Another simple resource - Plastic coated clothes line wire works great for antennas. Not super light but cheap, long lasting and can be bought in long rolls from local hardware store.
Always love the educational videos you do. You put a lot of passion into them. I like EFHW for 80M and build my own 49:1 transformers. Works every band in the digital portion under 2:1 and 30M is about 3:1. I am the guy with the 6ft wire around my wood fence in a J pattern and fed at the short end of the V. Field Day tomorrow. My club will be working as a 4 Foxtrot station (County EOC) with callsign WM5A all bands, CW, phone and FT8 beginning 6pm UTC. Jack K5FIT
Love your videos Callum, since recently getting my licence, you UA-cam guys (yourself, radio runner, ham radio dx, roly ZL1BQd, hamradio2.0, smoking ape, amateur radio vk3ye, Tim G5TM, etc etc) have been most helpful and inspirational !
Great video and great ideas , my first antenna support was a 5 m length of roofing batton for a few quid , screwed to the fence post also , lasted a couple of years until I had a chat with my neighbour who kindly said I could use there tree as a support , cheers for the great videos
Absolutely brilliant Cal. I had a few things knocking around in my head about a couple of lengths. After I watch this video, the light 💡 went on. Thanks so much for the effort you put into the explanations. Take care. P.S. Didn't even seem like 20 minutes. Wouldn't worry too much, when your having fun, the time slips by. 👍🏻
With your guidance I successfully made a loop that worked great on 40m and down. I've already made lots of dipoles (although I'd still like to try linear loading to try and get an antenna for 160m that would fit on my property). So now I need to make a vertical!
You're a good man Callum. Really enjoy your enthusiasm and your natural approach. I hope to work you one day. Regards Mark (yes, we have emailed) NSW Australia.
Good stuff. I used to use a rubber tipped arrow and low power bow to shoot fishing line over tree limbs. Then one of my friends came up with using a fishing casting rod with a lead sinker on the fishing line and casts the line over tree limbs. Then tie a long length of para cord to the fishing line, pull it over the limb and then pull up the wire antenna with the para cord.
I use to use a 66 ft approx efhw it worked great , I would keep the transformer low to ground this would allow me to by pass the transformer using a dipole connector with a counterpoise to ground a short wire with croc clip would clip onto the wire on the transformer this would make it a quarter wave on 80m worked a treat
Antennas are one of the least understood (or most?) but most fun parts of radio. Sometimes we "understand" more than we have fun. I guess it all depends on where one's interest in the hobby goes! Great vid as always!
The OCF dipole uses an atypical feedpoint to achieve favourable input impedance on more bands. The EFHW takes it to the extreme with a very high input impedance making the matching device somewhat more critical. The radiation pattern will not be appreciably different from the harmonics of an EFHW or 15m on a 40m dipole. Harmonic frequencies result in more commutation of the current distribution across the radiating element, and this is reflected in a radiation pattern that increasingly resembles a porcupine as the harmonic number increases.
Awesome content as per usual Callum but also need to recognise the incredible job of editing/filming you do on your videos - really engaging & easy to understand your sketched diagrams etc. Love it!
I'm starting to wonder if the goal of "self resonant" antennas is the correct goal. If the purpose of an antenna is to transfer EM waves into free space then it seems like the length of an antenna should be dictated solely by the speed of light. I'm wondering if when we trim our antennas to be self resonant that all we are really doing is changing the reactance of the antenna to compensate for reactance from the environment, but at the cost of degrading its ability to radiate into free space. Perhaps we should be cutting antennas to the length based on the math and then compensate for environmental reactance via a tuner or inductors/capacitors applied to the antenna.
@@DXCommanderHQ only has one layer on the Aussie stuff. Basically fig-8, 5x strand tinned copper, and 3x strand of stainless steel from memory. I was lucky to 'reclaim' heaps of it when I served.
