SWR for Newbies

[@M0RMY]

The original link to the paper is: www.iz2uuf.net/wp/index.php/2017/07/29/the-myth-of-reflected-power/

[@paulm0hpd319]

How was you able to post this link I've tried on several occasions to upload links to KZbin but it won't let me

[@M0RMY]

I have never thought about it - just works for me. Maybe because I pay for Premium? @@paulm0hpd319

[@DXCommanderHQ]

Tom can post a link because he's a Mod around here :)

[@M0RMY]

I think that the creator can give permission for links to certain people. @@paulm0hpd319

[@jackK5FIT]

I've watched a lot of your videos and I think the ones like this one, where you are teaching, are the best and you seem happiest. You never stop learning in amateur radio. Thanks!

[@DXCommanderHQ]

Thank you!

[@WECB640]

5:54 That sound! NAILED IT.

[@DXCommanderHQ]

HAHA!

[@DukeDave1]

Thank-you Callum. Very nice presentation. And good enough to get you going on the air. Great for a newbie. 😊

[@DXCommanderHQ]

Glad you enjoyed it!

[@DukeDave1]

@@DXCommanderHQ thank-you Callum. I got one of your "classic's" when you had the KZbinr discounts. I intend to catch you on the air on off these days.

[@paulm0hpd319]

Excellent, especially the mention of IZ2 UUF the myth of reflected power ,this puts to bed the misunderstanding of how reflected power is radiated by the antenna and not ultimately lost as many think

[@FromthehamshackwithNJ4Z]

Brilliant stuff Callum, I had not seen the IZ2UUF article before. Interesting reading for sure... always learn something every time I watch one of your videos. Thanks for all you do.

[@DXCommanderHQ]

Ah John.. Yes, it's deep but fun.

[@thomasperina2990]

Hello Lord Callum; Just a quick note to thank you for this video. IMHO you can gorgeous the tuner cause nothing beats a resonate antenna. Happy Easter old chap and my best to Wendy and the dogs. TMP, Unit 22 from N.J.

[@DXCommanderHQ]

Thank you too!

[@DonDegidio]

Hi Cal, You made that topic easy to understand. Happy Easter to you and the family. 73 WJ3U

[@DXCommanderHQ]

Thanks, you too!

[@Yozimbo]

Thank you for a very informative series of vids... as an aspiring new HAM these are really great help to visualize some of the theory! 73 from Athens, Greece

[@DXCommanderHQ]

Glad it was helpful!

[@johnpentony]

Great content. Studying for the Extra. It's always nice to get context.

[@DXCommanderHQ]

Great to hear!

[@Calico5string1962]

Hopefully you will address what happens to that "reflected" wave of energy... where does it go? Is it really "lost"... or does it go somewhere? (It has to go somewhere!) That's the great debate! I know the answer, but hope you will cover it in some manner in a future video. Great stuff Cal... thanks. Oh, and happy Easter Cal! 73 from west Texas! ~Alan

[@paulm0hpd319]

Goes back to antenna if there's a tuner in place or the power isn't produced by the transmitter, there many videos on KZbin with so few that actually explain it well

[@Calico5string1962]

@@paulm0hpd319 Exactly! However, many hams still believe (and spread) the myth that that power is "lost" somehow... that it never makes it to the antenna, or goes back into the transmitter and is "burned up". 😅

[@DXCommanderHQ]

Up and down.. up and down.. Lossy coax.. Up and down :)

[@paulm0hpd319]

@@DXCommanderHQ just improve the coax 🙂

[@G6EJD]

@@Calico5string1962well actually that is correct, the travelling wave reaches the antenna and some of it gets propagated, but because of the impedance mismatch that creates the high VSWR, some gets reflected back to the transceiver but in doing so it gets attenuated (again there and back each time) and eventually the energy is dissipated down to zero. Then whilst all this is happening new wave fronts are being produced by the transmitter and so the process continues.

[@Kartrampage]

Am I right in assuming that I change the skip distance with the antenna length because I change the Radiation angle of the antenna depending on whether I have 1/8 1/4 1/2 or 1/1 lambda? Ok ok you still have to look in which reflection layer you are.

[@DXCommanderHQ]

Well.. wrong video to comment on but an end-vertical at a moderate height - say a wavelength off the ground will produce a "sweet spot" closer to the horizon.. Much higher then anything works.

[@KeystoneInvestigations]

Thanks so much Callum for the explanation on SWR. I learned something new. Here all these years I thought SWR stood for Sexy Wigan Rugger!

