DIY $4 QRP Multiband Endfed ultra simple + lightweight 40/20/10 (30/17/12)
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- Опубликовано: 5 сен 2024
- I have build a ultra simple multiband endfed antenna. It weight 58 Gram only.
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parts list:
1x FT50-43 ferrite toroid
1x 100pF 1000V capazitor
1x 50cm of 0.25mm enameled copper wire
1x SMA female device connector
1x PVC pipe diameter 28.5mm length 60mm
1x 12m 0.14mm2 insulated wire
Other Material:
-hot glue or epoxy
-solder iron
-tape
-some shrink tubing
PLEASE READ THIS!!!!
I did 3 bifilar primary +7+1+7
This is 18/3=6
6x6= 36
36:1
36x50 Ohm
Is about 1800 Ohm
But anyway this antenna works.
Not good but it works all the bands.
I will do a measurement video soon!
Ham radio, it is what it is-experimenting fail and win.
This time a mistake with a win at the end 😉
73 David DL1DN
Moreover every pass of the wire thru the toroid is a turn. So actually it's 7 + 1 + 7 ))
Anyway great job simple and efficient 👍
@@user-xj8oh6fo2f count the bifilar as well?
I made 3 bifilar+7 +7
Is it 14/3 or 17/3?
@@QRP.lifestyle
3 + 7 + 1 (cross pass thru the core) + 7
3 + 15
3t primary 18t total
3/18
1/6 voltage
1/36 impedance transformer
@@user-xj8oh6fo2f thanks ok the cross also!
Why do you say "not good" when describing how it works?
Great work, only a minor point, that minor assymetry forced on the winding by the connector schewes the frequency response some (yes even toroids are affected by neatness of winding) and thus the SWR some, just minutely (worst was 0.04 units) but on QRPp it might pay to chase the extra with a 7mm longer unit
Thanks for sharing. Very simple and lightweight. Best of all, it obviously works. If you have an antenna analyser or VNA, it would have been interesting to see what the match looks like across the bands.
Vna F is ordered but will receive it at least in January
A bit similar in looks to the sparkplug efhw antenna. Thank you for sharing your ideas.
Hi David,
I think you try to build an 1:49 ratio, not an 1:64 ratio.
But the two turns twisted ( in your video 3 turns ) counts also!
So you have to wind 2 turns twisted, 5 additional turns, than 7 turns in the other side.
This would be 1:49 or 2/6+8 turns for 1:64.
But if it works in your case...fine business 😊
Keep your good work ! Prost and 73, DL2MAN
Thank you, everything is very interesting and described in detail!
We are waiting for new interesting videos.
Very nice small compact antenna. Thanks for the idea.
Love your pen with the bottle cap. Great video.
Beer is my second hobby
Thank you David. I like the QRP spirit. Keep it light and portable. It works and thats what matters. Im a fan of QRP. 73 from NZ de ZL1REY
QRP is a real lifestyle
With the way the antenna connection is coming out of the toroid, there is no reason to do the crossover winding. Just wind them all the same direction, and the SMA connector will fit better.
Thank you!
Everybody noticed the mistake in the UNUN ratio. But running the FT817/818 from the internal battery limits the power to 2.5 Watts, so your TX is even 3 dB down. Which makes the result even better! ;-)
I like the practical part of the video. Most show only the schematic and the end result. Not the struggle to get the wire on the toroid.
And making mistakes is key to evolution. Edison wanted to make a device to speak to hard hearing people and invented the phone...
Alexander Graham Bell invented the telephone.
Just so your viewers are curious, the crossover turn on the transformer is do the ends of the wire are 180° apart. No other magic.
Interesting. You gave me some ideas for my own portable EFHW plans. Thanks.
Klasse Antenne David!!! Genial simpel und effektiv! Werde ich mal versuchen nachzubauen. Thanks by the way for the qso on 20 m vorgestern. 73 aus Dalarna in Schweden hope to hear You again soon
SA4GWT
Perfect timing! My ebay shipment of toroids arrived today!
Interessanter Beitrag, danke.
Very nice. Thanks for sharing the detailed steps! Well done.
Winding the toroid, the TWO bifiliar turns also count so you made 9 (NINE) primary turns and 7 secondary turns on the other side of the toroid. Go back and look at your video of your drawing.
I made 3 +7+7 this was a mistake but the result is better than expected. Maybe this is the reason why it works on nearly all bands
coole videos, tolle projekte! habe gleich mal abboniert :D
Very good job David! Thanks for the video ;) 73, Paul
Well done! Nice QRP antenna!
Thank you Andy I like your vids too
Nice sharing. I see a twist wire turn clockwise but when a single wire first turn on 7 turn is backward am I right?
