I made this coil and antenna today... spent about 4 hrs on it trying to tune it.... 20m and up, its all good....but I couldnt get 40 or 80m to get lower than 5:1... I even tried 2 different value coils. I added wire, trimmed wire...SWR was just all over.. It was about same height overall off ground as yours..... I finally called it a day and licked my wounds.... not sure what to try, that I already havent?? 73
Hello Darby, thanks for sharing your experience , even if it was not so good :-). I had no problems in building mine. In your case, I would make sure, firstly, if my transformer is wound properly on the proper type of toroid ( FT-43 or similar material preferably). Then I would test the transformer with no antenna but the 3kOhm non-inductive resistor connected, using nanoVNA or antenna analyser. The SWR should be less than 2 on all bands of your interest. If not, something's wrong with the transformer. Secondly, I would cut the antenna wire for 40m halve wave and trim it for the best SWR on 40m band ( in my case it was 19.8m) first .Then, I would connect the loading coil with some 4 m or more of wire "pigtail" attached to it. Thirdly, I would trim the pigtail for the best resonance on 80m segment of my choice. Last but not least, the 4m long counterpoise wire is very much welcome to use, and if not, I'd make sure my coax cable is not shorter than 4m long as it's shield would act as a counterpoise in the absence of the wire c'poise. In this case, the RF choke unun is very much welcome too, connected at the radio side, or at the 4m mark on the cable looking from the transformer's side ( it could be just the same feeding cable wound on the ferrite toroid or just coiled on itself, in the cheapest way). So, this strategy of building and tuning the antenna usualy works, at least for me. HTH 73! Linas LY2H.
Great video👍❗️ I absolutely love the EFHW Antenna an I have been winding my own 49/1 UNUN’s for over 40 years back when they were very unpopular. Recently I talked my best friend into building one so I went over and we-built him the 49/1 UNUN put it up last week and he is having a ball with it. They are GREAT Antennas 73 KV5P
Awesome Mike! 40 years ago the ferrite toroids were of a bit different quality, so the open wire line fed EFHWs were the way to go, like my favourite DL7AB :) . 73! Linas LY2H
Very cool, Linas! Thanks for sharing! and seeing someone operating outside always makes me want to go outside even more. 👍🏻👍🏻 hear you on the bands. by the way: what are your experiences with antennas surrounded by bushed and trees? we always try to avoid them close to the emitting wire.
Thanks for watching! I’m not sure what do you mean by detailed specs :) The measurements are in the video, and they are not that critical, the the loading coil for instance. It is recommended to be 110 microH , I made abt 80 microH and it’s easy to compensate with the end after-coil part of the antenna. The size of the wire is not critical, any diameter 1-2mm will do if you run up to 100W into it. 2-3mm if running more. I was using the manufactory made transformer (by Myantennas.com) and its specs are on their website , I guess. The home made transformer would perfectly do too adopted to your own needs. In my antenna system, I do use the 4m long counterpoise wire (0,05 w/l on the lowest 80m band) and the CMC in line but many people don’t as the coax itself makes for a good return path for a quite modest antenna current at that point of the antenna. Some people insert the CMC (common mode choke) at the 0,05 w/l of the coax. Let me know what else could I tell you about this project! 73! Linas LY2H
I built the same design for my small back yard. My coil, seeing that it is a fixed station antenna, is substantially larger to handle 50 - 100 watts. My coil is a 105uH coil, so the end wire is only 2.1 meters long. Also, to fit the antenna in a 16 meter long yard, I erected it as an Inverted-L. 7.5 meters is vertical at the transformer end, the wire is supported by a paracord an insulator from the top of a 10 meter mast and they remaining wire to the coil (12.3 meters) slopes down to the loading coil and end wire. The coil and end wire are about 3 meters up and the end of the antenna is tied off to a mast at the fenced end of the yard. No tuner is required from 3.5 MHz to 3.65 MHz on 80 meters, nor is it required on 40 meters. The 20 meter resonance is around 14.40 MHz, so the internal tuner is used. A full sized dipole would be better, but it would have to be tied off in the next yard, not an option for me, hi! Well done, a great presentation and hope to CU on the bands soon! 73, Keith, WB2VUO here near Buffalo, NY.