My first antenna was a Qwave of transformer wire I scavenged out of a transformer and measured out, stuffed into the coax fitting on the back of the radio and hung out the 2nd story window. And it worked. No swr meter, just measure, cut and throw it out the window and let it hang. The radio was an old 23 channel CB mobile that was given to me from inside an old chicken barn, chicken crap was free. And I used an old car batter and charger to run it. From there on I collected ever radio and antenna tech manual I could get, and many old ARRL books. I didn't get my ham license until many years later when my life allowed me the time to do so.
my most efficient simple antenna wich I use for long time was Dipole for 40m band hanging between tree and top of my roof and connected to same feed point inverted V for 20m band
Nice videos Callum. I know you do not have the room but have you ever considered making/modeling a Rhombic antenna...at least on MNANA? I have done some searching on the internet but info is kind of hard to find. My QTH here has a moderately large chunk of land so maybe I could find a way to fit a 20m rhombic. I read they are fairly high gain....somewhere around 20 banana's. Anyway maybe it would be interesting to other veiwers. 73's Tim - K5DEZ. P.S. My DX Commander has been up permanently for a couple years now. Still kicking ass and taking names as the metaphor goes.
I have a Fritzel FD-4 OCFD that seems to work pretty good... Made contacts in Hawaii and Chile on 10m from just south of Boston. Saving up for a Nebula can't wait! Time to hit the books for my general. K1CBX 73
I have been using Vaseline (recommended by you) since watching your videos (over a year). It works great! Thanks for the recommendation. I finally took my dx commander classic out of the box (~8 months). My goal is to build it this week. I'm totally looking forward to it. Can't wait to make contact with you while using it. So I typically use a OCF dipole (MFJ 2010) about 30 feet in the trees, but requires a tuner. I have no idea what he pattern is and would like to know. Mu contacts are all over the dish, not consistent. I can't wait to use a resonant antenna like the dx commander.
OK, some parts of SOME bands (behond 20m probably) will have some gains - and some losses. Difficult to discuss here sorry! DXC will be fabulous. Enjoy.
DX Commander Classic == 40, 20, 10, 6 meters. MMANA says that transmitting on 2 meters radiates primarily off the 40 meter element (21st harmonic). Radio says SWR
Not worked this out but 6. Is a 1 3/4 and 7th harmonic.. So yes you are probably right at 21st harmonic.. Steve opened a repeater away about 40 / 50 miles so SOMEWHERE there must be a tiny lobe low down.. I ca. See it on the modelling..
Phone drop wire was copper plated steel, bloody strong stuff. For radials a cheap solution is stripped down CAT5/6 it is cheap as chips, and you get 8 wires out of it....
Great video cal !!! Gonna try making a receive loop tomorrow.if it's only used for receive dies the wire have to be a certain length or more wire down the better?? Loved this one 👍👍
Andy, So I have practical experience of a) a small loop on the ground and b) a large 90m loop 30cms off the ground. I preferred the large loop. Size doesn't matter but if I had ONE to chose from,, it would be a 1m or 2m high loop around any garned / back-yard with a 4:1 balun. You might find it's tune on some bands just by accident but for RX only, don't fret about it.
Good morning sir! Wondering if you would be willing to teach on the use of 75 ohm 1/4 wave matching stub for impedance matching (instead of using a 4:1) Would love to learn how to do it, how to measure the proper length, when it would be advisable to do it, etc ....
I am buildong a dx commander classic. My radials will be #10 awg thhn. It was free, and I can add as many as I want as time goes on. As for odd wire to use on transmit. I wonder how electric fence wite might work. Even spicier, they make electric fencing rope, hi vis, the stranded wires are woven into the rope, which is the size of parachord or less. I am not using it. But that would be a interesting thought........ I mention it just to throw a wrench in the " traditional" transmit wire train of thought.
You don't look that old, but the average age of licensed hams is 68, according to ARRL (I fit that description). And I notice many of us have guitars hanging on the wall. Must be some common trait.
