Debunking SWR Myths Once and For All!
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- เผยแพร่เมื่อ 1 มิ.ย. 2024
- Welcome to the channel! In this eye-opening video, we embark on a quest to unveil the truth and debunk the most common SWR myths once and for all.
Join us as we dive deep into the world of SWR and dismantle long-standing misconceptions. With their vast knowledge and practical insights, you'll gain a comprehensive understanding of SWR and its true significance in the realm of ham radio communications.
Throughout this informative video, we shed light on several key topics, including the importance of SWR measurements, the impact of antenna impedance matching, and how SWR affects transmission line efficiency. Prepare to have your mind expanded and your understanding challenged, as we obliterate SWR myths that have persisted for far too long. Gain insights that will transform your approach to SWR optimization and enhance your overall proficiency in the field of ham radio communications.
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That video has been living rent-free in my mind for the past week. only CB operators don’t believe in SWR. but that’s totally fine with me because that means that their super jank and spurious 5 kW antenna amplifier never operates at capacity.
lol, thanks for watching man 👍
I added in the CB channels for AM and FM on my EmComm HT to monitor them too not all that long ago, and those dudes are way over the top. Hams can be pissy and childish sometimes, but CBers are like humanoid cartoon caricatures. No disrespect, but I was surprised, to say the least. I'm not the sort to get offended by any of it. Cheers.
Bit of a a generalisation comment from two sad hams
@@AndrewSparkfish Nope. 100% observation. This has been the only sort of thing I have heard on CB. Currently someone has an alarm sound on channel 39 and that is all the action I'm currently picking up on it. Cheers
It’s not just the free-for-all mentality and constantly taking ownership of channels, cursing out anyone who speaks between their monologue. It’s the distortion of a poorly modified 10 meter amplifier, turning the mic gain up all the way so the AM power meter needle stays glued to the edge, and the bragging about irresponsible power levels like 500 to 10,000 watts. There’s been a few times watching the SDR, one guy was broadcasting 3 channels wide. I love the idea of a license free channelized HF band. But unlike FRS that only affects a 10 mile radius, it’s overrun by people that like to hear themselves around the world. As for equipment, all CB equipment is second rate because nobody cross checks quality like hams do.
You can summarize it this way - SWR is “ONLY A PROBLEM TO THE EXTENT OF THE LINE LOSS“ in your transmission line. The most widespread myth is that the power reflected back to the radio is lost. It’s NOT. It’s reflected back to the antenna with little loss. On its way back to the antenna, power is lost again in the transmission line and part of it gets radiated and a part reflected back again and so on If the transmission line has a small loss like for ladder wire or short runs of good Coax, SWR is NOT a big problem except that some radios will reduce their output power if there’s too much power coming back to it.
50ft of LMR-400 loses 3.4% each bounce at 40m. So at 2:1 SWR after 2 reflections 95% of the power is radiated. Not bad.
I think that’s pretty much what we covered albeit with more context 👍
Totally agree many have a hard time understanding that the reflected power adds to the forward power back to the antenna ,some even believe reflected power is common mode current
Great job! Continue relentlessy educating the hams out in TH-cam land....
When I began my ham hobby in the early 1970's, I was taught to create a 'dummy' antenna with a 60 watt incandescent bulb in a socket. I used my regular length (50 feet) of coax that I fed my dipole and tuned my transmitter. I could VISUALLY see the results of a poorly tuned load because the light bulb would either shine brightly or dimly, or not at all. Now, I realize the light bulb was a resistive load, but I wish new hams could either 'see' what the results of their poor SWR is doing, or to 'feel' the coax getting warm (losses) or the external antenna tuner getting hot (poor SWR causing the tuner to get as close to 50 ohms for the transceiver-- resulting in losses in heat). A great tool today is an SWR/WATT METER that displays the FORWARD and REFLECTED power--giving the operator a decent sense of how much is making it to the antenna, and how much is being sent back. Keep up the good work! - Stan WB5UDI
Hey Stan, thanks for checking out the video. I've seen people do the light bulb test but haven't tried it myself.
I also used a 60 watt lamp. I had a military surplus ARC-5 aircraft transmitter I converted from motor-generator power to conventional power. No coax, it used a built-in roller-tuned long wire. My antenna was a television mast vertical mounted on a quart size 7-Up bottle and the ground was the water pipe system that came in off the street. Not bad for a 16yo kid with no budget and I made a lot of contacts across the US and Hawaii, Canada and Mexico. It was magical. My receiver was a home-made regenerative mode job that worked well enough to fill lots of pages in my log book. Very few contests then and rag chewing was great fun.
I started in the 70's too with KW valve gear and a long wire and tuner and simply tuned for maximum r.f. out while watching the KW SWR meter. Maximum r.f. out = low SWR.
After an FT101E about 30 years ago I went QRP, 5 Watts max. with a h/b s.s.b./c.w. tcvr and still tuned for max. r.f. out and no longer had the SWR meter, did this at special event stations with a vertical. As I said above I knew that max. r.f. out = low SWR.