Thanks for watching and sharing your own experience Keith! It looks like your set-up is a maximum what one could do in your lot, so well done to you! What I like about this antenna is that it's not critical to the dimensions or size of the coil, the end "tail" would compensate for small discrepancies. As it comes to the power, the coil shown in the video wound of the same antenna wire was running 100W from my FT-891 in the go-box with no problems. The 49:1 transformer is really more sensitive to the power applied. Have fun with your antenna, many Dx and Merry X'mas! 73! Linas LY2H
Thanks a lot for watching and subscribing! It's important for me! Please let us know how's your antenna version working! CU on the bands! 73! Linas LY2H
Thanks Eduardo! There is no simple answer to your simple question. The End Fed Half Wave antenna is a dipole in its nature, just with the feedpoint moved to an end of it. The "normal dipole" could be called Centre Fed Half Wave antenna. So, the properties of the EFHW antenna are actually the same as of the CFHW antenna, with some variations , like EFHW being able to get resonant on an even harmonics etc. As it comes to the gain, the gain of a dipole can be expressed as combination of the Directivity and the Radiation Efficiency. Theoretical gain of a dipole is 2.15 dBi ( 2.15 db compared to the "i"- isotropic - theoretical omnidirectional radiator) only taking the directivity factor, no radiation efficiency ( or losses , in other words) into account. In practical life, the dipole itself is a reference point for other antennas gain measurements (measured in dBd) so we can say that the dipole's , including EFHW, gain is 0dBd if the dipole is lossless. As it is not possible to be lossless in this practical Earth life, we must take ohmic losses ( losses due to electrical connections, feeding cable losses, transformer losses, etc) and ground losses ( losses incured by proximity to the ground, like the hight of the dipole above the ground, the soil type, the configuration of the dipole's shoulders etc.) into account and detract these expressed in dB, from our gain figure. Since dipole's gain based on directivity alone is 0dBd, so adding negative dB of losses to it we'll have negative gain of the overall dipole system. So the conclusion is , the EFHW antenna is not a gain antenna which will multiple your transmitter's radiated power, on the contrary, it will "eat up" some power of your transmitted power and convert it partially into heat of the antenna construction elements, partially into heating worms up in the soil :). Nevermind all this, the properly constructed/located dipole in general, and the EFHW dipole in particular is a very good antenna ! HTH 73! Linas LY2H
👍👍👍👍 Great video.. Good antenna project, I'm sat here wondering what materials are in my junk box.. Not sure about operating in amongst the trees, surely out in the clear is better for radiation pattern ?
Thanks for watching! There is more coming! As to the radiation pattern, well, it's really difficult to predict it :) It depends on so many components, but mostly on the hight of the centre part of the antenna and the general shape: whether it's a horizontal wire, or sloping, or inverted V ir zig-zaged in any crazy way :). The soil nature of the area might be important too. So it is a good idea to have the end of the antenna longer than calculated for a few feet or so and to make final SWR adjustment in-situ folding back the unnecessary length ( NOT cutting). It is possible to guess the pattern running a WSPR for the day or so and watching the reports on you, or if you work CW, call lots of cq and check regularly with the Reverse Beacon Network. The trees or bushes do not really matter so much on the HF spectrum especially on the Low Ham bands, like 80 or 40m. So everything will work just let's go and do it! 73! Linas LY2H
Algimantas Karaliunas Yes, it’s a dipole with all the dipole properties, just fed from the end. I don’t think the feeder’s point makes any influence to the directivity. On the other hand, low - hanging Inverted V might have some unpredictable patterns :)...
Hello, HNY! I used the PVC-coated multistrand (16 strands) copper wire. The diameter measured on the coat is 1,5mm, on the wire itself - 0,8mm (0,5 square mm). As you can see it’s unusually thin PVC coating making this wire pretty lightweight yet with thick enough copper conductor. This makes this wire ideal for the antennae construction. I put 100W into this antenna and it handles the power nicely. Last but not least, at 0,10EUR/meter this wire turned to be the cheapest option in town, I buy it in my local robotics/electronics shop. Unfortunately, I don’t know the make of this wire nor the producer. I will check with the shop guys when the lock-down lifted. 73! Stay safe!
Thanks for watching! It worked surprisingly good on 80m! My goal was to have been heard good on 80m band by the local/regional stations in order to give them the unique WWFF reference. All local stations within LY were giving me 59+, I also was called by some Polish stations and even by a Danish which was really uniuque for all the activity was taking place during day time, at abt 10-11 UTC. As to the other bands, 40m and up it was working as good as any EFHW full-size antenna would work, i.e., excellent! Usually I do some DX stations on 40-30-20m bands from the USA and Canada with it. I ‘ve tried this antenna multiple times but only in an Inverted V configuration with the centre on my 6m or 8m masts top. The other configurations, higher, into the trees, could give different, may be even better results. I will make more experiments in the future. Wish you too! Stay safe until then!
linas, why 80uH ? i always find description for a 80m coil have 110 uH. how broadband is your coil on 80m? i found my just around 45 khz without tuner, raising very high at the ends.
