HAM RADIO: Build a Small Garden EFHW for 80M
Вставка
- Опубліковано 6 сер 2024
- HAM RADIO: Build a Small Garden EFHW for 80M, wind a 110uH coil so you can turn a End Feed Half Wave for 40M into one for 80M, akin to a video I made little time ago about the same subject however in this upload, I will show you how to calculate the number of turns for the size of former and how it works.....
I do hope you enjoy it and subscribe for more..
Many thanks
Mike - M0MSN
To get notified of the next upload .click that bell and subscribe.. - Розваги
The golden rule - wind 10% more turns. It is easier to shorten the wire than to lengthen.
Great videos as usual. Taken me many videos to realise these are 'kitchen projects' hence the kitchen table. You demonstrate the advantages of using the right tools. Thst pipe cutter was nifty.
Cheers Mark
Nice Mike. Love the HSE attention to detail. Looks like it works well. Good job.
HSE... Not needed if the wife see's me more like the undertaker :)
Very neat coil winding and I learnt from this that windings calculators are an approximate guide. You might have saved me from making some big mistakes!
Glad it helped!
Outstanding project on the coil.
Thank you very much!
Great video Mike! I also make it bigger than calculated. Theory and practice differ most of the times. Before cutting the wire I measure it with my Peak Atlas LCR45, really happy with that meter. UK made. 73 PA5BAS
Nice work Mike. Going to do the same to my EFHW 10-40m to get the 80m band. I just don't have the room for a full size 80m EFHW antenna. 73 Joe
the short version works quite well.. 👍🏻
Good build Mike 👍🏻
Thanks Ian.
Woooow..190 turns is quite something. Good job sir, looks very professional made and I am sure it works fantastic. Keep up good work. 73's de Uncle Günter
Thank you very much!
The minute you say "Back in the Kitchen" I know it is going to be a good video.
Oh yes! good to be back indoors. 👍🏻
good video as always 73's mike..
Thanks 👍
MIKE , TNX !!!! from VICTOR US4ET , 73 !!!!!
Just built one of these and you are not joking when you said it works well. I did have a random length end fed with a 9:1 fed directly from the shack. 7MHz /14mhz was always a struggle on receive. The EFHW is fed at the bottom of the garden run vertical to an over hanging tree branch and then out to the house. Signals have been fantastic I’m my location with this set up.
Really enjoying your vids Mike.
Ivan G0BON
I really enjoy your channel, a nice pace, I watch them to the end. Very inspiring. de ON8EI John.
Awesome, thank you!
Great video. I recently made such a coil for a friend, it was nowhere near as neat and tidy as yours!! For anyone who doesn’t have a suitable meter to measure the inductance, there are cheap and cheerful ones in all the usual places for £10-15, a decent little bit of kit. 73, love your videos. M0EUK
Very cool!
good job well done
Your poor old kitchen, you need to convert your garage into your workshop next Mike, anyway another handy video!
I wish!
Nice!
Very good!
Thanks!
Impressive 👍
Thanks 👍
Good tutorial
Excellent video you should get yourself a shed for antenna project lol
Maybe one day!
NICE............................................
Many thanks
You could have rectified mistake by unsoldering, passing wire through hole then resoldering it...
Hmmm 1mm wire is about 18 gauge wire so 190 turns will take about 50 feet of 18ga.(49 and a fraction) wire.
I need to get some heat shrink material for this too.
I will be extending my 40-10 efhw in this way too. Thank you for the construction details. very nice. 73 de w8nsi jim
have fun.. :)
Thanks a lot for this video!!!
vy 73 DK7- - Peter
Thanks Peter👍
Muito boa antena parabems amigo
Muito Obrigado
I love these antennas, simple yet very effective. Are you using a 49:1 or 64:1 in this setup?
Its a 64:1 Matt. Cheers
Great video Mike. Have, you tried this antenna on 30 or 17m? Thanks for the videos. John
Does adding the 80 coil, effect the previous (pre)tuning of the 40M wire?
Hi very nice video, thanks, love it.