[@GUNFREAK2000]

Speaking for newbie’s, where our homes are 20’ apart and power lines all over above our yards, in the US anyways?… my 40m dipole SWR went from 1.5 to 2.0 and NO DIP to be found 2.0 is as low as it would go! Long story shortish neighbor had installed new metal roof and I had hard lesson in REAL WORLD antenna placement, everything effects everything… a lot of my new friends that I’ve brought into this hobby need to know this other than MODELS on computer and TRIM IT TO PROPER TUNE…. I run legal limit so it means the world to me…. Just wanted to bring this up cause lots of us newbs starting out take your word for “absolute” hope I didn’t ramble on too much just wanted to say a friendly Hey 👋 Great info we’re just STILL learning thanks

[@DXCommanderHQ]

Hmm. Sorry about that SWR.. Change in height maybe..?

[@GUNFREAK2000]

I’m running through every scenario I can think of… height,angles,coax etc. y’all are our Elmer’s (that don’t judge) and I absorb your information and appreciate it! Still learning and thanks for responding

[@janedagger]

I'm starting ... so have a dongle and right now the cheapo tiny dipole that came with it. Having a ball in spite of the noise... Since I'm not economically robust I'm waiting but soon will get the MLA+ and hopefully be rewarded. I'm also only into listening right now so transmitting isn't part of my concerns. Thank you so much for your vids, I'm hopefully learning.. uuhhh, something

[@DXCommanderHQ]

Something is good!

[@janedagger]

@@DXCommanderHQTis but a start, sir, but a start. Wheee. Right now working on a truly rude anti-putin song ... I'mma ole punk from Lower East Side way back. Let's see if putin can fly 13 floors up so high in the sky

[@GH0ST369]

Brilliant comparison to music, makes it relatable. I got "a little higgly piggely" with the Mrs this morning with the same and jestures.😂

[@omarramirez5764]

Wow! well explained. my y question is if may you to make a tutorial for a homemade 144Mhz SWR meter or 27mhz? thanks a lot.

[@DXCommanderHQ]

Home made antennas are pretty easy.. I have a video planned.

[@OnFireTiresCustomerSupport]

ok so as far as swrs for cb ,,, my cobra 29 as built in swr meter, when i tune the antenna using that i get 1.5 and below by shorting antena , then check it with external meter, external says i have to legnthing it ,,,,,why is that

[@DXCommanderHQ]

Because something doesn't work properly - or your coax is something like RG58

[@geirha75]

thanks for good information...By the way I'm still a newbie...imagine an multiband efhw. Let us say 40, 20 and 10. How would you adjust/cut to achieve lowest swr before adding atu. would it be wise to optimize/cut for 20 and then 40 and 10 will follow?

[@DXCommanderHQ]

Last line.. You are probably cock-on.

[@kmaniwani3435]

Nice video! My question is tuner location. What happens if we put it at the end of the coax by the antenna?

[@DXCommanderHQ]

An auto-tuner at the feedpoint is very cool - and I did that once with an SG230. However you need to remember the pattern changes for each band.

[@Kartrampage]

Why do you only do 1/2 lambda and not a full lambda? what are the differences in terms of radiation and reception? i think that a full lambda radiates flatter. Similar to when I place the antenna at an angle to the ground

[@DXCommanderHQ]

You don't get a good match. Almost all antenna have at their base, a half-wave dipole. And your question although simple is a HUGE topic :)

[@Calico5string1962]

Because a full-wave ("lambda") antenna has a feedpoint impedance much, much higher than 50-ohms... on the order of several thousand ohms. And actually, a truly "resonant" ½-wave dipole's feedpoint impedance is really closer to 75-ohms, not 50. Therefore, a perfectly resonant ½-wave dipole would show an SWR of ~1.5:1, not 1:1. A full-wave dipole would require an impedance transformer to correct the large mismatch between the 50-ohm feedline impedance and the high feedpoint impedance. Furthermore, a full-wave dipole has a VERY irregular radiation pattern, with many lobes and nulls. 73 from west Texas.

[@1958johndeere620]

Never could get my loop anywhere close. I think with the home made 600ish ohm ladder line and the 4 to 1 balun its just not on the same page. With my AT2K it is usable everywhere, close enough, just not flat.

[@m7trsradio]

Lol lover the ATU sound. Have you been practicing it. Great words Callum 😊 73

[@DXCommanderHQ]

EXPERT!

[@CanispaterChristmas]

BRILLIANT!!! 👍💥

[@StevenCasper]

Thanks, you made this very easy to understand.