I noticed that on your website you sell not only your DX10 but one called DX50. Could you do a video explaining the benefits and shortfalls of each and under what circumstances they would be most suited?
I'll add that to the log of videos.. Basically, DX50 and any Kevlar cored wire is only really needed for very high tension work.. Massive doublets or huge loops etc. But I will make a short video about these and other antenna wire. Good idea.
Have you considered Black Dacron instead of paracord? In my opinion, the Dacron is far superior. I have a dipole that is supported with Black Dacron that has been up for almost 20 years. Paracord will not last anything near that amount of time. The Wireman is a good source for it in the US.
Great video cal, and I hope your enjoying you hols. Ants, wires, trees loops dipoles all over the place, don't think so. Dx commander in the corner of the garden a few radials, easy to set up, and it will give you dx all day long. Job done, no brainer. 73 zl3xdj
Yes it does.. I have a loop on the ground. It's almost too quiet (depending on band) but works. My fav is a 90m loop about 30cm/12 inches off the ground.
I’m thinking about building a multi-band vertical. I have an aluminum collapsible flagpole I’m thinking about using. If I use this aluminum pole and don’t allow the wire to touch it, will the metal pole cause a problem?
Very nice video Callum! (as usual😊). I have a question about 40-15m GP: Which is the distance between 9,2m and 2m wires? Thanks a lot for the answer. Best 73 de Franco, iw2hus
Cal - any real world differences with EFHW vs 1/4 wave with verticals? I've done the MMANA model and I'm seeing only a 0.2 difference at 5* off the horizon (if I'm doing it right). Am I losing RF power with the 49:1 transformer to bring SWR in-line?
Good analysis.. My modelling has always shown that too.. Roughly.. Probably depends on ground conditions too. And 1/4 wave gives you SOME (not a lot) slightly higher angle stuff for the small 1000 mile hops.
hi callum please could you take a min to give me on the 20m half square fed at the top corner iv made one 2 quater wave verticals 16ft 6inch orizontal 36 feet my swr keeps changing ? thanks mark
thankyou calum it was my pl259 a pidgeon hit my orizontal wire my nieghbour told me lol all good back to 1to1 2 swr great dx but cant hear you or anyone in the uk lol but i still watch your vids saveing up for a commando probs rapide 7 thanks mate
Question: How come we always see fan verticals rather than using a single element vertical with a tuner? Is this because of coax loss? Could I instead feed such an antenna with window line? Or use a remote tuner at the feed point (if I were flush with cash lol)? Do the lobes go all weird when the vertical is nonresonant and used with an ATU? Will such an antenna pick up a ton of noise? If so, could I use a vertical with ATU for transmit only and switch to a loop on ground for rx? Sorry for all the dumb questions. It's just that I've been thinking of trying to strap 50 or 60 ft of wire and pvc pipe up the side of my chimney, bury some radials, and try to feed it with window line out of the ATU. But if that were something that worked well, I'd think more people would be doing it, right? Just wondering why not.
Impedance - hence the need for a transformer at the feedpoint. End fed random wire sort of deal. Potential thousands of Ohms at the feed point when non-resonant length. A good ATU will do it however - just with the usual compromises vs a tuned element.
Hi Lee.. See Tom's comment - and also I have made a video about long wires and using them for transmit.. Probably released next Friday.. Bottom line is getting a) a good match to 50 ohms (or your ATU) and b) the pattern [literally where the RF goes] becomes important..
@@DXCommanderHQ Thanks for the replies, gentlemen. So the short of it is, even if I feed a nonresonant vertical with some kind of low-loss feed line through an ATU, those sweet DX takeoff angles will still get all jacked up when the pattern goes wonky, so it's not worth fooling with?
Curious....you use 4:1 baluns on the loops, but every loop I've experimented with had an impedance in the range of 100 - 110 ohms meaning I had to ise a 2:1 balun as a 4:1 dropped the impedance to 25-30ohms and I couldn't get any decent swr out of the insulated house wire. Any thoughts on why there would be such a difference?