Now 5 attic dipoles for 20m to 10m and inverted vee for 60m. Made a resistive Wheatstone Bridge SWR meter about ten years ago, never above 2:1 SWR when tuning aerials. Calibrated it about 6 years ago after previously aiming for a low reading.
G4GHB.
@@lifegettingintheway2710 Good days!
The 7 Up bottle reminds me when doing special event stations at our local agricultural fair with three 5' slot together aluminium poles for an aerial and tuner with an empty bottle of Newcastle Brown Ale as a base insulator.
I have a 1944 Wireless 19 Set, much modified, xtal on tx for stability and QRP at 2 Watts c.w. only.
G4GHB.
Parallel feed line has it's place, just like coax has it's place. It's not a question of which one is better overall -- it's a question of which one better suits the requirements and goals of the antenna system you are designing. For me, I can only fit a single wire antenna and it has to work multiple bands. So my first attempt was a coax fed 6-band Fan dipole. It worked well until it came crashing down from the weight of the ridiculously large center connector I built. After that, it was a window-line fed 160m doublet with a tuner. It's my best performing favorite. Even so, I'm itching to try an OCFD. Truth be known, I hope I'm never satisfied with my antenna. I like tinkering too much!
I'm with you on the tinkering. Thanks for the perspective JD 👍
I hope to never have found the "perfect" antenna. Building, modifying/tuning is most of the fun and satisfaction. I first made a 5 leg fan for 6-80, then messed with some non-resonant verticals, and currently running an 80m OCFD and ot does well. However, a resonant ground vertical with radials has a super low noise floor in my case andnI really love it. It's good to have options, depending upon the time of day and band :)
My first antenna was also a 6 band fan dipole that i built back in 79 when I got my novice ticket. Worked the world with that and a 50w Heath HW-16. Built several verticals but they didn't work as well. Love tinkering with antennas. 0:12 are you speaking of radio tube?
LOL, I wasn't talking about @Ham Radio Tube
@@TheSmokinApe You mean this guy? th-cam.com/video/Uo0IJ_YFcVU/w-d-xo.html
Another good one Ape! I used open wire feed line on a doublet for the first time recently and have been very pleased with the performance. My old school impedance matching unit keeps the SWR as low as reasonably achievable.
Thanks for watching SF, one of these days I’ll do the open wire thing 🍻
Good stuff, Ape!
I remember some of this from the EE classes I had to take in college, but that was a long time ago in a galaxy far far away...and I was an ME taking required electives, so it really didn't stick.
Now, I'm studying up for my extra, and this shines a lot of light on the "why". Keep up the good work.
Hey Dell, glad you liked it. Thanks for watching bro!
HOLY SHNIKEYS!!! You know, I must have seen 50 videos about reactance, and this was the first time I ever got it! Therapy man, you should be invoicing us for HAM therapy!
Awesome Dewayne, glad it was helpful 👍
I feel like you were in my head when you made this....lol. Great stuff.
lol, thanks for checking it out Todd 👍
Does an antenna tuner really tune the antenna, or does it just present a happy match/load to the transmitter ? Also, does very lossy coax present lower swr due to high loss? Lastly, can a dummy load with an antenna port on the back end be compared to an antenna tuner?
1. No, it doesn't tune the antenna. The only way to really "tune" the antenna is to physically alter it's attributes.
2. Yes, the reflected power is attenuated and the same level as the forward power.
3. I have never seen such a thing so I have no idea but suspect the answer is no.
Dummy loads are a power sink; they're not tuning the sink discriminantly. Sometimes people refer to coils as dummy loads, but this is not actually true, though they are a compromised antenna.
@@TheSmokinApehave you read reflections by Walt Maxwell and how he describes how a tuner tunes the combination of the antenna and feedline to resonance?
Of course @paulm0ph319
@@TheSmokinApe so can we really say it doesn't tune the antenna?
Thanks Ape. I love the FWD and Reflected meters on my Amp. Makes it really easy to dramatically see the effects of SWR.
You bet! It shows on the flex tuna, and the flex amp. Pretty sweet setup.
Hey Don, I agree with you... better equipment is more better!
Great video Ape! You owe it to yourself to try out a doublet. I keep trying other antennas, but nothing I've tried beats my 108' doublet. I can tune it 10m-160m, and it gets out shockingly well even on 160m at 100w. It hears more than my DX Commander Sig 9 too. 73 de w8tam
One of these days I will, thank you for the encouragement
Nice explanation, Thanks!
Something I think is missing (or maybe not fully addressed) is that losses in a transmission system includes energy lost by things like absorption (heat) and radiation. That energy is not reflected back, also it tends to affect both incident and reflected power and this is logarithmic not liner . So if a transmission system transmitting 100W experiences 3dB of loss (half power or 50W) the reflected wave will also experience 3dB of loss so only half of the reflected power will reach the SWR meter causing the resulting ratio to look better than it should.
In an armature system these losses might be very small to the point of being negligible, but in high loss systems such as communication systems with very long transmission lines (e.g. a few hundred feet of coax with lots of connectors), very high power (e.g. the 97dBm radar I used to maintain), etc, they can make SWR measurements unreliable, and if the losses are high enough, a transmission system can indicate good SWR but still be radiating only a small percentage of the power out of the antenna.