Hello Jo, thanks for watching! There is no particular scientific reason, why 80 uH :) It’s just so happenned that I had the coil former 3-D printed and unused from another project and its size was more or less able to accommodate the coil “in the vicinity of 110 uH”. I wanted to have no mechanical /soldering joints between the coil and the antenna wire, so I wound the coil of the same antenna wire, so it’s got so many turns as it got, and it turned to be around 80 uH :). I was no worried about that, as I balanced this “reactances game” out by simply making the end tail after the coil a bit longer. I think, the Q of my antenna is a bit lower because of atenna wire used instead of some thinner “magnet wire”, so my bandwidth is a bit broader, though I can’t remember now how broad it was :). Actually, thanks for asking, next time I deploy it outdoorsy, I will take some measurements and ammend the description to the video. 73! Linas LY2H
@@Linas_LY2Hthank you linas for your quick response. i figure out the coil diameter has no or very less effect on the broadband, is it? but what make a coil to be broadband, or is 45khz the maximum we can reach? what about wire diameter of the coil? one thing you mention make me curious; the way you hang the antenna up, i will try different ways and see how it act. and last; if you wind a coil do you aim for the inductance like 110uH or for frequency resonance? tnx for now! 73
@@jomckarth4836 Thanks for your questions Jo! They all are very good and there is no single answer to none of them :). Only practical experimenting brings the real results, because they are conducted in real place on a real ground. The coil’s “broadbandedness” is dependent, most of all, on a Q factor, which, on its turn, is a complex of multiple other things, like the coil’s diameter, its ratio to the length of the winding, the wire’s gauge, spacing between the turns, etc. The higher the Q, the lesser the losses the coil incures on the resonant frequency. But also - the narrower the bandwith. And on the contrary - the lower the Q, the higher the losses, but the coil is more broadband. So, our task is to find an ideal coil with a “golden compromise” between the bandwidth and the losses. Practically, the loading coils vary in their bandwidth from 30 to 100 KhZ measured from the lower frequency point of SWR 3:1 to the higher frequency point of SWR 3:1. Hanging the EFHW antennas in some Inverted V form is one of the most used ones , as it is practical and easy, and it’s only logical as the midpoint of this antenna (as in any other dipole) is the maximum of the current, so it is supposed to be as high as possible above the ground for the maximum antenna radiation. But surely I encourage you to try many other ways of deployment as every new location might affect your antenna differently. The 110 uH coil is a mystery in itself :) It acts as a trap separating the 40-10m part of the antenna from the 80m part of it, but also it acts as a loading coil to compensate the capacitive reactance of the short antenna on 80m with the inductive reactance of the coil. So, I aim for the coil for the 110 uH of inductance, because smart guys in Netherlands have calculated this value as optimal one for both tasks. Tuning of this antenna to resonance could be tricky, therefore it is higly recommended to first assemble the whole antenna, including the coil ant the “tail” into one piece and then start pruning the longer piece of the wire (with the coil and the tail attached, that means you cut from the 49:1 transformer side, reconnecting the wire to the transformer after each cut) until it’s resonant on 40m band. And then only you get the resonance on 80m by prunning the “tail”. It takes more time to write about it, than actually make it :) HTH, but please note, this is just my personal findings and opinion, there might be numerous others, YMMV. Good luck! 73! Linas LY2H
@@Linas_LY2Hhi lina, tnx for your reply, i appreciate! yea i will follow your advice as i feel comfortable with it. i have now finished my coil for 80m and i measure 109,8 uH. i have measured the original one from hy-endfed - 93 uH. though i can not distinguish much difference if any. next step is to hung it in a inv-v shape, at the moment i have it in a sloper configuration. honestly i do not expect much difference either. however i have at least tryed a few options and i gain some experience in working with endfed antennas. dont get me wrong, i like these antennas very much, i only struggle with the 80m part and i want to get out the best i can. i will keep you informed. 73 have a good time!