David, options are 75 ohm coax at 1/4 wave less VF. Perfect tune for coax. Balanced tuners can bump up the cost for the average chap doing experiments.
That's fairly easy with coax. Put a PL259 on your 50 ohm coax, then get an, "electrical" quarter wave length of 75 ohm coax, one more PL259 and a double SO239 barrel connector. Put the other PL259 on one end of the 75 ohm coax and split the other end on the antenna insulator at the feed point. Attach both PL259's together with the barrel connector. The 75 coax might be 66 percent velocity factor if it has fairly clear or see-through dialectic or it might be closer to 80 percent VF if it has white foam inside. This only works for one band though. You can reduce the impedance of the loop by making it slightly shorter, such one length in space, rather than longer to make it more resonant. At least it will match the 50 ohm coax better. The QRP guys swear that an even slightly longer loop works better, even with some mismatch though. If you need a 4:1 balun, it should be a current balun, not the lower cost voltage balun, as it is the currents that need to be balanced between the unbalanced feed line and balanced antenna feed point. Look up how to make a half wave coax 4:1 balun, if you need that much matching, but again, it will be one band only. If your loop is a square or a triangle, you can shorten one dimension, while increasing the other. This will increase the impedance. A folded dipole has an impedance of around 300 ohms, so anything between a symmetrical loop and a folded dipole will have an impedance between the two antenna designs. Get it around 200 ohms and then use a 4:1 balun. With a triangle, lengthen one side and shorten two sides. With a square, lengthen two sides and shorten two sides. As this is increased, the impedance with approach that of a folded dipole at some point with the sides close together.
I built a full wave 80m skyloop out of cat5 cable, some home made ladder line and some 75 ohm tv coax, entire antenna was made for free, best receive and transmit I've had yet.- ve1qfa
![[UA] Team Vitality проти NAVI | IEM Cologne 2024](http://i.ytimg.com/vi/wttO1zVRTC0/mqdefault.jpg)
Another simple resource - Plastic coated clothes line wire works great for antennas. Not super light but cheap, long lasting and can be bought in long rolls from local hardware store.
Great tip!
Foldie-overie sorta thing. Callum, we speak the same engineering terms!
Always love the educational videos you do. You put a lot of passion into them. I like EFHW for 80M and build my own 49:1 transformers. Works every band in the digital portion under 2:1 and 30M is about 3:1. I am the guy with the 6ft wire around my wood fence in a J pattern and fed at the short end of the V. Field Day tomorrow. My club will be working as a 4 Foxtrot station (County EOC) with callsign WM5A all bands, CW, phone and FT8 beginning 6pm UTC. Jack K5FIT
Brilliant Jack!
Love your videos Callum, since recently getting my licence, you UA-cam guys (yourself, radio runner, ham radio dx, roly ZL1BQd, hamradio2.0, smoking ape, amateur radio vk3ye, Tim G5TM, etc etc) have been most helpful and inspirational !
Wow.. You listed some fab channels there!
I have used galvanized steel electric fence wire from a farm supply store with good results.
Great video and great ideas , my first antenna support was a 5 m length of roofing batton for a few quid , screwed to the fence post also , lasted a couple of years until I had a chat with my neighbour who kindly said I could use there tree as a support , cheers for the great videos
Haha. Nice one. A good tree is a fabulous toy for us!
Absolutely brilliant Cal. I had a few things knocking around in my head about a couple of lengths. After I watch this video, the light 💡 went on. Thanks so much for the effort you put into the explanations. Take care.
P.S. Didn't even seem like 20 minutes. Wouldn't worry too much, when your having fun, the time slips by. 👍🏻
Haha.. Yes, when I'm on a roll, I can't stop! :)
With your guidance I successfully made a loop that worked great on 40m and down. I've already made lots of dipoles (although I'd still like to try linear loading to try and get an antenna for 160m that would fit on my property). So now I need to make a vertical!