What would be the difference if I use a commercial antenna like the 40 - 10 EFHW myantenna, or others that comes with a 49:1 balun ?
Many thanks !
This can be added to any EFHW. :)
hi mike, got a loading coil on my 40m vert to get it on top band, and it loads ok, but just wondering how much loss there might be ? as its working but not that well. just wonder if you have any rough idea about losses in that situation. cheers
first you try to chop your hand off, then you try to roll pastry with your coil, are you the next Gordon Ramsey ??, pmsl keep it up Mike :)
Ha Ha. big smile. :)
I constructed and added your inductor design to my 40 meter end fed and now my antenna works nicely on 80 meters. Now, could one add a second inductor to add coverage of 160 meters? I have room to run about 10 additional meters of wire along my wooden privacy fence. I think I may experiment with that idea. Be nice to have a limited space 160-10 meter antenna. Thanks for your video!
yes you could but I have no idea of the value you will need
Thanks for the inspiration. Just built one tonight! One question: do I need to shorten my 40m antenna at all before adding the coil and 2m length? I would think if not, I’d be 2 meters longer than needed for 40m resonance. Thanks
The "extra" 2m is choked off so anything above 80m won't see it. Having said that, the coil may add a bit of loading on the higher bands, so it may need to be a little shorter. But you'd have to try it and see.
Mike quick question about this antenna. Ive seen lots of people running coax to the bottom of the garden as you have yourself. Does it perform better this way than say feeding it from the house end out????
so in general.. when you have to little inductance in your coil , you will need to go for a bit longer leg and if there is to much inductance you go for shorter. Correct?
Hi Mike, congrats it's a nice neat construction and just a question here : if we took for example a PVC pipe diameter 50mm (2") required turns would be approx 60 and coil 6cm long with 1mil enamelled copper ; inductance would too be 110 mH ; other than having less turns to wind (less job) therefore having less copper wire used (pi x 5 x 60 vs pi x 2.5 x 190 = 5.5m less wire) which would be cheaper too, what would it mean on a performance point of view? (sorry I am new to antenna building stuff, but i really WANT to build antennas :) )
To the best of my understanding, the highest Q coil, (most inductance for the resistance of the wire,) is a coil diameter almost as wide as the coil is long. I've built loading coils as large as two and a half feet in diameter with 35 pounds of copper wire on them, on Styrofoam cores. I don't know what effect that length to diameter ratio would have on the interwinding capacitance of the coil, (self-resonant frequency,) as all of my designs have used an interwinding gap of the same diameter as the wire, whereas this design is close-wound. I would advise using a coil program that allows you to specify the dielectric constant of the coil form material you are winding on, (it looks like he used PVC, but there are other possibilities,) as that noticeably affects the interwinding capacitance and heating losses in the plastic. Years ago all coils were air-wound or wound on ceramic forms and provided very high Q's for that very reason. Of course, a high Q also narrows the tuneable bandwidth, (low SWR range.) There are always trade-offs, so there will always be calculations and experimentation to do.
You appear to be measuring the inductance at a low frequency. I made a coil with 80 turns of 0.9mm wire on a 36mm former and measured the inductance with a NanoVNA. It was 89uH at 90kHz and 110uH at 3.7MHz.
I wonder if you have used any ground or counterpoises with this aerial? I had terrible RF in the shack until I installed several counterpoises and a choke balun where the feeder enters the shack.
Yes 60cm ground spike. :)
Apart from the different size coil, more turns and former than the last one you made, was there any difference in performance and band width ?
Nice video Mike.
Many thanks.. in answer..None, I'm just trying to show that you can use different size formers and wires.
Nice job, Mike! Are any measurements made with antenna analyser?
No, sorry. I have made so many now I just know they work.
Thank you. That was helpful. N0QFT
Glad it helped!
Great video. Just one slight error in coil calculation though. The image shows diameter to the centre of the conductor, not the I'd of the coil. It effects the number of turns required but obviously still in the ball park.
you are right. :)
Mike, I like this coil better than the new one you just made on the 20mm former.
