Links Vs Traps | An EFHW Deep Dive

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Ham Radio Tube

Ham Radio Tube

Күн бұрын

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@RichardDePas
@RichardDePas 8 күн бұрын
I didn't go that far down the rabbit hole before I decided on sticking with resonate antennas. Was great hearing your take. 73 K9WWW
@laszlokovacs8827
@laszlokovacs8827 8 күн бұрын
Wow! I'm exhausted just listening to this. You said it best at 21:37 -"I don't think it's worth it." Good info though. For me? I'll just throw the tuner in the go bag. It's not that heavy. This is also why I keep a Slidewinder coil, spike, mirror mount, and CHA SS17 in the go box for POTA. Or better yet, your favorite - an ATAS-120 - which I don't own one yet. It's on the list though. My life is complicated enough. Keep it Simple. 😉
@KO4AYE
@KO4AYE 7 күн бұрын
Mike you once said in a video you made talking about tools, “I don’t need a fluke I am an amateur”. Brother this is why you’re not an “amateur” the way people think about it. The trip through the rabbit hole is beautiful, now you own it. What makes it great, you’re sharing it. Your deep dive on the subject and the fact you're sharing what you learned, this collaboration is what I love about being an member of Amateur Radio. Great Job!
@DaveW6OOD
@DaveW6OOD 8 күн бұрын
I put together a 20-30-40 trapped dipole last month. It was more complicated than expected in practice. On the second try,😂😂 I was successful putting over-long wires on the far side of each trap and then tuning and soldering from the feed point out. It was definitely a “everything affects everything” scenario. It was a good learning experience. The tuning a trap part with the VNA was pretty cool. K6ARK should do a build video cause this is a perfect antenna for a tiny 3-band QRP rig.
@BLACKHEAT1028
@BLACKHEAT1028 9 күн бұрын
I swear I saw Alice, White Rabbit, and the Madd Hatter and everyone else. You might have hit China digging that hole. But I did learn a lot Thanks Mike
@VE6LK
@VE6LK 8 күн бұрын
Two comments for clarity: Trapped vs. Linked, your analysis is good but misses one vital point - the trapped EFHW is mechanically shorter (albeit heavier due to the traps) and will fit in places where a full-length wire cannot. Also loss in traps will vary depending on their design - and there's some damn well designed traps out there already. Summary - there's a purpose for each type and it's worth it to evaluate needs before settling on one way or the other (says the guy who uses each, interchangeably). Great video Mike and thanks for the shout-out. 73
@hamradiotube
@hamradiotube 7 күн бұрын
I said all of those things!! Thanks again for all your help with this!
@KB5UTY-Dave
@KB5UTY-Dave 8 күн бұрын
THANK YOU! You just kept me from going down the rabbit hole myself. Been wanting to figure this out.
@jonniez62
@jonniez62 8 күн бұрын
Really glad you're talking about traps.
@hamradiotube
@hamradiotube 8 күн бұрын
Talking about them, yes. Building them, prob not any time soon.
@chadkirkendall8520
@chadkirkendall8520 8 күн бұрын
Thanks Mike for answering my question. I started going down that same rabbit hole and it scared me! 😂
@MikeN2MAK
@MikeN2MAK 9 күн бұрын
Great stuff! There really are a lot of smart and helpful hams out there. Thanks for taking us down the rabbit hole on this.
@jerryKB2GCG
@jerryKB2GCG 9 күн бұрын
holy cow, that was an entire nest of bunnies down that rabbit hole!
@KI7JOM
@KI7JOM 9 күн бұрын
I sure do like my tuner. I can throw up that EFHW and push a button for each band I work! You have talked me out of building traps!
@LavaKimo
@LavaKimo 8 күн бұрын
One advantage to using the trap is that the lobes are more favorable. On an 80-10 EFHW, there are so many lobes on 10 meters it doesn't perform very well.
@jampskan5690
@jampskan5690 8 күн бұрын
I tried awhile back, just for fun, and because I liked the idea of a shorter antenna that could be resonant from 40m on up to 10m without having to take it down to put in or take out links. This took a long time just getting the tiny traps built (tiny because it was for QRP-10w). Tunning the thing was a different story... It took awhile... A long while. I was able to get it resonant on 30, 20, 17, 15, 12, and 10. Or maybe I had to ex-ney 12m, I can't really remember as I was trying different things to get 40m to work. I could not. I even used fancy schamncy surface mount mica caps (with 1,000v-500v ratings) for increased stability. I have since shelfed this project until I gather more motivation for winding more tiny toroids. I think I am going to try different mixes of toroids at some point in the distant future among other things. Anyways, it's cool that you spent the time on this one, because I'm sure others have, or will have, this same exact question!
