Remake of a 64/1 Unun (transformer) EFHW End feed Half wave.. 80m to 10m Antenna
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- เผยแพร่เมื่อ 31 พ.ค. 2020
- Ok time I remade this very successful 49 or 64:1 Unun (transformer). I had originally made one from odd and ends, about 4 weeks before this build, to replace my single 43 type. However, I have decided that I should build one that is from one piece of wire.
I have based the build on Steve Nichols G0KYA EFHW
A shortened multiband antenna, about 23m long, for 80m-10m that offers low SWR (1.3:1) on 80m and 40m, and below 1.7:1 on 20, 15 and 10m. The antenna has a full 300kHz bandwidth on 80m between 3:1 SWR points. But performance is down against my dipole on 80m.
Things have moved on a bit Since I made this video I have been able to remake the whole thing with much better results see my other uploads.
Many thanks and enjoy....
Mike M0MSN - วิทยาศาสตร์และเทคโนโลยี
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Interesting to see this follow-up Mike, thanks for making the video.
Superb video Mike you have a calm and relaxed way of communicating that I and suspect many others enjoy. Useful video too to add the cherry on the cake. 73
Thanks Tim, your comments always help a lot :)
Nice upgrade! Should be able to run full Italian contest power on that now 👍
Enjoying these videos.
great video... You make this complex hobby a bit more understandable
Thanks Mike, best regards,carl.👍🇬🇧
Great video thanks mike
Great job 👏
Hi Mike...thank you very much for your interesting Videos...!!! Greetings here from Germany ..😀🙂🙂🙋🏻♂️
Hello there!
Found a heap of toroids in one of my junk boxes from my old Broadcasting days....
They are T200-1 though and good up to 5Mhz.... makes sense really because they would, have been used with our AM Broadcast systems.
I can give a couple fo them a go on 80mtrs though which could be a bit of fun.
Hi Mike. For 80M, a single core doesn't really provide enough inductance for the number of turns. That's why 2 cores improves the SWR on the lower bands. I have found a couple of drops of superglue to be good for holding the cores together. Of course, 2 cores will also improve your power handling -- so the balun shouldn't get as warm. 31 material is also good for 160-40M.
73 Bruce G4ABX (aka Dr.T.)
Nothing wrong with that S.W.R. and it appears to be woring fine, good job Mike. To let some ventilation and allow some spiders in so you car roast them with RF you can drill holes in the bottom, if you go to your electrical store, you can get right angle plastic Glands, take out the rubber seal and you have weatherproof verts for further up, just point the gland downhill of course., if they prove hard to get you can get plastic fittings for plumbing, nothing like a through put of air to keep things cool. You can also use these glands to feed cables through plastics etc where you want to waterproof things as the rubber grip inside will also seal against water for the best part. You get straight ones and right angle ones, 20 and 25 mm ones and maybe even bigger.
Very interesting 👍
Great work
73 q r o dans toute les vidéos le travaille est toujours très bien soignée et bien intéressant merci mike a plus
Good job man
A 52 mix core is a little more efficient also a little more expensive. In order to have the higher bands in tune you have to cut the wire for the cw section of 80. I haven't tried it but I watched a video where they cut the wire in half and added a 250-500 pf capacitors and then you get the ssb section of 80 and it's in tune for the higher bands. Can't remember the video. I think it was Steve Ellington video.
Jeff ke4fwe
52 mix if you're using 3 cores. 1 or 2 cores, 43 mix. That's from Steve Ellington video.
I made a similar balance design but without the 7 turns on the opposite side of core. My inverted L is resonate on 80 to 10 metre bands.
I just rebuilt mine with two ft240-43 toroids for same reason. My efhw is a 40-10 version. I also have a 80m full wave loop fed with ham 450 ohm twinline and a mfj autotuner so I decided not to make my efhw to add 80. I could add the loading coil to the end if I change my mind.
Finally someone winds one correctly. Whole lot of bad YT videos of hams winding the improper ratios.
Many thanks
Nice video. Do you use a choke also on the coax to reduce noise?