Nice one Randy!
You're a good man Callum. Really enjoy your enthusiasm and your natural approach. I hope to work you one day. Regards Mark (yes, we have emailed) NSW Australia.
Thanks Mark 👍
Good stuff. I used to use a rubber tipped arrow and low power bow to shoot fishing line over tree limbs. Then one of my friends came up with using a fishing casting rod with a lead sinker on the fishing line and casts the line over tree limbs. Then tie a long length of para cord to the fishing line, pull it over the limb and then pull up the wire antenna with the para cord.
Yes, I made a home-vrew fishing rod / antenna launcher once!
I use to use a 66 ft approx efhw it worked great , I would keep the transformer low to ground this would allow me to by pass the transformer using a dipole connector with a counterpoise to ground a short wire with croc clip would clip onto the wire on the transformer this would make it a quarter wave on 80m worked a treat
Perfect
Antennas are one of the least understood (or most?) but most fun parts of radio. Sometimes we "understand" more than we have fun. I guess it all depends on where one's interest in the hobby goes! Great vid as always!
Steve, I am often so amazed you watch more than half my stuff! LOL. Great comment as usual :)
@@DXCommanderHQ it's really Mrs TO you should thank. She loves your stories, so I can get away with watching ham radio vids when she's around.
The OCF dipole uses an atypical feedpoint to achieve favourable input impedance on more bands. The EFHW takes it to the extreme with a very high input impedance making the matching device somewhat more critical.
The radiation pattern will not be appreciably different from the harmonics of an EFHW or 15m on a 40m dipole. Harmonic frequencies result in more commutation of the current distribution across the radiating element, and this is reflected in a radiation pattern that increasingly resembles a porcupine as the harmonic number increases.
Ah yes, the "Porcupine"! :)
@@DXCommanderHQ
Yup, very spikey!
Awesome content as per usual Callum but also need to recognise the incredible job of editing/filming you do on your videos - really engaging & easy to understand your sketched diagrams etc. Love it!
Much appreciated!
I'm always learning from your videos. Thanks for the content! While I watch FedEx closely as my 12.4 comes this way.
You are fighting... the razor!
Awesome, thank you!
Excellent Cal... real world, common sense advice... so useful... 73s Dave G0KPZ
Ah. Glad you liked it Dave!
I'm starting to wonder if the goal of "self resonant" antennas is the correct goal. If the purpose of an antenna is to transfer EM waves into free space then it seems like the length of an antenna should be dictated solely by the speed of light. I'm wondering if when we trim our antennas to be self resonant that all we are really doing is changing the reactance of the antenna to compensate for reactance from the environment, but at the cost of degrading its ability to radiate into free space. Perhaps we should be cutting antennas to the length based on the math and then compensate for environmental reactance via a tuner or inductors/capacitors applied to the antenna.
Indeed, that is another way of looking at it. BUT it's a heck of a lot easier just to make the numbers right on the cheap :)
I use military Don-10 for my 160m horizontal loop. Works a treat, and nice and strong!
Ah-ha.. Have a look each year because the outer layer of insulation material can degrade leaving the inner insulation .. Then it snaps.
@@DXCommanderHQ only has one layer on the Aussie stuff. Basically fig-8, 5x strand tinned copper, and 3x strand of stainless steel from memory. I was lucky to 'reclaim' heaps of it when I served.
My first antenna was a Qwave of transformer wire I scavenged out of a transformer and measured out, stuffed into the coax fitting on the back of the radio and hung out the 2nd story window. And it worked. No swr meter, just measure, cut and throw it out the window and let it hang. The radio was an old 23 channel CB mobile that was given to me from inside an old chicken barn, chicken crap was free. And I used an old car batter and charger to run it. From there on I collected ever radio and antenna tech manual I could get, and many old ARRL books. I didn't get my ham license until many years later when my life allowed me the time to do so.