@hamradiotube
@hamradiotube 7 күн бұрын
Thank you for confirming my hypothesis that it is much easier and less frustrating to just get up and unlink a wire than to make traps for all these bands. It sounds really cool, but the practicality of it all makes it less than desirable for me. If you ever get it working, we will of course expect a full review of your findings.
@stephanhersey1186
@stephanhersey1186 7 күн бұрын
Wow, glad it was you that had to do all that research. Linked or EFHW, that's the way I see it. Thanks for doing the homework. Steve, k7ofg.
@cidcolead1115
@cidcolead1115 8 күн бұрын
I like traps on beams, up on towers, where I cannot reach to disconnect links. I like traps on my 4BTV that allows my SDR to receive on multiple bands and the same time. But I have smoked a trap or two due the resistance in the coil winding wire. I am putting the final touches on an otherwise pristine HW-8 to take out to the park. 80, 40, 20 and 15 meters. You have convinced me to try the linked dipole build. Maybe an end fed after that, but most installs I would make have one good support near the rig. Since I am usually out in the daytime, I can leave the 80m add-on section at home.
@TrzCharlie
@TrzCharlie 8 күн бұрын
Wow, just wow. My brain exploded around 12:23 into the video. Kudos for chasing this brother. You never cease to provide useful information with a witty delivery...Kudos.
@KG5RJR
@KG5RJR 7 күн бұрын
Love it when rabbit holes suck ya in like that. Learning things like this is FUN!!
@markviers998
@markviers998 7 күн бұрын
Wow! Just wow on the amount of digging you did on this one! Great information, loved learning about it but I don't know that i would have followed that rabbit for as long as you did. Thanks for the work!
@hamradiotube
@hamradiotube 7 күн бұрын
All for the love of antennas!
@thesavo
@thesavo 8 күн бұрын
I love that @21:45 you come to the conclusion that, "it just isn't worth it". I feel like I know more now, than if I just skipped to that time code. You explained it so well and with good aids. Thank you.
@hamradiotube
@hamradiotube 7 күн бұрын
That would be great if it only took me 21:45 to figure that all out though lol!
@chris_w4mpt
@chris_w4mpt 8 күн бұрын
Toroid Coil Winding Calculator is still alive in the Wayback Machine
@jampskan5690
@jampskan5690 8 күн бұрын
Hopefully somebody revives that thing, it was pretty accurate! Sad to see it go.
@hamradiotube
@hamradiotube 7 күн бұрын
Good to know. Now I need to go on a deep dive about what is a Wayback Machine lol!
@briantalley8415
@briantalley8415 8 күн бұрын
Thanks, Mike, that was really helpful. I'm one of the lucky ones who doesn't lack for space, so I'll stick with the long wires resonant on many bands.
@vicmiller7191
@vicmiller7191 8 күн бұрын
Ouch that was a rabbit hole that really sucked you in. I had thought about trying traps too. After all they use traps on Beams that are hung up in the air. So it seemed it should work but as you found out it appears it may not with out a whole lot of building and rebuilding traps till you get the magic combo achieved. Thanks for the good video. Vic de KE8JWE
@ChrisKD9YSW
@ChrisKD9YSW 8 күн бұрын
Thanks and yeah that was a rabbit hole
@ThomasT341
@ThomasT341 4 күн бұрын
Thank you for this!
@daveengstrom9250
@daveengstrom9250 4 күн бұрын
This was a GOOD video. Thanks for making it.
@dangerwillrobinson23
@dangerwillrobinson23 6 күн бұрын
Interesting video. I looked into traps for a bit, but decided that it would be better for me to start with building linked dipoles before I tackle something that looks to be much more complex to design, build, and tune. Maybe after I get some more experience I'll try a trapped antenna.
@LarryTaylor-l5m
@LarryTaylor-l5m 8 күн бұрын
I am waiting for Adam, K6ARK, to put out a kit for this exact build.
@hamradiotube
@hamradiotube 7 күн бұрын
Yeah but he's so evil he'd prob make it with the tiniest parts in the world lol!
@P.SeanCoady
@P.SeanCoady 8 күн бұрын
I've used traps on radials for a elevated vertical. Worked well vertical was 30feet above ground
@hamradiotube
@hamradiotube 7 күн бұрын
Good lord, how was that for tuning all the different wires and traps? And would you do it again?