Mike is there any particular reason for having the matching unit at the bottom of the garden? In the process of erecting one, and was going to attach to a small pole on the house. Not used one before. As always love the videos Thanks
Merci
nice
Thanks
The vswr will raise if the core gets saturated u need at least 2x cores
Just received 2 x 240 31mix to double up to use ...hopefully on 160m 80m 60m ....80m wire to be bent round my and neighbours garden ...thanks for the video ... Steve G4htz
31 mix. cool
@@mike-M0MSN hopefully the 31 mix is ok for 160m ...
Very good video thank you...
What gauge enameled copper wire are you using?
1.5mm or 15 Gauge. :)
Very nice...............What size is the capaciter did you use, ans whae length antenna and ground radial.
Greetings could you tell me what gain have the EFHW antenna. Excellent your video
W4EDY
Two turns for the primary winding is ok for one 200-43 toroid. If you use two of the same toroids, the permeability and the Al factor is greater. Did you try to compute the reactance? I also suggest you a 100 pF capacitor trimmer on the primary winding to find the right fixed capacitor value. 73s.
I have a small beam made for fox hunting. When I place electrical tape on the end of the driver element to potent some eyes the SWR changed and went up. I was surprised.
Wow. that is strange
Really a well done video Mike. Very easy to follow. How long is the radiating wire/antenna? Best 73, George K2WO
check out Steve Nichols G0KYA for full details but its around 64'6"
Nice work Mike. I have had my 80-10m EFHW up for about two years with zero problems. I used 3-43 mix Ferrite Rings for better power handling and heat dissipation. My home brew antenna made the trip twice now to Callum from Florida with 100 watts. I want to change the antenna configuration from a sloper to an inverted L or Inverted Vee. What do you think the best orientation would be best? 73 Joe
Hi Joseph, It's horses for courses each configuration has its good and bad points, its what suits you.. :)
@@mike-M0MSN I knew you were going to say that Mike :p. That's what I would say if I were asked. That's why us Hams do a lot of Experimenting. 73 Joe
Hi Mike
I am thinking of making an EFHW antenna.
Using a vertical section would be the way to go BUT how will that impact on the new EMF assessment in a very small garden?
If I put the 64:1 at the top of the mast, and run purely horizontal I suspect that will help with the assessment and here is another BUT, I will then have only 47 ft to play with.
So I wonder if can add a bigger coil than you used in your other video and how did you calculate how much wire to add on the end.
Also if I use a Fibreglass telescopic mast, I could run a counterpoise down the middle of it.
I gather they dont have to be very long.
By the way a transformer such as this one has a loss of 0.6dB plus 0.2 dB for the PL259 so that takes the EIRP down a little.
Love your videos, my workbench is also in the kitchen but not as tidy as yours.
Kind Regards and 73
Mike
G3ZCC
A problem many of us will have, when you mount the 64:1 at the top of a pole the coax becomes the counterpose so the problem still exist? or does it?
After watching this , I am wondering if I need to rethink mine . I have a 49;1 with a 120 ft of wire . No coil at the end . Hmmm sir seems a bit high for me on 40 and 20 . It is also on 3 type 52 Cores . Any thoughts ?
It should work, I have always preferred type 43, and winding a 64:1. You could always just try replacing the wire length with the shorter 20.5 and coil to see if your SWR comes down, if it doesn’t then perhaps the transformer?
Try lengthening your wire by 10-15 feet. That should lower your resonant freq. on 40m and 20m.
@@dezwatson6993 I may have to take it down and measure the wire . I am guessing at the 120 . Thanks for the info
Hello Mike...So if Im running max 100 watts do I need only two Toroids? Thanks
No one should be OK. :)
Mike how much power were you able to throw on this thing?
I love the flexability of these. And it does 10-80?
80 - 100 watts maybe???
hy mike, How long is the wire behid the 1:49 and no coil in the line ?
20M of wire before the coil and 1.5M after the coil.
I made one today for the CB band. Also included the 10p 3kv capacitor. Tried it with 5.5 meter wire (indoor), and the MFJ analyzer. I get no resonance anywhere. Don't know what i did wrong. Its in the junk basket for now. FAIL :(
Great video what size antenna wire your using for this 64/1.