A final tidbit:
Some transmission line failures may not be apparent during low power conditions such as during testing. For example arcing at connections, and/or breakdown of the dielectric. I can't tell you how many times I have had to argue with installers who insist their tests (using low power testers) passed, only to have the system fail when at power.
I did cover it a bit but you are correct, there are ohmic resistance losses 👍
FWIW another loss in the feeder is dielectric loss, power lost in the insulation with every change in polarity, the loss logically becomes greater with increasing frequency and increasing voltage. A mismatched feeder has nodes along its length with current maxima and others with voltage maxima.
A strange analogy with the loss in the feeder is like a taxman taking a percentage of every transaction. the radio produces perhaps 100w, 90w gets to the antenna, perhaps 10w gets reflected of which just 9w gets back to the radio, it is reflected back to the antenna where it has magically reduced to 8w. (As you said "rinse and repeat"). With an antenna that is matched the cable only gets to deduct "the tax" once. High SWR is a further issue with systems transmitting high speed data or video...
For those of us with limited space a doublet fed with open wire feeder can be very effective as a multiband antenna, definitely a subject worth covering. 73
Thank you g0fvt, great info as always. I like the tax analogy 👍
Ok my question if I run 450 ohm ladder line to my antenna I will need to use a 9;1 transformer the transformer will cause heat witch will cause loss say my feed line is 50 foot long what is the difference in loss between that and lmr 400 run with 1;1 swr I hear a 9:1 transformer is lossy
Why would you use a 9:1 with 450ohm feedline? I've never heard of anyone doing it but I am sure someone has. Hang on, I think I see what you have done. No, 450ohm ladder through a 9:1 does not equal 50ohm. So, how it works is this... The feedline must match the antenna at the frequency we are using, but it rarely does, not least because we keep changing frequency. Often the total ohms of the feedline and antenna will be in the many thousands of ohms (above the frequency the antenna is tuned to) and so we often ( usually ) use a 4:1 balun to reduce that to hundreds of ohms (sometimes still in the low thousands.) Then we use an "external" ATU to match that hundreds of ohms to 50 ohms. So why would we do that? Well ladder line is virtually lossless. Compared with coax there is almost no losses at all, even with the balun and ATU. Unfortunately, some people take that logic and use it for low loss coax and that is not the same. Coax has a lot of advantages over ladder line, it is easier for one and it is well shielded from interference. You can often tune an antenna so it will work multiple bands on an internal tuner with coax. But ladder line users really look towards a really good external one, which is an added cost. I hope that explained a bit. The question you should be asking is do I have an external ATU? If so then you could try ladder line and a 4:1... if not then stick to coax for the main run and use an internal ATU where you can. Now where you do see a 9:1 used is with a non-resonant wire with coax, the idea here is simular. You are taking thousands of ohms and reducing them to the low hundreds or even tens of ohms where most internal ATU can tune them on several bands and there is some clever calculations people have done to get wire lengths that will tune on every band with an internal ATU (and even without an ATU at all in some magically rare almost theoretical cases)
Hey Vet, here is a video I did measuring loss in 9:1 ununs: th-cam.com/video/6j1Yc1Y4Ly0/w-d-xo.html
I actually have quite a few measuring various core types, that might help you out.
Thanks for watching!
Ape, I don't think you are a baby, I think you do a darn good job at explaining ham radio issues and things that can cause confusion. Thank you so very much for presenting this somewhat perplexing issue. The clowns need to be shut down. NOW!
Hey Janice, glad to hear you like the videos. Thank you for watching 👍
Do common mode currents have an effect on the VSWR? Does changing the length of coaxial transition line have an affect on the VSWR of an antenna?
Yes and yes.
@@TheSmokinApe Can there be common mode currents on a transmission line when there are no standing waves on the antenna?
Does the length of the transmission line transform the feed point impedance?
Excellent explanation.... compared to some other long repetitive lectures.
Thanks Andrew 👍
Take a bow Ape. Everything you stated is 100% correct. 👍
Thanks Hollywood! I still want to catch up and talk more about those Baluns.
At about 4:02 or so AC current is brought up and that is worth examining a bit further. So imagine a battery, a potentiometer that swings 360 degrees, a coax cable, and a voltmeter. The pot is attached across the battery, the coax center conductor is attached to the wiper and the shield to either of the battery terminals, and finally the voltmeter is attached to the far end of the coax. As you might imagine, rotating the potentiometer through a complete turn will create measured voltage from zero to battery voltage and back to zero. Now imagine it is possible to motorize the wiper and spin it at 500,000 turns per second producing a 500 kHz stream. Now place a 50 ohm resistor and an oscilloscope at the far end. It will measure a sine wave but because the source is DC the current is not alternating - it is rising and falling and the current is flowing forward (key word) passing energy to the load. That we call a wave. If we place a balun in the circuit we will get an AC signal out of it because of backemf in the inductor. The direction of the incident wave in the coax cable is always toward the load and the reflection wave, if it exists, will be in the opposite direction. An analog is a vacuum tube amplifier. The current always flows from cathode to anode as DC. The output audio transformer converts that to a low impedance alternating current at audio frequencies. Just something to think about.