@P.SeanCoady
@P.SeanCoady 7 күн бұрын
@hamradiotube it really wasn't that hard. In fact i did it twice first time with home made coax traps (they worked well) second time with W2AU traps a little $$ but I was having fun. So first I decided 2 sets of 3 to cover 40 through 10 or 7 bands yes it doesn't divide evenly so one set had extra. Also had to consider 40m will also match 15m bonus. Here we go you take W2AU cheat sheet for his trap dipole and you build it. Tune it cut it half and you have two radials. Then dupe half for the third radial. Do it again for the next band set and done. 6 tuned radials for 7 bands. I made the third one of each band set a tad shorter to give it broader bandwidth.
@hamradiotube
@hamradiotube 7 күн бұрын
@@P.SeanCoady That's pretty awesome. I've still not messed with raised radials let alone a raised vertical! I was watching more videos on traps last night. Don't ask me why, glutton for punishment I guess! But one of them mentioned the narrower band width as well. Something I didn't come across in my rabbit hole, but I guess I'm still down there.
@PaulGriffith
@PaulGriffith 8 күн бұрын
Enjoyed the rabbit hole with you.
@HamManCT
@HamManCT 8 күн бұрын
That makes a whole lot of sense! Thank you!
@madalinbetea9871
@madalinbetea9871 2 күн бұрын
Another disadvantage of using traps is narrow bandwidth of target frequency.
@wildbill1
@wildbill1 8 күн бұрын
All this trap stuff is got my brain fried 😂 sounds to me like the squeeze ain’t worth the juice, just rock with the harmonics link system, or whatever, and ham on!
@kevinkd9txitransmitindiana133
@kevinkd9txitransmitindiana133 8 күн бұрын
Hey Mike can you go over that again. JK good info I was going to look into all of that myself so thanks for saving me all that torment so now I know traps suck! 73 buddy see you in Dayton
@hamradiotube
@hamradiotube 8 күн бұрын
Oh you got jokes lol!
@tomking8597
@tomking8597 7 күн бұрын
I like the Traps if you are putting the antenna real high permanently. I’ve added 80meters to my 40m EFHW. By just adding a 110uhenry inductor then about 10 ft of wire. Still works on 10,15,&20.
@Mandarin110631
@Mandarin110631 8 күн бұрын
Wow thanks Mike!!!
@labcat73
@labcat73 6 күн бұрын
This is what I came across when looking at that a while ago: "VK3IL Blog - Trapped five band EFHW SOTA antenna" for 40/30/20/17/15m. It looked very intriguing, but also finicky to tweak, if you can't use exactly the same parts as VK3IL did. 73 Tobias
@CaseyStanton
@CaseyStanton 8 күн бұрын
Shocked that anyone still checks Yahoo! 😅
@hamradiotube
@hamradiotube 7 күн бұрын
Leave no stone unturned 🤣
@Tokyo1991.JL1AJE
@Tokyo1991.JL1AJE 7 күн бұрын
A minor but important point of confusion needs to be cleared up. Loading coils are not traps. Everything else you covered well but here’s a summary with that point in mind. And an idea for a potential antenna to experiment with. Loading coils allow you to shorten the overall antenna length, getting lower frequencies on shorter antennas at the cost of harmonics and reduced bandwidth. The opposite of that would be a loading capacitor which is the little brother of the trap. In contrast traps won’t physically shorten your antenna but it will appear electrically shorter at specific frequencies, as if a lazy POTA activator had gotten out of their camping chair and disconnected a link ;-P I’ve seen multiple loading coils and multiple traps (not on the same antenna). But if you take into account that a trap is kind of an over engineered capacitive loading device (I.e. the opposite of a loading coil) it’s somewhat counter intuitive to mix in both a device that lowers resonance on a shorter element with a device that raises resonance on a longer element. Not to say that it can’t be done. A coil shortened 40m EFHW (that looses 15m) with a trap for 15m might be a place to start. Don’t know if this will display well in the comments. ---||---=-- matching unit -- elements || trap for 15m = loading coil for 40m You could make this work by linking in the trap and loading coil to an existing linked EFHW though you might need to make the 40m element (2-2.5m) that comes after the loading coil (27-35uH). 73s John
@KeepEvery1Guessing
@KeepEvery1Guessing 8 күн бұрын
Nice work, Mike. I guess that I'll summarize my thoughts: Traps are lossy, have weight, and cost significantly more than a link Harmonic resonances are unlikely to be present because of the differing shortening effects of the inductor at the various frequency. As you point out, a trap per band, except for the lowest (so not N but N-1) is potentially required. And even rain can throw these careful tunings off Traps are a good choice for that tri-band beam on top of that 80 feet of Rohn 45. You could use (lots of) treaps on a wire antenna if the installation is hard to lower and too high to reach. In such a case I'd probably go back to my wet dream of a remotely controlled link.