DX10... works a treat. :)
You get the “like” for the rope measurement trick. Thx! 👍🏻
Happy to help!
Don't most EFHW run 49:1? What's the benefit to 64:1?
Nice video Mike, wish i could source a couple of 43 cores here in NZ. Tried Amazon but every supplier i look at do not ship to NZ :(
Let me know if you want me to purchase two for you Roly and send them down under, (if I can find some, world shortage??) cost around £18 (UKP) plus the shipping...
I have used this supplier twice and I know a few others that have too. Very happy with the service.
www.ebay.co.uk/itm/FT240-43-FERRITE-TOROID-ORIGINAL-FAIR-RITE-5943003801/303618812110?epid=12034398071&hash=item46b11768ce:g:dRwAAOSwGFpZvqWr
72/3
Tony G4WIF
Why are the wounds separated and not just side-by-side like a normal transformer?
I can't help but think that the enamel on that wire seems a tad brittle which could result in shorts especially when gripped without padding. Looks pretty good though.
Fair-right is non conductive so the only short would be between turns on the coil..
Why do you need a 3000V (100pf) volt capacitor at a high current low voltage, low Z point where the 50 ohm coax connects? A 500 volt silver mica should do...no?
Have any ideas for using the old cores found in a computer power supply?
They are unlikely to be the right material.
I made the same direction of winding)))
Use double or triple cores - FT240-52 cores, don't put take on the cores, this will trap heat and ruin your swr. Glue them together. Built like this, it will handle 1500 watts !
Hi Mike, what wire are you using to wind the coil please? Regrds Brian M0CTI
1.5mm enamel coated copper wire..from Brocott
@@mike-M0MSN Thank you, stay safe 73 Brian
Hi Mike.... yesterday i ve made a 49:1 unun, SWR is less than 2 but not optimum, now going to take it down and will make it 64:1 following your instructions, just one question, whats the guage of wire are u using, i have both 14 guage and 18 guage, will be using only 100 watts...so what should i use ? Thanx 73s
14 bigger the better. :)
hello, please tell me what brand of ferrite do you use? Is the FT140-43 suitable? Respectfully yours, Evgeniy UT8IBX, 73!
... it's the mix that determines the bandwidth and overall efficiency of the core, so unless your running high power you should be OK. The 140 diameter core (1.4") should be OK up to around 100 watts ssb or cw, maybe a little more. You don't want to saturate the small core with high power, because it'll heat up and it's characteristics will change. 43 material is an overall good compromise, and it's what most guys use for the EFHW baluns... The Amidon #2 red mix which is an iron powder core seems to be best 10mhz and up, although the QRPGuys use #2 for their 9:1 40 through 10M UnUn. The 31 mix is better for the lower frequencies... 160, 80 and 40. In the end, there are no hard and fast rules, and it takes experimentation. .
@@richardfryer8646 I don't know what to do anymore, I can't get this antenna ... I can't tune the antenna into resonance.
Mike I run 25 to 1800 watts here. How many toroids should I need to be able to operate at that output ?
a lot.
hello, can it handle high power like 500 watts?
I thinking to replace the balun in the comet chb250 to make handle more power
73 DE HZ1YA
you have not answered my question ..
sir i have lot of color color ferites ,but i dont know how test them for my usage. pls suggest sir
Just wind the cores and see if they work..
My wife was VERY curious what kinda video I was watching after hearing the music........:-)
Just a ham radio thing honey!! Promise.
lol
why some are 64:1 and many other are 49:1 ? also why do you state 8-12dB loss on 80m against a dipole ? is it because it is the short version or the choice of cores ?
The shorten element on 80M, plus core loss however as it is quieter the receive is better than my Vertical ??
from time to time that why I keep playing. :)
@@mike-M0MSN so you need 64:1 on the shorter version with a loading coil correct ?
Aleziss yes. I found the 64:1 better on the short version. :)
going to rework my 49:1 to a 64:1... how many capacitors did you use??
Just the one, 150pF 3000v.
Mike I see in your description box that you found that on 80 M that the antennas performance was 8 to 12 db less than a dipole.
How did you measure that sir?