That's interesting, thank you for sharing
Could you define the terms for me in the context of the video? I have looked up the words but lost the flow when comparing without the video. Or attach a link to a previous video? Thanks. Newbie.
Hey John, which terms in particular were you interested in?
@TheSmokinApe from about 3'30" through 4'40. I am studying for my license here in New Zealand. This stuff is not easy 😕 thanks. Appreciate you getting back to me and your channel. Karl
RG58 here but only short runs to 5 attic dipoles and an outdoor inverted vee for 60m, running QRP I get my SWR as low as possible.
The most stupid myth is that of C.B.'ers trimming coax inch by inch to get a perfect ½λ to the aerial.
Then they lengthen their carefully and painstakingly trimmed coax cable by adding an SWR meter and jumper lead which they say must be 3', 6' or 9' and 3' increments but not carefully trimmed to length. Why not trimmed?
Do they not realise it becomes one cable? Do they think an SWR meter is some kind of isolation device?
Point this out and they say they use what works for them and want the best from their system.
G4GHB.
Hey Bill, thank you for watching. I wouldn’t limit that misunderstanding of transmission lines to CBers though.
@@TheSmokinApe True, I've seen only one video of an amateur saying coax length is important. Thanks fir the video.
G4GHB.
👍
Very well done Mr Ape! Thank you!!!
Thanks Randy 👍
That was a pretty good presentation on Standing Wave Ratio. You mentioned that SWR should actually be called VSWR. Yep, that's half correct. SWR can also be ASWR which is Amperage Standing Wave Ratio. I actually had an ATLAS 350 transceiver that had a built in ASWR meter. OK, it's the same thing as far as the ratio goes but one measures Voltage reflection and the other measures Amperage reflection. As to Open wire feed lines and Coaxial feed lines, there is no contest that open wire feed lines are the absolute best as long as conditions are perfect. Uh Oh..... Whatever you do, don't let rain, snow, or Ice get on the open wire feed line because then all bets are off and open wire completely sucks until the Rain, Snow, or Ice completely goes away and the feed line gets back to completely dry. Also, open wire feed lines are very picky about how long they are. You better do your math before cutting and installing open wire feeders. Hmmm.... Using open wire feed line in the hot desert might be the perfect place to use it but not in the far northwest or Alaska. I'm a high quality Coax freak because those issues don't plague coax users. I'm sure you are going to have future videos involving BALUNS and I look forward to watching them. They absolutely have their place but I would never use one because it has been my experience that Baluns correct impedance issues and improve matching but the gain in correction results in power losses that pretty much equal the use of no balun at all. I think that you probably should have mentioned that Standing waves on the antenna is good but standing waves on the feed line is bad. If the antenna is cut perfectly, then no standing waves are sent back down the feed line. Here is something else you might want to look into: 75 ohm coax hears better than 50 ohm coax but 50 ohm coax transmits better than 75 ohm coax. I used 75 ohm hardline for years on HF and eventually swapped it out with the highest quality Coax I could afford and I can't tell the difference between them. OK, OK, I used an antenna tuner on both systems. In a pinch, I have no issue with using high quality 75 Ohm coax in a SHTF station setup. Yep, you're going to probably be able to get a 1:1 with high end Coax and about a 1.5:1 with 75 Ohm coax. It's not going to hurt your radio at all, especially if you use an antenna tuner. Page Keith Veazey: WD4OIM: Advanced Class Amateur and holder of a General Radiotelephone License. I look forward to watching future videos.
Thanks for the informative post Page, great point about ASWR. I did neglect to mention that as most folks use the voltage meters. Thanks for calling it out 👍
It was not too long ago that I was building a fan dipole down in the cellar hanging the wire span about 5 feet above the cellar floor. When I added the second band to the dipole and attached my VWSR meter to the center connector, I did notice that with the dipole, Any swing or sway between the fanned wire elements (yes especially sideways) cause pretty big swings in the VWSR on my meter. Oh, and BTW, the VSWR readings down in the cellar were essentially useless. Heating pipes and electrical wires and a distance below ground made for pretty bizarre VWSR readings. Art W1SWL
Hey Art. Yeah, fan dipoles can be difficult given the elements interact with each other. Also, what works well in one location might not work so well in others given that conditions will vary. Thanks for watching and for the comment 👍
I'm pretty sure I saw the video you refer to.
I made comment on it, I explained that the example given, 10ft of RG-58 coax in a mobile situation with 10:1 SWR @ 27mhz, still has 18% loss.
The video creator then tried to argue that is wrong.
It's not hard, go the the KV5.. coax loss calculator, plug in the above and it comes back with 18%.
So that is near 20w of power being lost out of 100w on the first pass, then the relection is another 4w then the next is .8w
So you lose 25w in power, which will likely go up to 26-27w.
I don’t understand why anyone would think losing that much power having a 10:1 miss match is a good idea, when you could always match the antenna properly and not loose that power.