@hamradiotube
@hamradiotube 7 күн бұрын
Back in the day George from PackTenna was trying to work on a remotely operated link. That would be so cool! But at the same time, would it be worth all the extra effort?
@KeepEvery1Guessing
@KeepEvery1Guessing 7 күн бұрын
@@hamradiotube Probably not. As I said, a wet dream. While I could see a latching reed switch as being light enough, I don't know if they exist. Powering the circuitry is already a thorny problem without having to power a non-latching relay. I've never come up with a power scheme. If you have a way to deliver power, then control isn't too hard.
@OldinMariner
@OldinMariner 8 күн бұрын
Another good source for antenna info is the ARRL antenna manual
@hamradiotube
@hamradiotube 7 күн бұрын
I did read a couple articles from old issues of QST. That could have been a separate rabbit hole all of it's own.
@Maker_Mikey
@Maker_Mikey 7 күн бұрын
TL;DR - The rabbit hole just might be worth it... For anyone who has a few years of their life to dedicate to physics and non-linear circuit analysis... (Concerning LRC circuits) Inductors can be used as low pass filters, capacitors can be used as high pass filters, so each circuit can be configured (as it is frequency dependent) to perform the necessary functionality. So a low-pass, band-pass, notch and high-pass filter are combinations (parallel and series) of impedance, capacitance and inductance. The antenna simply needs to be considered as a system with the various traps being proposed. Sometimes I feel like we believe too much voodoo is involved. Capacitors: voltage leads current Inductors: current leads voltage ...When we look at the antenna pictures with waveforms we always draw the current and the voltage as sinewaves, but we forget (visually), that is exactly what we are influencing with the LRC 'traps, coils, et al'
@crobarrm8695
@crobarrm8695 7 күн бұрын
Chameleon emcomm 2. Problem solved. I didn't bother checking 30m, but the internal tuner in the ic7300 easily matched every other band its capable of. 6m through 160m.
@RadioExpeditionProject
@RadioExpeditionProject 8 күн бұрын
Pastor Mike, Preaching the antenna gospel!
@hamradiotube
@hamradiotube 7 күн бұрын
I mean, I am an ordained minister...
@RadioExpeditionProject
@RadioExpeditionProject 7 күн бұрын
@ Excellent! 😆
@escheytt9326
@escheytt9326 8 күн бұрын
Excellent job of research and explaining the application and design and consideration of traps. Keep up the good work, it is appreciated. Ed KK7UNA
@robertmeyer4744
@robertmeyer4744 8 күн бұрын
Great stuff. I look at trap for each band adds some loss in antenna. Having traps for all the bands is a lot of loss. Looking what is out theirs for antenna . I linked antenna is the way to go. The outher choice is use random wire 9:1 or 4:1 . Will have less loss than all them traps. Just need tuner. The Coffee and ham radio Poseidon is a great choice for multi band. Easy to build. 4:1 UNUN easy to wind. Just measure wire cut . Works super great multi band. And most tuners will easy tune for the band you want. A lot less work and works great . 73
@willian.direction6740
@willian.direction6740 7 күн бұрын
Dead right Mike walk over to open a link is much easier than wearing out a pair of boots walking around you antenna build with a trap to make it work everywhere else. Thanks for all the ground work though interesting final theory on it all. My link end fed has 1 link with a 1.7 T 1 vswr on 10.1 mhz with the resonate point actually 9.6mhz but a fantastic vswr on 17m where I want it. The harmonic of 10.1 mhz makes the next sweet spot in 19 or 20 mhz not 18mhz. Like you say Vudu at work. regards vk5cz ..
@bill-2018
@bill-2018 7 күн бұрын
I have an inverted vee for 60m, it was originally for 40m but I later suffered broadband interference so I extended it for 60m where things were quieter. Now it's gone to fibre the QRM has cleared up and I want 40m again but also keep 60m so I'm thinking traps because a link would involve me climbing on the extension roof. There seems to be no details for these frequencies so I'll have to look at a trap calculator. Maybe a variable C to test it. I have five attic dipoles for 20m to 10m. QRP is okay for me, everything here is QRP. G4GHB.
@StevenHailstone
@StevenHailstone 7 күн бұрын
Great video, Mike. I could feel the sighs every time you didn't get to your answer. Glad you found Alan explaining it clearly. For your linked EFHW, do you find 20m works better isolated that way (unlink the section beyond 20m) rather than as a harmonic of 40m? Steve/K3SLH
@hamradiotube
@hamradiotube 7 күн бұрын
I'm not really sure if it matters one way or another honestly. I've never really compared the two different configurations but I've also never had them all linked and said to myself "man I'm not getting any contacts, let me unlink this" and then made more contacts. Sure you could do WSPR comparisons but there's always going to be the variable of the bands constantly changing. If you did enough over time you may see some different results between the two, but that is a rabbit hole I don't see myself going down any time soon.