Brilliant!
Smiling!
Always entertaining and informative sir.
Thank you kindly!
my most efficient simple antenna wich I use for long time was Dipole for 40m band hanging between tree and top of my roof and connected to same feed point inverted V for 20m band
Lovely!
Nice videos Callum. I know you do not have the room but have you ever considered making/modeling a Rhombic antenna...at least on MNANA? I have done some searching on the internet but info is kind of hard to find. My QTH here has a moderately large chunk of land so maybe I could find a way to fit a 20m rhombic. I read they are fairly high gain....somewhere around 20 banana's. Anyway maybe it would be interesting to other veiwers. 73's Tim - K5DEZ.
P.S. My DX Commander has been up permanently for a couple years now. Still kicking ass and taking names as the metaphor goes.
Hey Tim, apparently indeed they are great. Not modelled of even thought of one for the last couple years.. You have re-lit my interest..!
I have a Fritzel FD-4 OCFD that seems to work pretty good... Made contacts in Hawaii and Chile on 10m from just south of Boston. Saving up for a Nebula can't wait! Time to hit the books for my general. K1CBX 73
Wow.. OK Good luck! PS - The Signature 12.4 is a fabulous alternative!
I have been using Vaseline (recommended by you) since watching your videos (over a year). It works great! Thanks for the recommendation. I finally took my dx commander classic out of the box (~8 months). My goal is to build it this week. I'm totally looking forward to it. Can't wait to make contact with you while using it.
So I typically use a OCF dipole (MFJ 2010) about 30 feet in the trees, but requires a tuner. I have no idea what he pattern is and would like to know. Mu contacts are all over the dish, not consistent. I can't wait to use a resonant antenna like the dx commander.
OK, some parts of SOME bands (behond 20m probably) will have some gains - and some losses. Difficult to discuss here sorry! DXC will be fabulous. Enjoy.
@@DXCommanderHQ Thanks Callum. I know what I'm getting into. Been reading up and watching a lot of videos regarding your antenna. Wish you the best!
DX Commander Classic == 40, 20, 10, 6 meters. MMANA says that transmitting on 2 meters radiates primarily off the 40 meter element (21st harmonic). Radio says SWR
Not worked this out but 6. Is a 1 3/4 and 7th harmonic.. So yes you are probably right at 21st harmonic.. Steve opened a repeater away about 40 / 50 miles so SOMEWHERE there must be a tiny lobe low down.. I ca. See it on the modelling..
I’ve always been told best to start at 1/4 wavelength above the ground
For what I wonder..? It's all about patterns.
What a gentleman.
The 80Mtr HW may even work on top band with some help from an ATU, , ? ?
Ah-ha!
Phone drop wire was copper plated steel, bloody strong stuff. For radials a cheap solution is stripped down CAT5/6 it is cheap as chips, and you get 8 wires out of it....
Good tips!
Great video cal !!! Gonna try making a receive loop tomorrow.if it's only used for receive dies the wire have to be a certain length or more wire down the better?? Loved this one 👍👍
Andy, So I have practical experience of a) a small loop on the ground and b) a large 90m loop 30cms off the ground. I preferred the large loop. Size doesn't matter but if I had ONE to chose from,, it would be a 1m or 2m high loop around any garned / back-yard with a 4:1 balun. You might find it's tune on some bands just by accident but for RX only, don't fret about it.
@@DXCommanderHQ thankyou so much cal
Good morning sir! Wondering if you would be willing to teach on the use of 75 ohm 1/4 wave matching stub for impedance matching (instead of using a 4:1) Would love to learn how to do it, how to measure the proper length, when it would be advisable to do it, etc ....
Great suggestion! I'll add it to the list!
@@DXCommanderHQ thanks!