But I will say in a mobile application, say at 40m you will have a coil loaded antenna, most likely.
In this situation, you will get loss due to the coil, it would be interesting to see how a coil loaded antenna compares to using a tuner and a vertical.
I'm guessing the tuner method would suck as you would still lose heaps of power heating coax and need to lug a massive tuner around.
The loss calculator includes all passes of reflected power at the swr figure you put in ,in his video he states at the lower hf frequencies this loss isn't to much of a worry especially with low loss coax
Yeah, he is a little out there.
@@TheSmokinApe and not far wrong
Hi TheSmokinApe,
Thanks for the most excellent VSWR synopsis.
Possibly needed to expand a little re the 1dB transmission line loss (cable attenuation) resulting in a ~20% power loss; no matter the transmit power. I had to rush off and do the maths. :) 3dB is of course 50% lost power.
The subsequent interaction between 1dB cable loss and a 2:1 SWR (~11% power loss) was really well dealt with.
For me It's why antenna gain (multiple + dBs) and good receiver sensitivity (multiple +dBs) are critcal in any end to end path loss calculation. Oh and a 'quiet' receive location.
73's VK5ZEJ
Hey VK5ZEJ, here is the maths:
p = (10 ^ X/10) *100
p = (10 ^ -1/10) *100
p = (10 ^ -.1) *100
p = .7943 *100
p = 79.43%
Double checked here:
calculator.academy/db-to-percentage-calculator/
@@TheSmokinApe Sweet🤗
So roughly ... -1dB = -21%, -2dB = -37%, -3dB = -50%.
Sounds about right
I achieved laminar flow once and my SWR decreased to negative infinity. I talked DX on 33cm and was able to modulate a full AM signal using nothing but a 9v battery and 2 nickels taped to a potato.
Russet or Yukon Gold?
@@TheSmokinApe I tried russet first but found out Yukon gold works better at this point in the solar cycle.
@@HouseOfThe8Strings I heard Yukon was the was to go
@@TheSmokinApe wait until you try yams!
Putting it on the list!
Some very good points, in particular it is always surprising how much power is lost with only 1dB of feedline loss.
For sure and when you start add it up with tuner / transmatch loss it can be an eyeopener. Thanks for watching Pez 👍
@@TheSmokinApecan you explain how a tuner loses power ,, if a tuner is introduced it allows the transmitter to put its full power into the system therefor more power to the antenna than without one
@@paulm0hpd319 I guess it's like a transformer so there is loss even if only a small loss.
G4GHB.
lets assume i lose 20w as you said and only 80w will be radiated instead of 100w, does the opposite party realize that? the loss in my antenna switch is 0,01db , thats nothing... , have i missed something...? @@TheSmokinApe
Insertion loss...
Well explained, thankyou.
Glad you liked it, thanks for watching...
that was great. that is why a 9:1 UNUN can heat up more with a tuner. that power keeps bouncing threw the core. the torrid see forward power and adds reflected power to heat and power sent back from tuner . I normally use cross needle watt meter. I want to see reflected power in watts. still read VSWR where the 2 meters intersect . I just did a test today with a 49:1 using 2 -FT 240-61 cores at 500 watt FT8. and SWR under 1.5 and stayed cold. 10 AWG windings . did the same with type 43 and that changed the tune a tad . but still under 1.5 buy the cores heated a little. so less heating at 500 watts with type 61 core. this mono band cut 1/2 wave 10 meters wire. a great way to tell if ferrite heating up is VSWR jump up. 73's
Hey Robert, I bet the 10AWG wasn't easy to wind 👀
@@TheSmokinApe my fingers hurt 2 days and was hard to solder as well.
LOL, I bet bro!
In the days of parallel line and pi outputs, tube transmitters...dip and peak. The old timers didn't worry about SWR. That issue became prevalent with cheap available coax after WW2.
Yeah, totally agree. Thanks for watching Phillip 👍
I was taught that antennas have impedance, and feedline has SWR. VSWR is just a way to see the mismatch in a graphical sense between the complex impedance of an antennas' feedpoint, and the feedline's characteristic impedance.
Isn’t that what I said in the first sentence on the first slide?
Not in the sense that understand it. But we're in agreement. @@TheSmokinApe
Awesome, thanks for checking it out Matt 👍
Very well explained 😊😊
Glad you liked it
Thanks Ape. As always, an easey explanation on what is happening in a antenna system. De LB8PE
Thank Bjern, glad you liked it 👍
Hey Ape! I'm still trying to separate the wheat from the chaff on the SWR issue. I get the feeling that the truth lay some where in the middle. I keep hearing Theories, and opinions (even from those so called experts) not quantifiable and undeniable proof. There have been mistakes in the past that still linger on until today (like Amplitude Modulation actually modulating the carrier instead of generating sidebands).
I do think many Hams take any signal loss way to seriously, lets face it in the real world even 6db (75%) loss is only 1 S-Unit. QRP operators running 5 watts are voluntarily operating 13 db (95% or ~2 S-Units) of loss compared to my 100 watt rig and still making contacts and having fun.