Looking forward to trying this! Thanks
Thank you David for sharing! 73, Dave, KU9L
Tolle und leichte Antenne...Danke
Frohe Weihnachten!
Very good video, thanks. Let me be sure I understand, you worked all these bands with no tuner on the FT-817 with low SWR???
Surprisingly yes
40/20/10 is perfect but 30/17/12 also possible without changing anything and no tuner
can the antenna design be upgraded to 100W ( ft-891)
Very nice job!
Good job! I hope to find you on-air. I like QRP and EFHW antenna too.
IU5KHP Nicola
Erst kommentieren dann ansehen :) Klasse David - weiter soo.
Hi, when You measure the roe, it's with the 9 mts cable? , It's elevated? Or in the floor?
Outstanding 👍👍👍
Really love learning channels !
73
Julian oh8stn
Thank you I will subscribe you aswell.
My channel is very practical
Is it okay if i use an UHF connector for the Radio? Or can i only use it on an SMA connector?
Yes no problem
hi nice work, in the video wen you go to 20M and talk to filipe do you have the callsign, i think its me but i'm not shure
Amazing...
Cool antenna. Where did you get your mast and what type is it? Keep up the great work. WV3V- Jason
It is the spiderbram 12m HD
How does the connector not short to the turns on the toroid? especially forcing it in to fit?
The copper wire is insulated
@@QRP.lifestyle The connector was inserted very tightly. The insulation could be damaged by the thread of the connector. 73!
@@R1CBU it was space enough, I fill it up with epoxyde glue. This will be no problem
nice video
Fantastic video, thanks David.
Does anyone recommend a good resource (book, site, etc) on how to build this type of antenna? For example, if I want to build one that accepts 100W, what should I change in the materials and turns and dimensions? Thanks.
Search for PD7MAA
I have the same in big for 100W
@@QRP.lifestyle thanks, David, checking it out now!
FT240-43 toroid with at least #18 wire, otherwise same winding instructions. I used 2 high voltage 220 pf caps in series for the capacitor. I have an efhw wound for 64:1 that easily handles 100 watts on 40-10 meters. Higher power? Stack 2 or more toroids.
@@QRP.lifestyle Callooh, callay! The-same-thing-but-bigger is exactly what I was looking for. Gratefully I already have an FT240-43. Many thanks!
Danke für's Zeigen, tolle Idee. Werde ich direkt mal nachbauen
Hi David! :) You mentioned that you "tuned" the antenna. What method did you use if you did not have an antenna analyzer Sir? :)
I was checking the SWR at my trx and first try on 20 and 10 was no problem the 40m coil was more interesting ;)
Thanks a lot for this very interesting video!!
Enjoy the XMAS-days and 73 de DK7WS Peter from the Baltic Sea
Danke für das Video.
Aber eine Frage bleibt: Eichhofener?
Ok du meinst das Bier. Nein es kommt aus Lübeck, Eichhofener habe ich noch nicht testen dürfen, war mir bis gerade unbekannt.
At 6:36, how did you tune the antenna. Seeing your big challenge would be helpful.
First without coil on 20m
Than add the coil and cut the +2m wire begin with 10m and at the top 2.5m
Many TNX. I am trying to do the same ato home with reused components I find my boxes. Can I use a 1000pf capacitor instead 100pf?
Many tnx again.
EA6AOL
No use 100p
You can use 2 x 220pf série . Never 1000pf.
so should it have been 2 bifiliar turns then 6 turns on each side ...or??
Read my new commend
Hallo, this configuration corresponds to an 1:49 transformer (7 x 7)
Yes just read my upper commend
I see the unun ratio not correct, but it did work!
I seen a resistor but where does it go?
Your video was fantastic!
Forget it, it does not belong to
Will this handle 5kw?
How many meters of wire does that antenna have?
It is all in the video
this transform ratio is 49:1, not 64:1.
Yes just reas my pinned commend
Hi! Would the wire/coil sizes work with 1:49 unun? You use 1:64 as you say, but I have spare 1:49 unun, so I am wondering if I could use it or if I need to re-tune it...? Thanks!
Technically, that’s a loading coil, not a trap.
Yes, load coil.
Exelente test!!! Tks 4Z9KGT
Thanks for the good information. You gave me a idea. Thanks K7WHN
You can get toroids for $4?
I bought 10 for 4
You say 2 bifilar turns but run 3.
Yes I saw it right now, but maybe thisnis the reason why it works so good. I will do some measurements
Good job! Il''do it too ;) 73! IU5MOT
You unun 1:49, non 1:64.
Yes it is 21.7:1
Bad sound, so much echo's. Very annoying