Thanks for watching! The TX power from my FT-891 in the Go-Box was at about 90W, the battery at that time was a DIY LiFePo4 12V/12Ah, later I've upgraded the Go-Box up to Bioenno 12V/20Ah, please take a look for details at "Go-Go Box" videos on my channel. 73!
Hello I have this question. Is it good to give a half wave radiator for a given bandwidth i.e. on 80m = 40m, 40m = 20m etc. Please tell me if I would like to build an antenna for the bands 80, 60, 40, 30, 20, 17, 15 and 10m, should I make a separate combined radiator for each band of course? So for example for the 80m band everything would be combined. Is it better to use harmonics? How will the antenna be more efficient? Regards SQ2ODE Mariusz
Hello Mariusz! Thanks for your questions! I think, you would have so many answers to them, as many people you had asked for! So , my own experience is that an End Fed Half Wave antenna fed via the adequate 49:1 (or 64:1) transformer and cut for the half of wave length on 80m band, can work on the harmonic bands up from the 80m, in theory. In practice, the length of wire good as a 1/2 wl on 80m will be too short on the higher bands and the resonance will be higher up on the band then you need it to be. So, in this reality you can either use an antenna tuner and get the problem fixed (If the mismatch is no bigger than 3:1, most tuners will do that), or you can use some tricks, like planting a tiny loading coil some distance from the feeding point into the antenna wire, which will make the wire “look longer” electrically and bring the resonances back into the wanted ranges. This method is used by some EFHW manufacturers with certain success. So, my conclusion: this type of antenna is very convenient, once installed and tuned it can work on harmonic bands without a tuner. But , it takes quite a lot of patience to adjust the general length of the wire and the precise location of the tiny loading coil. Also, such an antenna will NOT acceptably work without a tuner on the non-harmonic bands like 60, 30 and 17m bands. Your idea of “giving a half wave radiator for each band” is very good, alowing to avoid all of the above mentionned problems. This type of the antenna is widely called a “linked EFHW” (could be a traditional center-fed dipole too) as it is made of separate links, made of pieces of wire cut for resonance on each band. No harmonics involved here! In this version, you cut the antenna to resonance first on the highest band (shortest wire) make a link connection, then add more wire and tune this new link to resonance on the lower band, repeating this untill you have the lowest band covered. This method allows for the precise tune of the antenna on each band you want, including the 60,30,17m with no problems. The only inconvienience- each time you switch the band, you need to lower the antenna down and connect or disconnect links accordingly. It’s a not big deal if operating outdoors, like park-activation or a field day etc. with lightweight installations. Surely, if you want a permanently installed antenna on the roof of the condominium house, the “linked” type of the EFHW would not be practical. HTH, good luck in your experiments! 73! Linas LY2H
@@Linas_LY2H Hello Linas Thank you for your comprehensive reply. Finally confirmed my thoughts. I am getting down to building a combined radiant. I will brag about my achievements. Greetings Mariusz SQ2ODE
rajesh huddar It's in the video, my dimensions. I wound 80 turns on 40mm former, it could be around 80 microH. The original source suggests 110 microH. I think it is not critical for you can always adjust the length of the wire after the coil. In my tests, antenna's SWR was under 2:1 on 80,40,20,15 and 10m bands. It did take a tuner on 30m band. Try it yourself, it's fun!
Thanks Lars! I like it too! It's a CHUWI Minibook 8" 8GB RAM, 128GB SSD Win10 laptop/tablet ( it folds in the middle and can become a tablet if one would like it to :)). 73! Linas LY2H
I enjoyed your video very much Linas, good explanation and video of the EFHW "in action" .. Looking forward to see more. Thank you! 73!
I made this coil and antenna today... spent about 4 hrs on it trying to tune it.... 20m and up, its all good....but I couldnt get 40 or 80m to get lower than 5:1... I even tried 2 different value coils. I added wire, trimmed wire...SWR was just all over.. It was about same height overall off ground as yours..... I finally called it a day and licked my wounds.... not sure what to try, that I already havent?? 73
Hello Darby, thanks for sharing your experience , even if it was not so good :-). I had no problems in building mine. In your case, I would make sure, firstly, if my transformer is wound properly on the proper type of toroid ( FT-43 or similar material preferably). Then I would test the transformer with no antenna but the 3kOhm non-inductive resistor connected, using nanoVNA or antenna analyser. The SWR should be less than 2 on all bands of your interest. If not, something's wrong with the transformer. Secondly, I would cut the antenna wire for 40m halve wave and trim it for the best SWR on 40m band ( in my case it was 19.8m) first .Then, I would connect the loading coil with some 4 m or more of wire "pigtail" attached to it. Thirdly, I would trim the pigtail for the best resonance on 80m segment of my choice. Last but not least, the 4m long counterpoise wire is very much welcome to use, and if not, I'd make sure my coax cable is not shorter than 4m long as it's shield would act as a counterpoise in the absence of the wire c'poise. In this case, the RF choke unun is very much welcome too, connected at the radio side, or at the 4m mark on the cable looking from the transformer's side ( it could be just the same feeding cable wound on the ferrite toroid or just coiled on itself, in the cheapest way). So, this strategy of building and tuning the antenna usualy works, at least for me. HTH 73! Linas LY2H.