That doesn't mean I intentionally run cheap coax and high SWR's. It means that I take losses with a grain of salt, and try to look at them with a real world perspective.
Keep up the Good Work! 73 mike
Thanks for watching and for the comment. I tend to agree, hams get whipped up over a bunch of stuff and SWR / Loss is one of them. I run 100' of RG-8X which is lossy and I don't lose any sleep over it...
@@TheSmokinApe You might want to check out this video and his 4 PDF references "Antenna Engineer Vs Ham Radio Myths! True or False?" Mark the Ham Florida Man
73 - mike
I love your fact driven videos
Thanks Steven 👍
Good vid Ape!
Thank you BA 🍻
The primary issue is the argument that your loosing far less than one s point. Yep even if you loose half your power. And even a whole s point (6db) is insignificant.
I'm not agreeing with that. But that's the argument.
Also I'd want proof of any significant distortion of the transmitted signal due to swr. Sure at really high swr you might get some non-linear effects in the cable. I worked out you need an swr of 27:1 to reach the breakdown voltage of rg58u using 100w. So a some point before that the cable might become non-linear.
For me, it’s more about discussing what happens not the amount of loss, what people choose as acceptable is an individual decision. The clown, in his video, was inaccurate and misleading.
👍Thank you sir.
You are welcome
Well done.
Thank you 👍
Came for the thumbnail 👌and stayed for the 'splainin'
Howdy Mike, thanks for checking it out 👍
Was thrilled from the first declarative throw down. Some clowns will unwrap a Super Size Baby Ruth Bar and toss it into a public swimming pool! And make $$ off of the clicks.
You ain’t one of them, son…Thanks for calling them out…73 de K4FMH
Thanks for checking it out Frank and for the kind words 👍
I have heard that SWR can harm the finals in the radio. Is this true?
I feel like this might be a trick question. Most modern radios fold back on power output when SWR is high, they do this to protect the radio.
@@TheSmokinApe Its not a trick question. I am new. I have tried to watch videos made you Yaesu but they talk in "electronics speak" and very fast so that I cannot really understand the topic. I end up more confused than before I watched it. I am an old guy and learning new tricks aint what it used to be. There are no radio clubs anywhere near me so I am on my own.
@@daveengstrom9250 sorry Dave. Some folks like to argue that voltage and not current damage the finals. So yes, transmitting with higher power and high SWR can absolutely damage the finals
Thank you thank you thank you SA. I have been seeing these wack jobs on TH-cam. Thank you for calling them out. They are very dangerous.
I also thank you for not discussing commode currents in a serious discussion. Common mode current is a real thing but no one properly handles that topic as it's an offset along the line between the current in one lead (such as the center conductor) and the other lead (such as the outer conductor).
Too many TH-camrs are smoking methods that don't exist. I like you, SA. You are going to get it all right. You are almost to the summit. The view is good from where you are. Thank you.
I do appreciate the comments BDRFI, it lets me know you enjoy the videos 👍
@@TheSmokinApe the proof is in the math.
But don't think you can't do well with none resinent antennas. I had a dobblet cut fot 80 and fed with ladder line. You have to consider the whole system. Your length of feed line matters too. If very short you have very little loss at hf.
I’m not saying anything about using non resonate antennas, I use them all the time 👍
The transmitter supplies constant power to the coax and antenna system or (mismatch). Any power returned is due to the loss or mismatch of the coax and antenna in the form of a SWR, which is maintained by the transmitter output. Because the power is constant and the impedance of the mismatch never changes, the loss is a one-time or instantaneous amount. Ohms law. SWR, antenna dissipation, and loss are constant.
I was a little scared too! That clown face will be in my nightmares!
lol, thanks for watching Gap 👍
Howdy. Ok.
Exactly what myths did You debunk ?
Regards.
I was explaining how SWR actually works and not saying that it “adds power”
@@TheSmokinApe Howdy again-
Aha; Ok. Fair enough.
Regards again.
Thanks Eugene
I think it is important that people understand that a standing wave is a wave without momentum. So all this talk about the power going backwards and forwards should have been nipped in the bud at that. A high SWR actually means a high amount of power just standing around, and not going anywhere. It is caused by reflected waves meeting waves going forward. But all that is kinda beside the point really isn't it. Standing waves don't move along the coax as they should, and that should be the end of it. Anyone who tells you that you can have a high SWR and the waves will still move along the coax normally, and you lose no power, doesn't even know what SWR stands for.
Impedance is Resistor+Inductive+Capacitive It all is +++, but Inductive and Capacitive is 180 degrees out of phase. And mostly around 90 degrees out of phase with the resistor.
And when it is resonant, inductive and capacitive is the same and cancel each other out, keeping just the resistor... You have to see them as vectors and treat them as such.
Then you have two types of resonant. Parallel resonant our serie resonant.
Serie resonant is very high in resistance if it is resonant, and parallel resonant is very low in resistance when it is resonant.
And now for the big question does SWR matter, it depends. On shortwave where frequencies are low and feedline losses our low.
You probably will not notice the loss.
