. Antenna resonance and SWR are two separate things. And then you jumped to antenna pattern which was somewhat irrelevant to the subject unless you explain why. And you did not mention resonance as an important factor either. I think you have just misled and even confused a bunch of people out there. Was this intentional because you don't really know what you are talking about in full?
Like the video - use of home made props was nice :) With the Vector Network Analyzers for testing SWR ..... its true professional equipment is hell expensive but you can buy decent budget testing devices like the MiniVNA products for a few hundred bucks.
So we've established VSWR is not exactly the ratio of the power coming out of the antenna compared to the reflected power. For example, an SWR of 2:1 with 100 watts input, with a lossless transmission line, would mean about 11 watts is reflected back. So that's a ratio of 89:11, or for easier comparison, 8.9:1.1 which = about 8.09:1. Anyway, that's hardly 2:1.
@@CAGreve1231 but it's not right though, is it? It's a different ratio. What is VSWR, and it's the first thing that comes out of your mouth. Yet all these people are saying, oh, I could never understand SWR and now I do. And, it's the best explanation I've ever seen, and I've had it explained to me by professors. But it's fundamentally wrong, from the outset.
Awesome! Went fom murky grey kinda get it, to flat out "gotcha!" concerning VSWR and it's place in antenna specs. Thank you very much for taking the time to make and post informative videos.
Great explanation. I’ve had very talented and knowledgeable engineers try and explain this to me only to further confuse me. You on the other hand can be excellent at teaching to laymen .
So let me see if my thinking is right. If your swr is bad then your tx has more milliwatts used for getting the swr right and therefore means less range.
Kurtis Towery - Almost, but not quite. if you have low SWR, your transmitter wastes more power generating a standing wave and less power gets out the antenna.
Confession time, I was all geared up to make disparaging comments, however your video seriously surprised me. All in all a down to earth and HONEST explanation that just about covers what people need to know.
Video Aerial Systems , yes, there are many "teachers" who seek to impress the audience more than they want to pass on knowledge. I did smile at the rope between the RV and the tree. (What ever could go wrong now?"
Great Alex. SWR being zero whould mean impdedences are being matched, and no power is being wasted. The signal plot gets into directionality, gain, and stuff. Right?
Video Aerial Systems Thanks Alex. I guess the output power is a metric that needs to be examined. It sounds like some people did the antenna model themselves, got a SWR of 0 (On Taranis), but had no range. They probably killed the circuit. One way of treducing VSWR is to ruin the transmitter. LOL
@@Pioneer936 - Absolutely not. A dummy load, for example has perfect SWR, but is just a resistor and is 0% efficient. Efficiency is based on how well the antenna emits or receives a signal. SWR is an impedance measurement.