Excellent demonstration video, Linas, thank you! I will build this for my 40M EFHW for my small yard. 73!
Thanks my friend excellent answer , it was a doubt that I had was to know more less.
Thanks one more time .73 W4EDY
Fantastic antenna. Very cool portable contest station setup. Enjoying your videos. CW forever! 73, N7SR
Thanks for the revert. Will definitely try.
Great video👍❗️ I absolutely love the EFHW Antenna an I have been winding my own 49/1 UNUN’s for over 40 years back when they were very unpopular. Recently I talked my best friend into building one so I went over and we-built him the 49/1 UNUN put it up last week and he is having a ball with it. They are GREAT Antennas 73 KV5P
Awesome Mike! 40 years ago the ferrite toroids were of a bit different quality, so the open wire line fed EFHWs were the way to go, like my favourite DL7AB :) . 73! Linas LY2H
Good job!
Thank you for the video and demonstration on you 80m extension to the normal 40m endfed. And you can talk to us and copy cw at same time FB .
Very cool, Linas! Thanks for sharing! and seeing someone operating outside always makes me want to go outside even more. 👍🏻👍🏻 hear you on the bands.
by the way: what are your experiences with antennas surrounded by bushed and trees? we always try to avoid them close to the emitting wire.
Excellent video!!
Great Job, Subscribed
I would love to get detailed specs on your entire antenna system. This looks absolutely great for SOTA applications. 73
Thanks for watching! I’m not sure what do you mean by detailed specs :) The measurements are in the video, and they are not that critical, the the loading coil for instance. It is recommended to be 110 microH , I made abt 80 microH and it’s easy to compensate with the end after-coil part of the antenna. The size of the wire is not critical, any diameter 1-2mm will do if you run up to 100W into it. 2-3mm if running more. I was using the manufactory made transformer (by Myantennas.com) and its specs are on their website , I guess. The home made transformer would perfectly do too adopted to your own needs. In my antenna system, I do use the 4m long counterpoise wire (0,05 w/l on the lowest 80m band) and the CMC in line but many people don’t as the coax itself makes for a good return path for a quite modest antenna current at that point of the antenna. Some people insert the CMC (common mode choke) at the 0,05 w/l of the coax. Let me know what else could I tell you about this project! 73! Linas LY2H
@@Linas_LY2H Hi there, thanks for the quick response. I was actually looking for the type and size of wire, but you have answered that.73 ZR6RDS
Amazing!!
Great video thankyou 😊
I built the same design for my small back yard. My coil, seeing that it is a fixed station antenna, is substantially larger to handle 50 - 100 watts. My coil is a 105uH coil, so the end wire is only 2.1 meters long. Also, to fit the antenna in a 16 meter long yard, I erected it as an Inverted-L. 7.5 meters is vertical at the transformer end, the wire is supported by a paracord an insulator from the top of a 10 meter mast and they remaining wire to the coil (12.3 meters) slopes down to the loading coil and end wire. The coil and end wire are about 3 meters up and the end of the antenna is tied off to a mast at the fenced end of the yard.
No tuner is required from 3.5 MHz to 3.65 MHz on 80 meters, nor is it required on 40 meters. The 20 meter resonance is around 14.40 MHz, so the internal tuner is used. A full sized dipole would be better, but it would have to be tied off in the next yard, not an option for me, hi!
Well done, a great presentation and hope to CU on the bands soon!
73, Keith, WB2VUO here near Buffalo, NY.