Have you noticed a difference in noise or reception?
No not really.
Appreciate the video. If I want to target somewhere on the 75m band, say 3.850 Mhz, would you change anything? What uh coil should I try to achieve? Thanks!
Should be good
Hello Mike - What book were you using that showed the information for building the coil? I’d like to get a copy. I’d like to build a 20m end fed half wave and add the coil to make it 40m. 73, KC2KNA
What is the title of the book you using? I been looking for this design online but they only show the picture of it.
mike i want to put one up,why did you put the transformer at the bottom of the pole then run the wire up then across to the house.i was going to attach the transformer to my alloy pole on the side of the house then from there run the wire down the garden then across like a L shape,
i have around 30 meters from my pole back to the shake.im hoping that will work. what do you think?
Mike what type of cable are you using as the radiating element? Is it bare or insulated? I finished my coil. I used a larger former because it all I had on hand. My reading came out to be 99.8uH.
Yes a larger former will give a higher reading, I'm using 1mm enamel coated hard drawn copper.
To calculate any inductance (for example @xxxjab : Turns 60, Diameter 5cm, longitude 6cm, we can use next formula:
L : 0,00987 x (DxD) x (NxN) x K / l (longitude)>>>>>>>>>>>L: 0,00987 x 25 x 3600 x K / 6
K : 1/ 0,457.d /l +0,995>>>>>>>0,457 x 5 = 2,285>>>>>2,285/6=0,380>>>>>0,380 + 0,995 = 1,375>>>>>1 / 1,375 = 0,727
L: 0,00987 x 25 x 3600 x 0,727 / 6>>>>>>645,8 / 6>>>>>>> = 107,7 mHy, more and less.
By the way, K is the Nagaoka number, or D/l ratio.
Why do these chopped onions taste of leaded solder Dad ? Thanks for the clips, which have helped me get through lockdown. Would a 5/8 wave antenna be possible to make like the T2LT ? 5/8 wave length wire with a 1/4 wave braid at the base and a choke coil, or would it have to have a matching coil added so taking away the all in one piece of coaxial cable ? Just mulling things over as you do. 73's and cheers Andy M6APJ.
Yes you can make a 5/8s but it all down to size ( is it practical )
Hi Mike, can you please tell me which manual this is in the video? Is it the 2020 from ARRL? Thank you so much for your great videos, I've seen them all (even in my free time as they are very entertaining). vy 73 de DD7ST
Many thanks, The manual is the RSGB 2020 radio communications handbook. (UK)
Hi I'd like to aak you for your opinion. I need a 80m antenna that would help on DX and the choices are EFHQ as a inverted L or a vertical. Which could receive less noise anf work as DX?
Regards
Javier
TI2JS
Unfortunately there is no simply answer here, I have both and both are inverted L's both work and both work better than the other on deferent days??? :)
Does the self resonant frequency need to be above or below the band you are effectively 'trapping'? For the 80m coil. I have a 40m EFHW. My understanding is you want the MUF of the 40m band below the self resonant frequency of the loading coil for 80m.
yep, resonant at 40, coil adds 80
Mine works out to be 117uH and self resonant at 7.434Mhz.
@@davkdavk sounds good. :)
Quite an impressive antenna! What do you use for a ground?
I have a 60cm copper pipe driven into the ground.
Thanks! I'm looking for a relatively easy earthing solution to try a long wire.
I have added 3 10m radials along the ground on mine, including earth stake. Night and day for receive on 20m
What was the book you were referring to Mike ? Another interesting video.
RSGB Year book
What edition of the handbook? Does it mention anything similar for topband?
2020 version latest from RSGB didn't see any 160M reference
Is the 2020 handbook available in the kindle version as well.
Thanks Mike, I made one of these recently but the 80m band is really noisy not sure why?
My experience with coils on dipoles (40m and a windom) is that they're pretty narrow banded. I can't imagine getting more than a fairly narrow slice of 80m.