@EricSolomon-op8ti
@EricSolomon-op8ti 7 күн бұрын
100% : KISS
@hamradiotube
@hamradiotube 7 күн бұрын
The only part of KISS I get is the last S 🤣
@rafaelgcpp
@rafaelgcpp 8 күн бұрын
The traps change the lenght the same way as a bobbin. I tried and figure out that it is (for me) impossible to build a 10m-12m-15m EFHW antenna, so I compromised with 10m and 15m. Funny enough, I still can operate 12m with an ATU, but I wouldn't try adding traps for every band, as the segment lenghts would become impredictable, and sometimes not possible at all!
@rafaelgcpp
@rafaelgcpp 8 күн бұрын
For those curious: I have single band EFHW antennas for my very limited space!
@gregiep
@gregiep 8 күн бұрын
I think for POTA, traps may not make sense. I do have a trapped dipole for 40/80m at my QTH, that I use for day/night NVIS.
@daniell8387
@daniell8387 8 күн бұрын
I have a ridiculously stupid quesiton, feel free to roast the hell out of me for it. Have you ever tried a fan EFHW? Like 10, 12, 15 , 17, 20, and 40m elements all going out of one transformer? I realize it's an awkward solution but I wonder if it works.
@RicksHamShack
@RicksHamShack 8 күн бұрын
Only works if the wires aren't resonant with each other. For instance, if you transmit on 10 meters with such a rascal, the 10m, 20m and 40m wires will all resonate...
@fullmetaljacket76
@fullmetaljacket76 8 күн бұрын
I had the same wondering since the phrase "a dipole is a dipole is a dipole" is everywhere, then would a fan work for an EF. I tried a fan dipole project once, thinking an EF design would be easier to cut in. The dxcommander verticals are "fans" as well so maybe those lengths would work in a horizontal run as well?
@daniell8387
@daniell8387 8 күн бұрын
@@RicksHamShack good point. Though it would be a nice f-u to an HOA
@dorvinion
@dorvinion 8 күн бұрын
I suspect if you wanted all those bands you'd have to do one ~66 ft wire for 10/15/20/40 and then one ~18.5ft for 12m and one ~29ft for 17m Suppose 12 and 17 could also be done by putting a mini-trap as demonstrated in the video at the end of the 12m section and then finish it off with enough wire to make it resonate on 17. Since 17 is only 100kHz wide even if its relatively high Q you should still be able to cover the whole band Suppose a coax coil trap would work also, but its also heavier. I kinda feel like trying that out now.
@PortableRadio
@PortableRadio 8 күн бұрын
Try it and you'll realize that it won't work, mainly because of the high feedpoint impedance, compared to a center fed dipole.
@DellFargus
@DellFargus 8 күн бұрын
All this talk about traps, and not one mention of Admiral Ackbar. I guess you're just not into Star Trek. I don't bother with traps or links on my portable setup. I carry a manual tuner and a 3' length of coax to put it inline. The tuner can dial in 40 down to 10 with no problem, and I don't even need to get up... although 12 is a little wonky, yet usable... but nobody uses 12 anyway. Props for going through all the nerdery.
@CoolDukeYT
@CoolDukeYT 8 күн бұрын
best video ever. 73
@ibuildsheds5654
@ibuildsheds5654 7 күн бұрын
Six minute intro to topic?
@M6JKW
@M6JKW 8 күн бұрын
🙂👍
@pieterdutoit9642
@pieterdutoit9642 8 күн бұрын
sounds way to many $$$$
@moselblues8694
@moselblues8694 8 күн бұрын
Wondering what you have to learn to earn your ham exam over there in the US. Thomson's resonance formula for LC circuits is an absolute basic. 😂 You can use any combination of C an L for your trap that is resonant on your desired band. Just use a cheap calculator and a pencil... I also would encourage you to take a look in antenna simulation with MMANA-GAL (or ezNec) to gain a bit of understanding about resonacese on antenna and the effects of electric shortened antennas. You will be maybe surprised how the radiation pattern of a 40/20/15/10m EFHW differs by band and maybe shocked as it looks on 10m😂
@dorvinion
@dorvinion 8 күн бұрын
Yes, we have to learn it to get Extra. Its not a requirement that we remember it, especially since its not something we'll use every day.
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