Thanks for watching and sharing your own experience Keith! It looks like your set-up is a maximum what one could do in your lot, so well done to you! What I like about this antenna is that it's not critical to the dimensions or size of the coil, the end "tail" would compensate for small discrepancies. As it comes to the power, the coil shown in the video wound of the same antenna wire was running 100W from my FT-891 in the go-box with no problems. The 49:1 transformer is really more sensitive to the power applied. Have fun with your antenna, many Dx and Merry X'mas! 73! Linas LY2H
not sugar....SIERRA! :).....p.s. Thanks for the antenna it is exactly what I need MUCH MUCH THANKS!
Very interesting video... I'll be making one and I've subscribed. Great job.
Thanks a lot for watching and subscribing! It's important for me! Please let us know how's your antenna version working! CU on the bands! 73! Linas LY2H
Greetings could you tell me what gain have the EFHW antenna. Excellent your video
W4EDY
Thanks Eduardo! There is no simple answer to your simple question. The End Fed Half Wave antenna is a dipole in its nature, just with the feedpoint moved to an end of it. The "normal dipole" could be called Centre Fed Half Wave antenna. So, the properties of the EFHW antenna are actually the same as of the CFHW antenna, with some variations , like EFHW being able to get resonant on an even harmonics etc. As it comes to the gain, the gain of a dipole can be expressed as combination of the Directivity and the Radiation Efficiency. Theoretical gain of a dipole is 2.15 dBi ( 2.15 db compared to the "i"- isotropic - theoretical omnidirectional radiator) only taking the directivity factor, no radiation efficiency ( or losses , in other words) into account. In practical life, the dipole itself is a reference point for other antennas gain measurements (measured in dBd) so we can say that the dipole's , including EFHW, gain is 0dBd if the dipole is lossless. As it is not possible to be lossless in this practical Earth life, we must take ohmic losses ( losses due to electrical connections, feeding cable losses, transformer losses, etc) and ground losses ( losses incured by proximity to the ground, like the hight of the dipole above the ground, the soil type, the configuration of the dipole's shoulders etc.) into account and detract these expressed in dB, from our gain figure. Since dipole's gain based on directivity alone is 0dBd, so adding negative dB of losses to it we'll have negative gain of the overall dipole system. So the conclusion is , the EFHW antenna is not a gain antenna which will multiple your transmitter's radiated power, on the contrary, it will "eat up" some power of your transmitted power and convert it partially into heat of the antenna construction elements, partially into heating worms up in the soil :). Nevermind all this, the properly constructed/located dipole in general, and the EFHW dipole in particular is a very good antenna ! HTH 73! Linas LY2H
👍👍👍👍 Great video.. Good antenna project, I'm sat here wondering what materials are in my junk box.. Not sure about operating in amongst the trees, surely out in the clear is better for radiation pattern ?
Thanks for watching! There is more coming! As to the radiation pattern, well, it's really difficult to predict it :) It depends on so many components, but mostly on the hight of the centre part of the antenna and the general shape: whether it's a horizontal wire, or sloping, or inverted V ir zig-zaged in any crazy way :). The soil nature of the area might be important too. So it is a good idea to have the end of the antenna longer than calculated for a few feet or so and to make final SWR adjustment in-situ folding back the unnecessary length ( NOT cutting). It is possible to guess the pattern running a WSPR for the day or so and watching the reports on you, or if you work CW, call lots of cq and check regularly with the Reverse Beacon Network. The trees or bushes do not really matter so much on the HF spectrum especially on the Low Ham bands, like 80 or 40m. So everything will work just let's go and do it! 73! Linas LY2H
Very impressive! What is a pattern of radiation of EFHW? I suppose same as dipole, that is perpendicular to the wire?
Algimantas Karaliunas Yes, it’s a dipole with all the dipole properties, just fed from the end. I don’t think the feeder’s point makes any influence to the directivity. On the other hand, low - hanging Inverted V might have some unpredictable patterns :)...
Hello, can I ask what type of wire you used to build this antenna? Thank you, 73
Hello, HNY! I used the PVC-coated multistrand (16 strands) copper wire. The diameter measured on the coat is 1,5mm, on the wire itself - 0,8mm (0,5 square mm). As you can see it’s unusually thin PVC coating making this wire pretty lightweight yet with thick enough copper conductor. This makes this wire ideal for the antennae construction. I put 100W into this antenna and it handles the power nicely. Last but not least, at 0,10EUR/meter this wire turned to be the cheapest option in town, I buy it in my local robotics/electronics shop. Unfortunately, I don’t know the make of this wire nor the producer. I will check with the shop guys when the lock-down lifted. 73! Stay safe!
May I request you to share what is included in your case. Looks neat and compact.