Yep it is narrow, but better to have a narrow useable bit than no bit at all.. :) 👍🏻
amature :P
For the EFHW antenna with the 80m coil, what is the length of the wire you have used. If I may request you to share the layout of your antenna as well. 73, VU3RHU
This should help. g0kya.blogspot.com/2017/01/a-shortened-multi-band-end-fed-half.html
What is the wire you are using? Braided bare stainless steel?
Yes, it is 1.5mm Stainless steel wire rope, it has a little bit of resistance so I may change it for hard drawn copper.
i have 2" diameter PVC pipe and 2.5mm insulated wire...how many turns i need to get 80m band for EFHW 40m?
go visit 66pacific.com
Hello Mike is possible to make coil for end fed to handle also 160m band?
👍yes
can I use small tiny toroid wound 110uH coil instead of big air core coil?
I wouldn't have thought that would work. The coil has a dual function, acting both as a 110uH choke to choke off the higher bands, and as a loading coil on 80m.
Nice info but somehow I missed the 80 meter coil working 80 meters ok on the other bands.
Good call! don't think I showed it..lol
Which book are you looking at? Is it the ARRL Antenna Book?
no the RSGB 2021 hand book..
Nice one Mike. Now how do I make the coil invisible?
Good question! Camo' Paint or an invisibility Cloth
@bob nip down to your local hardware shop and ask for a can of invisible paint, there normally next to the tins of tartan paint :)
@@kevinmatthews2620 Have they stopped making see through paint these days?
@@BoB4jjjjs i do believe thats a special order paint along with the sticky side out paint, and two tone paint :)
Me - successfully surviving another lockdown day involves getting out of bed in the morning. Mike -successfully surviving another lockdown day involves design and build of yet another antenna variation (with only minimal jeopardy to kitchen). Sigh M7BLC. 73.
Two soldering iron burns and a small hole... and I'm still alive, mind you wife hasn't seen the damage yet!!!
Mike-M0MSN I’m picturing 2 pieces of cardboard with aluminum (aluminium) sandwiched in between to prevent burn-through to prevent being sent to the doghouse. It’s too cold out there this time of year! Nice work as usual on your builds. Thanks for the time you take to share
Hi, how do you get to 110? What if you want, say a 10m wire?
hope this helps hamwaves.com/inductance/en/index.html#input
Thank you!
if the wire goes to the right or the left that affects something???????
yes, but I cannot remember what!
Mike est un as que dire de plus???? 73
Is that the kitchen table .
yep
Can't be married, my wife would have killed me... That why I have a bench in my garage.
Yes I'm married, she's very understanding and lovely and the best thing to ..... "can I stop now darling". :)
@@mike-M0MSN You're a very lucky man then... Take care of her because she is definitely a rare women. ;-)
That's just what I thought. My wife would divorce me for using "our" new kitchen..
@@m0bob It is HER kitchen, get it right before she files for divorce!
Has she any sisters 🤔
Can I pleas have the ISBN code of the book you were referring to?
-VU3FNW
Yes, it is: ISBN 9781 9101 9394 5
didn't they teach us at foundation never to drill anything that's not properly supported.
great video.
Hi ~ what is the Gain of a EFHW ?
Don't know. Checkout g0kya.blogspot.com/2017/01/a-shortened-multi-band-end-fed-half.html
Bonjour le bal un 1/49 et la trappe combien de tour sur 32diametre
120 de tour sur 32mm diametre
Merci de la réponse et le balun 1/49ou1/64 merci b’avance
@@gillesvanduyse5942 regarde plus haut une de ses reponses, c'est du 64:1
Looking for version for 80/60m…
I may look into that.
( "I've tried burning the bench with the soldering iron, now i think a few random holes will go down well......." )........chees
You must try harder Roly, Gail will love you all the more for it.
@@mike-M0MSN After 51yrs married it is not worth the risk, nor the retraining should tings go pear shape .......... 😳
@@ZL1BQDRoly Cost you a new worktop Roly! Not worth it.
Good job man. I made it, but it doesn’t work
I am surprised, works like a dream for me.
Ha you giving anyone born after 1990 ability to read a non lcd Vernier!!
👍🏻👍🏻