[@DXCommanderHQ]

Glad it helped!

[@AnthonyvanHamond]

offtopic. Callum mate, are you more energetic today or did the editor speed up the recording a couple of % :-) have a nice easterweekend!!!

[@DXCommanderHQ]

Extra Gin!

[@MattHeere]

You're right about the comments section on that article. You wonder how some of these guys get their swelled heads through the average doorway....

[@DXCommanderHQ]

Haha Mat!!

[@joewallace3920]

Great video, but the dummy load joke was the best😂

[@CurtNovitsky]

Fantastic info cal!!

[@DXCommanderHQ]

Hey Thanks!

[@DonzLockz]

Nice reflected wave animation Callum. I hear the G90 will tune a wet noodle with it's 10:1 AMU/ATU. There should be more 10:1 "tuners," especially external ones, so grumpy and lazy OM's dont have to fiddle with too many knobs on 80m to compare medical issues with other OM's!😂

[@DXCommanderHQ]

HAHA

[@sveinfarstad3897]

When 7 bananas is fresh and tree is bad, 4 in SWR

[@davidpatrick1813]

This is groovy. and helpful thanks.

[@DXCommanderHQ]

Rock on!

[@davidc5027]

I've noticed a lot of discussion about SWR in HF bands over the past couple months. Seems various influencers on KZbin following suit and giving their 2¢ in the matter as well. I'm not sure there will ever be consensus with the subject amongst all of ham radio :)

[@paulm0hpd319]

There should be an even consensus as we all reading from the same license study books

[@richardmillican7733]

😂 The ATU sound effect was awesome ... but if that's the noise your kenwood actually makes..🤔 get it in to ML&S for a service! 😂

[@DXCommanderHQ]

HAHA!

[@Stan_DaniPaget]

Great insight. Thanks. Stan AI5SS

[@oasntet]

"It's more complicated than that..." Actually, you're entirely right, it really isn't that complicated. Check out a couple recent experiments done by Alpha Phoenix on his channel, in which he accidentally steps backwards into explaining impedance matching of transmission lines by measuring voltage at many points along a circuit with different loads attached with a very fast scope. It looks almost exactly like that impedance reflection graphic. Tuners aren't just about making the radio happy, though. They actively switch in inductors and capacitors (reactive loads) into the circuit to null out the reactive mismatch of the entire antenna system, and then step up or down the voltage to compensate for the non-reactive mismatch. Of course, what they can't do is stop the mismatch-caused reflections between coax and antenna, which is why a tuner between coax and antenna is better than a tuner between radio and coax.

[@DXCommanderHQ]

Perfect!

[@maartenc6099]

Is SWR important? It depends. On shortwave you do not have many losses because of a bad SWR. And yes your antenne tuner can balance out the mismatch. What will happen at the antenne is that a part of your power is reflected back from the antenne to the antenne tuner. Once it reaches the antenne tuner it is NOT LOST. It will bounce back towards the antenne. And keeps bouncing until it is lost. There is a guy on youtube explaining all this about the SWR myths. Basicly it is that if you lose a couple of dB's on HF probably none is going to notice. But as soon as you go up in frequency, let's say 70cm and up. Your SWR get's really important. Losses in your feedline will be much much more and signals will get weak and weaker. So does SWR matter, yes and no. IT matters if the losses are getting high, like the VHF and UHF frequencies. That's why there are no antenne tuners for VHF-UHF and higher.

[@DXCommanderHQ]

You need to read the article published in description for a better idea. You have to remember, I'm keeping this simple.

[@maartenc6099]

@@DXCommanderHQ And you are doing a great job.

[@Rod_2E0RLR]

Not being ego 15 mins foundation ..25 mins 2E0.lol

[@GoodLuckBP]

Dummy load fertility clinic? Thanks you made me laugh. You Brits have a better way of stating things at times! Thanks for the good explanation.

[@DXCommanderHQ]

HAHA

[@N1NJAKIDD]

Funny thing is you showed a dummy load circuit in this video😂

[@DXCommanderHQ]

Indeed.. But I didn't have one to hand, so I filmed that separately. Se tomorrow video! :)

[@Calico5string1962]

Yep! Perfect (almost) 1:1 SWR, but ZERO radiation.

[@frankthetank3342]

Reactance has entered the chat 😅

[@DXCommanderHQ]

You have some fun in you today!

[@Rod_2E0RLR]

55 mins full 27/58 no tuition pandemic ..oh fk ..lol