I am buildong a dx commander classic. My radials will be #10 awg thhn. It was free, and I can add as many as I want as time goes on. As for odd wire to use on transmit. I wonder how electric fence wite might work. Even spicier, they make electric fencing rope, hi vis, the stranded wires are woven into the rope, which is the size of parachord or less. I am not using it. But that would be a interesting thought........ I mention it just to throw a wrench in the " traditional" transmit wire train of thought.
Yes, I've seen that stuff... Interesting project!!
You don't look that old, but the average age of licensed hams is 68, according to ARRL (I fit that description). And I notice many of us have guitars hanging on the wall. Must be some common trait.
I noticed that on your website you sell not only your DX10 but one called DX50.
Could you do a video explaining the benefits and shortfalls of each and under what circumstances they would be most suited?
I'll add that to the log of videos.. Basically, DX50 and any Kevlar cored wire is only really needed for very high tension work.. Massive doublets or huge loops etc. But I will make a short video about these and other antenna wire. Good idea.
Another great video - Cal, really interesting. Mark, 2E0MSR
Glad you enjoyed it
Have you considered Black Dacron instead of paracord? In my opinion, the Dacron is far superior. I have a dipole that is supported with Black Dacron that has been up for almost 20 years. Paracord will not last anything near that amount of time. The Wireman is a good source for it in the US.
Greg, also Mastrant Cord. Superior again..
Great video cal, and I hope your enjoying you hols.
Ants, wires, trees loops dipoles all over the place, don't think so. Dx commander in the corner of the garden a few radials, easy to set up, and it will give you dx all day long.
Job done, no brainer.
73 zl3xdj
HAHA Brian! Eventually, everyone will come to the same conclusion! LOL!!
Is it true if you put an antenna on the ground, it makes for a great receive ant. Very quiet. Loop, dipole, long wire?
Yes it does.. I have a loop on the ground. It's almost too quiet (depending on band) but works. My fav is a 90m loop about 30cm/12 inches off the ground.
I’m thinking about building a multi-band vertical. I have an aluminum collapsible flagpole I’m thinking about using. If I use this aluminum pole and don’t allow the wire to touch it, will the metal pole cause a problem?
Use the metal pole as the longest element (say for 40m band) and then string the other bands a couple inches (maybe aq bit more) away. It'll work.
Thank you. I’ll try it.
Okay, so you can make an antenna tunable with a foldover, but what does it do to impedance?
Very little
@@DXCommanderHQ How about efficiency?
Wonderful explanation as always do you recall what the length of the section that you removed on your 40 m loop to create the 80 m halo
Pat.. I just guessed. I seem to remember it was about 2.5m.
@@DXCommanderHQ ok - thanks gonna give it a whirl
Very nice video Callum! (as usual😊). I have a question about 40-15m GP: Which is the distance between 9,2m and 2m wires? Thanks a lot for the answer. Best 73 de Franco, iw2hus
Doesn't matter too much, I string mine right next to each other..
@@DXCommanderHQ TU! I'll try to build the antenna to compare with my multiband EFHW 80-10m
Cal - any real world differences with EFHW vs 1/4 wave with verticals? I've done the MMANA model and I'm seeing only a 0.2 difference at 5* off the horizon (if I'm doing it right). Am I losing RF power with the 49:1 transformer to bring SWR in-line?
Good analysis.. My modelling has always shown that too.. Roughly.. Probably depends on ground conditions too. And 1/4 wave gives you SOME (not a lot) slightly higher angle stuff for the small 1000 mile hops.
hi callum please could you take a min to give me on the 20m half square fed at the top corner iv made one 2 quater wave verticals 16ft 6inch orizontal 36 feet my swr keeps changing ? thanks mark
Hmmm. Mark, send me some pics via email and I'll take a look.
thankyou calum it was my pl259 a pidgeon hit my orizontal wire my nieghbour told me lol all good back to 1to1 2 swr great dx but cant hear you or anyone in the uk lol but i still watch your vids saveing up for a commando probs rapide 7 thanks mate
Question: How come we always see fan verticals rather than using a single element vertical with a tuner? Is this because of coax loss? Could I instead feed such an antenna with window line? Or use a remote tuner at the feed point (if I were flush with cash lol)? Do the lobes go all weird when the vertical is nonresonant and used with an ATU? Will such an antenna pick up a ton of noise? If so, could I use a vertical with ATU for transmit only and switch to a loop on ground for rx?