But on VHF-UHF-SHF and higher, SWR really does matter. You really lose many many dB's......
VSWR is a real thing. I don’t understand these hams that put out videos saying it doesn’t matter. I work in professional radio and we use return loss to check an antenna system for impedance mismatch. If you think about this logically, using return loss you can literally see how much power is being radiated by the antenna vs what is being reflected back for a given frequency. Also, radios do not like a high VSWR. It can cause all sorts of problems. On analog, it makes the transmitted signal seem distorted and full of static because it is feeding back into the radios finals and modifying the signal by adding to or subtracting from the forward signal depending on the VSWR in the transmission line. On digital modulations, everything will sound fine but your range will be significantly affected. Also, ladder line and window line are great. But they are not very durable and they don’t like to get wet. They also can’t be put too close to things such as walls, trees or other runs of ladder line such as you would see how coax is ran up a tower. Which is why we use coax and coax is great so long as you understand the way it works and take into account VSWR, common mode currents, and cable loss when designing an RF Network.
Great post Skrux, thank you!
"Absorbed by the antenna." It's not a direct measurement of it, but wouldn't that basically be radiated by the antenna, assuming you're transmitting of course?
So here's the thing... Energy that is absorbed by the antenna is either consumed by radiation resistance or or ohmic resistance; one is radiated as RF and one is dissipated as heat. Hope that helps.
@@TheSmokinApe Yep, makes sense. I was thinking the line reflected portion (or at least a portion of that portion) would turn into heat, but it makes sense that a portion of the other would too. 73
Thank you. I too have been angered by a self proclaimed elmer who pretends that a SWR meter can prove no power loss by its power meter function.
Haha, thanks Wondering 👍
But why does my power dial go to 11? More power. The others only go to 10.
You might have the new firmware! 🤣
Great video. There is a fellow on TH-cam (with the name Florida Man) pushing that reflected power always gets radiated. He quotes an old article by Maxwell in the 70s. the TH-camr basically said that the reflected power goes back and forth several times and eventually gets released to the antenna without loss. Of course how this "magic" of defying physics happens is never explained. I replied in his comments that this is incorrect.Thanks for straightening out these self-appointed "myth busters" who are basically misreading a 1973 article and reinterpreting it to suit his "defying physics" theory. 73 de Scott W1AL
The Florida man is absolutely right. SWR is only a problem to the extent of line loss. At HF frequencies this is not a huge problem. At 2:1 SWR, with 50ft of LMR-400, 95% of the energy is radiated.
Thanks @W1AL
I didn't commit the Florida Man's video to memory but I don't recall him ever discussing lossless line or LMR400 but maybe we watched different videos.
you can say that again...
@@microflite Big difference between "not much of an issue" and FL Man's claims. He says "no power is lost in heat" at the transmitter.
So what happens to the reflected power, returning to the radio?
Your information is lacking. I suggest you read and comprehend Maxwell's book "Reflections", then maybe post-up more accurate info.
73 from Texas...
I covered that, maybe you missed that part when you were typing up your clever comment…
👍👍👍👍👍👍
Thanks Robert 👍
So you’re saying you’re going to catch my country music award on fire ? 🤔
lol, thanks for watching Jay 👍
Just run 1-5/8" hardline and tune for least reactance. Youre welcome ;)
Sage advise 🤨
A high SWR can burn up the finals over time, which causes the radio not to transmit.
That can happen 👍
ALC gang! 👇
Right
@@TheSmokinApe I use alc, its more accurate. If its not matched properly the alc goes nuts.
If the SWR is good, the transmit has plenty of fars. If the SWR is not so good, your fars leak out the wire and don't work as good. If the SWR is bad, the fars get stuck in the radio and the transmit button shuts off. So yeah. The SWR's is real and you don't want them stuck in your radio.
I couldn’t have said it better 👍
How about if we introduce a tuner ?
What are fars?
@@paulm0hpd319 The tuner will indeed fool the radio into giving out the fars. Unfortunately the fars will still leak out of the wire and not do as good.
@@bill-2018 A far is a unit of measurement. You put a little youngin in the back seat of a car with no electronic devices. Start driving. When the little youngin says "are we there yet" you will have gone 1 far. When there are multiple fars involved the little youngin will repeat the message and begin to fidgit in the seat.
You are wrong.
In the begining you mention vswr. It is vswr because we measure voltage. But, we can measure current. Swr would be the same. It is simpler to measure voltage
With swr of 2:1 all transmited power comes to antena and is radiated. If transmision line is ideal, without loss.
What if you transmit 100W into line with 3dB loss? Only 50W comes to antena even at swr 1:1. Or 2:1. Or 5:1.
I don't think I am...
1. I did say VSWR and in almost every Ham Radio book it is explained that way, I do agree that you can measure voltage or current to determine SWR. That said almost every meter in ever shack is a voltage meter and I would hazard a guess that if you asked the folks at any of the Ham Radio retailers they would tell you that nearly all of the meters they sell are are voltage meters.