I have this antenn a from 160meters to 6 meters is good
Tell us more about your coil, please.
Next question. How well did it work?
Thanks for watching! It worked surprisingly good on 80m! My goal was to have been heard good on 80m band by the local/regional stations in order to give them the unique WWFF reference. All local stations within LY were giving me 59+, I also was called by some Polish stations and even by a Danish which was really uniuque for all the activity was taking place during day time, at abt 10-11 UTC. As to the other bands, 40m and up it was working as good as any EFHW full-size antenna would work, i.e., excellent! Usually I do some DX stations on 40-30-20m bands from the USA and Canada with it. I ‘ve tried this antenna multiple times but only in an Inverted V configuration with the centre on my 6m or 8m masts top. The other configurations, higher, into the trees, could give different, may be even better results. I will make more experiments in the future. Wish you too! Stay safe until then!
linas, why 80uH ? i always find description for a 80m coil have 110 uH. how broadband is your coil on 80m? i found my just around 45 khz without tuner, raising very high at the ends.
Hello Jo, thanks for watching! There is no particular scientific reason, why 80 uH :) It’s just so happenned that I had the coil former 3-D printed and unused from another project and its size was more or less able to accommodate the coil “in the vicinity of 110 uH”. I wanted to have no mechanical /soldering joints between the coil and the antenna wire, so I wound the coil of the same antenna wire, so it’s got so many turns as it got, and it turned to be around 80 uH :). I was no worried about that, as I balanced this “reactances game” out by simply making the end tail after the coil a bit longer. I think, the Q of my antenna is a bit lower because of atenna wire used instead of some thinner “magnet wire”, so my bandwidth is a bit broader, though I can’t remember now how broad it was :). Actually, thanks for asking, next time I deploy it outdoorsy, I will take some measurements and ammend the description to the video. 73! Linas LY2H
@@Linas_LY2Hthank you linas for your quick response. i figure out the coil diameter has no or very less effect on the broadband, is it? but what make a coil to be broadband, or is 45khz the maximum we can reach? what about wire diameter of the coil? one thing you mention make me curious; the way you hang the antenna up, i will try different ways and see how it act. and last; if you wind a coil do you aim for the inductance like 110uH or for frequency resonance? tnx for now! 73
@@jomckarth4836 Thanks for your questions Jo! They all are very good and there is no single answer to none of them :). Only practical experimenting brings the real results, because they are conducted in real place on a real ground.
The coil’s “broadbandedness” is dependent, most of all, on a Q factor, which, on its turn, is a complex of multiple other things, like the coil’s diameter, its ratio to the length of the winding, the wire’s gauge, spacing between the turns, etc. The higher the Q, the lesser the losses the coil incures on the resonant frequency. But also - the narrower the bandwith. And on the contrary - the lower the Q, the higher the losses, but the coil is more broadband. So, our task is to find an ideal coil with a “golden compromise” between the bandwidth and the losses. Practically, the loading coils vary in their bandwidth from 30 to 100 KhZ measured from the lower frequency point of SWR 3:1 to the higher frequency point of SWR 3:1.
Hanging the EFHW antennas in some Inverted V form is one of the most used ones , as it is practical and easy, and it’s only logical as the midpoint of this antenna (as in any other dipole) is the maximum of the current, so it is supposed to be as high as possible above the ground for the maximum antenna radiation. But surely I encourage you to try many other ways of deployment as every new location might affect your antenna differently.
The 110 uH coil is a mystery in itself :) It acts as a trap separating the 40-10m part of the antenna from the 80m part of it, but also it acts as a loading coil to compensate the capacitive reactance of the short antenna on 80m with the inductive reactance of the coil. So, I aim for the coil for the 110 uH of inductance, because smart guys in Netherlands have calculated this value as optimal one for both tasks. Tuning of this antenna to resonance could be tricky, therefore it is higly recommended to first assemble the whole antenna, including the coil ant the “tail” into one piece and then start pruning the longer piece of the wire (with the coil and the tail attached, that means you cut from the 49:1 transformer side, reconnecting the wire to the transformer after each cut) until it’s resonant on 40m band. And then only you get the resonance on 80m by prunning the “tail”. It takes more time to write about it, than actually make it :) HTH, but please note, this is just my personal findings and opinion, there might be numerous others, YMMV. Good luck! 73! Linas LY2H
@@Linas_LY2Hhi lina, tnx for your reply, i appreciate! yea i will follow your advice as i feel comfortable with it. i have now finished my coil for 80m and i measure 109,8 uH. i have measured the original one from hy-endfed - 93 uH. though i can not distinguish much difference if any. next step is to hung it in a inv-v shape, at the moment i have it in a sloper configuration. honestly i do not expect much difference either. however i have at least tryed a few options and i gain some experience in working with endfed antennas. dont get me wrong, i like these antennas very much, i only struggle with the 80m part and i want to get out the best i can. i will keep you informed. 73 have a good time!