Sorry for all the dumb questions. It's just that I've been thinking of trying to strap 50 or 60 ft of wire and pvc pipe up the side of my chimney, bury some radials, and try to feed it with window line out of the ATU. But if that were something that worked well, I'd think more people would be doing it, right? Just wondering why not.
Impedance - hence the need for a transformer at the feedpoint. End fed random wire sort of deal. Potential thousands of Ohms at the feed point when non-resonant length. A good ATU will do it however - just with the usual compromises vs a tuned element.
Hi Lee.. See Tom's comment - and also I have made a video about long wires and using them for transmit.. Probably released next Friday.. Bottom line is getting a) a good match to 50 ohms (or your ATU) and b) the pattern [literally where the RF goes] becomes important..
@@DXCommanderHQ Thanks for the replies, gentlemen. So the short of it is, even if I feed a nonresonant vertical with some kind of low-loss feed line through an ATU, those sweet DX takeoff angles will still get all jacked up when the pattern goes wonky, so it's not worth fooling with?
good talk - 73
Curious....you use 4:1 baluns on the loops, but every loop I've experimented with had an impedance in the range of 100 - 110 ohms meaning I had to ise a 2:1 balun as a 4:1 dropped the impedance to 25-30ohms and I couldn't get any decent swr out of the insulated house wire. Any thoughts on why there would be such a difference?
What were you feeding the loop with? Sounds like coax was used? Typical full wave loops are fed with 450ohm or 600ohm ladder/window.
OK, impedance will often vary depening on height above ground.. I've personally discovered 4:1 to work fine. But I guess there are other variables.
David, options are 75 ohm coax at 1/4 wave less VF. Perfect tune for coax. Balanced tuners can bump up the cost for the average chap doing experiments.
@@DXCommanderHQ Yes - I didn't consider the extra expense of a tuner and audience. 73 David
That's fairly easy with coax. Put a PL259 on your 50 ohm coax, then get an, "electrical" quarter wave length of 75 ohm coax, one more PL259 and a double SO239 barrel connector. Put the other PL259 on one end of the 75 ohm coax and split the other end on the antenna insulator at the feed point. Attach both PL259's together with the barrel connector. The 75 coax might be 66 percent velocity factor if it has fairly clear or see-through dialectic or it might be closer to 80 percent VF if it has white foam inside. This only works for one band though. You can reduce the impedance of the loop by making it slightly shorter, such one length in space, rather than longer to make it more resonant. At least it will match the 50 ohm coax better. The QRP guys swear that an even slightly longer loop works better, even with some mismatch though. If you need a 4:1 balun, it should be a current balun, not the lower cost voltage balun, as it is the currents that need to be balanced between the unbalanced feed line and balanced antenna feed point. Look up how to make a half wave coax 4:1 balun, if you need that much matching, but again, it will be one band only. If your loop is a square or a triangle, you can shorten one dimension, while increasing the other. This will increase the impedance. A folded dipole has an impedance of around 300 ohms, so anything between a symmetrical loop and a folded dipole will have an impedance between the two antenna designs. Get it around 200 ohms and then use a 4:1 balun. With a triangle, lengthen one side and shorten two sides. With a square, lengthen two sides and shorten two sides. As this is increased, the impedance with approach that of a folded dipole at some point with the sides close together.
I built a full wave 80m skyloop out of cat5 cable, some home made ladder line and some 75 ohm tv coax, entire antenna was made for free, best receive and transmit I've had yet.- ve1qfa
Fabulous!