2. I said that AND I said we were talking about line with 1dBm of loss, maybe you watched a different video...
3. Not if you have loss in the transmission line, like the example in the video. Oh wait, you watched a different video.
@@TheSmokinApeno, I didn't watch different video. Your video is very good try but a lot of mistakes in it
Again
If your line is ideal all of your power will come to antena and will be radiated no matter the swr
So, simple. How much power is radiated from antena with swr 2:1 and ideal line, no losses? I say 100W
100W is transmited. 100W is reaching antenna (ideal line). 11W is reflected (11%). 89W remaining at antena. This 11W is reaching tx side (no loss line) and ADS to transmiting 100W. So, now is 111W reaching antenna(no loss line) and 11% is reflected. Now this 11% of 111W is reaching tx side, ads to 100W power. After few there and back 100W is radiated from antena. It is not matter what swr is if line is ideal.
That happens also on real line. With high swr you have standing wave of voltage and current. That peaks increases losses because you have real line. Higher the voltage or current higher the losses
The scariest thing is how many people agreed with that clown on his video. I never heard of his channel. I just did some googling to see what you were worked up about. I guess there is some SWR wormhole in Florida that’s different than the rest of the universe.
Things are different in FL 👍
Ha! Jokes on you! I am never exuberant and I never use facts!
Dang! Now I have to go back to the drawing board 🤨
Your channel is why I now have 3 bofwang ht's (petting my 5r now). I'm not sure yet if that is a good thing :) but keep doing what you're doing as it's very entertaining with a touch of enlightening.
Was a CB operator in the '60's & '70's & Everyone was Well aware of SWR & tried to have it Minimum on their installations......06:00 in my experience when the 50 ohm Tx (Rig) Final output is well Matched to the 50 ohm Coax cable (The Usual situation) but Terminated by a Defective or mistuned Antenna, the antenna's high Reflected power is Mostly Absorbed (Producing additional Heat) by the Tx final amplifier Stage (The Tx final Is Bilaterally well Matched to the coax Z) & Little to No Significant Rf power is Reflected or "Bounced" back repeatedly Toward the Antenna.....Just my Experience using dual Simultaneously connected Swr Meters back in the days when high antenna Swr Likely Red plated Tx tube finals or Overheated the Final's output Transistor.....Maybe you can kindly address or explain ?
Reflected power is not absorbed within the transmitter finals ,it does indeed join the forward power back to the antenna, its the impedance the transmitter sees that the reflected power has changed at the line input that causes the issues
Paul, an impedance mismatch will reflect power back which will get absorbed by the finals and will cause them to heat up. Heating them is proof, assuming that you are not overdriving them and you have appropriate cooling and ventilation.
Tom, I agree. I think what is the topic of debate is that the reflected power can be re-reflected by a tuner which would stop it from getting to the finals.
@@TheSmokinApe reflected power from an antenna impedance mismatch is reflected back towards the transmitter, this reflected power changes the impedance at transmitter coax junction, this mismatch reflects the reflected power back to antenna , the transmitter is trying to put its full amount of power into this mismatch which causes the heating up of components ,the transmitter is unable to put its full power out ,add a tuner the transmitter is able to put its full power out with no heating of components
@@TheSmokinApe I think another important point That's overlooked here is that the feedline becomes an impedance transformer when standing waves are present perhaps this could be brought up in a future video on the subject
I promise he's not talking about me.
😳
It matters, but the question is how much. At a 2:1 mismatch you're losing less than 1dB. The bigger worry is the transmitter reducing its power. If you can get SWR down to where the transmitter's happy a reasonable SWR might be better than the insertion loss of adding a tuner.
I would agree. To me the video is more about what's actually taking place and what / how to look for that. Thank you for watching and for the comment!
X equals zero.
That Mark the Ham Florida man was saying that a 20w radio with 10w reflected power equals 30w to the antenna. He also claims that an SWR increases power because the reflected power eventually radiates and reflected power is not lost. It's exhausting to try to correct him because he has so many ignorant followers.
Right, that guy is out in left field 😮
You may have misunderstood what mark said, he said reflected power adds to the forward power he didn't say that it radiates extra power, some of what he said may have not been explained in full and a little rough around the edges but in the main is correct, it's easy to check this information by referring to arrl books and reflections by Walt Maxwell rather than try to discredit someone who is trying to help with the general misunderstanding in the hobby
I didn’t call anyone out directly, you did. Thanks said I do appreciate your comment and that you watched. If you are referring to the video I think you are, I don’t believe he spoke about the potential for signal degradation or line loss.
@@TheSmokinApein one of the videos in question mark mentioned reflection gain,I believe this is where the most misunderstood part of this subject is misunderstood and misinterpreted perhaps you could do a video to help it being more understood
I might, thanks for the interest in this video Paul
The fact that less power is being radiated is very easy to prove. Just look at the RSSI with a receiver and you can see that there is less signal strength. It's not rocket science.
Some folks make the concept difficult 🤨
Sounds like a bunch of Liberals! I have a saying, "to the inexperienced, anyone can pretend to be an expert."
What makes you think that it “ sounds like a bunch of liberals “ ?
That saying is gold!
Bored me in the first minute. Next time...
Sorry bro…