Yes I should/will remove that comment, it is more like 3dB down and as it turns out only on some signals (directionality) . The EFHW is quieter in general but that does not make it a worse antenna. Equipment used was a HP Spectrum analyser and signal generator.
Mike. Did that metal pole detune the antenna much?
No metal pole here, they are glass fibre. :)
@@mike-M0MSN Ah. I asked because it looked like a metal mastl. Ta
What have you for the copper wire 1,5, 2,0 or 2,5?
1.5mm
Thanks
Mike Momsn how many meters of wire does your antenna have please
20M plus a short coil for 80M
Sir I made same but VSWR 2.0 between 6 MHz to 14mhz but not full band 3 to 30 MHz pls help out sir
g0kya.blogspot.com/2017/01/a-shortened-multi-band-end-fed-half.html
...did you ever try a #2 mix core (red colour) for your 49:1 or 64:1 EFHW? They seem to be popular for the UNUN's.. why not EFHW? They are supposed to be superior to the 43 mix, particularly 10mhz and above and equal on 40. Noticed you took off the white Teflon tape for the 64:1 experiment.. good move as you get a tighter wind. The enamel on the wire has proven to be sufficient.
will try that mix
Three toroids will give you 160-6 and not get hot.
240-43
I run 400 watts through mine
Thank you for this video. I love your "autistic" measurement approach very much (i have adhd, i am allowed to make that judgement ;-)). The wire trick is awesome, as is the winding with pliers. Thanx for yet another trick in the hobbiest handbook.
A 49-1 unun is not meant for a dipole antenna as it has the wrong impedance conversion .
Yes Joe you are right, should have read against a dipole not on or with.. many thanks.. :)
Would this work for my sail boat
Yes, I have a mate with one on his boat..:)
Hi Mike. Callum suggested that I ask you my question. When dealing with a long wire (or end fed wire) how do I determine what size unun is needed? What determines if I need a 4:1 or a 9:1? Also, I have a mystery balun or unun that all the writing has worn off of. It is just a piece of sealed PVC pipe with an SO239 on each end. How do I determine what it is?
The length of the wire if it is a half-wave then you will need A 49:1 or 64:1 if it is a random length that is not a 1/4 or 1/2 wave then a 9:1 if it is a 1/2 wave folded into a square then it’s a 4:1 all these are due to the impedance that the wire shows at the connection point. So for your balun put a 450ohm resistor on the antenna side and then measure the SWR if it is 1:1 it is a 4:1, It is likely to be a 1:1 test with a 50ohm resistor.
@@mike-M0MSN Thanks Mike. Sounds like a half wave lenght wire for 80m would be a good match for my 4:1 unun. W4MKH
Bonjour il faut la quelle ferrite merci d’avance
Bonjour la ferrite est un mélange de type 43.
Why that many turns? other ratios can get you the same transformer action. Why the cap? Why that winding pattern? I assume you are twisting to cancel out the capacitance on the input, why that spacing, what is your insertion loss on that?
It might be best, for you to purchase the RSGB Radio Communications handbook.
@@mike-M0MSN So many questions, so little time. He needs the RSGB book and a quiet corner to contemplate all his new discoveries. 😎
@@mike-M0MSN No, I know the reasons I just don't think you do, too many cook book hams in the world giving half bake advice.
@@mrkattm Well I guess this is your opportunity to teach, please pass your knowledge on to others, so that we (the cook book generation) can be better informed.
@@mrkattm I checked out your channel. Very empty! Why not put up a few giving us your wisdom? Putting your money where your mouth is....so to speak.
You can Use a Large Nut to make One of these Transformer,
If you put three cores together it will handle 1500 watts
maybe
I need one to. Run 1.5kw I get long winded so I build it for 3kw
Use 3 cores and 1.8mm copper, let me know how you get on.
@@mike-M0MSN thank you I will
You need three toroids to be able to run leagal limmit
Not in the UK... LOL
@@mike-M0MSN Yes in the UK. get a NOV for 30 dbw or more by RSGB application, I have 2 since 1985. 3 x FT240-52 is good for 1500w pep ICAS
Background music is very distracting.
Why the annoying music ?
Sorry I couldn't stand that music!
Thats OK, :)