What power/battery you are using?
Thanks for watching! The TX power from my FT-891 in the Go-Box was at about 90W, the battery at that time was a DIY LiFePo4 12V/12Ah, later I've upgraded the Go-Box up to Bioenno 12V/20Ah, please take a look for details at "Go-Go Box" videos on my channel. 73!
Hello
I have this question.
Is it good to give a half wave radiator for a given bandwidth i.e. on 80m = 40m, 40m = 20m etc. Please tell me if I would like to build an antenna for the bands 80, 60, 40, 30, 20, 17, 15 and 10m, should I make a separate combined radiator for each band of course? So for example for the 80m band everything would be combined.
Is it better to use harmonics?
How will the antenna be more efficient?
Regards
SQ2ODE Mariusz
Hello Mariusz! Thanks for your questions! I think, you would have so many answers to them, as many people you had asked for! So , my own experience is that an End Fed Half Wave antenna fed via the adequate 49:1 (or 64:1) transformer and cut for the half of wave length on 80m band, can work on the harmonic bands up from the 80m, in theory. In practice, the length of wire good as a 1/2 wl on 80m will be too short on the higher bands and the resonance will be higher up on the band then you need it to be. So, in this reality you can either use an antenna tuner and get the problem fixed (If the mismatch is no bigger than 3:1, most tuners will do that), or you can use some tricks, like planting a tiny loading coil some distance from the feeding point into the antenna wire, which will make the wire “look longer” electrically and bring the resonances back into the wanted ranges. This method is used by some EFHW manufacturers with certain success. So, my conclusion: this type of antenna is very convenient, once installed and tuned it can work on harmonic bands without a tuner. But , it takes quite a lot of patience to adjust the general length of the wire and the precise location of the tiny loading coil. Also, such an antenna will NOT acceptably work without a tuner on the non-harmonic bands like 60, 30 and 17m bands.
Your idea of “giving a half wave radiator for each band” is very good, alowing to avoid all of the above mentionned problems. This type of the antenna is widely called a “linked EFHW” (could be a traditional center-fed dipole too) as it is made of separate links, made of pieces of wire cut for resonance on each band. No harmonics involved here! In this version, you cut the antenna to resonance first on the highest band (shortest wire) make a link connection, then add more wire and tune this new link to resonance on the lower band, repeating this untill you have the lowest band covered. This method allows for the precise tune of the antenna on each band you want, including the 60,30,17m with no problems. The only inconvienience- each time you switch the band, you need to lower the antenna down and connect or disconnect links accordingly. It’s a not big deal if operating outdoors, like park-activation or a field day etc. with lightweight installations. Surely, if you want a permanently installed antenna on the roof of the condominium house, the “linked” type of the EFHW would not be practical. HTH, good luck in your experiments! 73! Linas LY2H
@@Linas_LY2H Hello Linas
Thank you for your comprehensive reply. Finally confirmed my thoughts.
I am getting down to building a combined radiant.
I will brag about my achievements.
Greetings
Mariusz SQ2ODE
May I request for the specifications of the coil. Is a tuner required for this antenna.
rajesh huddar It's in the video, my dimensions. I wound 80 turns on 40mm former, it could be around 80 microH. The original source suggests 110 microH. I think it is not critical for you can always adjust the length of the wire after the coil. In my tests, antenna's SWR was under 2:1 on 80,40,20,15 and 10m bands. It did take a tuner on 30m band. Try it yourself, it's fun!
What computer u use for logging? Looks cute and small.
Thanks Lars! I like it too! It's a CHUWI Minibook 8" 8GB RAM, 128GB SSD Win10 laptop/tablet ( it folds in the middle and can become a tablet if one would like it to :)). 73! Linas LY2H
Very good work Linas! I will build this antenna and I think i will use 1mm dia wire (speaker wire)... Vy73 de va3kwx Christophe
Thanks Christophe! I think, 1mm wire diameter is just fine for QRP to 100W work. Good Luck! 73! Linas LY2H